Station Blackout Accident at FukushimaSAFETY

An analysis of the phenomenology of the earthquake and tsunami-induced station blackout accident at the Fukushima Daiichi plant, Japan and its consequences, is attempted. Substantial fuel damage and partial core meltdowns are surmised to have occurred in units 1, 2 and 3 with flooding in the reactors basements from suspected leaks in the piping to the containment vessels. Core uncovery occurred in unit 1 at 5 hours after the combined earthquake-tsunami event with the fuel temperature reaching 2,800 oC at 6 hours into the event. Partial core damage of unit 1 with the formation of a debris bed at the bottom of the core occurred at 16 hours into the accident with its reactor building’s basement flooded under 4.2 m of water. The pressure vessels of units 2 and 3 are likely to be damaged and leaking water from their bottoms. Units 4-6 were not operational and were shut-down for maintenance. However, hydrogen produced in the fuel damage of unit 3 flowed through a gas treatment line into unit 4 through damaged valves, leaked through ducts on the 2nd, 3rd and 4th floors and caused a fire and explosion. Hydrogen explosions occurred in the units 1-4. A postulated full core meltdown, in which the molten corium material would melt its way through the pressure vessel, was averted by judicious supplemental cooling. The implications of the accident are discussed.

Por el el DR. MAGDI RAGHEB, Departamento de Ingeniería Nuclear, de Plasma y Radiológica, Universidad de Illinois, Campus de Urbana-Champaign, 216 Talbot Laboratory, 104 South Wright Street, Urbana, Illinois 61801, EE.UU. https://netfiles.uiuc.edu/www/mragheb mragheb@illinois.edu

Introduction

Japan generates 29 percent of its electricity from nuclear power plants. The facilities are designed to withstand earthquakes and tsunamis that are common in Japan, which generates its nuclear electricity from 54 nuclear power reactors at 17 plant sites. These include 24 Pressurized Water Reactors (PWRs), 30 Boiling Water Reactors (BWRs), and 2 under construction.

A state of emergency was declared on Friday, March 11, 2011 by Japan's Nuclear and Industrial Safety Agency, NISA at the Fukushima Daiichi (number one) site and later at the Fukushima Daiini (number two) site BWRs after a combined earthquake of magnitude 8.9-9.0 on the Richter scale near the east coast of Honshu, and a tsunami event generating a 15-24 m-high wave. The earthquake event is designated as the Tohoku-Chihou-Taiheiyo-Oki earthquake. Official records dating back to the year 1600 inspired the deterministic or mechanistic safety analysis design of the plant to withstand the strongest earthquakes at the

Figure 1. Station Blackout loss of power to the control room of the Fukushima Daiichi unit 1 reactor on March 24, 2011 (left). Restoring offsite power to units 1 and 2 and power to the control room of unit 2 on March 26, 2011

Year 31 Nº 122 2011

8.6 magnitude level for the Fukushima prefecture. The Jogan earthquake in the year 869 produced a tsunami that reached 2.5 miles or 4 km inland with waves 26 ft or 8 m high at Soma, 25 miles north of the plant site. The plant was built on a 14-23 feet or 4.3-6.3 m high cliff offering natural protection against tsunamis. Eighteen-foot high offshore breakwaters offeredprotection against typhoons, but apparently, not tsunamis. A 1960 contemporary tsunami in Chile that was caused by a 9.5magnitude earthquake that produced a 10.5 ft high tsunami wave was used as a reference point for an 18-foot or 5.7 m design point, below the 27-ft or 8.2-m event. The location is 150 miles or 250 km north of the greater urban area of Tokyo inhabited by 30 million people, and 40 miles from the earthquake epicenter in the Pacific Ocean. It is the most powerful event in Japan since the start of historical record-keeping in the 1800s.

Eathquake Magnitude and Strength

Magnitude Scale Referred-to in Japan as “san ten ichi ichi” or 3/11, the earthquake is estimated to have involved two 50 miles thick tectonic slabs and unleashed an energy of about 480 Mt of TNTequivalent, moving the position of part of the coastline 3.6 m to the east. The Nagasaki nuclear device yield was in the range of 20-22 kT of TNT equivalent. The energy release is thusequivalent to about 480,000 / 20 = 24,000 such devices. As a result of the enormous energy release, the seabed buckled along a 300 km stretch along the fault-line involved. An estimated 67 km3 of ocean water moved towards 860 km of the Japanesecoastline with a wave reaching about 24 m in height.

The reported M9.0 magnitude earthquake was more powerful than the design-basis magnitude M8.6 earthquake. The difference between two Richter scale magnitudes is given by:

(1)

he ratio of magnitudes can be calculated by using the relation:

(2)

Since the Richter scale is a base 10 logarithmic scale, each whole number increase corresponds to a factor of ten increase in themeasured amplitude:

(3)

This implies that the ratio between the design M1 and the

experienced M2 earthquakes on the magnitude scale is a factor

of:

(right). The hanging ceiling tiles resulted from the earthquake. Source: Tepco.

Figure 2. Aftermath of Fukushima Daiichi accident on March 18, 2011, one week after the accident. Rubble from hydrogen explosions in units 1, 3 and 4 is spread over the site. Damage from the earthquake and tsunami to the electrical systems is apparent along the water front. Steam still emanating from unit 2. Source: DigitalGlobe

Strength, Energy Release, Destructiveness The magnitude scale compares the recorded amplitudes of waves on a seismograph and does not directly describe the magnitude of the energy release from an earthquake. The energy release is what affects structures and causes the damage they incur. To estimate the energy release E, an empirical formula is usually used that relates it to the magnitude M as:

(3)

The energy release or strength can be estimated from:

(4)

From which:

(5)

The ratio between the strengths or energy release E2 of the

incurred 9M earthquake to the design 8.6M earthquake E1 can be

estimated as::

The actual earthquake was hence 15 times the strength of the design earthquake and hence destructiveness. Large earthquakesevidently have much larger strength or energy release factors than small ones and are hence are much more devastating.

Accident Progression

The situation with cascading failures is unprecedented at two sites and with multiple reactor units simultaneously involved,following a Station Blackout Accident with a loss of off-site and on-site power. Such an event jeopardizes simultaneously both the control and cooling functions of the plant. This situation is characterized as a “beyond-design-basis accident.”

The following sequence of photos were taken from the 4th floor of the waste processing building at the power plant. They were shot over the course of a minute and reveal how quickly the tsunami inundated the area. Source: TEPCO

The earthquake triggered a safe shutdown of the three fission chain reaction of the operating reactors at the site as designed. The three others were already shut down for maintenance. There were 6,415 people at the site of which 5,500 were subcontractors.

The earthquake put out of service a transformer station about 10 kms from the plant cutting out the site connection to the electrical grid system. Because of this situation, even though the grid system was restored within 50 minutes from the earthquake, offsite power remained unavailable to the plant.

Emergency Core Cooling System, ECCS Because of the shutting down of the reactor as a result of the earthquake, the turbines were also tripped as the main steam isolation valves shut down the steam supply to the turbines. Accordingly, the main turbines became unavailable for electrical power generation that is usable by the plant systems as well as their associated instrumentation.

With the loss of onsite as well of offsite power, another line of defense was available in the Emergency Core Cooling System, ECCS. Power could still be provided to the plant by 13 emergency diesel generators inside and outside the plant’s enclosure, each capable with its fuel supply of delivering 6 MWhr of energy. Eight of these diesel generators, each the size of a locomotive, were located in the basement number 1 of the turbine hall. The turbine halls lie about 140 m from the seashore. Two other diesel generators were on the ground floor behind unit 4 which was shut down for maintenance purposes, and 3 others were inside and outside the enclosure of unit 6 which was also offline for servicing.

Upon arrival of the tsunami wave about 15 minutes after the earthquake wave, it crashed over a 2.5 km breakwater consisting of 60,000 concrete blocks and 25 tons tetrapods, as well as a 5.6 m height wall on the seabed facing the site. The plant was built on solid rock ground 10 meters above sea level.

In spite of these defenses, which would have been able to withstand the effects of a major hurricane, a 15 m high wave flooded parts of the plant in 6 meters of water before retreating back to the ocean. The sea water intake structures for the normal and emergency service water were apparently affected, possibly through silting.

The most notable effect was the flooding of the below-grade parts of the plant particularly in the basements of the turbine halls as well as other buildings. The water level reached about 4.2 m in one turbine building. This disabled 12 of the 13 emergency diesel generators and affected their associated electrical switching gear as the sea water shorted the electrical circuits. Within an hour after the earthquake that started at 2:46 pm, at 3:41 pm all onsite power from the diesel generators had failed, plunging the plant into a full-fledged “station blackout.”

hasta ahora no se había producido ninguna sucesión de fallos semejantes en dos instalaciones

y con varias unidades de reactores afectadas simultáneamente tras un accidente por apagón

total

Emergency Battery Power Banks of charged electrical “coping batteries” were still available, and were deployed to provide emergency cooling. These could deliver power for about 12 hours until external or onsite power

The Kobe earthquake, in 1995, had a local magnitude of 7,2 points on the Richter scale, and caused 6.400 deaths.

Figure 7. Spent fuel storage pools (top) showing fuel assembly being moved through gate between pool and reactor top. Yellow object is removed core dome. Steam emanating from the fuel storage pool in unit 4 on March 15, 2011, under the loading crane showing at the center of the picture (bottom).

Figure 8. Highly energetic vertically propagating hydrogen or possibly steam explosion at the Fukushima Daichi unit 3 BWR on March 14, 2011 was followed by a fire and suspected reactor fuel damage. Heavy debris possibly composed of the concrete shield plug or crane components was vertically ejected and is seen falling back down in the photograph. No damage to the reactor pressure vessel can be inferred

could be restored to the plant.

The monitoring and control equipment failed, probably as a resultof the electrical circuits malfunction denying the operators information about the plant status. At 4:36 pm, within 2 hours from the earthquake, the Tepco utility acknowledged thesituation, and 9 minutes later notified the authorities. At 7:03 pm, a “nuclear emergency” was declared prompting the evacuation of the nearby population, which was expanded to a radius of 20 kms within 24 hours later.

Residual Heat Removal System, RHR The earthquake initiated an automatic shutdown of the plants by insertion of the control rods as designed. Nuclear power plants differ from other heat engines in that after shutting down the chain reaction, the fission products resulting from the fission of the fissile elements in the core continue emitting both gamma and beta particles radiation that decreases at an exponential rate. This “residual heat,” “decay heat,” “afterheat,” or “afterglowheat,” needs to be extracted and rejected until it has decayed within days to a level that does not need active cooling any more.

Under normal conditions, the excess heat in a BWR is rejected bybleeding steam from the steam lines and is quenched in the main condensers in the turbine part of the plant. After shutdown orduring servicing and maintenance procedures, a Residual Heat Removal System, RHR is also incorporated in the design of nuclear power plants for this purpose. Residual heat pumps and heat exchangers are used until such time when its heatgeneration is comparable to the heat generated by the mere pumping of the water. At such time, the RHR pumps can be switched off. The RHR usually consists of 4 pumps, 2 heat exchangers and their associated piping, valves and instrumentation.

A mode of RHR operation allows the removal of heat from the primary containment following a Loss of Coolant Accident, LOCA.Another operational mode is as a Low Pressure Coolant Injection, LPCI system after the reactor has been depressurized in a postulated LOCA.

Loss of Reactor Core Isolation Cooling System, RCIC Failure of the reactor cooling function carried out by the Reactor Core Isolation Cooling, RCIC system occurred in units 1, 2 and 3 at the Fukushima Daiichi site and at unit 4 at the FukushimaDaiini site; a situation stipulated in article 15, clause 1 of the “Act on Special Measures Concerning Nuclear Emergency Preparedness” in Japan.

The RCIC provides makeup water to the core during a reactor shutdown if the feedwater flow is not available. It is started automatically upon receipt of a low water reactor water level signal from the control system, or manually by the reactoroperator. Cooling water is pumped to the core by a turbine-driven pump using steam from the reactor system. It normally takes its suction from the condensate storage tank through a common line to the High Pressure Coolant Injection, HPCI pump suction. The RCIC can also pump water from the pressure suppression pool.

Nuclear Pressure Relief System The nuclear pressure relief system protects the Reactor CoolantPressure Boundary, RPCB against damage due to overpressure. Pressure operated main Safety Relief Valves, SRVs are available to discharge steam from the Nuclear Steam Supply System, NSSS to the pressure suppression pool.

Part of it is the Automatic Depressurization System, ADS which depressurizes the NSSS in the case of a LOCA in which the High

from the absence of the reactor’s top plug in the ejecta. Source: NTV / NNN Japan.

The earthquake and subsequent tsunami which affected the japanese coast in march, having caused thousands of deaths and missing people, is considered economically the most expensive disaster in history.

Pressure Injection System, HPCI fails to maintain Reactor Pressure Vessel, RPV water level. The HPCI pumps generate a high head and consequently a low flow rate.

The depressurization of the NSSS allows the operation of the LowPressure Coolant Injection, LPCI system with a low head but large flow rate to adequately cool the fuel in the core.

Main Steam Isolation Valves, MSIVs The main steam system in the BWR operates during stable and transient conditions to:

Receive the generated steam in the core and convey it to the turbine for electrical power generation.

Bypass any excess steam above what is needed by the turbine and its auxiliaries to the condense

Main steam line flow restrictors of the venturi type exist in each steam line inside the primary containment. They limit the loss of coolant resulting from a main steam line break outside the primary containment. The coolant loss is limited so that the reactor vessel water level remains above the top of the core during the time required for the Main Steam-line Isolation Valves, MSIVs to close to protect the fuel barrier.

Usually 3 MSIVs are installed on each main steam line. Theseconsist of two MSIVs, one located inside, and the other outside of the primary containment, and a Main Steam Stop Valve, MSSV that is located downstream from of the outboard MSIV.

The part of the main steam line supply system between the outboard MSIV and the MSSV are designed to assist in eliminating air leakage from the MSIVs after a postulatedaccident. In case a main steam line break occurs inside thecontainment, closure of the isolation valve inside or outside the primary containment acts to seal the primary containment itself.

The primary MSIVs automatically close to isolate the Reactor Coolant Pressure Boundary, RCPB in the event of a pipe break downstream of the outboard isolation valve. This procedure limits the loss of coolant and the possible release of radioactivity from the NSSS.

Figure 3. Main isolation valves and safety relief valves used in the depressurization of a BWR plant. Source: GE.

Depressurization, Steam Venting As no circulation of the core was provided, the water turned into steam uncovering the core. In most BWRs a core spray system would spray the fuel assemblies to cool them. Steam was generated increasing the system’s pressure. The safety reliefvalves automatically vented the steam into the pressure suppression pool, quenching and condensing it.

In the process of venting steam to reduce the pressure in the containment system, a stipulated hydrogen explosion was reported at the Fukushima unit 1 on March 13, 2011 at the Daiichi site with associated fuel damage, containment structure damage, partial core meltdown and fission products release. Small amounts of radioactivity were vented. The reactor had 400 fuel assemblies loaded in its core, and the storage fuel pool had 292. The rubble from the roof covered the reactor’s loading deck and fell into the fuel storage pool.

If the core gets uncovered, the zirconium cladding interacts with the hot steam releasing hydrogen; a noncondensible gas. Under normal conditions, the steam and hydrogen gas are directed to the filtered ventilation system and ventilated from the exhaust stack and released at an elevated location. Hydrogen recombiners exist at most BWRs burning the hydrogen in acontrolled manner by sparging it above water. Because of the Station Blackout situation, the exhaust system and the hydrogen recombiners may not have been operational, and the steam and hydrogen accumulated inside the secondary containment structure. Hydrogen is combustible at concentrations in the airabove 4 percent, and reacts explosively with oxygen above a concentration of 8 percent. A spark or auto-ignition can initiate the process.

An explosion was reported in unit 2 on March 15, 2011 reportedly damaging its pressure suppression pool. Fuel damage and a

partial core meltdown is presumed with some fission products vented. The core had 548 fuel assemblies and the storage fuelpool had 587.

A more energetic presumed hydrogen explosion associated withsteam depressurization followed at the unit 3 on March 14, 2011 with a fire and may have lead to pressure suppression pool damage. This unit uses a Mixed Oxide, MOX fuel mixture of UO2and PuO2 which raised concern because of a lower melting point

of Pu than U, as well as the combined chemical and radio-toxicity of Pu. The reactor core had 548 fuel assemblies and the storage fuel pool had 587 assemblies. The reactor containment vessel may have been damaged and spent fuel may have been uncovered. A suspected “long vertical crack” running down the side of the containment vessel was reported by a utility official. There is also a suspicion of molten corium material leaking onto the concrete base mat and interacting with it. The powerful explosion may have ejected components at the top of the reactor including concrete shield plugs and parts of a loading crane.

Hydrogen produced in the fuel damage of unit 3 flowed through a gas treatment line into unit 4 through damaged valves, leakedthrough ducts on the 2nd, 3rd and 4th floors and caused a fire and explosion. At 6 pm, March 15, 2011 a possible hydrogenexplosion occurred within the previously shut-down unit 4, which under an outage condition, had the fuel from its core transferred to its storage fuel pool. The pool is reported to contain 1,331 fuel assemblies of which 548 were removed from the core for maintenance considerations. Hydrogen release implies claddingoxidation and fuel damage.

A fire at the unit 4 lasted for two hours and was extinguished at2:00 pm on March 15, 2011 and reignited on March 16, 2011, then extinguished again. Units 5 and 6 were already shutdown when the earthquake and tsunami affected the reactors buildings. Cooling in the storage fuel pools became a concern. Unit 5 had548 fuel assemblies in the core and 946 in the storage fuel pool. Unit 6 had 764 fuel assemblies in the core and 876 in the storage fuel pool.

A hydrogen explosion is stipulated at another site at unit 4 of the Fukushima-Daini plant that was reported to have access to offsite power from the electrical grid and hence recovered as designed from the combined earthquake and tsunami event.

A population evacuation and a temporary rolling power blackout were implemented. A skeleton crew of 70-250 volunteer plant personnel managed the cooling of the damaged reactors. The fuelstorage pools became at risk of losing their cooling water and become subject to fuel damage.

Figure 4. BWR Reactor Core Isolation Cooling system, RCIC. A steam turbine uses steam to drive a pump injecting water drawn from thecondensate storage tank into the core. Exhaust from the steam turbine is directed to the pressure suppression pool. HPCI: High Pressure Coolant Injection system, RHR: Residual Heat Removal system. Source:GE.

Previous Earthquake Events Nuclear power plants are designed to withstand the maximum magnitude earthquake on the Richter scale at their location. The Fukushima plant is reportedly designed to withstand an 8.6M earthquake on the Richter scale, whereas it was subject to a larger 8.9-9.0M strength one.

The 2004 Sumatra earthquake and tsunami lead to the shutdown of the Kalpakkam nuclear plant near Chennai in India and of four plants in Taiwan. Japan’s worst earthquake was a magnitude8.3M one at Kanto in 1923 causing 143,000 deaths. Another 7.2M one at Kobe in 1995 killed 6,400 people. Japan lies near the Pacific Ring of Fire seismically active zone where 90 percent of the world’s earthquakes occur. A December 26, 2004 at Sumatra,Indonesia, earthquake and tsunami caused claimed the lives of 230,000 people and affected 12 countries. On February 2010, a magnitude 8.8M earthquake in central Chile caused a tsunami that killed 524 persons.

The earthquake was the most powerful in Japan’s recorded history, and the fifth in the world. Japan’s main island was shifted 8 feet or 2.5 meters as a result of the seismic movement, and the Earth’s axis was shifted by 10 cms or 2.5 inches. The fissionchain reactions in the BWR reactors, as designed, were successfully shut down through the successful insertion of the control rods by the automatic control system, but the decay heat removal system did not operate as designed to extract the fission products decay heat from the system leading to a loss of coolingaccident. The electrical components of the Emergency Core Cooling System, ECCS diesel generators at the plant were reportedly affected by flooding by the tsunami, causing their shutdown by affecting their switchgear components in the flooded lower parts in the plant.

On June 17, 2010, the Fukushima unit 2 BWR was scrammed due to a generator problem. Power was lost for a short time because the switch-over to the offsite power supply was not successful.The feedwater pump stopped and the water level in the reactor fell about 2 meters. The emergency diesel generators were successfully started. The ECCS did not need to be activated as the core water level was restored by the Core Isolation Cooling System, CICS pump. The combined earthquake and tsunami event caused a loss of power at the plant. If power from both offsite and onsite sources is unavailable, the event is designated as a “Station Blackout Accident.” This has resulted in a Loss of Coolant Accident, LOCA with fuel damage and radiation leakage similar to the Three MileIsland occurrence.

Radiation levels rose to 103 times normal level at the control room of unit 1 and to 8 times normal background level outside the facility as a result of fuel damage and fission products release. Cooling was jeopardized at two other units at the 6-unit plant at the Fukushima Daiichi site. The cooling ability wasapparently also jeopardized at a nearby Fukushima Daiini site which retained its offsite power supply and was able to recover according to design.

The Fukushima nuclear power plant’s emergency diesel generators could not be used because of reported damage to the plant electrical systems caused by the subsequent tsunami. To provide power to cool the reactors, emergency generators and fire trucks were brought in by the electrical utility Tokyo Electric Power Company to the site of the reactors.

Concurrently, a fire broke out in a transformer and was extinguished at the Tohoku Electricity Company's Onagawanuclear plant in northeast Japan as a consequence of the earthquake. A reactor at the Onagawa site experienced a coolant leak. Eleven nuclear power plants closest to the epicenter were safely shut down out of a total of 55 reactors, representing 20 percent of the total nuclear installed electrical capacity in Japan.

Decay Heat Removal

Upon shutdown of the fission power generation by the control rods, decay heat continued to be generated to an initial level ofabout 3 percent of the fission power at one minute after shutdown. It decreases exponentially as a function of time but must continue to be cooled over a few days period by the Residual Heat Removal, RHR system.

The decay heat power ratio is given by [10]:

(6)

where:

P0 is reactor fission power before shutdown, MWth,

P is thermal decay heat power generation, MWth

t is time after shutdown, days,

T0 is the time of operation of the reactor at the power level

P0 days.

At 1 second or immediately after shutdown, the decay power ratio would be for a reactor that operated for a period of T0 = 1

year = 365 days:

Assuming a plant thermal efficiency of 1/3, the thermal power of unit 1 would be 460 / (1/3) = 460 x 3= 1,380 MWth. Initially, at one second or immediately after shutdown, thus 1,380 x (6/100) = 82.8 MWth of thermal power cooling has to be provided. At one minute after shutdown it rapidly decreases to ½ the initial amount to: 1,380 x (3/100) = 41.4 MWth of thermal power cooling has to be provided.

Figure 5. Decay heat power release for a 3,000 MWth Light Water reactor, LWR for different operational times. The decay heat generation power decreases exponentially within a few days after shutdown.

If cooling is successful for 1 week or 7 days after shutdown, theamount of required cooling reduces dramatically to:

The amount of required cooling, one week after shutdown is now

just 1,380 x (0.24/100) = 3.31 MWth

Fission Products Release

The decay heat cooling needs to be actively continued for at least 24-48 hours. If no cooling is provided the fuel Zircaloy cladding is oxidized forming hydrogen, fuel damage results and a release offission products into the containment structure ensues. If the pressure suppression system is not able to quench the steam and reduce the pressure in the containment shell, the buildup of pressure in the containment, unless controllably released, wouldcause it to fail at its weakest links which are the piping and instrumentation penetrations. The earthquake event could have also affected the integrity of these penetrations. In this case the release of the volatile radioactive gaseous species such as I131

with a short half-life of 8.04 days, Te132 producing I132, and thenoble gases Kr87and Xe131 as a result of fuel damage to the environment takes place at about 24-48 hours into the accident.

The I131 isotope is used for the treatment of thyroid nodules and Grave’s syndrome, since iodine tends to accumulate in the thyroid gland. This also makes it a health hazard in the short term in reactor accidents. The main concern from the short livedisotopes results from I132 which is produced from the fissionproduct Te132: The decay of Te132 produces I132. An amount of 38 kilocuries of I132 is produced per megawatt thermal of reactorpower. The Te132 released from a reactor accident will also produce I132 outside the reactor according to the reaction:

(7)

with a half life of 2.3 hours, which seeks the thyroid gland, and can cause the occurrence of thyroid nodules.

En el caso más grave de daños en el núcleo asociados a altas temperaturas también se pueden liberar productos de fisiónmenos volátiles, como Cs137 y Sr90. In the more severe case of acore damage associated with high temperatures, the release of the less volatile fission products such as Cs137 and Sr90 would also occur. It must be noted that regarding human exposure, the biological half life of Cs137 is a short 110 days, whereas the biological half-life of bone-seeker Sr90 is a long 18 years, making it the moreserious consideration. On the other hand, Sr90 (boiling point = 1,336 CsoC) is considered as moderately volatile and is released only if higher temperatures are attained in a postulated accident, so that a smaller amount than the highly volatile Cs137 (boiling point = 670 oC) is released. In atmospheric nuclear testing both isotopes are fully released. The release of Cs137 over an ocean area would lead to the formation of cesium hydroxide (CsOH) and its harmless dilution in the vast volume of ocean water.

Figure 6. Cutout through containment and turbine hall showing the location of the fuel storage pool in a typical BWR. Components below grade level and hence affected by flooding from the tsunami event include pumps and electrical components. The dry well includes a sump. Any leaking molten corium material through the control rod seals could interact with the sump water as well as the concrete mat causing a steam explosion, then becoming embedded into the concrete. Source: GE.

Hydrogen Explosions

If the cooling system remains inoperative for many hours, the water would eventually boil away, the cladding would oxidize, and the fuel would begin to melt. Hydrogen can be formed from the steam and the metallic zirconium in the cladding interaction:

(8)

without a venting or a controlled burn of the generated hydrogen in plants equipped with hydrogen recombiners, a pressure pulse can be generated from the hydrogen interaction with the oxygen in the containment atmosphere:

(9)

A suspected hydrogen pressure pulse has been in fact reported in the Three-Mile Island accident but it did not cause any significant damage to the containment system to the degree observed at the Fukushima event. One ton of Zr can interact with 792 lbs of water to generate 88 lbs of H2 gas. Each meter length of fuel

rods cladding contain about 15.4 tons of Zr.

Water suddenly evaporating into steam expands to a large volume. A familiar event is the sudden flashing into steam when the lid of an automobile radiator is inadvertently opened with the water under pressure. When the pressurized water senses thelower atmospheric pressure than in the pressurized radiator and reaches its saturation pressure, it flashes into steam, and the coolant in the radiator is lost. Another familiar event is the explosive expansion of the water inside the popcorn kernel leading to its popping.

Steam explosions were observed in the steel industry when ingots of cast steel were suddenly quenched in water. The sudden quenching leads to the disintegration of the molten steel with alarge heat transfer area leading to evaporation of the water into

steam and its explosive expansion.

Yet other similar occurrences are dust explosions during delivery at the grain elevators in the American Midwest. As grain isdumped into the storage pits, dust is released in substantial quantities. With its large surface area, the dust can be ignited by a triggering event such as a spark from a starting motor or a lighted cigarette, causing a deflagration and significant damage.

Another postulated situation is one where the core melts down with the molten corium material melting through the steel reactorvessel and embedding itself into the reactor concrete base mat. In the case of a faulty design such as the RBMK-1000 with the water in the pressure suppression pool directly placed underneaththe reactor core, a steam explosion can occur like in the Chernobyl accident. It is worth noting that in the GE BWR designsMark I design, the pressure suppression pool is located at a lower level below the core, but not directly under it precluding a serious form of steam explosion. However, a sudden depressurization canstill lead to sudden flashing of the pressurized water into steam and an explosive expansion with an associated loss of coolant available to cool the core.

Fragments or particles of nuclear fuel from the spent fuel pools above the reactors were blown “up to one mile from the units” and pieces of highly radioactive material reportedly fell between two units (presumably 3 and 4) and had to be “bulldozed over,” to protect workers at the site. The ejection of fuel parts from unit 3 would imply a more serious event than a hydrogen explosion inthe form of a criticality excursion and a steam explosionassociated with a core meltdown.

It has been suggested that a more logical location for the pressure suppression pool is above the reactor core, avoiding such an eventuality and offering the benefit of providing passive natural circulation convection cooling of the core, upon equalizing the pressure between the core and the pressure suppression pool, without the need for active pumping requiring power supplies. Equally important would be the elimination of the possibility of molten corium material with water causing a steam explosion.

Leak Before Break, Vessel Leakage or Melt-Through

Richard Lahey, head of safety research for boiling-water reactors at the General Electric Company, suggested that at least part of the corium material which includes melted fuel rods and Zircaloy cladding, may have sunk through the steel lower head of the pressure vessel in unit 2 and that at least some of it is down on the floor of the drywell.

The major concern when molten fuel breaches a containment vessel is that it reacts with the concrete floor of the drywell underneath it, releasing gases such as CO, CO2, H2 and steam

into the surrounding area. At the Fukushima unit 2, the drywell has been flooded with seawater, which will cool any molten fuelthat would escape from the reactor. The corium material would not come out as a big glob, but rather it would leak out like lava. This is desirable since it is easier to cool.

The drywell is surrounded by a secondary steel-and-concrete structure designed to keep radioactive material from escaping into the environment. However an earlier hydrogen explosion at the reactor may have damaged it.

The reason for the suggestion is the detection of water outside the containment area that is highly radioactive and it can only

have come from the reactor core. The effective dose rate at a pool of water in the turbine hall of unit 3 was reported on March 25, 2011 as 20 cSv/hour or 20 rem/hr of gamma radiation. For aUSA maximum occupational yearly effective dose of 5 rems, emergency workers would be allowed to remain in the area for (5 x 60) / 20 = 15 minutes.

The ground effective radiation dose outside the reactor structuresis significantly lower, reported at 0.2 cSv/hr or 0.2 rem/hr. It is even lower at nearby communities such as the Iitate village at 40 km northwest of the site at 0.0013 cSv/hr or rem/hr, and atFukushima City at 61 km northwest of the site at 0.0008 cSv/hr or rem/hr.

Figure 9. BWR control rod drive mechanism at the bottom of a BWR reactor vessel showing the seal location [2].

Based on the principle of “leak before break” in accident analysis, another explanation has been advanced for the occurrence as being possibly related to leakage through the control rod seals at the bottom of the reactor vessel. Boiling water reactors have their control rods inserted from the bottom of the cores. They areequipped with a graphite stopper covering each control rod penetration that seals the primary cooling water. At temperaturesabove 350 oF, the graphite stoppers mechanical properties would begin to deteriorate.

It was suggested that as the debris from the damaged fuel rods collected at the bottom of the reactor vessel the seals may have been damaged by high temperature. If the graphite seals fail, water in the reactor would leak into a network of pipes in the containment structures and auxiliary buildings associated with the reactor.

Accident Mitigation Actions

Initially, about 3,000 residents within a 1.8 mile or 3 km radius of Tokyo Electric Power's, Tepco Fukushima Daiichi nuclear plant were evacuated. The larger number of residents within a radiusof 6.2 miles or 10 km, were initially advised to stay inside their residences. The risk from accidents resulting from panickyevacuation driving on the road system would exceed the risk of whole body irradiation from the released gaseous fission products indoors. Later on, 45,000-51,000 residents within the 10 km radius were advised to evacuate. The evacuation radius was judiciously later extended to 12 miles or 20 km with 170,000 residents.

Tokyo Electric Power released steam at the plants to relieve the reactor containment structure pressure and to exhaust theaccumulated potentially reactive hydrogen gas that resulted from the oxidation of the fuel cladding and its damage.

With an ocean-bound wind direction the released gaseous fission products would harmlessly decay, dilute and dissipate over the Pacific Ocean. The composition of the released fission products depends on the temperature reached by the damaged fuel. Cs137 appears to have been released, but no measurements about the release of the less volatile Sr90 were reported. If the containment ventilation system is operable, the vented air is routed through High Efficiency Particulate Air, HEPA filters, gas adsorption activated charcoal beds, lowering any fission product releases by a factor of 100-1,000.

Emisión de radionúclidos

Monitoring vehicles collected air samples and measured the activity density of the radionuclides of concern at the western gate of the Fukushima Daiichi site. The samples were analyzed at the Fukushima Daiini plant site using a Germanium solid-state counter for a measuring time of 500 s. Iodine131 reached just 45 percent of the statutory activity density level for workers engaged in tasks associated with radiation.

Table 1. Nuclides Analysis in the air at the Fukushima Daiichi Western Gate, March 27, 2011. Data: Tepco.

Nuclide Activity density [Bq/cm3]

Detection limit [Bq/cm3]

Statutory activity density limit to the 3-month average in the air to workers engaged in tasks associated with radiation [Bq/cm3]

Activity density ratio

Volatiles Co58 –

– 1,0 x 10-2 –

I131 4,5 x 10-4

8,2 x 10-6 1,0 x 10-3 0,4500

I132 1,8 x 10-4

1,3 x 10-4 7,0 x 10-2 0,0026

I133 - - 5,0 x 10-3 -

Cs134 1,2 x 10-5

6,4 x 10-6 2,0 x 10-3 0,0060

Cs136 - - 1,0 x 10-2 -

Cs137 1,4 x 10-5 6,2 x 10-6 3,0 x 10-3 0,0047

Particulates Co58 – – 1,0 x 10-2 -

I131 2,1 x 10-4 9,5 x 10-6

1,0 x 10-2 0,2100

I132 - - 7,0 x 10-3 -

Cs134 1,6 x 10-5 8,8 x 10-6

2,0 x 10-3 0,0080

Cs136 - - 1,0 x 10-2 -

Cs136 1,4 x 10-5 9,5 x 10-6

3,0 x 10-3 0,0047

Larger activity densities were detected in the sampled sea water by measuring 500 ml for 1,000 seconds in a Germanium solid state detector. Most are short lived isotopes except for Cs134 with a 2 years half life, and Cs137 with a 30.17 years half life.

Japan’s Food Sanitation Act provides “indices relating to the limits on food and drink ingestion,” indicated by the Nuclear Safety Commission of Japan. Materials exceeding a specific activity of 100 Bq/kg cannot be used in milk provided for use in powdered baby formula or for direct drinking by infants. Contaminated spinach and milk were withdrawn from the market.

Consequences

About 28,000 people were victims of the unprecedented combined earthquake and tsunami event, with destruction or damage to 20,820 structures. Millions of people were left without shelter, water or heat. The authorities distributed 230,000 units of stable iodine to evacuation centers from the area around the Fukushima Daiichi and Fukushima Daiini nuclear power plants. The ingestion of stable iodine can help to prevent the accumulation of radioactive Iodine131 in the thyroid gland.

Other detected nuclides

Te129 1,6 x 10-2 2,2 x 10-2 4,0 x 10-1 0,0650

Te129m 1,9 x 10-4 1,5 x 10-4 4,0 x 10-3 0,0475

Te132 1,2 x 10-4 5,7 x 10-6 7,0 x 10-3 0,0171

Table 2. Nuclides Analysis in sea water at the Fukushima Daiichi 30 m north from the discharge canal of units 5 and 6, March 29, 2011. Data: Tepco.

Nuclide Half Life

Activity density[Bq/cm3]

Detection limit[Bq/cm3]

Statutory activity density limit to the 3-month average in the air to workers engaged in tasks associated with radiation [Bq/cm3]

Activity density ratio

I131 8,041 d

2,7 x 10+1

4,2 x 10-2

4,0 x 10-2

665,8

Cs134 2,062 a

5,6 x 10+0 3,2 x 10-2

6,0 x 10-2 93,8

Cs136 13,10 d

5,6 x 10-1 3,2 x 10-2

3,0 x 10-1 1,9

Cs137 30,17 a

5,7 x 10+0 2,8 x 10-2

9,0 x 10-2 63,5

Ba140 12,79 d

8,8 x 10-1 1,2 x 10-1 3,0 x 10-1 2,9

La140 40,23 h

3,7 x 10-1 8,5 x 10-3 4,0 x 10-1 0,9

A seriously injured worker was trapped within Fukushima Daiichiunit 1 in the crane operating console of the exhaust stack, and two missing Tepco workers were later reported as drowning casualties in the flooded turbine hall of the plant. Four workers were injured by the hydrogen explosion, a contractor was found unconscious and taken to hospital, two workers of a cooperative firm were injured, one with a broken bone, have been hospitalized At Fukushima Daiini unit 3, one worker received aneffective dose of 10.6 cSv or rem. Other radiation exposure incidents are likely to be identified.

Aftermath

A postulated full core meltdown, in which the molten corium material would melt its way through the pressure vessel, was averted by judicious supplemental cooling. With alternate sources of cooling provided to the affected plants, the situation would getbetter by the day.

However, significant damage may have occurred. Eventually, the heat generation will subside as the damaged fuel disperses in the coolant water, collapses and forms a debris bed, burns itself out and is starved of too much water to cause it to reach a critical configuration. A critical configuration needs an optimal fuel to moderator ratio, optimal surface to volume ratio, and the absence of neutron absorbing elements to exist.

The now suspected existing debris beds in the damaged reactorscores and the damaged fuel in the spent fuel storage pools will eventually shut themselves down to the condition that happened in nature at the Oklo natural reactors which shut themselves down after being starved of the moderating action of water by Earth movement.

The International Atomic Energy Agency, IAEA initially rated the accident as a level 4 out of 7 on the scale of international nuclear accidents, and then upgraded it to the 5 level; “accident with wider consequence.” The Windscale and Three-Mile-Island events were rated at 5, and the Chernobyl event at 7. The cascadingfailures and involvement of multiple units is a unique feature of the event.

The Fukushima accident involved fuel damage and releases offission products such as I131 and I132 which the Three Mile Island accident did not. It appears more serious in its consequences than the Three Mile Island Accident. For this reason, the French authorities unofficially consider it at the 6 level.

Table 3. INES scale rating of some nuclear incidents.

INES level

Event Description

1 Mihama, Japan, 2004

Hot water and steam leakage from broken pipe. No radiation release. Five casualties, 7 injuries.

4 Tokaimura, Japan, 1999

Nuclear processing facility. Workers mix larger than indicated materials in buckets, breaking safety rules. Criticality accident occurred. Two workers casualties. Fourty injured workers receive treatment.

5 Three Mile Accident, USA, 1986

Small-break Loss of Coolant Accident in unit 2. Fuel and core damage. Minor radioactive release. No casualties. Unit 1 continues

On April 12, 2007, Japan’s Nuclear and Industrial Safety Agency, NISA, raised the accident rating to the level 7. The International Nuclear and Radiological Events Scale, INES runs from zero to 7as a major accident.

The normal background radiation from cosmic and terrestrial radiation absorbed dose rate is around the 80 nGy/hr range. Some surrounding cities recorded dose rate reading in the range1,213-3,024 nSy/hr. For comparison, an abdominal x-ray is associated with an effective absorbed dose (not dose rate) of 1 mSv or 1,000 nSv.

The radiation dose equivalent rate has stabilized at 0.05 cSv/hr or 0.05 rem/hr on site. Notice that for gamma rays, the radiation quality factor Q = 1, and accordingly the Gray (Gy) unit for theabsorbed dose and the Sievert (Sv) unit for the effective dose become equivalent. Also note that 1 cSv = 1 rem.

Some workers are reported to have been exposed to an effective dose or dose equivalent of 100 mSv or 10 cSv or 10 rem. The maximum allowable occupational dose rate in the USA is 5 rem / (year.person) or an average of 2 rem/yr averaged over a 5 years period. The maximum allowable dose equivalent rate to a member of the public at large is 170 mrem / (year.person) compared with that from the natural radiation background ofabout 220 mrem / (year.person).

Soon after the accident, Japan’s health ministry temporarily raised the maximum radiation level to which each worker can safely be exposed from 10 cSv/yr or rem/yr to 25 cSv or rem/yr to enable them to spend more time in the contaminated areas. As of April 1st, 2011, Nisa said that 21 workers had been exposed to radiation at levels exceeding 10 cSv or rem, although tests have shown that no one has been exposed to radiation high enough to damage their health.

About 28,000 people were thought dead or missing from the earthquake and tsunami event. More than 166,200 lived in shelters on high ground above the vast plains of mud-covered debris.

operation.

5 Windscale, Sellafield, UK, 1957

Fire in graphite reactor core. Release of radioactivity. Sale of milk restricted for a month period. Reactor enclosed in concrete. Site decontaminated. New reactors built on the site.

6 Mayak, Kyshtym, Chelyabinsk, USSR, 1957

Fault in cooling system. Chemical explosion in waste tank. Radioactive release of 70-80 tonnes. Contamination of surrounding area.

7 Chernobyl, Ukraine, 1986

Core criticality, fire in graphite core, steam explosion in one of four reactors. Fire burns for 9 days. Two casualties in steam explosion and 47 first responders from radioactive exposure. Radioactive release.

7 Fukushima, Japan, 2011

Station Blackout caused by earthquake and tsunami damage. Hydrogen and possible steam explosions, fires and fuel damage. Four units out of six at site to be decommissioned. Radioactive release.

The cost of the damage is about $433 billion or 300 billion euros, making it the world's costliest natural disaster after the 1995 Kobe, Japan quake which cost $100 billion and hurricane Katrina, USA in 2005 that caused $81 billion in damage.

Conclusions

A postulated full core meltdown, in which the molten corium material would melt its way through the pressure vessel was averted by judicious supplemental cooling.

As a result of an earlier earthquake-caused accident at the TepcoKashiwasaki-Kariwa plant in July 2007, emphasis has been placed on protecting reactors components from earthquake events. The plant automatically shut down and was adequately cooled in spite of a leakage of water containing a minor quantity of radioactivematerial that was released to the ocean without causing harm to humans or the environment.

Effective dose rate levels of 100-200 cSv/hr or rem/hr resulted at the ground level of unit 1. With an occupational maximum allowable effective dose limit of 25 cSv / (person. year) or rem / (person.year) in Japan, this limits the maximum exposure time at these areas to 4-5 hours, hindering the recovery effort and mandating the use of robotic systems.

About 20 percent of nuclear reactors in the world operate at the vicinity of tectonically active zones. The construction of newpower plants in tectonically active zones around the Pacific Ring of Fire and in the Middle East is expected to come under intense review as to the necessary implementation into them of passive rather than active safety measures as exists in the currently considered designs.

A renewed emphasis on the development of renewable wind, solar, geothermal, tidal and bioenergy sources will likely occur for a few years. Solutions in terms of energy storage to overcomethe intermittency nature of wind and solar system will beaggressively pursued. This would include the use of hydrogen as an energy carrier, thermal, flywheel, pumped storage, battery and other storage techniques. Along that time the inevitabilityand the need for nuclear power in the energy mix will be even more recognized for base load generation replacing the depleting fossil fuels and their carbon emissions. The bioenergy approach would cause increased acquisition of land and water resources by capital-rich nations. About 140 million acres of potentiallyagricultural land have been already acquired in the Sudan and Ethiopia region of Africa for food and fuel production. The food versus energy debate is expected to heat up with possible conflicts about historical water rights such as in the Nile Riverbasin.

Hydrogen produced in the fuel damage of unit 3 flowed through a gas treatment line into unit 4 through damaged valves, leaked through ducts on the 2nd, 3rd and 4th floors and caused a fire andexplosion in a unit that was already shutdown. This design flaw led to a cascading failure event and must be avoided in future designs.

Worldwide, the need to replace aging nuclear power plants by newer inherently safe and passive technology may have beendeemphasized under economical pressures to extend the life of existing plants. Brought into operation on March 26, 1971, the Fukushima BWR unit 1 had an age of 40 years; at the end of its initial design lifetime. A nuclear power plant is usually granted in the USA an operational license for 20 years with a built-in extension of another 20 years for a total of 40 years if the safetylevel of the plant is deemed favorable. The affected unit 1 reactor

was due to be retired in February 2011, but its license was extended for another 10 years beyond its initial 40 yearsoperational time after a safety review and upgrades. In the USA licenses for operating plants are being extended by 20 years beyond their 40 years licenses to 60 years based on a detailed review of their safety operational level. Most of the components such as the steam generators have been replaced or renovatedunder these license extensions, except for the pressure vessels.

The ambition to increase the electrical share of nuclear electricity in Japan from 30 to 50 percent faces serious hurdles. The emphasis would probably be redirected towards replacing existing aging plants with new plant designs benefiting from accumulated knowledge and advanced passive and inherent safetytechnologies and designs.

The need for passive cooling designs has been recognized and implemented in newer designs. The chimney effect is used toadvantage in the ABWR and the ESBWR concepts, with the latter depending solely on natural circulation convection cooling.

It is not yet clear what the role of the core spray system in the Fukushima accident has been. The timing of the initiation of the core spray system needs a renewed theoretical and experimental analysis. It is clear that the core spray system would cool the fuel elements upon core uncovery if their temperature has not reached a critical level. But beyond a certain temperature level the spraying of the hot cladding would generate steam with possible oxidation of the cladding and hydrogen production. If the source of water is initially relatively cold from the condensate storage tank, thermal stresses would also be expected leading tocladding damage.

As it becomes established that the flooding by the tsunami of the pumping equipment in the turbine hall and other buildingsbasements were a contributing factor in the accident sequence of events, then that situation should be considered in emergency planning for reactors in onshore as well as in inland areas thatwould be prone to other forms of flooding events, such as the Ohio and Mississippi Rivers basins in the USA.

The deterministic and probabilistic safety analyses of postulatedreactor accidents complement each other. In a deterministic safety analysis emphasis, the maximum historical magnitude earthquake or tsunami wave height at the reactor site, become the emphasis as stipulated for the Fukushima reactors site. The probabilistic analysis of different magnitude earthquake or tsunamis may have not been sufficiently emphasized in Japan as is the case in the USA.

Minuscule amounts of fission products I131 and Xe133 circulated the globe and were detected on March 27, 2011 at Nevada, USA, without causing any notable health risks.

Earthquakes are a way of life in Japan, occurring once every 5minutes on average. Structures are built to withstand Earth movements. It is recognized that the human toll of about 28,000 was tragically caused by the combined earthquake and tsunamievents; definitely not by the reactor accident. It can be argued that the Fukushima Daiichi site accident, as caused by the earthquake-tsunami occurrence, was a “beyond-design-basis” accident. A Tepco official in fact called it “sotegai” or “outside our imagination.”

Richard K. Lester from MIT offered the insight that the year2011 is the 100th anniversary of the discovery of the atomic nucleus:

In historical terms, that puts the field of nuclear

engineering today roughly where electrical engineering was in 1900. The creation of the electric power grid, television and telecommunications could not have been anticipated by the electrical engineers of 1900. Likewise, no one today can foresee the future of nuclear energy technology. All that can be said with confidence now is that the nuclear power plants of the year 2100 will have about as much resemblance to today’s; as a modern automobile has to a 1911 Model T. New materials and systems are being developed all the time to make nuclear safer. The need for intellectual vitality, flexibility and creativity has never been greater.”

Historically, among other natural and man-made causes, this event would have tested the courage, endurance,resilience and tenacity of the 127 million people of Japan, who under adversity have always recovered, rebuilt and thrived

Acknowledgements

The comments and reviews received from students, colleagues and from Dr. Madeline Feltus from the USA Nuclear Regulatory Commission, NRC about earlier forms of the manuscript aregreatly appreciated.

References

1. McCormick, Norman J., «Reliability and risk analysis, methods and nuclear power applications», Academic Press, 1981.

2. Lahey, R. T., Jr. y Moody, F. J., «The thermal-hydraulics of a boiling water nuclear reactor», ANS/AEC Monograph Series on Nuclear Science and Technology, The Division of Technical Information, United States Energy Research and Development Administration, American Nuclear Society, 1977.

3. Ragheb, M., Uluyol,O., Jones, B. J., (Univ. de Illinois), Ho, S. A. y Endicott, R., (PSE&G, Hancocks Bridge), «Station blackout simulation model for a BWR plant», Accident Analysis, Trans. Am. Nucl. Soc., Vol. 62, 11-15 de noviembre de 1990, 362-364.

4. Ragheb, M., Ikonomopoulos, A., Jones, B. J., Ho, S. A. y Endicott, R., «Best estimate analysis of station- blackout for a PWR plant», Joint Relap5 and Trac-BWR International User Seminar, Idaho National Engineering Laboratory and Commonwealth Edison Company, 17-21 de septiembre de 1990, 117-122.

5. Ragheb, M., Ikonomopoulos, A., Jones, B. G., (Univ. de Illinois), Ho, S. A., R. Endicott, R., (PSE&G, Hancocks Bridge), «Best-estimate analysis of a small-break loss-ofcoolant accident for a PWR plant», Accident Analysis, Trans. Am. Nucl. Soc., Vol. 62, 11-15 de noviembre de 1990, 358-360.

6. Ragheb M., Ikonomopoulos, A., Jones, B. G., Ho, S. A., Endicott, R, «Best estimate analysis of complete loss of normal feedwater without reactor scram for a PWR plant», «Power Plants Transients», The American Society of Mechanical Engineers, FED-Vol. 104, 25-30 de noviembre de 1990, 117-122.

7. Tsoukalas, L., Lee, G. W., Ragheb, M., McDonough, T., Niziolek, F. y Parker, M., «On-line model-based system for nuclear plant monitoring », Applications of Artificial

Intelligence VII, Proc. Of SPIE-The International Society of Optical Engineering, Vol. 1095, 1989, 372-380.

8. Tokyo Electrical Power Company, Tepco, http://www.tepco.co.jp/ en/index-e.html , marzo de 2011.

9. Ragheb, M., «Boiling water reactors », Nuclear, Plasma and Radiation Science. Inventing the Future, https://netfiles.uiuc.edu/ mragheb/www/NPRE%20402%20 ME%20405%20Nuclear%20Power% 20Engineering/Boiling%20W ater%20Reactors.pdf , 2011.

10. Ragheb, M, «Decay heat generation in fission reactors», Probabilistic, Possibilistic and Deterministic Safety Analysis. Nuclear Applications, https://netfiles.uiuc.edu/ mragheb/www/NPRE%20457%20 CSE%20462%20Safety%20Analysis% 20of%20Nuclear%20Reactor% 20Systems/Decay%20Heat% 20generation%20in%20Fission% 20Reactors.pdf, 2011.

Hygiene, Health And Safety Conditions Public Swimming Pools SAFETY

This study examines the level of compliance by swimming-pool construction and reform projects with the Health Regulation for Public Swimming Pools in Andalusia (Reglamento Sanitario de Piscinas de Uso Colectivo en Andalucía) and also identifies the nature of any breaches detected. The study takes in 30 swimming-pool design projects in the Costa del Sol, including a check of compliance with legislative requirements, a critical analysis of deficiencies and a Pearson chi-square test to evaluate the relation between breaches and four requisites. A total of 515 legislation breaches were detected; the main shortfalls were lack of slip-resistant material in circulation areas, lack of technical aids for the disabled, inadequate safeguards around the suction points, non-automatic chemical dosing devices and badly sized filters. The study draws the conclusion that the projected swimming pools show a poor compliance with health regulations in terms of risks to the health and safety of users.

By JOAQUÍN GÁMEZ DE LA HOZ. Biologist. Specialist in environmental health of the Higher Corps of Primary Health Care Officers. Public Health Service, Costa del Sol Health District. Andalusian Health Service . (joaquinj.gamez.sspa@juntadeandalucia.es)

ANA PADILLA FORTES. Health and Safety Inspector. Prevention of Occupational Risks Unit. Málaga Health District. Andalusian Health Service. (anam.padilla.sspa@juntadeandalucia.es)

Water-based recreational activities are extremely popular in sun-blessed environments, where holidaymakers often have prolonged bathing periods either in natural watercourses or the sea or in water facilities (swimming pools, aquatic parks, sports centres, Turkish baths, etc.).

The problems of swimming pool accidents and poor water quality are of great concern to scientists and the public at large. There is by now sufficient epidemiological evidence to show a correlation between contaminating agents in the water and the transmission of diseases, mainly of a gastrointestinal type, after contact with the water and also the appearance of bodily injuries and traumas related to the use of the facilities1.

A European Commission study2 has shown that water

contamination is an issue of concern to 42% of Europeans, the main environmental worry after climate change. Each year over 7 million people visit the Costa del Sol (Málaga, Andalucía), drawn in by its sunny climate (over 325 days of sun a year), by the quality of its beaches, holiday amusements and excellent tourism accommodation spread along the whole of the 150-kilometre coastline. The swimming pools built into these areas are an

The study showed up significant breaches in swimming-pool water treatment and purification requirements

Year 31 Nº 121 2011

important recreational resource used increasingly by tourists and residents of all ages. Although these leisure and relaxation facilities afford undoubted health benefits, they also pose threats that might have negative consequences on the health of users. These risks are highest in the areas of heaviest tourism. Quality bathing water and minimum safety conditions are therefore essential public health factors.

Public authorities are bound to look out for the health and hygiene conditions of public swimming pools (i.e. non-domestic pools for collective use). In Andalucía this duty falls on the Primary Public Healthcare Services of the Andalusian Health service (Servicios de Salud Pública de Atención Primaria del Servicio Andaluz de Salud), the body that provides health services for the general population. Health departments recognise that swimming-pool legislation is a valuable public-health protection tool, laying down the necessary arrangements and instruments to monitor the health and hygiene requisites for swimming pools of public use, marking the limits and demands for minimising health risks and also ensuring safety in the use of the facilities. The Health Regulation on Public swimming pools in Andalusia (Reglamento Sanitario de las Piscinas de Uso Colectivo de Andalucía)3 sets out comprehensible health-and-safety

requirements to cover the design, construction and subsequent commissioning and maintenance of the facilities, such as the design of the hydraulic circuit, purification cycle, bather load, type of physico-chemical water treatment, chemical product store , etc.

Swimming-pool use entails potential exposure to risk situations, involving bodily injuries and

traumas, risks of a chemical type and, above all, the risk of infectious diseases

Despite the many studies of the dangers posed by swimming pools and their results on public health, there are still uncertainties about how the conception and design stage should be controlled to minimise risks in the stages before opening the pool to the public. In Andalucía the construction and reform of public swimming pools is subject to municipal authorisation; this depends on a favourable health report from the provincial delegate from the Regional Health Ministry (Consejería de Salud del Gobierno regional).

The correct wording and subsequent execution of swimming-pool construction and reform projects is recognised to be important4

in minimising and preventing injuries, accidents and diseases after the facilities have been brought into use. Many decisions taken during this phase impinge later on the health and safety of swimming pool users.

The main remit of this study is to examine whether the technical solutions contained in the construction or reform projects, as reflected in the documents submitted for the municipal licence, meet the standards laid down in the Health Regulation, thereby ascertaining whether the minimum requisites are duly and unmistakably met. An analysis is also made of the relation between the legislative breaches observed and the possible effects on the health and safety of swimming pool users. A secondary objective of this study is to find out whether the gravity of the legislative breaches differs within the different classes of health requirements.

Materials and Method

The study concludes that the health authorities should do more to enforce health and safety conditions in swimming pools of public use.

Suncream or oil adhering to the bather’s body might produce slippery conditions at the poolside.

The lack of any specially designed building for storing the chemical products used in swimming pool maintenance is one of the most widespread breaches detected by the study

Sampling Thirty swimming-pool reform or construction projects, drawn up to obtain the municipal operating licence during 2010, were randomly selected from within the territory of the western Costa del Sol. The pool types were children’s pools and multipurpose pools. The activity sectors for which the facilities were designedwere hotels, municipal sports centres, beach clubs, homeowner associations and condominiums.

Checklist The degree of compliance with the swimming-pool health regulation in the design phase was assessed by means of achecklist, including a list of health requirements laid down from article 3 to 25 of the regulation. This legislation lays downstandards and stipulations for the water quality, design of the pool tank, water treatment, user information, etc, to reduce the risk to the bathers’ health and safety. An examination was made of the technical documentation of each project descriptive report, annexes and plans), pinpointing any breaches with thespecifications laid down in the articles, defining these as any non-conformance or deviation from each legal precept of the regulation by error or omission. A check was also made of whether the technical solutions were properly and clearlydescribed in the documentation in keeping with the current state of the technology and scientific knowledge.

Results A double entry contingency table was drawn up showing the joint distribution frequency of two variables: class of health requisitesand degree of non-compliance. Pearson’s chi-square (X2) test was used to gauge whether the differences between the frequencies of legislative breaches observed and those expectedcould be put down to chance, under a hypothesis of independence. This statistical test establishes any significant differences in the level p<0.05. Our aim was to find out whetherthe distribution of the gravity of the infractions differs for each class of health requisites or, on the contrary, if they can be considered to be independent. The software Microsoft Excel 2000v.9.0.2812 was used to calculate the means, frequencies, Pearson X2 statistic and graphic presentations.

Results

During 2010 an environmental health specialist examined the technical documentation of 30 public swimming pool construction or reform projects. Table 1 shows the distribution of frequencies observed for each class of health requisite and their breakdown into minor or serious. The number of observed breaches of theHealth Regulation for Public Swimming Pools was 515, with a mean of 16 (± 3.6) breaches in each project. 361 breaches of a minor character were observed and 154 serious breaches.49.13% were bound up with the design of the pool tank, 26.79% with water treatment and purification, 16.89% with surveillance and users, while a lower proportion of breaches, 7.18%, had todo with hygiene and services. Within each category most of the breaches were minor (figure 1).

Table 1. Breakdown of breaches observed

Type of requisite Type of breach Total

Serious Minor

Design of bathing zone 93 160 253

Hygiene and services 9 28 37

Water treatment-purification 22 116 138

Figure 1. Breakdown of breaches by type of health requisites

The percentage of serious breaches in the bathing area (60.39%) came out much higher than in the rest of the categories (figure 2); in the case of minor breaches about one half of all breaches fell into the category of the bathing area (44.32%), followed by water treatment and purification (32.13%). Table 2 shows a descriptive summary with the commonest shortfalls detected in the technical documentation of the studied set of swimming-pool design projects.

Figure 2. Breakdown of breaches by type of infraction.

Due control of swimming pools in the design phase offers a chance of minimising risks to the

health and safety of users before the facilities are brought into use

Surveillance - users 30 57 87

Total 154 361 515

Characteristics of the bathing area The gravest legislative breach was the failure of the technical documentation to account for the slip-resistance of the deck around the pool, to ensure the safety of bathers walking barefootover slippery surfaces covered with films of water, oil, soap,suncream, etc. Such situations are inevitable in view of the customary use of swimming pools, and any failure to provide for them with slip-resistant surfaces could produce falls by batherswalking in this area. Equally important are breaches stemming from the failure to fit pool-bottom drains with safety grilles and

guards to prevent risks to bathers, mainly due to suction of parts of the body when the flow rate is too high (thorax, abdomen, intestines, gluteus...) or the more usual forms of entrapment (clothes, hair or limbs) when the drains’ protective grilles are badly designed. Minor in character but great in impact was the failure to provide technical aids (crane, hydraulic hoist, ramp, adapted stairs) to help disabled persons enter and leave the pool. This is now a sine qua non to meet legal rules on accessibility and removal of all architectural barriers to the disabled.

The study analyses how far the technical solutions of swimming pool construction or reform design

projects abide by the swimming pool health standards

Table 2. Description of breaches of the swimming-pool health regulation

CHARACTERISTICS OF THE BATHING AREA

Pool tank. No indication is given of changes of slope or depth; there are no zones shallower than 1400 mm; the pool-bottom slope is steeper than the established gradient; presence of obstacles (ledges and low walls) within the pool tank that balk water flow; the children’s pool is deeper than 40 cm.; the pool bottom does not meet slip-resistance conditions; the drain protection system is inappropriate; lack of authorisation for discharging water from the pool; lack of entrance ramp or technical aids for the disabled; installation of a water slide without observing due safety requisites. The surrounding deck and poolside area is less than 1200 mm wide; failure to meet slip-resistance conditions; inappropriate design of the deck area; poolside obstacles.

Step ladders/stairs. The rise and run of the rungs are unequal in the same ladder; there are no handrails or their number is lower than the width of the free span; they are not adapted for people with reduced mobility; they protrude from the plane of the tank wall and the tread (ramp) does not meet slip-resistance safety conditions; the number of metal stairs is less than one per 25 metres of pool perimeter (or fraction thereof) and their relative distance is more than 15 metres (SU6 safety against drowning risk standard of the Spanish building code [código técnico de la edificación])6 ; the arms have the same height; some do not go far enough under the water and others reach the pool bottom.

HYGIENE AND SERVICES

Water quality and origin is not guaranteed

The number of showers is insufficient and there are no foot showers

Lack of first aid kits or first-aid room (for pools with a water surface > 600 m2).

No provision has been made for toilets; insufficient supply of equipment; the toilets are not disabled-friendly or separated by sex. Lack of litter bins or urban waste containers in the pool precinct.

WATER TREATMENT AND PURIFICATION

Hydraulic design. There is no system or valve to prevent water flowback from pool to mains; the perimeter overspill system is discontinuous; no provision has been made for a compensation tank or its design is inadequate; the number of skimmers is less than 1 per 25 m2 of water surface; the electro-pump flow is insufficient to complete the purification cycle in less than 4 hours in multipurpose pools; there are no measuring systems for verifying the purification cycle or they are fitted in the wrong place.

Physico-chemical water treatment. The sand filter is not big enough to meet the pool’s filtration needs; the chemical-product dosing systems do not have automatic regulation based on the water concentration of the product concerned; there are no chemical dosing devices (acid) for regulating water pH; manual application of chemical products; the UV water-disinfection system does not justify the minimum necessary dose(J/m2).

Chemical products. There is no specific and exclusive premises for storing the biocide chemical products for water treatment; the store shows design deficiencies and is downgraded to a plant room; the safety data sheets of the chemical products are out of date.

Sundry. The parametric limits of chemical compounds in the water do not abide by regulations; obligatory water quality control parameters are omitted and also ambient parameters in indoor pools; the air conditioning system is deficient in terms of hygienic air renewal; the pool tank has no thermal barrier to prevent energy wastage (Regulation on Thermal Plant in Buildings – RITE in Spanish initials) .

SURVEILLANCE AND USERS

Children’s pools are not properly fenced off or the barrier is not standardised (fitted with lock, unclimbable by children, resistant, properly anchored, height of 1.2 m.) to prevent access by children outside the authorised opening time or after the end of the bathing season. Likewise the whole swimming pool precincts does not have a complete enclosure to control user access.

There is no lifeguard service. Not enough lifebuoys are provided

The official figures and maximum occupancy of each pool are not displayed and there is also no indication of the pool bylaws

Services and hygiene The requisite most often breached was the failure to ensure a safe non-mains supply of bathing water. The absence of toilets inthe swimming pool and the failure to provide litter bins and urban waste containers were other failures that came to light in thestudy.

Water treatment and purification In over half the swimming-pool projects studied the chemical-product dosing system for water treatment (disinfection andmaintenance) was not automatic. In other words there was no system fitted with a programmable device that tripped and shut down the dosing operation according to a pre-set level of free chlorine (or other authorised disinfectant) or allowed ongoing analysis of its water concentration to maintain a correct level and an environment free of pathogenic micro-organisms. Instead of such automated equipment, dosing devices based on irregular

sprinkling of the water with the chemical product are used but without any sensors to measure the concentration. Such equipment does not ensure trustworthy regulation of the chemical product and does not rule out the human or random factor (organic matter, bather load, water flow,...) in the dosing procedure. The filters provided for the physical treatment of the water were silica sand filters. Strikingly, their performancefeatures did not meet the required standards for ensuring efficient dirt retention and water quality. Both the filtering sectionand the filter diameter were chosen without taking hydraulic calculations into account and fell short of the pool purification needs.

On many occasions the project engineers underestimated the need for a specific and exclusive store for biocide chemicalproducts; instead they fell back on the plant room as the storage facility, in breach of the law. This is unacceptable not only in terms of ensuring chemical safety but also because the water purification buildings do not meet the design standards for the storage of chemical products.

Surveillance and Users In over half of the projects no user information was displayed on maximum occupancy (broken down for each pool) and local bylaws. Infractions also came to light in the number of lifebuoys or their chord was shorter than the regulation length. One of the most important faults in terms of preventing the risk of drowning was the lack of a complete enclosure in many pool precincts to prevent user access, especially children, outside the openinghours or after the end of the bathing season.

The Pearson chi square test was carried out to ascertain whether the observed differences between the category of data could beput down to chance. The results fell within the critical region (a=0.05), which would tend to rule out the independencehypothesis (table 3). It would therefore seem that the degree of non-compliance and the category of health requisites are not independent of each other, i.e., at least two of the requisitegroups differ according to the type of infraction, suggesting that there is a relation between the categorised data groups. Thus,with a p-value very close to zero there is sufficient evidence torefute the null hypothesis and we decided that there were statistically significant differences, even though the observed and expected frequencies seem to be equal (figure 3). Nonetheless, if we look at the partial values of X2, the water treatment and purification class of requisites accounts for much of the detected variability, while the differences are very small in the rest.

The prevention of bodily harm, accidents and transmission of diseases in public swimming pools

calls for the adoption of suitable hygiene and health requisites and specific safety conditions in

their use

a. 0 boxes (0%) have an expected frequency lower than 5. The

Table 3. Pearson chi square test

Valor

Chi square statistic χ2 19,925a

Degrees of freedom 3

Asymptotic sig. (bilateral ) ,000176

minimum expected frequency is 11.06.

Figura 3. Observed and expected breach frequencies.

Discussion

The results show the importance of increasing public-health surveillance and control of swimming pools during the design-project phase as the stage of the whole process offering the best chance of minimising risks to the health and safety of users. A large sample of swimming pool projects was studied (n=30), identifying a significant percentage of minor and serious infractions in relation to health risks for users and safety conditions in the use of the facilities. We assess and weigh up these breaches in this present work.

Improper design of the guards and grilles protecting bathers from the pool-bottom drains

could lead to entrapment of fingers, hair, clothes or ornaments of children and adults, leading to

injuries and, in extreme cases, death

The enforcement of swimming-pool legislation is beingcompromised by the low level of compliance found in the projects studied. Our analysis suggests that efforts to prevent bodily harm and diseases should concentrate on compliance with the HealthRegulation in the swimming pool design and conception phase.

Breaches found in the design of the bathing area are especiallysignificant in terms of the gravity of their consequences and media impact. Witness some of the commonest breaches in this area. The regulation lays it down that the poolside deck should have an slip-resistant surface, referring thereto in a general butnot indeterminate way, insofar as the surfaces should meet certain characteristics in keeping with the particular circumstances obtaining in these circulation areas. In other words the term “slip-resistance” is not absolute, for different floors have different degrees of slipperiness; but the surfaces should offer resistance to slips and sliding under normal use conditions, withthe presence of water splashed from the pool or running off the bathers, suncream or oils sticking to the body, remains of soap after showering, with the added factor that users are normallywalking barefoot. Those projects, therefore, that refer to other causal conditions do not meet the law on this point. Some projects abide by the standard UNE-ENV 12633:2003 referring tobarefoot conditions, but some authors7 have shown that this does not meet the safety conditions required for walking barefoot

over surfaces impregnated or splashed with slippery agents.

As for the breaches relating to the pool-bottom drains, the regulation calls for suitable guards and grilles to forestall any risk situation. Note here that the regulation does not speak merely of “accidents” which would be a concept of lesser scope. The law isforced to fall back on «indeterminate legal concepts» since it would obviously be impossible to encompass in the law all the technical devices on the market, which are changing at a much quicker pace than the law itself. Nonetheless, working from some minimum logical criteria, technical knowledge and professionalexperience, it is easy to pinpoint those cases involving health risks in relation to the pool-bottom drains, such as the suction effect or entrapment, which might lead to serious injuries as aresult of sucking in parts of the body8 (intestines, thorax,abdomen, gluteus, limbs...) or even death by drowning. The preventive measures to minimise risks of this type have beentackled in the European Standard EN 134519,10, laying down the flow rate (< 0.5 m/s), increasing the number of drains and spreading them out evenly, establishing a minimum size for the protective guard and grille openings (< 8 mm-diameter), etc. Inclusion of a non-specific grille in any design project, therefore, does not guarantee abidance by the legislation; this calls for afiner level of detail and development in the design project in keeping with available technical and scientific evidence.

Another factor involved in dangers of this type is the use of protection barriers around the pool itself or fencing off the whole pool precincts. This is one of the most effective recognised measures for preventing drowning11 , controlling as it does theaccess of children and adults outside the supervised opening hours or after the end of the bathing season. Instead of suchmeasures, deficient projects allow only for ornamental elements such as hedges, partial fences, a low or easily-climbable fence, unlockable gates or even direct access from houses or building exits. Such arrangements are ineffective for controlling the entry of users, whose behaviour never exempts the swimming pool tenure holder from the obligation of adopting standardised safety measures.

Swimming pool regulations are a valid instrument for safeguarding the health of bathers and

ensuring safe use of the facilities

One of the commonest breaches is the lack of technical aids fordisabled bathers. In general the design projects meet the requisites for entering and leaving the pool precincts but the vastmajority fail to remove all architectural barriers to entering andleaving the pool itself. This means that it would be very difficult ifnot impossible for a disabled person or a person with reduced mobility to use the pool in a safe and autonomous way. Therequirement of removing all architectural barriers has raised some controversy, always in relation to the cost of the necessary reforms. This has led to a pronouncement by the Andalusian Ombudsman (Defensor del Pueblo andaluz)12 and the Consultative Council of Andalusia (Consejo Consultivo de Andalucía)13, who warn the public authorities of the need of bringing public swimming pools into line with today’s requirement of ensuring equal access for the disabled community and facilitating their full integration into all ambits of social life.

The differences found between the class of requisite and type of breach were most notable in the category of «water treatment and purification». These breaches are particularly important because poor water quality or insufficientdisinfection could impede the removal of pathogenic agents from

the water, potential vectors for passing on diseases to the bathers14. Here the regulation calls for the use of automatic chemical-product dosing and control systems according to ongoing calculations of the disinfectant present in the water. The commonest breach here is the use of dosing devices whose measuring of the disinfection level is based on the oxygen reduction potential (ORP) or redox. Perhaps the problem here lies in the fact that the Health Regulation specifies the threshold limits of residual free chlorine (0.4 – 1.5 ppm) in the water, i.e., it regulates the ppm level but not the redox values (mV). In general, ORP is not a good technique for measuring the disinfectant level. The logarithmic dependence of ORP on the concentration multiplies the errors in millivolts measured (Nernst’s equation, 1889). Swimming-pool water chemistry is complex and the thermodynamic redox equilibrium is seldom met. Due to the abovementioned exponential relation, therefore, small changes in the ORP reading translate into huge swings in the ppm values of residual free chlorine, regardless of the reference electrode. ORP readings are widely misused, badly understood and present significant limitations due to slow kinetic regimes, mixed potentials and electrode failures15,16. It is an instant test; this means that it is not sensitive to chlorine ions and neither should it be used as a direct indicator of residual oxidant due to the pH effect and the temperature of the readings. It does not, therefore, obviate the need of analysing the disinfection level with other standard tests. Automatic control systems based on Photo Ionisation Detectors (PIDs) or amperometric sensors17 are considered to be chlorine- and bromide-specific and therefore afford a more trustworthy control of water quality18.

One of the most important water-quality criteria is control of turbidity in the pool; this involves appropriate treatment of the water, which in turn entails correct sizing of the filtration system. Filtration is a critical stage in the elimination of pathogenic micro-organisms; a filter of deficient size will not ensure that water quality is kept within legal limits. One of the commonest project deficiencies in this respect was the selection of sand filters whose cross section and diameter did not meet the performance features established by the corresponding hydraulic calculations. This means that, even if the pool purification cycle was less than the established time of 4 hours, this was achieved at such high filtration rates, normally critical >50 m3/(h·m2), with such a quick water flow through the filter that the dirt was not effectively filtered out and returned to the pool after the purification process.

Failure to display user information (maximum occupancy, bylaws, safety pictograms, indications of depth and changes of slope,...) should not be downplayed in importance, as simple as this fault may seem. Neither should this obligation be fobbed off on non-professionals outside the project. The choice of an inappropriate colour, incomplete warnings or inappropriate text size all impinge heavily on perception of the danger and user understanding thereof19. Some authors have found a relation between bodily injuries in pools and the absence of depth indications20.

Health regulation of public swimming pools will only be effective if this is properly enforced and it is crucial to look into the factors that might hinder

its application

Design engineers and the professional sector in general tend to explain away the high incidence of breaches in terms of the subjectivism of the public authorities, ignorance of the sector and the poor technical quality of the regulations, leading to problems

of legal uncertainty. These critics defend the literal tenor of the regulation without any leeway for interpretations over requisites «unmentioned» in the regulation as written. This outlook obviously does not hold any water. Boiling down the swimming pool Health Regulation to a literal interpretation of the «positive rule» indicates a worrying dearth of arguments and sloppy thinking. The health regulation is much too complex to beunderstood in such a facile manner; its rules need to be intelligently adapted to each specific case, while public authority professionals need to be able to work with some leeway butwithin well marked limits, giving due grounds for their opinions in terms of certain health risks. True it is that there have been some cases of an improper use of these general rules. Nonetheless, thislegislative approach has been endorsed by the Constitutional Court itself in its judgements 62/1982; 122/1987, FD 3. and 150/1991, FD 5., which have defined the principle of legal certainty in broad and flexible terms that go well beyond mere knee-jerk response to each particular legal requisite.

Hidebound, overly specific rules cannot do real justice to theinternal logic of the target sector, with the concomitant risk of gearing the Health Regulation towards satisfaction of the professional sector by paring down the risk situations rather thanproviding a real safeguard for users. Referral to or application of UNE standards 21,22 or internationally recognised standards(DIN, BS, ANSI...) guarantees greater legal certainty than regulations with painstakingly detailed requisites that, paradoxically, hinder the application of the law and fuel more costs than benefits. This approach ensures that compliance with health requirements is not an ad lib affair and that the provisions of the regulation are not abused. The same health and safety conditions are thereby guaranteed for any European citizen ortourist in an increasingly complex multicultural society.

Our study shows that the design projects do not put forward technical solutions with grounds based on objective conditions. Neither the design of the facility nor the selection of its component parts was the result of a set of technical data objectively obtained from the calculations carried out. A mere declaration of good intentions vis-à-vis compliance with theHealth Regulation or churning out chunks of its text as guarantee of legal compliance is just not good enough. Design projects need to be so worded as to offer certainty about the technical solutions put forward, reasonably developed and documented with grounds. A rough idea of the reasons for project breaches would be the following: insufficient health training and instruction,underestimation of health requisites in architecture and engineering projects, cost cutting (undercutting the competition or satisfying the promoter). These translate into insufficient safety measures or substandard equipment, etc. Indeed, the Spanish Supreme Court (Tribunal Supremo)23 has pointed outthat the omission of swimming-pool safety measures, shirkinghealthcare requisites, represents an obvious cost advantage forthe tenure holder of the facility concerned, who thereby, to save money in his or her own interest, jeopardises the very legal right(public health) that the health regulation sets out to protect.

To avoid inconsistencies in the wording of projects and ensure their correct implementation, an immediate interpretative task needs to be carried out to select those technical rules that might top up the Health Regulation and be most conducive to the technical valuation criteria. Important support here can be gleaned from the official guides or recommendations drawn up by the professional sectors and public authorities, the interpretation of which should be duly crosschecked against the legal provisions. Publicity campaigns or professional events could be useful tools to help enforce the Health Regulation.

The quantitative and qualitative data culled therefrom could be

extremely useful in terms of improving available information, allocating resources and directing decision-taking in surveillance programmes for public swimming pools. Inspection activities, for example, could increase their effectiveness by means of regulation-enforcement actions wherever breaches have been disproportionately high.

The conclusions we can draw from this study are that breaches of the Health Regulation for Public Swimming Pools (Reglamento Sanitario de Piscinas de Uso Colectivo) are commonplace, resulting in poor compliance of the hygiene and health conditions and impoverished safety for users.

This study shows that legislation in itself is not enough to safeguard the health of the users of swimming pools designed and built in the Costa del Sol; effective enforcement of these regulations has to be ensured and it is vital to look into the reasons why the legal provisions are so often breached. The health authorities, for their part, have to work harder to ensure compliance with health and safety conditions in public swimming pools.

Our study has shown that the swimming-pool design projects do not provide technical solutions

with proper grounds

TO FIND OUT MORE

1. WHO. (2006) Guidelines for safe recreational water environments (vol. 2): swimming pools and similar environments. Geneva, Switzerland.

2. TNS Opinion & Social, 2008. Special Eurobarometer 295/Wave 68.2: Attitudes of European citizens towards the environment. European Commission. Brussels. Avaiable in http://ec.europa.eu/ public_opinion/archives/ebs/ebs _295_en.pdf

3. Decreto 23/1999, de 23 de febrero, por el que se aprueba el Reglamento Sanitario de las Piscinas de Uso Colectivo. BOJA núm.36, de 25 de marzo.

4. Vyles, T. Growth and evolution of a municipal pool safety and inspection program. J Environ Health. 2009 Jun;71(10):40-4.

5. Consejería de Salud (2009). Instrucciones generales de ejecución del programa de piscinas de uso colectivo. Servicio de salud ambiental. Secretaría General de Salud Pública y Participación, Junta de Andalucía. Sevilla.

6. Real Decreto 314/2006, de 17 de marzo, por el que se aprueba el Código Técnico de la Edificación. BOE núm.74, de 28 de marzo.

7. Ortega Sánchez, N., Rosa Máñez, D., Zamora Álvarez, T. & Pereira Carrillo, I. ACUASAFE, resbaladicidad de pavimentos para pie descalzo. Instituto de Biomecánica de Valencia. En Biomecánica 2007, 52: 27-29.

8. Girón-Vallejo, O., et al. Atrapamiento por succión en una piscina. An Pediatr (Barc). 2011. doi:10.1016/j.anpedi.2011.01.009.

9. Asociación Española de Normalización y Certificación. Equipamiento para piscinas. Parte 1: Requisitos generales de seguridad y métodos de ensayo. UNE-EN 13451-1:2001. AEN/CTN 147, AENOR. Madrid, 2001.

10. Asociación Española de Normalización y Certificación. Equipamiento para piscinas. Parte 2: Requisitos específicos

de seguridad y métodos de ensayo adicionales para escalas, escaleras y barandillas. UNEEN 13451-2 /AC:2004. AEN/CTN 147, AENOR. Madrid, 2004.

11. Thompson, D.C., Rivara, F.P. (2000). Pool fencing for preventing drowning in children. Cochrane Database of Systematic Reviews, 2: CD001047.

12. Defensor del Pueblo andaluz. Resolución nº 08/2724, de 14 de julio de 2008, relativa al incumplimiento de la normativa sobre accesibilidad en una piscina comunitaria. Sevilla.

13. Consejo Consultivo de Andalucía. Dictamen 121/1998, de 17 de diciembre, sobre proyecto de decreto que aprueba el Reglamento Sanitario de las Piscinas de Uso Colectivo. Marginal nº I.25. Sevilla.

14. Hadjichristodoulou, C., Mouchtouri, V., Vousoureli, A., et al. Waterborne disease prevention: evaluation of inspection scoring system for water sites according to water microbiological tests during the Athens 2004 pre-Olympic and Olympic period. J Epidemiol Community Health 2006;60:829--35.

15. Galster, H. (2000). Technique of measurement, electrode processes and electrode treatment. Redox fundamentals, processes and applications. Ed. Schüring J, Schulz H.D, Fischer W.R et al. Springer: Berlin. 12-23 pp.

16. Peiffer, S. (2000). Characterization of the redox state of a aqueous systems: towards a problemoriented approach. Redox fundamentals, processes and applications. Ed. Schüring J, Schulz H.D, Fischer W.R et al. Springer: Berlin. 24-41 pp.

17. Clifford White, G. (1999). The handbook of chlorination and alternative disinfectants. Wiley- Blackwell, 4th Edition; 1592 pp.

18. Health Protection Agency (2006) Management of spa pools controlling the risks of infection. HSE. Centre for Infections. London.

19. Wogalter, M.S., Conzola, V.C., Smith-Jackson, T.L. Research-based guidelines for warning design and evaluation. Appl Ergon. 2002 May;33(3):219-30. Review.

20. DeVivo, M.J., Sekar, P. (1997) Prevention of spinal cord injuries that occur in swimming pools. Spinal Cord, 35(8): 509–515.

21. Asociación Española de Normalización y Certificación. Piscinas. Parte 1: Requisitos de seguridad para el diseño. UNE-EN 15288- 1:2009. AEN/CTN 147, AENOR. Madrid, 2009.

22. Asociación Española de Normalización y Certificación. Piscinas. Parte 2: Requisitos de seguridad para el funcionamiento. UNE-EN 15288-2:2009. AEN/CTN 147, AENOR. Madrid, 2009.

23. Sentencia del Tribunal Supremo (Sala 1ª) 2492/2002 de 10.12.2008. Rollo de apelación nº 868/1998.

Small-craft waste management ENVIRONMENT

Every day coastal fishing and yachting activities generate thousands of tons of waste onboard the craft involved and in the ports; most of this waste is not properly managed or treated. This marine litter or debris has a huge environmental impact on the coastline, affecting not only water quality and sea beds but also the species living there; it might also pose a risk to human health and jeopardise safe navigation. With the aim of improving the management of this waste and heading off any marine pollution, a study was drawn up called Small-Craft Waste Management (Gestión de residuos a bordo de buques de pequeña eslora) based on fieldwork carried out in 34 ports of Galicia to find out the scale of the problem. The study identifies the type of waste generated and how it is dealt with both on board the craft and in the ports; it also analyses the impact to the marine environment and the best way of raising awareness and encouraging good practices among those involved.

By YOLANDA LISTA PERISCAL. Chemistry graduate. MA in Integrated Management. Occupational Risks Prevention Officer for the Small Craft Owners and Operators Association of Galicia (Asociación de Armadores de Artes Menores de Galicia: ASOAR ARMEGA).

The sea and coastline are vast sources of wealth and we depend on both of them for improving our economic and social development. According to figures of the Spanish Maritime Authority, professional fishery activities employ 52,000 people directly with an added knock-on effect of indirect and induced jobs. Yachting, for its part, is a growing-demand sector accounting for 15,000 direct jobs, a figure that soars to 114,000 if we take in the indirect and induced jobs. Furthermore the beauty of the sea and coast is one of the main tourism lures and driving forces behind the development of coastal areas.

Despite this, the recent study Sea Litter: a Global Challenge, drawn up by the United Nations Environment Programme (UNEP) and the Ocean Conservancy organisation, published on World Oceans Day 2009, calls attention to the «worsening global problem of marine litter». The sea has become a vast rubbish dump. The oceans of the whole world build up millions of tons of waste, ranging from plastic bags and bottles, glass, remains of fishing gear and tackle to cigarette ends, television sets, refrigerators or beds. Plastic litter, especially bags and bottles, is the main waste found in the world’s oceans today (over 80% of the total). It is particularly worrying because it is an enduring and cumulative problem: it is estimated that the plastic litter will take hundreds of years to degrade completely.

THE OCEANS OF THE WHOLE WORLD BUILD UP MILLIONS OF TONS OF WASTE, RANGING FROM

Seabed cleaning in the Port of Ferrol

Seabed cleaning in the port of Camariñas.

Seabed cleaning in the port of A Coruña

Year 31 Nº 122 2011

PLASTIC BAGS AND BOTTLES, GLASS, REMAINS OF FISHING GEAR AND TACKLE TO CIGARETTE ENDS, TELEVISION SETS, REFRIGERATORS OR

BEDS

The report explains how this marine waste slowly breaks down into smaller and smaller particles that may then be eaten by living beings at the base of the food chain. Plastic litter is mistaken for food by birds, fish, turtles or cetaceans (whales and dolphins). UNEP has calculated that this pollution kills over one million birds a year and about 100,000 mammals. Experts point to the bioaccumulation of these substances in the organism of living beings throughout the food chain. The health consequences might be very grave: contamination is likely to get worse in seafood. The waste might also cause heavy economic losses, damaging seagoing craft, affecting fishery and tourism.

This report also stresses the problem posed by cigarette remains, especially filters and tobacco packaging, which, in the Mediterranean and equatorial coastal zones, account for up to 40% and over 50% of marine litter, respectively.

The total amount of ocean debris is unknown due to the lack of studies and the fact that a lot of the waste is not seen. It ends up sinking to the seabed (only about 15-20% of this waste is washed up as beach litter; another 15% remains suspended in the water column and the rest is deposited on the seabed) or is ingested by marine animals. As for the source of these remains, 20% comes from maritime traffic (fishery activities, cruises, commercial shipping and yachting) and 80% from land-based sources. It is estimated that the world’s boats and ships throw five million items of waste overboard every day.

Most of the floating waste is made up by plastic litter (soft plastic and bags, bottles, hard plastic, etc.) and the rest by wood. On the seabed, however, the commonest waste is glass, accompanied by more plastic, cans, tyres, small and large batteries, scrap, rope, remains of fishing gear and tackle and even some large-scale objects such as mattresses, household appliances, furniture, vehicles, etc. This article includes pictures taken during the seabed cleaning days organised by the Association of Small-Craft Owners of Galicia (Asociación de Armadores de Artes Menores de Galicia) at various points of the Galician coastline.

On these days the cleaning areas were located in sheltered waters, inside the rias and generally in the vicinity of a coastal-fishing port.

EVERY DAY BOATS AND SHIPS AROUND THE WORLD THROW FIVE MILLION ITEMS OF WASTE

OVERBOARD. THIS FIGURE COULD BE DRASTICALLY CUT DOWN BY WASTE-REDUCTION

AND RECYCLING ACTIVITIES

The commonest seabed debris in the vicinity of ports is solid waste from boat-reform, -repair and -maintenance work (oil change, battery, painting, etc) carried out in the port area, such as oil and grease cans, paint containers, tyres used as mooring fenders, used engine batteries, cables, chains, iron fittings, etc.

Other debris often found in these areas stems from the wholesale fish market in the port, such as the trolleys used to carry crates of fish or the crates themselves, both wooden and plastic.

Seabed cleaning in the Port of Ferrol

Seabed cleaning in the port of Riveira.

Seabed cleaning in the port of Camariñas.

Seabed cleaning in the port of Fisterra.

Waste in the form of used batteries from radios and other navigation-safety devices as well as the smaller batteries from torches, telephones and other appliances carried onboard are also found on the seabed around ports and in other further off areas.

Typical fishery waste is also scattered along the seabed of the Galician rias, such as remains of mooring cables and lines, fishing gear and tackle , underwater torches, gloves and some work clothes.

Seabed cleaning in the port of Riveira.

THE TOTAL AMOUNT OF OCEAN DEBRIS IS UNKNOWN, DUE TO LACK OF STUDIES OR THE FACT THAT A LOT OF THE WASTE ENDS UP ON

THE SEABED OR IS INGESTED BY MARINE ANIMALS

Other objects found on the seabed of rias included a host of glass, plastic containers and cans, etc., partly from the consumption of food and drink onboard and in the port area.

Other waste found bears no relation to small-craft users, whether commercial fishery or leisure angling vessels, such as waste stemming from human settlements of the coastal zones, as shown in the pictures on these pages.

Prevention of Marine and Coastal Pollution

Better administration and reduction of waste, together with recycling initiatives, could dramatically cut down the amount of debris ending up in the sea and help to prevent marine and coastal pollution.

With this main aim in view, and also to raise awareness about the importance of waste recycling, a study has been drawn up called Small-Craft Waste Management (Gestión de residuos a bordo de buques de pequeña eslora), identifying the main debris and litter generated by inshore small craft users. It also analyses the abundance, composition and life-cycle of this waste, where it is found and its impact on the marine environment and examines waste management procedures and the current state of fishing ports and marinas in this respect.

Table 1. Fishery and recreational fleet by region.

REGIONAL Fishery Recreational

Seabed cleaning in the port of A Coruña

Seabed cleaning in the port of Fisterra.

Seabed cleaning in the port of Barallobre.

Work has also been carried out to raise awareness of small craft users to encourage «good practices» in terms of what to do with this waste and discourage the knee-jerk reaction of «tossing itoverboard», with the overall aim of improving waste management onboard and in the port area.

As fruit of this study a report has been drawn up on the main waste stemming from fishery and yachting activities as well as its impact on the marine environment. A good practices handbook has also been published for management of small-craft waste explaining the effects of throwing waste into the sea and the legal obligations laid down on this matter.

PLASTIC LITTER IS MISTAKEN FOR FOOD BY BIRDS, FISH, TURTLES OR CETACEANS. IT IS

ESTIMATED THAT THIS POLLUTION KILLS OVER ONE MILLION BIRDS AND ABOUT 100,000

MAMMALS EACH YEAR

The aim is not only to inform, however, but also to raise awareness of the problems of the marine environment, stressingthe need to conserve it properly and protect it, encouraging a rational and responsible use thereof to guarantee the ongoing quality of the seawater and seabed and ipso facto the biodiversity and productivity of coastal ecosystems.

AUTHORITY Fleet Fleet

Galicia 5.198 23.360

Asturias 339 4.825

Cantabria 168 5.799

Basque Country 263 9.557

Catalunya 1.040 59.873

Valencia Region 697 27.883

Murcia Region 221 15.449

Andalucía 1.750 34.193

Ceuta and Melilla 39 2.459

Balearics 432 30.064

Canaries 969 18.512

TOTAL 11.116 231.974

Seabed cleaning in the port of Corcubión.

Seabed cleaning in the port of Corcubión.

Seabed cleaning in the port of Corcubión.

General container with waste of all type in the port of Malpica.

In today’s Spain there is now a huge number of seagoing vessels, both professional and recreational, operating inshore within 60 nautical miles of the coast. The sheer amount of waste generated by these vessels is staggering; furthermore, it is thrown into the marine areas closest to the coast, within a few miles thereof, precisely the area most affected by the coastline human settlements.

According to the figures of the Operational Fishery Fleet Census (Censo de Flota Pesquera Operativa) as at 31 December 2009, taken from the website of the Ministry for the Environment and Rural and Marine Affairs (Ministerio de Medio Ambiente, Medio Rural y Marino) (http://www.marm.es/), Spain’s fishery fleet is made up by 11,116 vessels, 88% of them being less than 18 metres long. These boats are used close to the coast for coastal and inshore fishery purposes. To the waste generated by this fleet must be added the appreciable impact of the many recreational yachts sailing along the coast. According to figures of the Merchant Navy Directorate General (Dirección General de la Marina Mercante), under the Ministry of Public Works and Procurement (Ministerio de Fomento), 6828 new boats were registered in 2009, bringing the total fleet of recreational vessels in Spain up to 231,974.

Material and Methodology

Information was culled from fieldwork visits to 34 ports of the Galician coasts and 1132 surveys of both professional fishermen and yachters; further information was obtained from the seabed cleaning days.

The main waste was identified from the survey findings and the results to date of the seabed cleaning days organised by the Asociación de Armadores de Artes Menores de Galicia in the various ports of the Galician coast.

The surveys also gave information on waste management practices, while the 34 port visits enabled us to check the state of the waste reception facilities.

Reference was made to all the literature on the type and amount of waste generated by fishery activities and other activities in the ports of the Region of Galicia and also its impact on the marine environment (OMAR Project).

Likewise, a review was made of the pollution control and prevention legislation to be met by vessels of this type, as well as the legislation to be observed by the ports’ waste reception facilities.

Results

The upkeep of small seagoing craft (cleaning, mechanical overhaul, painting and caulking) generates waste such as used engine filters and oil, thrown-out engine batteries, mooring fenders made of end-of-life tyres, grease, paint and solvent containers , hawsers , cleansing water as well as clothes and rags stained with hazardous substances such as solvents, paint, motor oil, lubricants, etc.

Port of Caión (MARPOL Annex I oily waste reception facility).

Port of Corcubión.

Port of A Coruña (expanded polystyrene, wood).

Port of Corcubión

Seabed cleaning in the port of Camariñas.

Repairs and refits of these craft, for their part, generate mainly such waste as packaging, cables, glass fibre, chains, iron fittings, steel, rubber, glass, wood with remains of paint, old navigation and radio appliances, etc.

The consumption of tobacco, food and drink onboard and in the port area produces waste in the form of glass and plastic containers, cans, cartons, cigarette ends, cigarette packets, scraps of food, etc., as well as black water from the onboard sewage system.

The typical fishery waste involves remains of mooring ropes, cables and lines, fishing gear and tackle, underwater torches, gloves, working clothes, fish innards, etc. The fish market activities in the port then generate waste such as wooden or plastic crates (PVC, expanded polystyrene fish boxes,…), conveyance trolleys, etc.

MARINE WASTE COULD POSE A SERIOUS RISK TO HUMAN HEALTH AND ALSO CAUSE ECONOMIC LOSSES, DAMAGING SEAGOING CRAFT AND

AFFECTING FISHERY AND TOURISM

The main pollutant waste produced by navigation activities themselves, boat upkeep, repair and refits, fishery activities, yachting and other port activities such as wholesale port-side fish markets and slipways, etc., are therefore the following:

· Solid waste of a similar nature and composition to that produced in private homes, offices, shops and service centres, such as cardboard containers, plastic material (containers, boxes, gloves, mooring lines, ropes and hawsers, fishing gear and tackle, etc), mooring fenders made from end-of-life tyres, glass, wooden and plastic crates, metal scrap (cans, hooks, cables, iron fittings from repairs and reforms, chains, etc), cigarette ends, cigarette packets, scraps of food.

Hazardous waste such as: Oily water and sludge from the bilges or tank

washings, used motor oil, etc).

Wastewater (black and grey water) from the onboard sewage system.

Thrown-out starter-motor batteries and smaller batteries from radios, torches and other devices.

Cans of oil and grease, paint containers and other remains from similar boat-cleaning and -upkeep products.

Port of Camelle.

Port of Fisterra.

Port of Fisterra.

Port of Muros.

Clothes and rags stained with hazardous substances such as solvents, paint, engine oil, lubricants, etc.

The waste generated in port activities (upkeep, boat-repairs and -refits, sale of products, etc) and in wholesale port-side fishmarkets and slipways or waste from the port itself usually ends up on the seabed close to the port areas.

Onboard waste while the boat is at sea and typical fishery waste is usually scattered along the ria seabed and the coastal seabed out to a distance of about 10 miles, the usual limit of local fishingactivities.

The MARPOL 73/78 Convention made it compulsory for all boatsto discharge their waste into onshore reception facilities and laid down specific rules for discharging waste at sea. Spain is one of the countries that have ratified the convention so its annexes are enforceable throughout the whole national territory. The smallcraft we are dealing with here are bound by the following annexes in terms of waste generation and management: Annex 1(prevention of pollution by oil); Annex IV (prevention of pollution by onboard sewage); Annex V (prevention of pollution by garbage from ships) and Other garbage and waste.

This international convention also laid down the obligation for all ports to run services for the reception of this contaminatingwaste. In view of the type of waste generated by vessels of this type and the needs of most of the port facility users, the waste reception facilities have to be at least the following:

MARPOL Annex I Facilities. Port reception facilities for receiving oily bilge water and sludge or tank washings, used filters and residues from engine oil, transmission and lubricants.

MARPOL Annex V Facilities. Port reception facilities for solid waste (garbage) not classified as hazardous, including disused fishing gear and tackle, remains of wooden and expanded polystyrene fish crates, etc.

Other garbage and waste. Facilities for any garbage and waste not included elsewhere that vessels might also need to discharge. This includes material such as used small and large batteries, containers with hazardous substances or contaminated therewith, remains of material from onboard maintenance work (electrical appliances, insulating lining, paint remains), etc.

In Spain, furthermore the Seaports and Merchant Navy Act27/1992 (Ley de Puertos del Estado y de la Marina Mercante) of 24 November prohibits the discharging of any sort of waste within the public domain of the port and lays down fines for any polluting discharge from vessels in Spanish waters.

THE MARPOL 73/78 CONVENTION MADE IT COMPULSORY FOR ALL VESSELS TO DISCHARGE THEIR WASTE IN PROPER ONSHORE FACILITIES

AND LAYS DOWN THE PROCEDURE FOR DISCHARGE AT SEA

The survey results show that plastic, glass and cans all loom large in the category of garbage-like solid waste but a particularly important source of marine debris here is smoking-relatedactivities. 74% of the survey respondents smoke and 72.9% throw their cigarette ends into the sea.

Seabed cleaning in the port of Barallobre.

Seabed cleaning in the port of Barallobre.

Port of Fisterra.

As for hazardous waste 78.8% of the respondents throw away used engine oil and 69.7% do likewise with paint and solvent containers. 54.8% throw away small and large batteries and only 10% say that they generate black or grey water.

Only 12.5% of the respondents recognise the hazard pictogramsand understand their meaning; 33.9% are familiar with them but not their meaning and 53.5% are not familiar with them or withhold their opinion. Moreover, 54.1% do not answer the question about whether they use any product containing these hazardousness symbols during boat upkeep operations; 41.3% claim not to use them and only 4.5% admit to using them.

The great majority (84.4%) confirm that they themselves change the engine oil and paint the vessel, meaning that they are responsible for dealing with the waste from these operations.

Most of the floating waste hauled up in fishing nets is accountedfor by plastic and wood. A lower percentage of 30.9% report finding remains of mooring ropes and fishing gear while 20.1%report expanded polystyrene. The vast majority, 87.4%, do not answer the question of what type of waste they haul up in their fishing gear or claim they bring up none at all. 7% answer that they haul up remains of mooring ropes and fishing gear; 4.6% remains of seaweed and 2.1% containers, plastic and wood.

As for the management of the waste generated, 2% report that they throw it overboard. Most, 72.9%, say that they throw some overboard, like cigarette ends, and deposit the rest in portcontainers, without specifying if they classify it beforehand for disposal in the requisite port facility to favour selective collectionand subsequent recycling. Only 20.8% of the respondents declare that they classify the rubbish for proper disposal in the port containers for each type.

During the fieldwork it was observed that the professional fishermen habitually unload in port the fishing gear and nets that are no longer any use to them. It was also observed that both professional and recreational boat users deposit their used engine oil in the proper port container fitted out for that purpose.

SMOKING-RELATED ACTIVITIES ARE A SIGNIFICANT SOURCE OF MARINE LITTER. 74%

OF THE RESPONDENTS SMOKE AND 72.9% THROW THEIR CIGARETTE ENDS INTO THE SEA

As regards the state of the port reception facilities, the fieldwork carried out (visits to 34 ports of the Region of Galicia) showed

that one hundred percent of the ports visited had general waste containers and the lion’s share of them, about 90-95%, also had containers for glass, paper and containers/packaging as well asstockpiling zones or containers for remains of mooring ropes and lines, fishing gear and tackle, wooden boxes and MARPOL Annex Ioily waste containers. About half the ports visited, 52.9%, have containers for scrap and a lower percentage, 32.3%, also had containers for expanded polystyrene and batteries; only 11.8%have reception facilities for containers of hazardous substances.

Likewise, most survey respondents say that the port has ageneral waste container (97.4%), a glass container (87.8%) and MARPOL Annex I oily waste container (84.3%). More than half the respondents confirm that the port has containers orstockpiling zones for remains of mooring ropes, fishing gear and tackle (61.4%), wooden crates (57.4%), packaging containers (61.6%) and paper containers (52.3%). A lower percentage confirm the existence of containers for expanded polystyrene (41.3%), scrap (21%), batteries (9.6%) and hazardous waste (3.2%).

Fieldwork observations also showed that small craft users tend to accumulate small jerricans and drums with used engine oil in ports and in their working cabins, while waiting for the proper MARPOL Annex I oily waste reception facilities to be brought fully into service.

This prolonged and improper storage of small jerricans and drums in the port entails a grave environmental risk, with possible leakage and spills from these makeshift containers due to their bad state, holes or badly fitting lids. This could form a layer of oil on the floor which rain might then wash into the sea, with the consequent pollution. Besides the general soiling effect of this poor storage, it could also pose a risk to human health if any one passing through the area should slip over on the oilyfloor.

Conclusions

The competent authority in charge of this matter needs toimprove the management of port waste, offering a proper service to port users to suit the particular waste and garbage produced by their activity.

The public corporation in charge of running the port (the competent harbour authority) has to determine the wastereception needs in each port under its jurisdiction and guarantee provision of the waste reception service, either by direct management or by hiring the services of authorised companies for carrying out this activity.

These companies authorised by the competent authority for thereception of waste from seagoing craft have to be equipped with the necessary material, organisational and human resources forcarrying out the reception activity and also offer sufficient guarantees of maintenance of the conditions required under current legislation. This will avoid the problems found in 2010 in a service hired for the collection of highly polluting waste such as used engine oil. In this case the service was improperly run (unused containers, collection backlogs and build up of waste) and port users were unable to deal with their waste as required by the legislation .

THERE IS A NEED FOR IMPROVEMENT IN PORT WASTE MANAGEMENT PROCEDURES, OFFERING

PORT USERS A SERVICE TO SUIT THE PARTICULAR KIND OF WASTE GENERATED IN

THEIR ACTIVITY

It is also important for the port to have reception facilities for other hazardous waste as well as the Marpol Annex I reception facilities for used oil, such as containers for small and large batteries or paint cans, since waste of this type is also generated. Most of the small craft users, both professional and recreational, declare that they themselves paint their own boats and this seems to be a widespread practice in port areas. The antifouling paint used to prevent marine organisms from sticking to hulls is another significant pollutant, containing as it does heavy metals, like copper in oxide form, which have bioaccumulative toxic effects.

Small craft users need to be systematically informed of the type of waste produced by their activities, telling them whether or not this waste is hazardous and how to identify it, since the majority of survey respondents are not familiar with the hazard pictograms or know about them but do not understand their meaning.

As regards onboard waste management, the study shows that a high percentage of craft users throw some type of rubbish overboard. There is therefore a need for a specific campaign to stop this practice. The study also shows that many users dump their waste mixed up in general port containers, making it difficult for this waste to be selectively collected and then recycled. This practice, therefore also stands in need of improvement with advice being given about how to deposit the waste correctly.

The study also brought out the importance of users knowing about the effect of their waste on the marine environment. If they observe the effect of this waste, they are then more likely to discharge this waste in the proper port facilities, as is already the case with used engine oil and the remains of mooring ropes, fishing gear and nets. The rest of the waste, however, including hazardous waste like cans of paint used in boat maintenance, is currently dumped unsifted in general waste containers.

Craft users also need to be kept abreast of environmental legislation and the obligations incumbent on them, since any polluting discharge from boats in Spanish waters could lay them open to a heavy fine.

IT IS CRUCIAL FOR THE PORT TO HAVE NOT ONLY MARPOL ANNEX I PORT RECEPTION FACILITIES FOR OIL WASTE BUT ALSO OTHER CONTAINERS FOR SMALL AND LARGE BATTERIES AND PAINT

CANS

Furthermore the UNEP study also shows the following: firstly that smoking-related activities are a big source of marine litter, since almost all respondents who are smokers throw their cigarette ends into the sea; secondly that plastic litter (containers, packaging, crates, remains of mooring ropes and lines and synthetic fishing tackle, etc) is the main source of waste found in the world’s oceans and is generated in all activities carried out (maintenance, repairs, refits, navigation, fishing, etc.). Lastly, a high proportion of ocean waste comes from land-based sources, the seabed having been found to contain a huge amount of waste not produced by seagoing craft users, such as mattresses, household appliances, furniture, vehicles, etc.

Implementation of a monitoring system for gauging the effects of global change on the ecosystem functioning of protected areas in Spain and South America ENVIRONMENT

This article presents a system for evaluating and monitoring the responses of the ecosystem to global change in six protected areas of Spain, Argentina and Uruguay, setting alert thresholds and offering the results of the pilot scheme carried out in one of these protected sites, the Nature Park Cabo de Gata-Níjar in Almería Spain. The system is based on the analysis of a time series of low-cost satellite images for calculating the Absorbed Photosynthetically Active Radiation (APAR) by the vegetation as a proxy indicator of the net primary production (NPP) of the ecosystems. As a basic application of the system an analysis is made of the 2001-2008 trends in four of the descriptors related to primary productivity, phenology and seasonal carbon gain . This project offers protected-site managers a monitoring and alert system to keep track of changes in their ecosystem functioning. This scientific support tool for the management of those areas offers a twofold advantage: firstly, it is adaptable to other areas and, secondly, it can be consulted on internet by other scientists, site managers and the public at large.

The project was carried out in six protected areas, including the Nature Park Cabo de Gata-Nïjar in Spain, (left), the Protected Landscape of Quebrada de los Cuervos in Uruguay (top), the National Park El Palmar in Argentina (below left), and the National Park of Doñana in Spain (below).

Dr. of Environmental Sciences and research fellow in the Regional and Remote sensing Laboratory (Laboratorio de Análisis Regional y Teledetección) of the Agronomy School and IFEVA (Facultad de Agronomía e IFEVA), Buenos Aires University and CONICET (Argentina), and in the Plant Biology and Ecology Department (Dpto. de Biología Vegetal y Ecología) of the Andalusian Centre for Assessing and Monitoring Global Change (Centro Andaluz para la Evaluación y Seguimiento del Cambio Global), Almería University (Spain).

The catchment area of the Laureles stream, in Uruguay, made up by pastureland and woodland, is one of the six areas selected for this project.

The National Parks of Iguazú in Argentina and Brazil, chosen for the project, are an excellent framework for gauging changes in ecosystem functioning.

The vegetation of the Nature Park Cabo de Gata-Níjar in Almería (Spain), is dominated by semi-arid scrubland sharing many species with the arid

Year 31 Nº 122 2011

*Correspondence: Ctra. Sacramento s/n, La Cañada de San Urbano, Almería (España). Tel: (+34)950015932. Fax: (+34)950015069. email: dalcaraz@ual.es

J. Cabello. Dr. of Biology. Professor in the Dpto. de Biología Vegetal yEcología, Centro Andaluz para la Evaluación y Seguimiento del Cambio Global, Almería University (Spain).

C. Bagnato. Technician in the Laboratorio de Análisis Regional y Teledetección, Facultad de Agronomía e IFEVA, Buenos Aires Universityand CONICET (Argentina).

A. Altesor. Dr. of Biology. Professor of the Ecology Department (Departamento de Ecología) , Universidad de la República (Uruguay).

C. Oyonarte. Dr. of Biología. Professor in the Department of SoilScience and Agricultural Chemistry (Departamento de Edafología y Química Agrícola), Centro Andaluz para la Evaluación y Seguimiento del Cambio Global, Almería University (Spain).

M. Oyarzabal. Dr. of Farming Science. Coordinator of the Laboratorio de Análisis Regional y Teledetección, Facultad de Agronomía e IFEVA, Buenos Aires University and CONICET (Argentina).

J.M. Paruelo. Dr. of Ecology. Professor of the Agronomy School (Facultad de Agronomía) and y Director of the Environmental Sciences Degree Course, of Buenos Aires university, Chief Researcher of CONICETand Director of the Laboratorio de Análisis Regional y Teledetección, Facultad de Agronomía e IFEVA, Buenos Aires University and CONICET(Argentina).

Global change, in terms of the combined effect of climate change,biogeochemical cycles, land uses and biotic interchanges, poses a stern challenge for biodiversity conservation [1]. On a world level it has been proven that climate change is altering the duration and phenology of the growing season, the fire regime and food chain, i.e. multiple aspects of the ecological system[2]. Many of these effects have become evident in Spain and the SouthernCone of South America [3-9]. These changes also affect protected areas, where the greatest efforts are being made to preserve biodiversity [10]. It is therefore necessary to find out whether or not the structure and functioning of these areas is changing over time and quantify the changes [11]. This would help to develop adaptive management practices to minimise anybiodiversity loss and prioritise conservation efforts in light of these changes. At the same time quantifying the value that theassets and services of protected areas afford mankind and ascertaining the risk they run would boost social acceptance of the conservation measures [12].

It behoves us scientists and site managers to develop and implement monitoring instruments for gauging the health of ecosystems and the

changes occurring in them.

In light of all the above it behoves us scientists and site managers to develop and implement monitoring instruments that keep a constant check on the health of ecosystems (ecological integrity) and the changes occurring in them [13,14]. The variables to be factored into these instruments have to abide bythe following basic principles [14-17]:

1. they can be recorded at ecosystem level throughout large areas and in real time

2. they give an early warning of impacts to serve as a guide to effective adaptive management

3. they can be measured in an easy and direct way

zones of Africa and Asia

Doñana Nature Park takes in Mediterranean woodland and scrubland and saltmarsh

4. they pick up the time-space variability caused both by natural perturbations and anthropic impacts

5. they establish benchmark control values

6. they can be compared at both local and regional level

7. they facilitate the establishment of relations between them by means of different space scales.

For this purpose the functional attributes of the ecosystems (i.e., those related to exchanges of energy and material between the biota and the environment) offer several advantages. They show a quicker perturbation response than vegetation structure, preventing structural inertia from delaying perception of the effects of this perturbation on the ecosystems[18]. Furthermore,functional attributes favour monitoring by remote-sensing of different regions under a common observation protocol, allowing quantitative and qualitative characterisation of the ecosystem services [19]. Diverse spectral indices deriving from satelliteimages are linked to functional variables of the ecosystems, such as primary production, evapotranspiration, surface temperature, land surface albedo and precipitation use efficiency [20-22]. The vegetation index is one of the most important variables deriving from spectral data. Vegetation indices have been widely used in ecology for studying time trends and they play a key role in global change research [23]. They can be calculated from images with very diverse space and time resolution, so they have beenincorporated into many monitoring experiments [24, 25] carried out on a wide range of scales (from regional to worldwide). They have proven to be useful for detecting long term changes even at the scale of a protected area [6-8]. The use of ecology remote-sensing tools based on vegetation indices [26, 27] has improvedthe assessment of ecosystem functioning, particularly of net primary productivity (NPP) on a regional and even worldwide scale. The incorporation of these functional variables is vitallyimportant for ecosystem management, systematic conservation planning [28] and to factor the effects of global change into conservation strategies [10].

Despite all the knowledge built up on a global and continental scale the management of each particular protected site calls for an assessment in its own right, since a given area might not follow the pattern observed at regional level [6]. There are now many assessments based on large-scale remote sensing ofecosystem functioning of the protected areas of Spain and South America [6-8, 29-32], and also of the trends over time [6-8, 32]. Nonetheless, conservation practice and theory call for assessments with a high space resolution, paving the way for specific management actions to suit the particular effects of theenvironmental changes on the biodiversity-maintaining ecological processes of a protected area.

Objectives

One of our lines of research in the last ten years has been to gauge the effects of global change on ecosystem functioning in protected areas. This objective has both a theoretical andpractical side to it. From a theoretical point of view it has enabled us to understand better the environmental controls of the mean ecosystem functioning and its time trends over different space and time scales. From a practical point of view it has enabled us to develop monitoring and alert systems to support theconservation of protected areas. In this research work we have developed a conceptual framework and working tool that providessolid scientific information on the current situation and time trends in the ecosystem functioning of six protected areas of Iberoamerica. This tool is based on the study of spectralvegetation indices deriving from high resolution, low cost satellite images and it aims to furnish protected areas with an online

monitoring and alert tool for tracking the trend of net primaryproductivity , the fundamental service provided by the ecosystem when incorporating solar energy into the food chain. The methodology employed will enable the system to be easily extended to other ecosystem-functioning descriptors such as evapotranspiration or phenology, of great interest for assessing the effects of global change on biodiversity.

Materials and Methods

Protected Areas Studied This research was conducted simultaneously in six protected areas of Spain, Argentina and Uruguay. Nonetheless, by way of illustration, this article shows the results only for the pilot scheme carried out in the Biosphere Reserve of the Nature Park Cabo deGata-Níjar [32]. The six selected areas take in a vast variety of environments and land-use histories, representing an excellent framework for evaluating changes in ecosystem functioning through the different ecosystems and geopolitical circumstances(figure 1):

Figure 1. Maps of the ecosystems studied in each one of the six protected areas studied, showing the 250 m MODIS pixels of the ecosystems (white squares) that were sampled in the analysis

In Spain: 1) Biosphere Reserve of the Nature Park Cabo de Gata-Níjar, whose vegetation is predominantly semi-arid scrubland sharing species with arid zones of Africa and Asia; 2) National and Nature Park of Doñana, with Mediterranean scrubland and woodland and saltmarsh, a system of coastal wetlands.

In Argentina: 1) National Park Iguazú and its continuation in Brazil with National Park do Iguaçu, harbouring the last representation of the tropical rainforest of Paraná; 2) National Park El Palmar and its continuation in the Wildlife Refuge of La Aurora del Palmar, last redoubt of the temperate savanna dominated by espinal (thorny deciduous shrubland forest and palm groves).

In Uruguay a National System of Protected Areas (SNAP in Spanish initials) is being set up. Within this the following areas were chosen: 1) the first area brought into the system, the protected landscape Quebrada de los Cuervos, and 2) the catchment area of the Laureles and Cañas streams, candidate area to be incorporated in SNAP. Both areas are a patchwork of meso-xerophytic and meso-hydrophytic grassland with native woodland around the rivers.

Design of the ecosystem-functioning monitoring system The information system for monitoring the vegetation and supporting the decision-taking of the protected areas is based on that proposed by Grigera et al. [33] for monitoring forage production and it uses the Monteith model [34] for measuring ecosystem productivity on the basis of radiometric information. Oyarzabal et al [35] began to apply it to the P.N. Cabo de Gata-Níjar.

In a nutshell, the core of the information system is made up by a complete collection of biophysical databases, pride of place here going to satellite images (figure 2). The first step was to acquire the different information sources. These were then put through a quality control before being integrated into the system. Finally, by means of statistical models and analysis, the mean dynamic was identified and time trends and spatial anomalies of key biophysical variables were detected together with indicators of the ecosystem functioning to help site managers draw up their reports. One advantage of the proposed scheme is that it adapts to the level of available information. The maintenance and development of the system thus involves not only the systematic updating of the satellite information but also the calibration of the biophysical variables and incorporation of new additional information on the protected area.

The proposed information system combines the Grigera ‘et al’ method for monitoring forage

production and the Monteith method for assessing ecosystem productivity from radiometric

information

Figure 2. Information system scheme

Spectral vegetation indices and descriptive attributes of the ecosystem functioning The study of ecosystem functioning was based on analysis of spectral data provided by satellite images. This involved the use of two vegetation indices: the Normalised Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index EVI).Both enable us to monitor photosynthetic activity, productivity or the leaf area index of ecosystems for wide-ranging territories by means of time series of the satellite images. They are based onthe spectral property of green vegetation to absorb differentially the photosynthetically active radiation. The NDVI calculates the standardised difference of reflectance between two wavelengths in relation to the photosynthesis process (red and near infra-red bands), while the EVI incorporates a third wavelength (blue) to cancel out the influence of the soil and atmosphere.

The study is based on an analysis of spectral data from satellite images of two vegetation indices:

the Normalised Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI)

The EVI images were obtained from the MODIS sensor in 16-daycomposites with a spatial resolution of 250 metres. Thanks to their high quality and spatial resolution, these images form the core of the monitoring system. Nonetheless, they have been available only since 2000, so NDVI images from the NOAA-AVHRRLTDR database at 15 day composites were used to go further back in time. Despite having a 5 k pixel size these images are available for the 1981 to 2000 time period. The informationsystem downloads the images, filters out values with a low spectral quality and systematically records the «vegetationindices» product from a NASA server (ftp://e4ftl01u.ecs.nasa.gov/MOLT/ MOD13Q1.005/); for thisapplication the process was automated with Kepler and IDL+ENVI 4.6. This article shows only the results based on the MODIS images for the P.N. Cabo de Gata-Níjar.

As main indicator of ecosystem functioning a calculation wasmade of the absorbed photosynthetically active radiation (APAR) by the vegetation, an estimator of primary productivity, by means of the following equation:APAR = FAPAR x IPAR; where FAPAR is the fraction of absorbed photosynthetically active radiation by the vegetation and IPAR is the incidentphotosynthetically active radiation. The FAPAR was calculated

from a linear relation with the EVI (also calculated for the NDVI) using the method put forward by Ruimy et al [36], which requires fixing minimum (0%) and maximum (95 %) FAPAR values. In the case of the P.N. Cabo de Gata, the other term of the equation, the IPAR, was taken from daily readings of the meteorological station of Alme airport. For more details of the general APARcalculating algorithm see Grigera et al [33] and Oyarzabal et al[35].

The advantage of using APAR, instead of a vegetation indexdirectly, stems from a certain timelag in the interception of energy (FAPAR, calculated from the EVI) and incident radiation. The mean FAPAR peaked in February and bottomed out inSeptember, while the IPAR peaked in June and bottomed out in September. When this occurs the APAR (calculated from the above equation as the product of both readings) is a betterindicator of the vegetation’s photosynthetic activity than vegetation indices.

From the APAR, following the Monteith model, it is possible to calculate vegetation productivity by multiplying APAR by its Radiation or Light Use Efficiency (RUE or LUE,). In the method proposed herein this last step was not taken since there is not yet enough information to hand on the RUE and its determination is a very complex process, though it is likely to be phased in at some moment in the future [37, 38]. The system allows representation of the APAR values of eachpixel on each date, thus obtaining the annual APAR curve (figure 3), which then serves as the basis for calculating the following descriptive attributes of the annual behaviour of the APAR, whichare then used as indicators of ecosystem functioning: 1) the annual cumulative APAR (C-APAR), calculated as the product of the annual mean APAR and the yearly number of composite images (23 in the case of MODIS), and considered as a linear estimator of primary productivity; 2) the intra-annual coefficient of variation of APAR (APAR_CV), calculated as annual standard deviation divided by the annual mean and taken to be adescriptor of seasonal carbon gain; 3) the maximum APAR values (APAR_Max) and 4) minimum APAR values (APAR_Min) of the year, as indicators of the maximum and minimum photosynthetic activity of the ecosystems; and, lastly, 5) the moment ofmaximum APAR (MMAX) and 6) the moment of minimum APAR (MMIN). In sum, these six attributes provide us with informationon the productivity, seasonality and phenology of the ecosystems [23] (table 1) (figure 3).

Figure 3. Annual curve of the Absorbed Photosynthetically Active Radiation (APAR) by the vegetation and derived descriptive attributes of ecosystem functioning. Adapted from Baldi et al. [39].

Table 1. Descriptive indicators of ecosystem functioning

Detection of trends in ecosystem functioning Trends were sought in the size, seasonality and phenology of the APAR using the Mann-Kendall non-parametric test [6-9, 32], which has the advantage of robustness to non-normal data distribution, data gaps and temporal self-correlation. This rank-order non-parametric test calculates the monotonic trend in terms of the number of times that a year in particular shows a value greater or lower than any previous year. This method has proven to be powerful in preliminary gross-scale analyses of the Iberian Peninsula [6-9, 32] and South America [5, 7, 29, 39].This analysis was carried out in the six protected areas and their immediate vicinity on two spatial scales (MODIS 250 metres and LTDR 5 kilometres), although in this study the results are shown only for the P.N. Cabo de Gata-Níjar for MODIS.

Detection of spatial anomalies in ecosystem functioning As an example of the system’s capacity to support decisiontaking, spatial anomalies were detected in the APAR within the vegetation types «scattered scrub» and «dense scrub» in the P.N. Cabo de Gata-Níjar, to pinpoint areas in need of a restructuring of the plant cover, thus enhancing the ecosystem’s productivity and resilience. For each vegetation type, using the Map of Land Uses and Plant Cover of Andalusia, a random selection was made of 40 pixels fulfilling two conditions: complete inclusion within a

serving as the basis of this research.

Index Type of measure

Definition Biological significance

APAR Measurements of quantity, structure and condition of the vegetation

Absorbed photosynthetically active radiation (APAR) by the vegetation

Amount of energy absorbed by the plants during photosynthesis

C-APAR

Total productivity and biomass

Total amount of energy absorbed by the plants during a year of photosynthesis

Annual vegetation productivity

intra CV

Intra-annual coefficient of variability

Standard deviation / mean

Seasonal carbon gain

Max Total productivity maximum and biomass

Maximum value throughout the year

Maximum photosynthetic capacity of the ecosystem

Min Minimum total productivity and biomass

Minimum value throughout the year

Minimum photosynthetic capacity of the system

MMAX Moment of the year

Date on which the maximum value is reached throughout the year

Phenology of the ecosystem’s maximum photosynthetic activity

MMIN Moment of the year

Date on which the minimum value is reached throughout the year

Phenology of the ecosystem’s minimum photosynthetic activity

type of vegetation and location far from the borderline with other vegetation types.

The aim of these samples is to establish the characteristicvariability of the functional variable under consideration (APAR in the example) for a given ecosystem, establishing the normal range of variation. The values falling outside this range aredeemed to be spatially anomalous [40]. In this example the mean interval ± 1 standard deviation has been used. If we increase the number of standard deviations around the mean, the system will be more tolerant or less sensitive.

The system phases in new satellite images every 16 days, allowing us to evaluate the «new state»

of the protected ecosystems against the benchmark behaviour of previous years

Detection of alerts and evaluation of their relevance The system automatically phases in new images as they become available (every 16 days in the case of MODIS’s vegetation indices); this allows it to evaluate the «new» state of the protected ecosystems, taking as benchmark their behaviour of previous years. In graphical form the idea is to display the meanyear curve of the available time series, with its inter-annual variation interval (± 1 standard deviation) with superimposition on the same graph of the most recent up-to-date values for thesame variable. This will trigger an alert when the new value of the variable strays far from the average behaviour (mean ± 1 standard deviation). The relevance of the alert is evaluated on the basis of its strength, deviation and duration. The strength represents the differences between the new values and those expected on the basis of historic behaviour: the biggerthe difference the greater the strength. Deviation tries todetermine whether the alert may be simply a passing or tardy event, such as an early start to the rainy season or late start to the fire season. Duration measures the time over which the alerthas been recurring and is estimated from the number of previous dates on which the value reached by a functional attribute is lower (or higher) than the mean ± 1 standard deviation. Inassessing the relevance of the alert consideration is also given to the conservation value of the ecosystems affected and whether ornot they had already been recording long term trends.

Results and Discussion

Ecosystem functioning trends The results obtained for Cabo de Gata-Níjar (figure 4a) show that, in the time series considered, there was predominantly an increase in the APAR and, ipso facto, of net primary productivity. This chimes in with the global trend observed in the period 1981-2000 [41]. The grouped spatial pattern shown by the positive and negative trends serves as guidance for the management actions of P.N. Cabo de Gata Níjar and also favours research into the causes and consequences of these trends.

Absence of negative trends within the protected area indicatesthat no reduction in vegetation productivity is currently underway. This contrasts sharply with the situation outside theprotected area with a predominance of pixels with negative trends, in many cases significant (figure 4.b). Both the climate conditions and their trend are similar inside and outside the park; this suggests that the discovered differences in ecosystem functioning stem from the different use and management of the land in each case and the recovery and degradation of the plant cover.

Figure 4. Trend maps of absorbed photosynthetically active radiation (APAR) by the vegetation of the protected area Biosphere Reserve ofCabo de Gata-Níjar (Almería-Spain) and bordering zones in the period 2001-2008. The maps show: (a) the trend slope of the annualcumulative APAR (C-APAR) (left) and its significance level or p-valor (right); and the significant trends; (b) the maximum values (APAR_Max), (c) the minimum values (APAR_Min) and d) the coefficient of variation (APAR))_CV). The slopes were calculated with Sen’s method. Their significance was calculated with the Mann-Kendall trend test. The line shows the outline of the protected area. Adapted from Oyonarte etal [32].

The annual dynamic of the APAR also gives us insights into other aspects of ecosystem functioning, such as phenology or seasonal carbon gain. In this study a calculation was also made of the trends of the maximum and minimum annual APAR, of particular interest for the management of ecosystems with borderlineenvironmental conditions, such as the arid ecosystems of P.N. Cabo de Gata-Níjar, where changes in minimum values may be bound up with degradation processes. Analysis of the trends in maximum APAR (APAR_Max) and minimum APAR (APAR_Min) shows that the observed increase in cumulative absorbed radiation C-APAR over the years under study is due above all to an increase in maximum values (figure 4.c) rather than an increase in minimum values (figure 4.b). The presence of significant positive trends in APAR_Min values but not in APAR_Max values brought about significant falls in the intra-annual coefficient of variation, an indicator of seasonality (figure 4d). This means that the difference in absorbed radiation between the growing season and non-growing seasons has fallen, i.e., a reduction in seasonality.

The results obtained for Cabo de Gata-Níjar show an increase in APAR and, ipso facto, net primary productivity during the time series under study.

This chimes in with the overall trend observed for the period 1981-2000

Spatial Anomalies The results (figure 5) show, as was only to be expected, that the C-APAR is significantly higher in areas with «dense scrub» (604.3 MJ.m-2.year-1) than in «scattered scrub» (515.9 MJ.m-2.year-1); at the same time, its spatial variability is lower (coefficient

variation of 13.1% and 15.6%, respectively).

These results show «scattered scrub» to be the area in most need of restoration, and we use the benchmark levels to identify those pixels showing behaviour well below the average C-APAR for «scattered scrub». The final result is the map of spatialanomalies (figure 6) showing those areas with a behaviour below (15.9%), above (22.1%) or within the benchmark range (61.9% of the land surface) for the C-APAR of «scattered scrub».

Figure 5. Spatial heterogeneity of the annual absorbed radiation for twoland uses in the protected area. The points correspond to the mean of each one of the forty pixels sampled in the period 2000-2008; the lines show the variability intervals determined by the mean functioning of each class (the central line corresponds to the mean, the upper and lower lines to the +/- of standard deviation). Different letters indicate significant differences between means using a t test (p<0.0001 ).Adapted from Oyonarte et al. [32].

Figure 6. Map of spatial anomalies in the annually absorbed photosynthetically active radiation (APAR) by the vegetation in the land surface covered by «scattered scrubland». The classes are established in terms of the benchmark levels «accepted variability» for the type of land use. The interval is defined by the mean ±, a standard deviation of the selected sample (n= 40). All the pixels of the protected area belong to the type of land use area classified according to whether their value lies within this interval (grey), above (green) or below the lower interval limit (brown). As with the trends, this map shows that the pixels with anomalies are spatially grouped. This spatial continuity shows that theresults are scientifically consistent and useful for site management

purposes, marking as they do sufficiently extensive areas for carrying out activities that would have been non-viable if the result had been a series of small areas (pixels) spread randomly throughout the territory. Adapted from Oyonarte et al. [32].

Decision-taking support system The above analysis of spatial anomalies has already provided us with a short list of areas where action is most necessary. Given that available resources are limited, however, finer priorities need to be set in terms of which particular areas are to be acted on. To this we propose a decision matrix based on a combination of the information generated by the system on time trends and spatial anomalies. The decision matrix shown in figure 7 enables us to prioritise pixels in terms of their spatial anomaly in relative C-APAR (columns) and relative time trend (rows).

The matrix rates priority from least (1) to most (9): low (yellow cells), medium (orange cells) and high (red cells). The bracketed figure shows the percentage of land surface occupied by each class. In this case the top priority would correspond to areas with a low relative C-APAR and negative trend, while areas with a high C-APAR and positive trend are considered to be low priority areas.

Figure 7. Decision matrix to support management. This helps to evaluate management needs and priorities of a given area in terms of annual absorbed radiation and the trend over time. To interpret this matrix it is necessary to take into account the management objectives. This case, applied to zones of disperse scrubland, shows an example for the selection of reafforestation areas.

Mean APAR 1

Lower Normal Higher

C-APAR 2 time trend Positive 5 (5,3%)

2 (15,4%)

1 (5,9%)

Moderate 7 (9,5%)

4 (42,9%)

3 (15,0%)

Negative 9 (1,2%)

8 (3,7%)

6 (1,2%)

(1) Mean of the absorbed photosynthetically active radiation (C-APAR) in the time series 2000-2008. The pixels are classed in terms of their value against benchmark values for the type of land use: Normal: within the variability interval (mean ± standard deviation); Lower: below the lower interval limit; and higher: above the upper limit. (2) Trend classes for the time series. The pixels are classified in terms of the Mann-Kendall test slope (see Trends section). Classes: Negative, values below 0 (negative trend);Moderate, values from 0 to 15 (positive trend); and Positive, values over 15 (positive trend). In this example no consideration is given to the degree of significance offered by the Mann-Kendall test.

Implementation of an alert monitoring system similar to the one developed here is feasible and recommendable in all types of protected areas as

a backup to their adaptive management

Early alert system Management of a protected area calls for up-to-date information on the ecosystem’s state of health and the existence of any

changes as a guide to management actions, for example, tailoring the livestock load each year to the particular conditions of the ecosystem. Figure 8 gives a quick, intuitive check of an ecosystem against average behaviour in the past, showing, for example, the class of «scattered scrubland» in P.N. Cabo de Gata.

Preliminary versions of this tool already up and running include the «System for estimating and monitoring canopy productivity in real time» (SegF, http://larfile.agro.uba.ar/labsw/sw/gui/Inicial.page) and the Land Ecosystem Change Utility for South America (LechuSA, http://lechusa.unsl.edu.ar/, set up, respectively, by the Regional and Remote-sensing Analysis Laboratory of Buenos Aires and the Environmental Studies Group of the University of San Luis.

Figura 8. Gráfico para el sistema de alerta temprana. Las líneas continuas indican el rango promedio + una desviación estándar (en este caso 2001-2007), y la línea gruesa con puntos muestra la dinámica del año más reciente. Un dato cada 16 días. Adaptada de Oyonarte et al. [32].

Ejemplos preliminares ya en curso de esta herramienta lo constituyen el «Sistema de estimación y seguimiento de la productividad forrajera en tiempo real» (SegF, http://larfile.agro.uba.ar/labsw/sw/gui/Inicial.page) y el «Land Ecosystem Change Utility for South America» (LechuSA, http://lechusa.unsl.edu.ar/, desarrollados por el Laboratorio de Análisis Regional y Teledetección de la Universidad de Buenos Aires y por el Grupo de Estudios Ambientales de la Universidad de San Luis, respectivamente.

Conclusions

Implementation of a monitoring and alert system similar to the one developed herein is feasible and recommendable in all types of protected areas as support to their adaptive management. The analyses offered by this system enable changes in ecosystem functioning to be pinpointed exactly in space and detected early so that they can be acted upon before they cause structural alterations that might then be very difficult to reverse afterwards. This improves the husbanding of natural resources, heads off threats and increases confidence in the decision-making process. Furthermore, the system is based on the monitoring of an intermediate [42] or backup [43] ecosystem service, namely net primary production (NPP); it therefore directly plums the «state of health» of the protected areas and brings home the advantages they provide for mankind. This enables site managers to operate more effectively in the legal and political spheres to promote public appreciation of the protected resources.

Finally, the satellite images used are free, so the system is low cost and fairly simple to set up. It then builds up information

systematically and is written in open source software so the system is versatile and can be customised and its analysis capacity can be increased to phase in new monitoring needs of site managers and scientists.

ACKNOWLEDGEMENTS

Our thanks go to several collaborators who participated in the project: Agustín Giorno, Siham Tabik, Elisa Liras, David Vinazza, José M. Molero, Lucas Sevilla García, Antonio Castro. To Jeff Burkey (King County) for developing the basic code for the trend test. The authors have been subsidised by the following institutions and programmes: FUNDACIÓN MAPFRE (R&D projects 2008), Organismo Autónomo de Parques Nacionales (project 066), Junta de Andalucía and ERDF (excellence projects RNM1280 and P09-RNM5048), Inter-American Institute for Global Change Research (IAI, CRN II 2031 and 2094), and the Agreement «Desarrollo rural y sostenibilidad ambiental: diseño y ejecución de programas de seguimiento». The satellite images were downloaded from the MODIS Land website and the website of the Land Long-Term Data Record.

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