Students in some primary schools in West Bengal may be drinking water with high levels of arsenic, almost 60 times more than the permissible limit of 10 mcg/L (microgrammes per litre) prescribed by the World Health Organisation (WHO).Between September 2016 and September 2017, researchers from the School of Environmental Studies, Jadavpur University, sent several letters to headmasters and teachers in charge of five primary schools in West Bengal’s North 24 Parganas district, warning them about high arsenic contamination in the water being used by them.In the letters, Tarit Roychowdhury, director, School of Environmental Studies, asked the authorities to switch to alternative water sources. “Supplement of arsenic-free water is highly recommended. Installation of a deep tubewell/alternate source as well as an arsenic remedial plant on the school premises is recommended for the purpose,” said the letter written to the headmistress of the Medudandi Suiecegate Sishu Sikhsha Kendra (MSSSK) in the Basirhat I Block.The letter, dated September 15, 2017, puts the arsenic content in the school tubewell at almost 60 times the WHO limit.Researchers also recorded a high concentration of arsenic in the urine samples of children. A mean value of arsenic content in the urine of 45 children in the MSSSK is about 213 mcg/L, whereas the WHO’s permissible limit is between 3-26 mcg/L.“There is little that I can do but allow children to drink this arsenic-laced water. We have raised this issue a number of times but nothing has been done,” Suchitra Sarkar, headmistress of a primary school, told The Hindu. The headmistress said 76 students from pre-primary to Class IV are provided a mid-day meal in the school.“What is alarming is that in many schools, a mid-day meal is cooked using the same water source. So the children are not only drinking water highly contaminated with arsenic, but arsenic is getting into their system through food also,” Prof. Roychowdhury said.Problem at home tooThe high concentration of arsenic in the urine samples, finger nails and hair of the children is an indication that they might be drinking water with high arsenic content even at home, he added.“Children will only show manifestation like pigmentation of skin or keratosis when they grow older, at about 12 years of age,” said Dr. Kunal Kanti Majumdar, a public health expert. He added that long exposure to arsenic could be carcinogenic.Arsenic in groundwater has been reported from 83 of the 241 blocks in the State. Districts like North 24 Parganas, Nadia, Murshidabad and Malda have recorded a high concentration in groundwater. “We have inspected schools in Gaighata block and we will be soon issuing letters,” Professor Roychowdhury said.