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The use of alternative safe water options to mitigate the arsenic problem in Bangladesh: a community perspective

Md. JakariyaM.Sc. Thesis, Department of Geography, University of Cambridge, Aug 2000


Bangladesh faces multi-faceted problems in relation to groundwater. At present there is a new threat - arsenic contamination in groundwater. Arsenic is a shiny, grey, brittle element possessing both metallic and non-metallic properties (Train, 1979). Arsenic compounds are ubiquitous in nature, insoluble in water, and occur mostly as arsenides and arsenopyrites. Arsenic exists in the trivalent and pentavalent states in nature and its compounds may be either organic or inorganic. Trivalent inorganic arsenicals are more toxic than the pentavalent forms both to mammals and aquatic species. Though most forms of arsenic are toxic to humans, arsenicals have been used in the medical treatment of spirochaetal infections, blood dyscrasias, and dermatitis (Merck Index, 1968).

The degree of toxicity of arsenic depends on its chemical form and speciation. Humans are exposed to arsenic mainly through ingestion and inhalation. The World Health Organization (WHO) has recently revised its original guideline value for arsenic in drinking water of 0.05mg/l (WHO, 1984) to a provisional guideline value of 0.01 mg/L (WHO, 1993). The Bangladeshi government level is 0.05 mg/l (DoE, 1991). Water with high levels of arsenic leads to health problems such as melanosis, leuko-melanosis, hyperkeratosis, black foot disease, cardiovascular disease, hepatomegaly, neuropathy and cancer (Khan and Ahmad 1997). Arsenic tends not to accumulate in the body but is excreted naturally. If ingested faster than it can be excreted, arsenic accumulates in the hair and fingernails (Khan, 1997). The toxicity of arsenic depends on the chemical and physical forms of the compound, the route by which it enters the body, the dose and the duration of exposure, dietary compositions of interacting elements and the age and sex of the exposed individuals.

As regards manifestation in a person’s body, the symptoms of arsenic toxicity may take several months to several years. This period differs from person to person, depending on the quantity and volume of arsenic ingested, nutritional status of the person, immunity level of the individual and the total time period of arsenic ingestion (DCH, 1997). Malnutrition and poor socio-economic conditions aggravate the hazards of arsenic toxicity. Although arsenicosis is not an infectious, contagious or hereditary disease, arsenic toxicity creates many social problems for the victims and their families (Khan and Ahmad, 1997).

There is a need to know more about the impact of arsenic poisoning on human health. For instance, there is no clear understanding of why some members of a family or community are affected, while others in the same family or community who are subject to the same contamination are not. Early symptoms of arsenic poisoning can range from the development of dark spots on the skin to a hardening of the skin into nodules - often on the palms and soles. The World Health Organization (WHO) estimates that these symptoms can take 5 to 10 years of constant exposure to arsenic to develop (DCH, 1997). Over time, these symptoms can become more pronounced and in some cases, internal organs including the liver, kidneys, and lungs can be affected. In the most severe of cases, cancer can develop in the skin and internal organs, and limbs can be affected by gangrene. While evidence exists that links arsenic to cancer, it is difficult to say how much exposure and for what period of time, will result in this disease.

The source of arsenic in drinking water is geological. Arsenic occurs naturally in the sediments of Bangladesh bound to amorphous iron oxyhydroxide. Due to the strongly reducing nature of groundwater in Bangladesh, this compound tends to break down and release arsenic into the groundwater (Nickson et al., 1998). Although arsenic occurs in alluvial sediments, its ultimate origin must be the outcrops of hard rocks higher up the Ganges catchment that were eroded in the recent geological past and then re-deposited in West Bengal and Bangladesh by the ancient courses of the Ganges. At present, these source rocks have not been identified. It is also important to understand that arsenic does not occur at all depths in the alluvial sediments. Although there is not enough evidence to draw firm conclusions, it appears that high concentrations of arsenic are restricted mainly to the shallow aquifer (less than 50 meters deep) (DPHE/BGS/DFID, 2000).

However, there are lots of controversies over the origin of arsenic in the groundwater. Indiscriminate use of agro-chemicals in the agricultural field for higher rice production and excessive use of groundwater for irrigation purposes i.e. oxidation process, are also some of the alternative hypotheses for the release of arsenic in groundwater. Therefore, it is very important to find out the exact cause in order to be able to implement different options.

Many organizations have implemented different arsenic programmes, most of which have focused on testing tube well water for arsenic. The World Bank is taking the lead in co-coordinating an integrated response to the arsenic crisis and through the Government of Bangladesh is supporting the Bangladesh Arsenic-Mitigation Water Supply Project (BAMWSP). A key component of the BAMWSP will be the use of community-based, demand driven projects, in which community members play an active role in choosing and implementing solutions to the site-specific problems of arsenic contamination.

2.1 The arsenic problem elsewhere in the world

Arsenic contamination is not unique to Bangladesh. Highly elevated levels of arsenic of natural origin have been reported in groundwater in many parts of the world. Arsenic poisoning due to excessive exposure to natural and anthropogenic arsenic in drinking water has been reported in Argentina, China, Taiwan, Thailand, India, Mexico, USA, Ghana, Hungary, United Kingdom, Chile, New Zealand, and Russia (CSIRO, 1999). The following are brief descriptions of the arsenic problem in each of these countries:


In Argentina, groundwater arsenic concentration in some places ranges from 100 to 2000 microgram/l. Reports from epidemiological studies in Argentina indicated that 0.3mg/l arsenic in drinking water resulted in increased incidences of hyperkeratosis and skin cancer with an increased consumption of water (Trelles, et al., 1970).


According to a survey carried out in some parts of China, the main sources of arsenic poisoning in drinking water are deep wells in basin areas rather than shallow hand tube wells. The arsenic concentrations range as high as 0.6 to 1.2 mg/l. The epidemiological data demonstrated the evident association of arsenic poisoning with the arsenic concentration in drinking water (Nie et al., 1997).


The sources of arsenic contamination of groundwater in Thailand are high-grade arsenopyrite waste piles and alluvial mineral deposits. In some parts of Thailand shallow tube wells were found to be contaminated with arsenic at concentrations of more than 5mg/l but the deeper aquifer was less contaminated (Fordyce et al., 1995).


In Taiwan the groundwater arsenic problem was reported as early as 1968 and a large number of people suffered from arsenical dermatosis. They gave arsenicosis the name ‘black-foot disease’. Arsenic concentrations in the tube wells ranged from 10 to 1820 microgram/liter, and 19% of the wells had arsenic levels of over 50 microgram/liter (Hsu et al., 1997).

West Bengal

Six districts of West Bengal including 466 village and many municipal areas were found to be contaminated with arsenic. About one million people were drinking arsenic-contaminated water and about 200,000 people already showed the symptom of arsenical skin lesions (Das et al., 1996).


The sources of arsenic in well water in Nevada, Arizona and California are geological, though the nature of the arsenic-enriched deposits is as yet unknown. In Nevada, elevated concentrations of arsenic occur in several groundwater basins, and five community water systems exceed the current 0.05mg/l standard for the USA (Fontaine, 1994).


In some parts of northern Mexico, chronic arsenic poisoning is endemic, leading to changes in skin pigmentation, keratosis, skin cancer, black-foot disease and gastro-intestinal problems. An average concentration of 0.4 mg/l of arsenic was recorded in some parts of northern Mexico (Del Razo et al., 1994). The source of arsenic was assumed to be geological.


In the south-eastern part of Hungary, drinking water wells were contaminated with arsenic in concentrations high enough to pose long term health hazard to about 0.4 million people. Arsenic pollution in Hungary was believed to spread due to the use of pesticides containing arsenic (Halvay, 1988).

United Kingdom

Arsenic levels higher than the current Environmental Protection Agency standard have been discovered in private wells in New England, New Hampshire, Cornwall. A study of arsenic in surface waters in Cornwall has shown soluble arsenic in specific catchments to range from 10 to 50 microgram/l (Aston et al., 1975). However, extraction of surface water for processing and distribution avoids water contaminated by past mining activities, and water processing using aluminium hydroxide removes the majority of the soluble arsenic. As a result arsenic in drinking water in Cornwall rarely exceeds 10 microgram/l (MAFF, 1982).


Chronic arsenic poisoning has been reported in a population exposed to elevated concentrations of arsenic in surface waters (rivers, creeks, lakes, etc.) used for drinking water and irrigation purposes. The sources of the arsenic have been reported as being volcanic sediments, minerals and soils (Carceres et al., 1992). Dermatological manifestations of arsenicism were noted in children in Antofagasta, Chile who used a water supply containing an arsenic concentration of 0.8 mg/l (Borgonno and Grieber, 1972).



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