The State pollution control board will collect water samples from Tondiarpet on Wednesday to check the level of contamination from oil seepage.

Groundwater in the northern neighbourhood has been contaminated for the past six months due to oil seepage from a pipeline belonging to Bharat Petroleum Corporation Limited (BPCL).

“An earlier set of samples was collected only from borewells that were pumping out oil along with water. That was done to find the petroleum contaminant. We found diesel and petrol in the samples,” said an official of the Tamil Nadu Pollution Control Board (TNPCB).

The samples will be taken from adjacent streets to find the direction of flow of groundwater.

“You cannot see or smell the fuel but the contamination from dissolved hydrocarbons can be found through testing. After the direction of groundwater flow is found, further samples will be lifted. The water will be collected in glass bottles instead of plastic ones so it does not react with the plastic,” the official said.

The testing will be done according to parameters set by IIT-Madras whose expert team is assisting TNPCB and BPCL in implementing remediation measures in Tondiarpet.

Soil samples too will be taken from areas adjacent to the 12 affected borewells. A private company with the expertise to collect such samples will be roped in. Soil testing is needed to find the extent of contamination.

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