Evaluation of hexachlorocyclohexane contamination from the last lindane production plant operating in India

α-Hexachlorocyclohexane (HCH), β-HCH, and lindane (γ-HCH) were listed as persistent organic pollutants by the Stockholm Convention in 2009 and hence must be phased out and their wastes/stockpiles eliminated. At the last operating lindane manufacturing unit, we conducted a preliminary evaluation of HCH contamination levels in soil and water samples collected around the production area and the vicinity of a major dumpsite to inform the design of processes for an appropriate implementation of the Convention.

Soil and water samples on and around the production site and a major waste dumpsite were measured for HCH levels.

All soil samples taken at the lindane production facility and dumpsite and in their vicinity were contaminated with an isomer pattern characteristic of HCH production waste. At the dumpsite surface samples contained up to 450 g kg(-1) Σ HCH suggesting that the waste HCH isomers were simply dumped at this location. Ground water in the vicinity and river water was found to be contaminated with 0.2 to 0.4 mg l(-1) of HCH waste isomers. The total quantity of deposited HCH wastes from the lindane production unit was estimated at between 36,000 and 54,000 t.

The contamination levels in ground and river water suggest significant run-off from the dumped HCH wastes and contamination of drinking water resources. The extent of dumping urgently needs to be assessed regarding the risks to human and ecosystem health. A plan for securing the waste isomers needs to be developed and implemented together with a plan for their final elimination. As part of the assessment, any polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF) generated during HCH recycling operations need to be monitored.