Abstract
In 1983, the first person with clinical manifestation caused by the consumption of arsenic contaminated ground water was diagnosed in the state of West Bengal (India), followed by neighboring Bangladesh in 1991. In the following years arsenic has also been detected in some other states India and also in Pakistan and Nepal. People are exposed to inorganic arsenic through domestic hand pumps, and irrigation wells, which extract water from underground aquifers. Estimated 60 million people of Bengal basin (West Bengal and Bangladesh) are exposed to arsenic contaminated water and now regarded as the worst environmental disaster in the world. An estimated 1 million people from this region have arsenic related skin lesions. According to some experts, in coming days, arsenic will emerge as leading cause of cancer in this region. Since 1984, the literature on the subject of arsenic poisoning has been confined mostly to the natural and biomedical sciences. Several issues still remain unexplained and unexplored or have been partially probed - especially the social determinants and distribution of arsenic exposure and its manifestations, how social dimensions are linked with existing development practices and their contributing in further arsenic exposure. Hence, a few questions remain unanswered, for instance, how deprivation and inequality are linked with further deterioration of local ecology and human health, people’s perceptions and individual/public actions in relation to the problem. We also need to know, to establish and to contemplate into the complex relations among these factors in order to identify the prime intervention areas for establishment of sustainable strategy.
Methods
In order to fill the research gap, the social epidemiological approach has been adopted here to examine the social determinants influencing the extent and distribution of arsenicosis and identifying the ‘attributable factors’. In order to get the wider perspective, an interdisciplinary approach was therefore adopted. The data were collected from field visits in two affected districts in West Bengal and also by extensive analysis of secondary sources (research documents, government and NGOs reports, systematic analysis of literature relating to both West Bengal and Bangladesh). In the selected villages, household visits were conducted along with one-to-one interview of the selected cases, focus group discussion, and analysis of water samples. In the study, the specific questions that were asked, related to the extent of arsenic pollution in water; who are being affected; their demographic characteristics in terms of age, gender, ethnicity, socio-economic status, occupation, nutritional status, treatment-seeking behaviour, official institutional responses to the problem – including preventive, curative, and rehabilitative services. The study further explored the policy implications of the findings in terms of prevention and treating arsenic poisoning and limiting its impact, how the existing agriculture policy contributed in arsenic contamination of groundwater, further dependence on groundwater (both in domestic use and irrigation) and magnified the toxic exposure. The study conducted SWOT (strength, weakness, opportunity and threat) analysis of the existing strategies.
Results
Out of total 7,678 exposed populations, 410 were found having single or multiple manifestations. Both the domestic hand pumps and irrigation wells are contaminated with arsenic. 53 (13%) cases were exposed to arsenic less than 50ppb per day (permissible limit in Bangladesh). It supports the argument of WHO to reduce the safety level to 10ppb. Association between arsenic exposure level and severity of manifestation was found to be significant (p<0.05). Women were less exposed to arsenic due to occupational pattern, as men had multiple water sources for drinking, thus the chances of arsenic contamination were greater. Poor landless laborers were exposed to higher levels of arsenic, as major source of drinking water at their workplaces were contaminated irrigation wells. Poor people suffered from more severe form of manifestations even with similar level of exposure. Persons suffering from chronic arsenicosis at younger ages were mostly found among the poor, which could be due to early exposure of arsenic and/or associated factors such as poor nutrition. Moreover, only higher socio-economic status could afford to shift to alternative sources of water. There was a clear gender disparity regarding treatment seeking and mode of expenditure. While 97% of males got treatment, 88% of females did. The association of severity of symptoms and nutritional status was found to be statistically significant (p<0.05). More than 90% lands were irrigated with groundwater for decades. Institutional support and rural credit in irrigation encouraged the farmers to draw groundwater as it has been perceived as free commodity. Moreover, due to growing demand of groundwater, it became popular commodity in rural market. Due to rice cultivation in dry season and lack of regulation, there is always over withdrawal of groundwater, which eventually triggered the leaching of arsenic. Despite good rainfall the traditional water resources (lakes, ponds, canals, rivulets) lost their potency due to silting owing to lack of maintenance and resulted in frequent floods during rainy seasons. Crops and animal products in the affected areas contain high arsenic due to contamination of the food chain. Existing strategy to promote arsenic filters posing new threat as the improper disposal of high arsenic containing sludge contaminating soil, plants and surface water. Lack of community involvement in planning and implementation resulted in failure of several arsenic mitigation strategies.
Conclusion
Contamination of groundwater with arsenic, an increasingly severe public health issue in Bengal basin is caused mostly by unsustainable agricultural and water supply policies. The study explored the policy implications of the findings in terms of prevention and treating arsenic poisoning and limiting its impact. Disregarding social dimension of the problem in mitigation strategy has failed to curb the progression of arsenic menace, mostly due to existing inequalities, which affected its accessibility and acceptability in the rural society. There is a need of convergence of interdisciplinary research findings in policy level to develop sustainable strategy where community will be one of the important stakeholders. The strategy will unfold the further scope of multidimensional operation research and set an example for the researchers in other part of the globe.
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