Extent and severity of groundwater arsenic contamination in Bangladesh

In Bangladesh, the majority of the irrigation and drinking water is supplied from underground sources due to the limitation of surface water. In recent years, arsenic contamination has emerged as afresh blow to the country. This paper gives an overview of the extent and severity of groundwater arsenic contamination in Bangladesh, as well as a review of the latest statistics and findings of numerous investigations about this issue. Recent reports of the British Geological Survey show that the groundwater in all 61 surveyed districts out of 64 is now contaminated with arsenic. On the other hand, a survey report of School of Environmental Studies, Jadavpur University, and Dhaka Community Hospital shows 47 districts are contaminated. The population exposed to the arsenic poisoning through drinking water is more than 25 million. In regard to arsenic pollution, Bangladesh is the most vulnerable country in the world. Unfortunately, until now, the cause of groundwater arsenic contamination has not been detected. Initially, several anthropogenic sources of arsenic were presented. Gradually, all were rejected based on the field observations. Finally, it was recognized that the source of arsenic is in the geological deposits. The two prevailing hypotheses, pyrite oxidation and oxy-hydroxide reduction, describe the cause of contamination. However, neither has been studied thoroughly with accurate field data. Therefore, the verdict is still out whether to support one hypothesis over the other. Thousands of people are suffering from arsenic diseases ranging from melanosis to skin cancer and gangrene, and many have even died. Unfortunately, there is no specific treatment for chronic arsenicosis, other than ceasing further intake of arsenic contaminated water. To overcome this predicament; awareness of the problem and the creation of watershed management are necessary.