Coastal water to be checked for heavy metal pollution too

The Union environment ministry has proposed the inclusion of specific standards for seven heavy metals and one toxic insecticide as additional parameters during

The Union environment ministry has proposed the inclusion of specific standards for seven heavy metals and one toxic insecticide as additional parameters during coastal water quality tests.

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Environmentalists have welcomed the move, as the presence of heavy metals in seawater, especially adjacent to urban areas such as Mumbai, have toxic effects on marine life and seafood, thereby affecting the entire food chain.

A draft notification published by the Ministry of Environment, Forests and Climate Change (MoEFCC) on February 20 amended the Environment (Protection) Rules, 1986, to add safe standards for cadmium (3.03 microgram per litre (µg/I) or less), copper (4.1 µg/I or less), mercury (0.38 µg/l or less), zinc (10.6 µg/l or less), lead (4.6 µg/l or less), arsenic (3.5 µg/l or less), chromium (8 µg/l or less), and for water-soluble toxic insecticide – monocrotophos (89 ng/l or less). The criteria for testing these trace materials is based on an estimate of the highest concentration or toxicity of each material an aquatic environment is exposed to or affected by.

“Currently water quality tests do not indicate the level of toxicity that heavy metals are contributing. We have called for suggestions and objections under the Environment (Protection) Amendment Rules, 2020, to check the impact of municipal waste and industrial effluents entering coastal waters that can harm the overall marine ecosystem and impact human life due to these trace metals,” said a senior MoEFCC official.

A compilation of research studies over the past decade by an independent researcher and member of the Mangrove Society of India, Pramod Salaskar, Indian Institute of Technology-Bombay (IIT-B), National Institute of Oceanography, University of Mumbai, and other researchers have revealed that the heavy metal concentration was eight times higher (than unpolluted coastal zones along the west coast) at the Thane creek.

“Samples collected from Airoli, Vashi and Trombay have indicated the presence of all the seven metals mentioned by the Centre is much above the proposed standards. The source of the pollution is untreated sewage and industrial effluents. Not only have they led to a decline in fish species, but the fish which are caught for consumption also have high metal content in them,” said Salaskar.

“If there are other toxic elements affecting marine biodiversity or being identified in the fish catch, citizens can write to us over the next two months and their suggestions will be considered,” the MoEFCC official said.

Based on the Central Pollution Control Board (CPCB) guidelines, the coastal states currently come up with a single number (grade) water quality index that expresses the overall quality of a certain water sample for broad parameters such as biochemical oxygen demand (level of oxygen that affects the quality of water), chemical oxygen demand (level of toxicity), faecal coliform (FC) content (bacterium found in human and animal excreta that indicate the presence of pathogens), acidity (pH), total dissolved solids etc.

Marine biologist E Vivekandan said, “These guidelines should have been implemented at least a decade ago as studies identifying heavy metal traces, effects on marine biodiversity, and parallel impacts on the central nervous system and immunity for humans have been documented for decades now.”