Assessment of polychlorinated biphenyls and organochlorine pesticides in water samples from the Yamuna River

Polychlorinated biphenyls (PCBs), hexachlorocyclohexane (HCH) and dichloro-diphenyltrichloroethane (DDT) are toxic, persistent and bioaccumulative long-range atmospheric transport pollutants. These are transported worldwide affecting remote regions far from their original sources, and can transfer into food webs with a wide range of acute and chronic health effects. India ratified the Stockholm Convention with the intention of reducing and eliminating persistent organic pollutants (POPs), and encouraged the support of research on POPs. Despite the ban and restriction on the use of these chemicals in India, their contamination of air, water, sediment, biota and humans has been reported. In this study, surface water samples were collected during January 2012 from the Yamuna River in Delhi, India, and analyzed for PCBs and organochlorine pesticides (OCPs). The concentrations of Sigma PCBs and Sigma OCPs ranged between 2-779 ng L-1 and from less than 0.1 to 618 ng L-1 (mean 99 +/- 38 ng L-1 and 221 +/- 50 ng L-1, respectively). The PCB homolog was dominated by 3-4 chlorinated biphenyls. In calculating the toxicity equivalent of dioxin-like PCBs (dl-PCBs) using World Health Organization toxic equivalency factors, dl-PCBs accounted for 10% of a total of 27 PCBs. The concentration of Sigma HCH ranged between less than 0.1 and 285 ng L-1 (mean 151 +/- 32 ng L-1). However, Sigma DDTs concentrations varied between less than 0.1 and 354 ng L-1 (mean 83 +/- 26 ng L-1). The concentrations were lower than the US guideline values; however, levels of lindane exceeded those recommended in guidelines. Further in-depth study is proposed to determine the bioaccumulation of these pollutants through aquatic biota to assess the risk of contaminants to human health.