An overview of arsenic in groundwater in Tamil Nadu – A report by Water Resources Department

Now-a-days heavy metal arsenic poses a health risk problem throughout the world. Arsenic may be found in water which has flowed through arsenic-rich rocks. Severe health effects have been observed in populations drinking arsenic-rich water over long periods in countries world-wide.

A study of this kind involves the accurate measurement of arsenic in drinking-water at levels relevant to health requires laboratory analysis, using sophisticated and expensive techniques and facilities. Analytical quality control and external validation remains problematic in the absence of well trained staff in many parts of the world. Furthermore, field test kits can detect high levels of arsenic but are typically unreliable at lower concentrations of concern for human health. The reliability of field methods is yet to be fully evaluated.

As a part of the study about 412 groundwater samples were collected in the entire state of Tamil Nadu. These samples were analyzed using sophisticated Atomic Absorption Spectrophotometer (Perkin Elmer) using expensive techniques of Mercury Hydride System (MHS) with a well trained and skilled staff, since arsenic was present in the groundwater sample in very low quantity.

The data were compiled district-wise and the range of arsenic present in the groundwater samples (microgram/litre) are given in the statement. As per Bureau of Indian Standards (BIS), the maximum permissible limit of arsenic in the drinking water is 0.05 mg/L (50 μg/L). 

As per the study, from the data it is seen that arsenic present in the groundwater sample of Tamil Nadu within the safe limit of 0.05 mg/L (50 μg/L) as fixed by the Bureau of Indian Standards for the drinking water. However the highest amount of arsenic 8.62, 16.67 and 11.5 μg/L have been noticed in the districts of Kancheepuram, Perambalur and Virudhunagar respectively. In Theni and Erode district the lowest amount of Arsenic 1.00 μg/L have been noticed.

A bar chart showing the presence of arsenic in the districts of Tamil Nadu with the permissible limit of BIS limit is appended with this report.

Download the report here -