Marine Pollution Bulletin 64 (2012) 1261–1264

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Marine Pollution Bulletin

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Baseline

Concentration of selected radionuclides in seawater from Kuwait

Saif Uddin ⇑, Abdul Nabi Al Ghadban, Abdulaziz Aba, Montaha BehbehaniKuwait Institute for Scientific Research, P.O. Box 24885, 13109 Safat, Kuwait

a r t i c l e i n f o a b s t r a c t

Keywords:3H90Sr210Po137Cs

0025-326X/$ - see front matter � 2012 Elsevier Ltd. Ahttp://dx.doi.org/10.1016/j.marpolbul.2012.02.025

⇑ Corresponding author.E-mail address: sdin@kisr.edu.kw (S. Uddin).

No baseline existed for the radionuclides in Kuwait territorial water. With changing trend in the region toembrace nuclear energy, the baseline study is imperative to create a reference and to record the influ-ence-functioning of upcoming power plants. The first one in Bushehr, Iran is ready to start and severalmore are likely to come-up in UAE, Saudi Arabia and Kuwait. The present baseline concentration of thefour considered radionuclide’s show low concentration of tritium, polonium, strontium and cesium; theirconcentration is comparable to most oceanic waters.

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Kuwait lies at the northwest of the Arabian Gulf (AG). The AG isa shallow water body located in a subtropical, hyper arid region(Sheppard et al., 2010). Many of the oil producing Gulf countriesare considering nuclear energy option to meet their growing en-ergy demand. Currently, there is only a single nonoperational nu-clear plant in the region at Bushehr, Iran; while the entirenorthern, western, and southern coastline is without any nuclearinfrastructure. The decision of the United Arab Emirates (UAE) tohave its nuclear plant by 2020 and other countries, like Saudi Ara-bia and Kuwait (Huber, 2007) having nuclear aspirations is likely toinfluence the radionuclide levels in the Gulf water, which is extre-mely important to sustenance in the region. The information onradiochemistry of Gulf water is very limited. There have beenfew studies done on surface sediment concentration (ROPME,2000) and core sediments (Al-Zamel et al., 2005) in Kuwait. Fewstudies from Oman and UAE have reported radionuclide concentra-tion in seaweeds and seagrasses (Goddard and Jupp, 2001) and inOmani fishes (Goddard et al., 2003). Radionuclide concentrationin local foodstuff was also screened in an earlier study in Kuwait(Husain et al., 2003). However, to the best of the authors knowl-edge, there is yet no published information available on radionuc-lides levels in seawater for Kuwait territorial water. This study,therefore, provides baseline concentrations of 3H, 210Po, 90Sr and137Cs, in coastal waters of Kuwait for future local and regionalstudies.

The importance of the Gulf waters is further strengthened bythe fact that most of the freshwater needs of the region are metby desalination, with a cumulative desalination capacity of thecountries in the Arabian Gulf, being around 11 m3/d (Lattemannand Höpner, 2008) including, Kuwait, Saudi Arabia, Bahrain, Qatar,UAE and Iran.

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The study was carried out in the territorial waters of Kuwait,much of the area being <30 m deep. With very low annual precip-itation of <80 mm, over the past 4 years. The Shatt Al-Arab riverand the Third River drains into the northwestern AG supplying lim-ited quantities of freshwater to the Gulf and lots of sediment, mak-ing a large portion of the northern Arabian Gulf turbid. The seasurface temperature fluctuates between 10 and 35 �C. Based onmulti-criterion evaluation using bathymetric condition, hydrody-namic flow regime, sediment transport and accessibility, a numberof stations were identified for sample collection (Plate 1).

Water samples were collected at a depth of 1 m below thewater surface using 5-l Niskin bottles. The water sampler wasmounted on a winch, lowered to the sampling depth, and released.The sampler was pulled and sample transferred into appropriatesample bottles, preserved and stored. One hundred litres of samplewas collected from each location into 5 containers of 20 l each. Thecontainer was labeled with date time, and GPS location and a sam-ple ID was assigned. The container was closed and sealed.

The standard procedures were used for measurement of radio-nuclides. The tritium (3H) was measured by liquid scintillationspectrometry using Quantalus 1210 after electrolytic enrichmentusing the procedure developed by Ostlund and Werner (1962).The method is precise and useful for environmental samples withlow 3H concentrations. The lower detection limit for this method is0.2 tritium unit (TU), corresponding to 0.025 Bq/l for a 100-mincount (Al Ghadban et al., 2010).

Polonium (210Po) determination was done in water samples, byelectrodeposition on a 0.064-cm thick silver disk of 1.2-cm diame-ter using the method proposed by Fisenne (1997). Reagent blankswere analyzed along with the samples. The 5.305-MeV energy linewas used for quantification. A six-chamber alpha spectrometrysystem from Canberra was used. Strontium (90Sr) was determinedby yitrium in growth and beta-ray spectrometry (La Rosa et al.,2001). Cesium (137Cs) concentration in water was determined

Plate 1. Identified sampling locations.

Table 1Radionuclide concentration in seawater samples.

Station 3H (TU) 90Sr (mBq/l) 210Po (mBq/l) 137Cs (mBq/l)

1 1.26 ± 0.01 0.68 ± 0.08 0.50 ± 0.06 1.06 ± 0.012 1.04 ± 0.01 0.73 ± 0.05 0.68 ± 0.08 1.06 ± 0.013 1.36 ± 0.01 0.65 ± 0.05 0.54 ± 0.08 1.06 ± 0.014 1.22 ± 0.01 0.78 ± 0.10 0.63 ± 0.02 1.04 ± 0.015 1.10 ± 0.01 0.77 ± 0.08 0.68 ± 0.02 1.01 ± 0.016 1.01 ± 0.01 0.61 ± 0.08 0.64 ± 0.20 1.04 ± 0.01S 1.12 ± 0.01 0.57 ± 0.05 0.48 ± 0.07 1.06 ± 0.01Z 0.92 ± 0.01 0.68 ± 0.10 0.49 ± 0.08 1.04 ± 0.01

1262 S. Uddin et al. / Marine Pollution Bulletin 64 (2012) 1261–1264

using ammonium phosphomolybdate (AMP) method (Yamagata,1963); Molero et al., 1993). The water samples were not filtered,for the reason that total radionuclide concentration was deter-mined rather than by soluble fraction.

The radionuclide concentration in seawater samples collectedon 10 May 2010 were determined for tritium (3H), strontium(90Sr), polonium (210Po) and cesium (137Cs). The results are pre-sented in Table 1.

Tritium, requires special consideration because of its highmobility in the environment and its importance in the hydrologicalcycle in the biosphere. Tritium occurs naturally and in very smallquantities, being produced in the upper atmosphere by cosmic rays.Natural (pre-nuclear age) levels of tritium in precipitation are 1–5 TU (EPA, 2006). Nuclear weapon testings during the 1950s and

1960s created large amounts of tritium which reached the environ-ment in addition to discharge from nuclear power plants.

S. Uddin et al. / Marine Pollution Bulletin 64 (2012) 1261–1264 1263

The low baseline level of tritium in 0.92–1.36 TU range in theregion can be attributed to very limited atmospheric tritium fallout due to scanty precipitation. The major source of tritium dis-charge are nuclear power plant, and there is none operational inthe area. The likely fall out from atmospheric nuclear testing inthe 1950s and 1960s decayed significantly due to the short half-lifeof tritium (12.32 year) resulting in this low baseline.

Strontium-90 concentration in Kuwait territorial water rangesbetween 0.57 ± 0.05 and 0.78 ± 0.10 mBq/l. Stable strontium natu-rally occurs in seawater along with sodium, magnesium, calcium,and potassium. The concentration of stable strontium in seawateris strongly influenced by changes in the rates of continental weath-ering relative to oceanic crust alteration over geologic past(Shields, 2007; Spooner, 1976). The average oceanic concentrationof strontium is considered to be �8 ppm, although it is not fixedand varies with salinity. The seawater samples analyzed for stron-tium showed a range of 8.94–9.60 ppm. The 87Sr/86Sr ratio werealso determined (Table 2). The seawater in the study area gives87Sr/86Sr ratios in range between 0.709128 and 0.709157. The87Sr/86Sr ratio is a firm indicator of geochemical process (Shields,2007) with modern day seawater having a ratio of �0.709. Thereare two major sources of strontium such as the submarine, chem-ical alteration with a characteristic 87Sr/86Sr ratio of 0.703 (Hof-mann, 1997) and the subaerial chemical weathering of thecontinental crust and sedimentary cover, with 87Sr/86Sr ratio of�0.712 (Palmer and Edmond, 1989; Peucker-Ehrenbrink and Mill-er, 2006). It had been reported that the bulk of strontium is con-tributed by river runoff rather than the hydrothermal exchange.The 87Sr/86Sr ratio of continental input can be viewed as a functionof the ratio between carbonate and silicate weathering rates withrespect to strontium. In areas where the strontium contributionis dominated by silicates its reported to have an 87Sr/86Sr ratio of0.7077; whereas, the areas where strontium is derived from car-bonates it showed to have a higher ratio of 0.7090 (Shields,2007). The 87Sr/86Sr ratio in the region suggested that the stron-tium originates from carbonate rock dissolution, possibly due toexcessive sediment input from northern rivers and also due toacidification of Gulf water (Uddin et al., 2010, 2009, 2008).

Polonium arises as a naturally occurring radioactive element inthe earth’s crust. The concentration is in traces and is quite fre-quently associated with phosphates. There are many elementalforms of polonium, but in this study 210Po was considered, becausebulk of Po takes in this form, and the half-life is 138 d, and specificactivity is quite high (4500 ci/g). Another factor of considering210Po was that it comes about as a decay product of radon-222gas. Radon concentration in Kuwait is reasonably high, and the de-cay product is expected to land on terrestrial and marine environ-ment. The baseline concentration of 210Po in seawater rangesbetween 0.48 and 0.68 mBq/l.

Cesium occurs in nature as a low melting point metal, that re-acts violently with cold water. The bulk of the radioactive cesiumoccurring as 134CS, 135CS and 137Cs is a fission product of 235U. Mostof the radiocesium found in the environment comes from spent nu-

Table 287Sr/86Sr concentration ratios in seawater samples.

Station 87Sr/86Sr Uncertainty

1 0.709143 0.0000062 0.709151 0.0000133 0.709128 0.0000104 0.709138 0.0000095 0.709157 0.0000116 0.709140 0.000013Z 0.709154 0.000007S 0.709153 0.000013

clear fuel, radioactive waste, and soil erosion. In principle, radioc-esium adheres to sediment and its concentration in interstitialwaters is extremely low. The baseline 137Cs concentrations in sea-water samples from Kuwait range between 1.01 and 1.06 mBq/l.

The 90Sr concentration ranges between 0.57 ± 0.05 and0.78 ± 0.10 mBq/l, which is comparable to the observations madeunder International Atomic Energy Agency (IAEA) coordinated,Worldwide Marine Radioactivity Studies (WOMARS) in the Pacificand Indian Oceans. Their Observations reported the estimated aver-age during the year 2000 to be 0.1–1.5 mBq/l (Povinec et al., 2005).The 90Sr concentration in the Arabian Gulf is far less as compared tothe Caspian Sea, where the mean 90Sr concentration during 1995was 8.0 ± 1.6 mBq/l (Povinec et al., 2003). This concentration ap-peared to be higher than that expected from global fall out in thislatitude belt (IAEA, 2001). It was mainly attributed to river input,suggesting remobilization of 90Sr from the catchment.

The 137Cs concentration in Kuwait marine water ranges be-tween 1.01 and 1.06 mBq/l. This concentration is comparable tothe range reported from Pacific and Indian Oceans where the137Cs concentration during year 2000 ranged between 0.1 and2.8 mBq/l (Povinec et al., 2005).

The current baseline data generated suggested that the levels ofdifferent radionuclides in the Kuwait marine environment provedto be comparable to other marine waters in the northernhemisphere.

Acknowledgements

The authors wish to thank the Kuwait Foundation for theAdvancement of Sciences (KFAS) for their financial support. Thanksare due to Dr. Naji M. Al-Mutairi, Director General and MohammadJ. Salman, Deputy Director General, Kuwait Institute for ScientificResearch for their support. Appreciation is due to Dr. Nader Al-Awadhi, National Liaison Officer, Kuwait, for his excellent supportin coordinating with the IAEA. Thanks are due to Dr. A. Shamsi,Head of Technical Cooperation, Asia – Pacific, IAEA; Dr. HartmutNies, Head Radiometrics Laboratory, Marine Environmental Labo-ratory, IAEA, Monaco; and Dr. Mats Eriksson, Technical Officer,Marine Environmental Laboratory, IAEA, Monaco, for their valuableguidance. Authors are extremely thankful to Dr. Scott Fowler forcritically reviewing the manuscript and for suggesting significantmodifications towards improvement of the manuscript.

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