Executive Summary : | In India, policies to curb air pollution are mainly focused on exhaust emissions. However, road dust is one of the non-exhaust air pollutants that has evidence of adverse effects on the human respiratory system. In addition, road dust could also alter the biogeochemical cycle of the aquatic environments through stormwater road runoff. Evidence shows that urban road dust could be heavily contaminated with microplastics (MPs) and per/polyfluorinated substances (PFAs), two of the major emerging contaminants of the modern world. MPs in hydro systems could adversely impact aquatic animals through digestive obstruction, and impaired reproduction causing up to 250 million pounds of economic loss globally. On the other hand, a cluster of organo-fluoride chemicals, or PFAs are now among the top emerging pollutants having an adverse toxicological effect on the flora and fauna of the aquatic bodies. Minimum exposure to PFAs can be extremely harmful to living cells as they can bioaccumulate for up to nine years for their high-fat solubility. The interconnection between MPs and PFAs is now also well established as some of the PFAs such as fluoropolymers or poly/perfluoropolyether can break down into MPs. As previously mentioned, urban road dust remains heavily contaminated with both these emerging pollutants, the untreated storm-water run-off could effectively transport these two pollutants to the aquatic ecosystems. However, despite the harmful effects, studies on the MPs and PFAs are very limited in India. In fact, to date no study has ever been conducted in India, investigating MPs and PFAs on urban road dust-leached stormwater run-off. The present study proposes to investigate the concentration, chemical character, and speciation of MPs and some selected PFAs in the stormwater run-off over a densely populated urban atmosphere Kolkata, situated in the Gangetic Delta. The city is surrounded by major aquatic systems such as the river Ganges, the East Kolkata wetlands, and the Sundarban Mangrove ecosystem. Many studies have reported high road dust emission in Kolkata and thus the stormwater run-off is expected to be contaminated with MPs and PFAs. Samples would be collected from the six locations across the city out of which two would be close to the irrigation canals connected with Sundarbans, two would be near the East Kolkata wetland and two would be close to the Ganges. For each category, one sampling site would be near the residential/slum area, and the other would-be major traffic/commercial junction. Samples would be processed and analyzed with a Scanning Electron Microscope (SEM) and FTIR for the number, morphology, and functional group detection of MPs. On the other hand, samples would be processed and chemically analyzed in an LC-MS for detecting the PFAs. The proposed study hence would add value to understanding the importance of managing urban road dust to not only just prevent inhalation health risks but also to restrict aquatic contamination. |