Investigations on the co-occurrence of microplastics and other pollutants in the River Yamuna, Delhi

Abstract The Yamuna River is a threatened resource of freshwater in Delhi, India. The present study is focused on investigating three important contaminants, namely microplastics (MPs), heavy metals, and fecal coliforms in the surface water of the river, with major emphasis on MPs occurrence and characterization. MPs showed an increase in abundance in the river from the Wazirabad barrage (n = 500 MPs/m3) to the Okhla barrage downstream (n = 3,900 MPs/m3) in Delhi, with a maximum abundance downstream to the Najafgarh and Shahdara drain outfalls. White color and fragmented shape were prevalent characteristics of the isolated MPs. Attenuated total reflectance–Fourier transform infrared (ATR-FTIR) spectroscopy revealed five types of polymers. Heavy metals (chromium, lead, manganese, and iron) and fecal coliforms were at unacceptable levels at most of the sampling sites. Due to the emergence of issues concerning the tendency of MPs to actively interact with heavy metals and pathogenic microorganisms, investigation of the co-occurrence of such harmful pollutants is very important. The present study is aimed at this issue and urges similar kinds of investigations in other riverine regions of our country, as well as globally, due to their scarcity in literature. This study can further provide a baseline database to help the Government of India's efforts to clean and revive the Delhi stretch of the Yamuna River.