Guwahati, July 26: An investigation carried out by the civil engineering department of IIT Guwahati has found excess lead in drinking water in the city.
The investigation was conducted on three samples submitted by the Guwahati Metropolitan Drinking Water and Sewerage Board from its water treatment plant located in the Zoo Road area.
The report said the permissible limit of lead should not exceed 0.01mg per litre. But the study found 0.07mg and 0.04mg per litre in the two samples of untreated water and 0.08mg in the sample of treated water.
The board had sent the samples after getting a letter from the Assam Public Health Engineering Department Retired Engineers Forum.
"We came to know about the presence of lead in the water in Guwahati when Priyanka Kotoki Duara, a post-graduate student of Assam Engineering College, presented a research paper in a programme organised by us on March 22 as part of World Water Day. She had examined water samples from six water treatment plants of the city and an excess amount of lead and arsenic was found," said forum secretary Satyabrata Sarma.
Priyanka had carried out the water test in two phases in the laboratory of Assam Engineering College. During pre-monsoon season in March, she collected water samples from the GMC's water treatment plants at Panbazar, Satpukhuri and Kamakhya, the PHE department's water treatment plants at Panbazar and Jalukbari and the Guwahati Metropolitan Drinking Water and Sewerage Board's treatment plant at Zoo Road.
The amounts of lead found in these six samples (untreated) were 0.97, 1.04, 0.31, 1.67, 0.47 and 0.68mg per litre. For treated samples, the amounts were 0.28, 0.24, 0.26, 0.18, 0.27 and 0.3mg per litre. Moreover, against the permissible amount of 0.01mg per litre, the amount of arsenic found was 0.10mg in all of them.
In the second phase of tests, when samples were collected during monsoon in April, the arsenic level was below the permissible level but the amount of lead found was a real cause of concern.
The lead levels were 1.15, 0.63, 0.66, 1.18, 0.43 and 0.83mg per litre for untreated water samples while for treated water samples, the amounts were 0.41, 0.40, 0.56, 0.31, 0.26 and 0.31mg per litre.
On the solution, Sarma said, "Eliminating lead from water in a treatment plant is very costly. Even in developed countries, it is not done. The only way to reduce the amount of lead is through cooperation. The industry, forest and pollution departments should work together to solve the problem. Source of lead is mainly industries. So, industrial waste should be treated properly before it is released."
Priyanka said she will start a project on lead-free water treatment from August.
GMC mayor Mrigen Sarania told The Telegraph, "The water treatment plants of Guwahati are plagued by outdated technology and machines. I will write to the government as soon as possible to plan a project to upgrade the water treatment plants."
