Arsenic was a very rarely heard term in the water sector till a few decades back. However, in recent years, the number of areas reporting arsenic contamination have gone up drastically with over 20 countries from different parts of the world reporting arsenic contamination of groundwater (Bordoloi, 2012). With the constantly increasing number of occurrences, especially in the South Asian region, it is now recognized as a major public health concern affecting a large number of people around the world.
In South Asia, arsenic contamination in groundwater in the Ganga- Brahmaputra fluvial plains in India and Padma-Meghna fluvial plains in Bangladesh has been found to have a huge impact on human health and its consequences have been reported as the world’s biggest natural groundwater calamities. In India, West Bengal, Jharkhand, Bihar, Uttar Pradesh in the flood plains of the Ganga, Assam and Manipur in the flood plains of the Brahamaputra and Imphal rivers and Rajnandgaon village in Chhattisgarh state have been reported to be affected by arsenic contamination in groundwater (Ghosh and Singh, nd)
What is arsenic?
Arsenic (As) is an odourless and tasteless metalloid widely distributed in the earth’s crust. Elemental arsenic is a member of Group VA of the periodic table, with nitrogen, phosphorus, antimony and bismuth. It has an atomic number of 33 and an atomic mass of 74.91.
What are the forms of arsenic available in nature?
Arsenic and its compounds occur in crystalline, powder, amorphous or vitreous forms. It usually occurs in trace quantities in all rocks, soil, water and air. It is the 26th abundant element in the earth’s crust.
Which form of arsenic is the most toxic?
Arsenite [As (III)] is most toxic form of arsenic and causes acute toxicity. Forms of arsenic such as As (III) and As (V) lead to chronic toxicity. Previously it was thought that methylated forms of arsenic [MMA (V), DMA (V)] were less toxic. However, current studies indicate that these two forms of arsenic are highly toxic.