Tag Archives: arsenic

High levels of arsenic found in groundwater in UP

Umashankar Mishra

Arsenic concentration in groundwater of Uttar Pradesh shown by blue, green and red circles

New Delhi: A new study has found that as many as 2.34 crore people in rural areas of Uttar Pradesh are exposed to high levels of arsenic in groundwater.

A total of 40 districts in the state are exposed to high concentration of arsenic in groundwater. Balia, Barabankhi, Gorakhpur, Ghazipur, Gonda, Faizabad and Lakhimpur Kheri are the worst affected districts. Majority of them are in the floodplains of Ganga, Rapti and Ghaghara rivers. Ten other districts with moderate risk of arsenic contamination are Shahjahanpur, Unnao, Chandauli, Varanasi, Pratapgarh, Kushinagar, Mau, Balrampur, Deoria and Siddharthnagar.

About 78 percent of the population in the state lives in rural areas and depends on ground water for irrigation, drinking, cooking and other domestic use. Risk of exposure to arsenic is much higher in rural areas than cities as piped water supply is not available in most villages.

Groundwater samples were tested using arsenic testing kits and findings were then validated in laboratory. In all, 1680 groundwater samples from different regions of the state were analysed. Using these inputs, researchers developed a map of arsenic-affected regions reflecting the risk due to arsenic contamination.

Twenty parameters that affect arsenic level in groundwater such as land cover, aquifer depth, chemical and biological structure of soil, drainage system etc were evaluated.

“The risk map indicates the need for a widespread testing of wells in various regions of Uttar Pradesh. It could be helpful in reducing long-term exposure of people residing in highly populated clusters exposed to arsenic. Within these identified regions, districts like Ballia, Varanasi, Gazipur, Gorakhpur, Faizabad, and Deoria are evidently experiencing a public health crisis due to arsenic exposure,” said Dr. Chander Kumar Singh, who led the study at the TERI School of Advanced Studies, while speaking to India Science Wire.

Natural contamination of groundwater with arsenic poses a health threat in many regions where people rely on hand pumps or tube wells for drinking water.

Arsenic exposure causes skin lesions, skin cancer, bladder, lungs and cardiovascular diseases as well as reduced intellectual function in children.

Apart from Dr. Singh, his research student Sonal Bindal was involved in the study. The study results have been published in journal Water Research. (India Science Wire)

Indian scientists find how arsenic reduces immunity

Monika Kundu Srivastava

New Delhi: A group of Indian scientists have figured out how exposure to arsenic reduces immunity.

Arsenic’s role in disrupting body’s immune response by hindering development of thymus – gland that helps develop immunity-providing T lymphocytes or T cells– is known. A new study done by scientists from Lucknow-based Indian Institute of Toxicology Research (IITR) has now explained the mechanism behind this.

This may help explain why people exposed to arsenic become susceptible to infections like tuberculosis.

Researchers investigated the effect of arsenic exposure on the process by which T cells transform into specialized cells (CD4+ and CD8+) and the role of regulatory T- cells. CD4+ cells are found on helper T cells and direct the body to fight viral infections, while CD8 are found on fighter T cells that protect the body by killing infected cells.

The study exposed mice in the laboratory to arsenic. It was noticed that arsenic exposure enhanced transformation of T lymphocytes in the thymus into CD4+ cells without affecting the CD8 population. The cells then moved to the spleen and got transformed into regulatory T cells that decreased functional activity of other immune cells and further reduced immunity following arsenic exposure. CD4+ cells got converted into another form and not what they were meant to do. At the same time, secretion of cytokines that help in fighting an infection also decreased.

Researchers also found that treatment with wortmannin – a drug used for cancer treatment – can significantly bring down arsenic-induced increase in regulatory T cell population. It resulted in reversing the effects of reduced immunity by hindering conversion of CD4+ cells to regulatory T cells within the body.

“Our study is significant as it has shown that regulatory T cells can be a potential target to intervene in arsenic-induced immune suppression. This could help in prevention of prevalent infectious diseases in arsenic-affected areas,” pointed out Dr Debabrata Ghosh, who led the research team. Low cost inhibitors can be designed that potentially interfere with regulatory T cells and can be used to reverse effects of reduced immunity in arsenic-affected regions in the country. The study has been published in the journal Scientific Reports.

The research team included Ruchi Gera, Vikas Singh, Sumonto Mitra, Anuj Kumar Sharma, Alok Singh, Arunava Dasgupta, Dhirendra Singh, Mahadeo Kumar, Pankaj Jagdale, Satyam Patnaik and Debabrata Ghosh. (India Science Wire)

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