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Evidence Based Environmental Policy and Management 1: 1-? (2007) Blue Gold: A Deadly Gift Evaluation of the removal of naturally occurring arsenic from groundwater in Bangladesh via a household filtration system based upon a composite iron matrix Published by the School of Geography Environment and Earth Science Victoria University of Wellington, New Zealand 1

Arsenic in Bangladesh

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Page 1: Arsenic in Bangladesh

Evidence Based Environmental Policy and Management 1: 1-? (2007)

Blue Gold: A Deadly Gift

Evaluation of the removal of naturally occurring arsenic from groundwater in Bangladesh via a household filtration system based

upon a composite iron matrix

Ame Alexandra Plant

Environmental Studies, School of Geography, Environment and Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand.

Published by the School of Geography Environment and Earth Science Victoria University of Wellington, New Zealand 1

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Abstract High concentrations of naturally occurring arsenic are found in the groundwater of Bangladesh. A wide range of technologies have been created to remove arsenic from drinking water. The SONO filtration system is a household level technology, and through coagulation, filtration and precipitation processes the arsenic is transformed from its potentially deadly soluble form into an insoluble solid that is exposed of as waste. The system is highly effective in its removal of arsenic and currently provides safe drinking water to millions. Such an achievement provides a small step in the direction of achieving the Millennium Development Goal of providing clean safe drinking water to a larger majority of the population. The system provides an affordable short term solution

Keywords: Bangladesh, arsenic removal, household level, Filtration, Composite Iron Matrix, contamination, groundwater

Introduction

Water, ‘blue gold’ is finite, all the water that will ever be is, right now (National Geographic, 1993). The freshwater that we as the human race depend on amounts to 0.01% of all water on earth, illustarted below in figure 1 (Miller, 2005). With global trends set to see a human population of nine billion in 2050 the importance of water security is imminent (Crop Life International , 2004). The United Nations has addressed this threat in their Millennium Development Goals (MDGs) under goal seven, a difficult task in which they have stated “it will require extraordinary efforts” to achieve (United Nations, 2008).

Figure 1: The distribution of the World's water resources with emphasis on the distribution of fresh water.

Source from (Lannoe, 2007)

A pressing issue of the global water crisis is concerned with water quality as it is the quality of water that determines its purpose (Department of the Environment: Water Heritage and the Arts, 2008). Many pollutants of both human and natural origin contaminate water undermining its quality (Miller, 2005). The effect on humans specifically can be devastating. The United Nations states that contaminated drinking water and poor sanitation kill 1.5 million children a year (United Nations, 2008). The contamination of water supplies via anthropogenic processes is generally

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easy to rectify once the cause has been identified. Identifying contamination via natural processes on the other hand is much more difficult (Miller, 2005).

One such problem is the contamination of water with arsenic. The effects on its consumers are horrific; acute poisoning results in diarrhea, vomiting, convulsions and blood in urine which may later be followed by coma or death. Chronic poisoning causes skin lesion, abnormal growth, and cancers. There is a great deal of concern about the later form of poisoning as it may take up to ten years before any symptoms are revealed (A. H Welch et al, 2003).

This was the case for millions of people in Bangladesh. For years the people of Bangladesh had suffered epidemics of cholera, typhoid and dysentery as a result of drinking from pools and streams that where contaminated with harmful microbial pathogens (Baxter, 1998)

During the 1970s UNICEF and the Government of Bangladesh encouraged its people to drink water from tube wells (Anwar, 2007). These tube wells accessed the abundant reservoirs of groundwater below their feet and promised high quality water. Regrettably the water contained the deadly poison arsenic (A. H Welch et al, 2003). By 1993 when the first symptoms of arsenic poisoning began to appear there were millions of tube wells throughout Bangladesh supplying water to around 90% of its population (BBC NEWS | Science/Nature | Water scarcity: A looming crisis?, 2004).

The British Geological Survey was asked to test a proportion of these wells for arsenic contamination. The results indicated that approximately fifty percent of the tube wells tested were over the World Health Organization standard of ten parts per billion. In many cases the concentrations were greater than 200ppb (British Geological Survey). In addition hazardous concentrations of arsenic have been detected in forty seven of sixty four districts (SOES/DCH, 1998). The Government, UNICEF and others had to counteract their initial approach and encourage people not to drink from contaminated groundwater (Baxter, 1998).

Millions of people are at risk from arsenic poisoning and the majority of those concerned are completely unaware of the daily hazard they face. Arsenic itself is colourless, odourless, and tasteless even in high concentrations requiring special chemical tests to detect its presence in drinking water (Lepkowski, 1999). Added to these problems are the socio-economic background of Bangladesh and the overwhelming dependence of its people on groundwater (DPHE/Danida, 1999).

In view of the above factors there is an urgent need for a suitable treatment system for the removal of arsenic from groundwater. Socio-economic conditions of Bangladesh demand low-cost, easy to use, convenient, small treatment units that can be implemented in households and communities (Saha, 2001).

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A variety of technologies have been used for the removal of Arsenic from groundwater, including:

1. Co-precipitation with ferric chloride

2. Absorptive filtration and exchange resins3. Ion exchange4. Membrane processes like reverse osmosis

High iron concentrations may decrease the effectiveness of the above technologies. As ferrous iron will be oxidized and form a ferric hydroxide coating upon surfaces, or in the case of number four above block the pores of membranes (Hering J. G, 1996) (McNiel, 1997) (Sorg, 1978). The ‘Bucket Treatment Unit’ (BTU) developed by DPHE-Danida will be the focus of this literature based research report (Owen, 2001).

Aim

The aim of this study is to evaluate the removal of naturally occurring arsenic from groundwater in Bangladesh via a household filtration system which is based upon a composite iron matrix.

_____________________________________________________________

Objectives

Answering this question necessitated breaking the task down into three information seeking objectives as follows:

1) What is the Bucket Treatment Unit and how does it operate?

2) Determine the arsenic removal capacity of the SONO filter

3) Determine the social aspects of the SONO filter:

The management of spent material

The manufacturing and distribution

The social acceptability

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Methods

Each objective requires the same procedure of obtaining information when searching databases. Thus the methods of searching literature for information on each objective will be the same.

........................................................................................................................................

Sample set and Procedure

a) Search Databases

Search engines Google, Yahoo, AltaVista, and Ask.com (useful for acquiring basic information surrounding the objective)

Google Scholar peer reviewed papers, thesis, books and abstracts from professional societies (useful for more reliable sources of information)

Subject Gateways BUBL, Intute: Science, Education and Technology, Intute: Health and Life (academically reliable information.)

Books Worldcat (access to electronic books) Databases science research.com, web of knowledge / web of science, water

resources abstracts Journals Directory of Open Access Journals News Sources : EureaAlert, New Scientist, BBCi: Science and Nature (keep up-to-

date on subject.

Before searching will ensure that the correct source has been chosen. To do so i will simply ask; does it have full text? Does it cover the right subject matter? Does it contain peer reviewed information?

The next step in gathering information for each objective will involve being prompt.

P-presentation: How is the information communicated? If pages are not clearly communicated then no more time will wasted upon them

R-Relevance: information may not be relevant to my search due to; the geographical aspects, level (too basic or too specialized), emphasis.

O-Objectivity: good information should be devoid of bias and be well balanced presenting information on both sides of an argument

M-Method: the way information is produced; an opinion, research, reviews of research.

P-Provenance: who produced it where did it come from provides useful clues its reliability; authors, organisations.

T-Timeless: The date of production/publish important indicator of reliability. Thus any information that does not have a date will not be considered for this report.

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Sample set and Procedure

b) Key Words

Objective 1: Household, Filtration, System, Arsenic, Bangladesh

Objective 2: Removal capacity, Arsenic, Bangladesh, Filtration, System, household

Objective 3: Management, waste, material, manufacturing, distribution, social, cultural, acceptable, benefits, arsenic removal, Bangladesh, household

........................................................................................................................................

Sample set and Procedure

C) Search Limits

Objective 1: Terminology has proven to hinder some searches as BTU is the simplest terminology the technology is known by and used throughout this study. The technology has various names. Very specific search provides a limited number of peer reviewed journals.

Objective 2: Due to the specific nature of the report, the geographic location and socio-economic nature of the study area in addition to the fact that the technology was only created in 2001, there were very limited papers addressing the issue in focus.

Objective 3: the barrier of language means that the peer reviewed literature sourced from Bangladesh is written by those who can afford an education; it is therefore difficult to truly state the social aspects of the SONO filter with certainty that what we read is correct.

...............................................................................................................................................

Sample Set and Procedure

D) Rational of limits

Objective 1: As the bucket treatment unit is fairly new technology and a specific topic all literature available was thoroughly researched.

Objective 2: The scarcity of the quantity of peer reviewed literature, although the few papers providing the in depth information needed where of high quality. Therefore all relevant information was thoroughly studied.

Objective 3: Those who are educated are voices for their country and people, and are informers of the crisis in which they face daily. Other peer reviewed literature where compiled of author from less bias nations.

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E) Key Content

Objective 1: Structure and operation of the SONO filter system

Objective 2: Effectiveness of SONO filter system in reducing arsenic concentrations

Objective 3: Manufacture, distribution, management and social acceptability of SONO filter

F) Focus

Objective 1: Basic illustrations and descriptions of how the SONO filter operates

Objective 2: Graphs and Tables from key sources illustrating how effective the SONO filter is at removing arsenic from ground water.

Objective 3: Qualitative descriptions and illustrations of the social factors surrounding the SONO filter

Results

Objective 1: What is the Bucket Treatment Unit and how does it operate?

The BTU is a two-stage, pour-collect filtration system and was developed with Bangladeshi villagers in mind. The BTU consists of two 40-litre plastic buckets and illustrated below in figure 2. The top bucket is red in colour and contains the composite-iron matrix (CIM) in between two layers of sand. The bottom bucket is green in colour and has a simple sand and charcoal filter that cleans the water of iron and other impurities that may have drained from the first bucket (Figure 2) (A. Hussam, 2001) (Rasul, 2002).

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Figure 2 A schematic representation of the Bucket Treatment Unit

Source from (A. Hussam, 2001)

To produce clean drinking water groundwater is collected from a local well and poured into the upper red bucket which contains 32 kg of material. The water filters down through 10 kg of course river sand which are obtained from local river sediments and thoroughly washed before use. The course sand layer contains 95% SiO2 and acts as a filter oxidising soluble iron.

The product of iron oxidation is the precipitate Fe(OH)3 (s) which is effectively trapped in the sand (A. Hussam, 2001). The course sand layer also provides mechanical stability by stabilising the flow of water. In addition this layer reduces the production of fine particles. This results in a low probability of the pores spaces between the sand grains clogging up, and a higher probability of the sand layer lasting for longer without compromising the quality of water (Mortoza, 2008).

The water then passes through 5-10 kg of the composite iron matrix (CIM) which contains 92-94% Fe. The CIM is manufactured iron turnings obtaining from local industries. The turnings are washed and treated to enhance HFO formation. The CIM is the surface upon which ions of elements such as arsenic are captured and immobilized.

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Iron hydroxide has a remarkable capacity to capture ions of other elements. This is because of its molecular structure illustrated below in figure 3 which is full of gaps.

Figure 3: The molecular structure of iron (III) hydroxide, (the ball within the shaded green area is iron; blue = oxygen; white = hydrogen) note the openess of the structure.

Source (Clark, 2003)

Effectively, hydrogen atoms are remote enough from iron and oxygen in the structure for them to produce localised positive charges at the surface of the mineral. Consequently negatively charged anions can attach to the surfaces of the iron hydroxide by adsoption. Iron (III) hydroxide therefore acts like a ‘chemical mop’ (Pierce, 1982).

The water then flows through a second layer of course sand (10kg) before being manually taped and piped through plastic tubing to the second green bucket (Wilkie, 1996) (A. Hussam, 2001).

The water is filtered through a third layer of course sand (10 kg) which retains any iron leached from the first bucket. The following layer contains wood charcoal that is obtained from the firewood used for cooking.

The charcoal absorbs any organic matter, and although passive to As this layer provides better tasting water. The water then flows through 9kg of fine sand derived from rivers and acts as a fine filtration system designed to catch ant residual particle. Finally the water passes through 3.5 kg of brick chips, obtained from local manufactures. The brick chips stabilise water flow before being manually tapped into any container below (A. Hussam, 2001) (Yuan, 2006) (Raven, 1998).

The structure itself consists of two 40 litre buckets made of food-grade high density polypropylene buckets. These buckets are produced by local plastic modelling industries and are fitted with a top cover to reduce further contamination and are moulded with outlets for the flow control taps. The flow controllers are made of

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either moulded plastics or metal taps and control the flow of water through the system. Lastly a metallic filter stand made by local welders provides support for the buckets and completes the Bucket Treatment Unit (A. Hussam, 2001).

Objective 2: Determine the arsenic removal capacity of the unit

The BTU was tested with contaminated groundwater by Hussan and Munir from six different tube wells in six different households; Fatic, Caurtpara, Zia, Alampur, Kaliskhnpur and Juniadah (A. Hussam, 2001). The CIM removed the inorganic arsenic through a series of possible reactions which are visible in appendix D for reference.

The results indicate that arsenic concentrations ranging from 32-2423 ug/L where entered in to the filtration system. The potable water that had been filtrated on the other hand only contained between <2 ug/L (which is the detection limit) to 8+/-4 ug/L of arsenic. Table one below illustrates the results obtained from BTU in the six districts.

Table 1: results from six BTU filter monitored for approximately 2-5 years in active use by householders in the Kushtia District Bangladesh

Extracted from (A. Hussam, 2001)

Therefore the optimum arrangement of the sand, CIM, and charcoal layers removes the arsenic ions effectively. The BTU is also unique in its ability to decrease arsenic concentration with increasing water yield as illustrated below in figure 4 (Adeel, 2001).

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Figure 4: BTU filter performance at filter 5 (table 1) illustrating the decrease in waste arsenic against water yield

Source (A. Hussam, 2001)

Hassun et al attribute this quality to the generation of new complexation sites on the CIM through insitu iron oxidation (rust) (A. Hussam, 2001) (Orville, 1977).

The BTU was extensively for the effective filtration of arsenic by Hussan et al, USEPA, WHO, and the Government of Bangladesh the results of which are illustrated in table 2 below.

Table 2: Comparisons of arsenic concentration in groundwater after filtration from a BTU (or otherwise known as SONO filter) USEPA, WHO, and the Bangladesh Government.

Extracted from (A. Hussam, 2001)

Of the 590,000 L of groundwater that where filtered through the BTU at the six locations identified in table one, the filtered water met the institutions recommendations for the amount of arsenic present in drinking water (Adeel, 2001).

The BTU effectiveness at removing arsenic from groundwater decreases by 20-30% per year due to the clogging of pore spaces in sand layers. In such an event the flow rate of water through the BTU decreases indicating that the upper sand layers need to be replaced (A. Hussam, 2001).

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Objective 3: Determine the social aspects of the SONO filter:

The management of spent material

The manufacturing and distribution

The social acceptability

The Management of Spent Material

Spent materials are contaminated with high concentrations of toxics (Noyes, 1993). Thus the process and complexity of waste disposal affect their technical viability, cost, and social acceptability (Prosun Bhattacharya, 2007). At present, the only way to identify toxic waste is to leach the solid material under ‘laboratory’ conditions, to determine if the levels of toxic species released into the environment exceed regulatory limits (Timbrell, 2002).

In this case the spent material was apparently nontoxic with less than 5 ug/L of arsenic in all forms (NEA, 2007). The arsenic ions that have collected in the used sand and CIM are in their oxidized form and are firmly bound with solid CIM, producing an insoluble product. The disposal of which has been is therefore safe according to Hassan et al.

The wastes produced are disposed of on land. The Environmental Protection Agency has a recommendation of 2 kg of disposed arsenic per hectare of land. NEA (National Academy of Engineering) and Hussan et al have corresponded this to mean that 10 million liters of water with a concentration of 200mg/L of arsenic can be disposed of over a hectare of land (Khan, 2000). From such results the evidence indicates the safe disposal and easy disposal of arsenic contaminated water collected form the SONO filter.

The Manufacturing and Distribution

The large-scale manufacture and distribution of the apparatus was primarily funded through local nongovernmental organizations (NGOs), local governments, and international institutions (e.g., UNICEF). The filter itself is manufactured by an NGO which uses indigenous materials for its construction, although the CIM requires an appropriate licensing agreement. They have been disturbed on a large scale via transportation of the units using flat bed trucks and filter distributers in villages, which use flat bed rickshaws (Jakariya, 2007).

Once the filter system has been delivered the set up of the filtration system requires consumers to follower simple guidelines, in doing so the set up of the system can be completed within 20 minutes with potable water available within 3hrs. In some cases the filter system has been scaled up by connecting adjacent units. This practice has enhanced the flow rate for small communities (Abul Hussam, 2008). The filters are now present in many social institution; primary and secondary schools, homes,

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villages, restaurants and cafes. Estimates sate that around half a million people all over Bangladesh are benefiting from the SONO filtration system (A. Hussam, 2001).

Social Acceptability

At a cost of $35 to $40 for five years, the equivalent of the one-month income of a village laborer in Bangladesh, SONO is one of the most affordable water filters available on the market. Monthly payment schedules available through the NGOs that distribute the filters can make them even more affordable (Abul Hussam, 2008).

Unlike other technologies available the SONO filters do not require additional chemicals or consumables. The estimated operating cost therefore is no more than $10 over a five year period. In addition this cost is only in the event of the flow controller being replaced, which has been stated to be a rare (Abul Hussam, 2008). One unit can meet the needs of two families for drinking and cooking water for at least five years. Provided that the instructions provided are followed the filter system will be self mostly self maintained providing clean, soft water (A. Hussam, 2001).

Studies have shown that water collection and maintenance of the SONO filter are done mostly by women, who enjoy the system as they do not have to walk long distances to and from arsenic-free well (Bagla, 2003). Many people who had drunk from the filtered water for two years or more showed some improvement in arsenical reported a general sense of well-being and improvement in health (Hering J. G, 1996). The filter has a flow rate of 20 liters per hour, which produces enough water for drinking, cooking, and other purposes. Hussan et al during their studies found no social or cultural stigma associated with the dissemination or use of the filter “except the reluctance to share filter water with neighbors” (A. Hussam, 2001).

Unfortunately there is still a large number of people who are unaware of their daily consumption of arsenic and thus many NGOs have implemented training and cultural programs to encourage and motivate people to drink arsenic free water (Khan, 2000).

Concerns expressed in the search limits regarding the validity of the peer reviewed literature researched where highlighted. Unease regarding the legitimacy of the experiments conducted with the SONO filter and its waste disposal where strongly expressed. Many believed a different filtering process was used to gain recognition and verification from such organisations as WHO. Others were interested in the unmonitored disposal of waste upon the land and feared the consequences of such activities on the environment and their future health (Husain, 2007).

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Analysis and Discussion

In 2000 world leaders from across the globe put their differences aside and came together at the United Nations Headquarters in New York. During this conference the Millennium Development Goals (MDGs) were born (WHO, 2008). In total there are eight goals.

The management of water quality impinges directly or indirectly on all eight of the MDGs (WHO, 2008). The United Nations filed the water quality problem into Goal 7 labelled under Target 10; “Half by 2015 the proportion of people without sustainable access to safe drinking water and basic sanitation”. (United Nations, 2008)

The target is for people to have improved access to safe drinkable water by 2015. By safe drinkable water they refer to the percentile of the population with access to at least 20 litres of water a person per day from an improved source within one kilometre of a person’s dwelling (The World Bank, 2008).

The two spheres of a problem compiled in target 10 are one of the same. By improving basic sanitation the quality of water in that area will also be improved and vice versa to have adequate sanitation facilities safe water is needed.

The achievement of such a goal would be a miracle, and the United Nations addresses how difficult a task this really is; ‘with half the world without basic sanitation, meeting the MDG target will require extraordinary efforts’ (United Nations, 2008).

Since the establishment of the target Bangladesh does not seem to have benefited. Table 9.1 and 9.2 below where been constructed from information sourced by the UN in working towards the achievement of Goal 7 Target 10.

Proportion of the population

using improved drinking sources

Mean 80.6 80.3 80.6 81

Total 78 78 79 80

Urban 88 87 86 85

Rural 76 76 77 78

Figure 9.1 Table illustrating the proportion of the Bangladeshi population that have access to improved drinking water.

Source derived from (United Nations Statistics Division, 2007)

Proportion of the population

using improved sanitation facilities

Mean 33.3 34.3 36.3 38.3

Total 26 28 32 36

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Urban 56 34 51 48

Rural 18 21 26 32

Figure 9.2 Table illustrating the proportion of the Bangladeshi population that have access to improved sanitation facilities

Source derived from (United Nations Statistics Division, 2007)

A larger proportion of the population have access to safe drinking water than they do sanitation. Overall both are improving very gradually. There are noticeable trends in both table 9.1 and 9.2. Notice how in both cases the rural areas have significantly less access than the urban areas, but they are improving. In contrast the urban areas are declining steadily.

The SONO filtration system is evidently still in high demand and needs to be further distributed to those areas experiencing the worst affects. Interestingly the connection between water quality and sanitation also influences the filter system. Someone of poor hygiene operating the filtration system will surely contaminate the supply and those others who drink from it.

A reduction in illnesses from pathogenic bacteria has been observed through the simple practice of pouring five litres of hot water into each bucket every month. In areas where illness is high, this protocol can be followed once a week. It seems apparent now that one cannot be addressed without the other; water quality and sanitation. For the effective operation of the SONO filtration system a certain standard of hygiene is needed.

The system itself consists of two 40 L buckets through which water is filtered. The water passes through a sequence of course and fine sands, wood charcoal, brick chips and the CIM. Through the combination of coagulation, filtration and precipitation processes the arsenic in the groundwater is converted from its soluble potential deadly state to a safe insoluble solid.

The effectiveness of which was illustrated by the results obtained by Abdul Hussan, 2001.The filter was proved to be highly successful by reducing the arsenic concentration to well below the detectable limit of 2ug/L in some cases.

This therefore provides a useful mechanism which can reduce the concentration of arsenic in groundwater providing safe drinking water to its consumers. The proportion of the population using the filtering system therefore have access to clean safe drinking water contributing a small step toward achieving the Millennium Development Goal 7.

In addition to the effectiveness of the system in producing high quality water that is within the recommendations made by the WHO, the social aspects of the filtering system needed to be addressed.

The concept of arsenic poisoning is reacted to differently all over Bangladesh due to the majority of citizen being ill informed of the nature of the problem.

Many people view skin lesions, a product of chronic arsenic poisoning, as being contagious. Those exhibiting the defects become socially excluded.

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Furthermore new technology may be looked upon with caution as many people ran from the villages crying ‘devils water is coming’ when the first tube wells where sunk, and many consider that had they listened to their instincts then there communities may have been saved from chronic arsenic poisoning.

Granted some citizens in various literatures have expressed their concerns regarding the filtration system and its operation, although most after continued use of the clean drinking water have expressed feelings of physical and mental well-being.

The SONO filter system has been welcomed by the majority of the nation and has been incorporated into; schools cafes and restaurants. The easy construction, maintenance and disposal of the waste material makes the units user friendly, and by adjoin units parallel, can provide small communities with safe drinking water.

Although a short term solution this technology provides good quality drinking water for many and is the basis for many other NGO incentives and initiatives the most pressing of which are highlighted in the diagram below.

Figure 5: other initiatives and incentives of NGOs

Source (Ahamed, 2008)

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Conclusion and Recommendations

To conclude, the household filtration system is extremely effective at removing naturally occurring arsenic from groundwater. The technology is simple and yet effective, through following a set of instructions the filter systems can be constructed, maintained, and disposed of in a cost effective and user friendly manor. The CIM is key to the filters success. The spaces available in the iron hydroxide molecules sets up chemical attractions and in effect traps soluble (potential deadly) arsenic and converts it into an insoluble (safe) solid waste product.

The SONO filtration system acts as a short term solution which can help toward the United Nation Goal of increasing the number of people who do not have access to safe drinking water.

Recommendations

1. The SONO filtration system should be stronger structurally and the quality of the buckets improved to prevent damage.

2. Re assessment of the time in which the water is required to be in contact with the CIM (which is currently 3hrs) should be a continuous processes as the filter system ages.

3. The Filtration system should be promoted in those areas that are suffering from the worst arsenic poisoning

4. Alternative water treatment systems should be region specific depending on the geography of arsenic contamination in specific areas. Therefore area specific water characteristics should be known and researched.

5. All personnel who which to operate the filtration system should be trained in basic hygiene.

The above recommendations are toward a short term solution. A United effort should be enforced whereby research is conducted in the aim to address the core of the problem; to understand the genesis of arsenic contamination in the groundwater of Bangladesh. Only when the source and origin of the problem has been completely addressed and researched can a long term solution be produced.

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Blas, A. d. (2007, Nov 27). Earth Beat Radio National. Retrieved Jun 12, 2008, from Devil's Water: http://www.abc.net.au/rn/science/earth/stories/s1249604.htm

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Central Intelligence Agency. (2008, Aug 07). CIA---The World Factbook -- Bangladesh. Retrieved Aug 2008, 2008, from Bangladesh: https://www.cia.gov/library/publications/the-world-factbook/geos/bg.html

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Appendix A: Response to Proposal

Although the initial proposal meet several of the necessary requirements some key changes were made. Outlined below are the recommendations from the marker followed by the changes made in response.

1. The finally report was required to be much shorter than the Preliminary Analysis submitted.

Much of the information in the proposal was provided for the lay reader, this majority of this material has been cut from the finally report, with additional information being provided in the appendix for those readers who wish for a little more reading.

2. The aim of the proposal was much too ambiguous for the requirements of the assignment.

My approach to the proposal has been modified to assess what options are available to Bangladesh in terms of mitigating the problem.

The aim of the issues was revised from i) to ii):

i) An investigation into the genesis of arsenic that contaminates the groundwater of Bangladesh. The study will take an Earths Systems Approach and thus be focused into four separate compartments; atmospheric, hydrological biological, lithological. The compartments will not remain closed as with further study the interconnections between them will become apparent

ii) The aim of this study is to evaluate the removal of naturally occurring arsenic from groundwater in Bangladesh via a household filtration system which is based upon a composite iron matrix

3. The final report needed to produce a; very tight, very focused and very-in-depth analysis of one aspect of the issue covered in the proposal.

To make this key change the aim of my report focused on one method of mitigating the problem of arsenic contamination in the groundwater of Bangladesh

4. The introduction needed to be broken up into paragraphs for easier reading and should include illustrations to add variety for the reader.

The above recommendations were carried out not only throughout the introduction but maintained throughout the report.

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5. Basic spelling and grammar mistakes

The mistakes within in the text where rectified to the best of my ability in the hope of producing a more coherent piece of writing.

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Appendix B: Periodic Table (College, 2008)

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Appendix C

Arsenic it Occurrence and Effects

A Brief Introduction in to the Chemistry of Arsenic

Arsenic behaves as a metal being shiny, soft and malleable and electrically conductive. But it also has properties associated with non-metals as a result of being in Group V of the periodic table. Here it sits below Nitrogen and phosphorus and above antimony and bismuth on the boundary between metals and non-metals exhibiting properties of both as a consequence (IUPAC, 2008). Arsenic has an unusually large range of oxidation sates (oxidation and reduction are discussed in Chapter 2) commonly -3, +3 and +5. Under normal circumstances arsenic comes into contact with organisms in aqueous solutions (dissolved in water) as arsenate ions (AsO4-3) in its 5+ state (Orville, 1977).

Negatively charged arsenate ions can adhere tightly to the surfaces of some common minerals where their molecular structure produces a positive charge. Asinine gas is by far the most toxic form of arsenic followed by dissolved arsenite and then arsenate compounds. The elemental form of arsenic is the least toxic, which is a powerful statement as taking just small quantities of the element can be fatal (A. H Welch et al, 2003).

Arsenic in the Earth’s Crust

The bulk of arsenic in crustal rocks resides in sulphide minerals such as pyrite (FeS2) by replacing the sulphur ion (Ra Bonewitz, 2005). Arsenic plays virtually no role in the dominant silicates of the Earth’s crust and mantle. In fact it is one of the least abundant elements in the rocks of the continental crust with something of the order of 0.00021% (Mathematica, 1999). The relative abundances of the elements in the Earth’s crust are shown below in Figure 4.2.1

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Plot of abundances of elements in the Earth’s crust on a sorted scatter with a log scale. The y-axis is the percentage of the elements in the Earth’s crust relative to the abundance of silicon (set arbitrarily at 10^6/1million).

Source (Mathematica, 1999)

Arsenic contamination of Water

In natural waters concentrations are generally well below 10ppb (parts per billion), the WHO recommended maximum for safe drinking water (WHO, 2001). The oxidising conditions of the modern Earth’s surface favour +3 and +5 oxidation states (Lee R. Kump, James F. Kasting, Robert G. Crane, 2004). Thus arsenic in modern water will occur as arsenite and arsenate ions, which are more soluble than their negatively, charged counter parts.

Arsenic has all of the attributes of an element which first came into contact with organisms after the Earth’s surface become dominant with oxidising conditions. Due to its low crustal abundance throughout Earth’s history arsenic has rarely come into contact with organic matter, thus its prime candidate for having retained its deadly poisonous effects is ‘by virtue of its rarity’ (International Labour office, 1930).

4.4 Decreasing the Distance between Arsenic the Human Population

The human population has gradually been increasing its connection with the deadly poison. This lethal element has over time had many uses for the human race and become a waste product of many practices. Arsenic is the by-product from metal mining for industries, for instance the mining of gold produces between 7500-100 000 tonnes of the element every year (WHO: International Program on Chemical Safety, 1992). Astonishingly arsenic is used as a growth promoter for pigs and poultry in some areas, albeit in very small quantities (Sperling, 2005) (INCHEM, 1982). Its potency to all life forms has been harnessed for its use in rodenticides, wood preservatives and tanning (Levy, 2004). Recently it has been found to be an effect treatment against some malignant diseases such as leukaemia. It has been shown that it can be used to encourage programmed death of the cancerous cells (A . Evens, 2004).

The Effect of Arsenic on Human Health

Once arsenic is ingested into the system it rapidly combines with the haemoglobin molecule in blood cells and thus travels through the body via the circulatory system (Meharg, 2005). It accumulates in organs and tissues by the substitution with other elements. An example of this process is the substitution of phosphate by arsenic on Adenine Triphosphate (ATP). ATP plays a fundamental role in the transfer of energy in both animals via respiration, and plants via photosynthesis. Within twenty four hours arsenic redistributes itself to the skin, liver, Kidney and Spleen (Meharg, 2005) (Table 3.1).

Symptoms of acute arsenic poisoning by high dose begin with headaches, confusion, and dizziness. As the poison develops, the breath may smell like garlic and the

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fingernails change colour (Lundberg, 1998). Later symptoms include diarrhoea, vomiting, blood in urine, cramping muscles and finally a coma followed by death (Kevin J. Knoop, 2002). If recognised at an early stage, acute arsenic poisoning a can be treated by chelation therapy. The treatment involves administrating compounds with exploit arsenics desire to bond with other elements to gain a stable structure. Arsenic is more strongly attracted to the chemicals administrated than to the biochemical elements in the cell structure of the animals and plants. It is then expelled from the cell rapidly. Unfortunately such treatment is; expensive, time consuming and does not reverse the damage already done (Kevin J. Knoop, 2002).

The symptoms of chronic arsenic poisoning develop through gradual build up of arsenic in the system, from repeated small dose such as drinking arsenic contaminated water (Wilson, 2008). The general term for the effects is arseniasis. The most obvious early signs are complaints of itchy skin, skin lesions on the hands and feet which tend to develop gang green infections and dark blotches on the skin, which eventually turn cancerous. Arsenic is now known to cause cancer of the lungs, liver, kidney and bladder, although the link to arsenic is not immediately noticeable. It can also affect the nervous system causing numbness and eventually muscular paralysis and loss of coordination (Wilson, 2008).

Arsenic clearly poses a threat as a drinking water contaminant across the globe. Natural aquifers now used for drinking water in; Argentina, Bangladesh, Cambodia, Chile, China, Ghana, Hungary, Inner Mongolia, Mexico, Nepal, New Zealand, Philippines, Taiwan, the USA and Vietnam have been found to contain worrying concentrations of arsenic (Wilson, 2008). Below is a world map that highlights some of these areas as being at risk from arsenic poising.

1  US Unknown 8  India 1,000,0002  Mexico 400,000 9  Bangladesh 50,000,0003  Chile 437,000 10  Thailand 1,0004  Bolivia 20,000 11  Vietnam Millions5  Argentina 2,000,000 12  Taiwan 200,0006  Hungary 20,000 13  China 720,000

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7  Romania 36,000 14  Nepal Unknown

A map and additional text illustrating the number of people across the globe that are at risk form arsenic poisoning

Source (Pearce, 2003)

From the map it is clear that the fifty million people at risk from arsenic poisoning in Bangladesh is the largest in the world.

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Appendix D

The Geography of Bangladesh and its Groundwater

The Geography of Bangladesh

Bangladesh is the World’s most low-lying major country. It lies at the head of the Bay of Bengal on the great Northern plains of the Indian peninsular, between the Himalaya, central India and Myanmar (Burma) (Central Intelligence Agency, 2008).

A map illustrating the location of the chosen study area, Bangladesh

Sourced from (Central Intelligence Agency, 2008)

Nearly all of the 133 910 square kilometres (sq km) of land remains below one hundred meters, a great deal of it never reaching a few meters above sea level. As illustrated on figure 5.1.1, most of the country is situated on the interlocking deltas of the two great rivers; the Ganges and the Brahmaputra, that flow from the Himalaya and the major tributary called the Meghan. All discharge into the Bay of Bengal. The Ganges connects with the Brahmaputra, and then joins the Meghan,

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which drains part of Northeast India, giving the total area of both land and sea to be 144 000 sq km (Central Intelligence Agency, 2008).

Almost 10% of Bangladesh seems to be covered by river channels and much of the country is cyclically inundated with flood waters during the monsoon season (Baxter, 1998). The climatic extremes experienced by the country due to its global location (figure 5.1.1) causes high river flow, sea-level surges and catastrophic floods. After the floods have calmed deposits of fertile silt are left behind. The agricultural exploitation of the fertile silt supports the eighth largest population of the world (Baxter, 1998).

The Creation of the Bangladeshi Groundwater Supply

Since the Himalaya began to rise around 50 million years ago when the Indian subcontinent collided with Asia through plate tectonics, their growing elevation has encouraged the monsoon climate of South Asia. The monsoon period can produce precipitation up to six meters in a few months in Northeast India and over one meter in the Himalaya foothills (Valdiya, 2001). The result, the Ganges-Brahmaputra-Meghan river system comprises the third largest source of freshwater discharge into the world’s oceans (Tamil Nadu, Kerala, 1979). The annual volume of flow is 795 billion cubic meters; this is equivalent to 318 million Olympic sized swimming pools.

The flow is not continuous but highly seasonal in nature. The seasonality and volume of the flow affects sediment transport, and has done so over geological time (Asit K. Biswas, 2001). To illustrate the rivers effects on sediment load in 2006 the sediment carried to the delta during the monsoon period of that year reached 13 million tonnes of sediment (Anwar, 2007). This is the highest sediment load carried by any large river in the world. It is therefore no wonder that there is a surplus of sediment beneath Bangladesh in which to contain abundant quantities of groundwater.

Tapping into the Groundwater

Fifty years ago Bangladesh faced epidemics of cholera, dysentery and typhoid which killed a quarter of a million children a year (Mortoza, 2008). Such annual catastrophes where caused by drinking from highly contaminated ponds and rivers. To reduce the death toll an alternative source of water supply was needed. The answer, tube wells. Tube wells accessed the abundant reservoirs of groundwater trapped under the sediments of Bangladesh (Mortoza, 2008). The groundwater’s promised pristine quality, straight from the snows and mountain streams of the Himalayas hundreds of kilometres to the north.

Great suspicion greeted those first wells in rural villages. The first deep well sunk for agriculture left people running from the villages crying “Devils water is coming”, “Devils water is coming” (Blas, 2007). During the 1970s extensive campaigns where launched by UNICEF and the Bangladeshi Government to educate people and popularise tube wells. During this period a large number of tube wells were sunk. Like many inventions the technology was simple, wholes where dug into the Bengal Delta (figure 5.1.1) and long tubes where sunk through the sediments

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into the abundant reservoirs of underground water. The simplicity and affordability of technology led villages to dig their own private wells. Within three decades millions of tube wells throughout Bangladesh where dug (Bagla, 2003).

The villages may have been right! In 1993 doctors began to notice a growing number of skin lesions known to be a symptom of arsenic contamination due to recent studies undertaken in neighbouring West Bengal India. With more than 2-5 million tube wells supplying 95% of the population with ‘safe’ drinking water the extent of the possible epidemic at hand was horrifying. The groundwater turned out to be far from safe, contaminated with something colourless, odourless and tasteless, naturally occurring arsenic (Owen, 2001).

Researching the Extent of the problem

In 1997 the British Geological Survey (BGS) were asked to investigate how many of these wells were contaminated with unacceptable levels of arsenic. The World Health Organisation (WHO) had a recommended maximum concentration of 10 pbb, the Bangladeshi standard was set five times higher than this at 50 ppb (Anwar, 2007). Regardless of either recommended guideline the results uncovered by the BGS where sickening. More than 50% of all the tube wells tested where above the WHO recommendation, and more than 27% were higher than the Bangladeshi maximum concentration (British Geological Survey, 1999).

The difficulties in assessing the risk from poisoning by arsenic arise with the well-well variability in arsenic concentrations. The variations make it difficult to predict what concentrations of arsenic can be expected to be found on a local scale (British Geological Survey). In addition it has been noted by some researches that one survey per well is not enough as those tested to be safe have over time become contaminated. Approximately 30% of all wells tested as safe have now followed this path (Jakariya, 2007).

Despite the above something had to be done. UNICEF in 1998 began a long process of trying to prevent people from drinking contaminated well water. The same people they had previously convinced to put their sceptic ideas to rest and drink from the waters of the wells. Those wells that where tested where either painted red for contaminated or green for safe (Zaman, 2001).

The problem is even more widespread than initially thought. Rice the staple diet for millions throughout Bangladesh is grown in paddy fields deliberately flooded with arsenic contaminated water. Research has shown that both the soils and the rice contain high levels of arsenic. Through their diet alone millions are exposed to the maximum recommended daily intake of arsenic, on top of this they are drinking the water (Meharg, 2005).

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The Origin of the Arsenic Pollutant

Scientists have investigated many theories and are still debating the exact mechanism by which arsenic safely locked up in rocks become freed into the water supply (Anwar, 2007).

Thus it remains a mystery as to how water from the world’s highest mountain range that has been filtered over hundreds of kilometres of sand and silt, and has not seen the light of day for hundreds of years can poison an area the size of New Zealand. Without an understanding of the exact causes of the problem no solution can provide a long term solution.

Appendix E: Possible Chemical reactions

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