Plasticizers and bisphenol A: Emerging organic pollutants along the lower stretch of River Ganga, north-east coast of the Bay of Bengal.

Abstract

Hooghly River (HR), the other name used for the lower stretch of River Ganga, is a prime freshwater source in the eastern part of India. However HR has been evidenced with a variety of emerging organic pollutants (EOPs) in the recent past. Given the extensive use of plasticizers and additive in plastic products, we have investigated seven plasticizers and bisphenol A (BPA) in the surface and storm-water of HR up to the tip of the Bay of Bengal. Further using a previously published sediment data we have estimated the fluxes for the aforementioned EOPs. Surface water and storm-water concentrations of seven plasticizers varied between 92.62 and 770ng/L (176.1±104.8; Avg±SD) and 120.9-781.5ng/L (355.2±232.5), respectively. BPA varied between 43 and 8800ng/L (658.3ng/L±1760) and 117.9-2147ng/L (459.3±620.2) in surface and storm-water, respectively. With the increase in salinity, a decreasing trend for bis-(2-ethylhexyl) phthalate (DEHP) was evidenced. However, concentration of BPA increased with the increase in salinity. Significant and strong correlation between DEHP and BPA (R2=0.6; p<0.01) in the suburban corridor might have resulted from sludge disposal of the scrap recycling activities. Using site-specific principal component analysis, unregulated disposal of plastic waste, particularly from such industrial belts and tourist spots were identified as the possible point sources for plasticizers and BPA in this region. Net diffusive flux based on fugacity fraction showed a trend depending on the pollutant's aqueous solubility and partition coefficient. However, transfer tendency from water to sediment was noticed in the sites having point source. Estimated ecotoxicological risk posed by BPA was higher for edible fishes and for lower order organisms, PAEs was the major contributor.