Spatio-temporal patterns of microplastic contamination in surface waters of Hooghly River Estuary: Causes and consequences

We conducted a pilot study in Hooghly River Estuary (HRE) at ten stations covering rural, urban and tidally mixed stretches to the confluence to quantify levels of microplastic (MP) contamination in HRE, the first distributary of the major River Ganga. Surface water samples from the HRE were contaminated with MPs. Stations, within the city recorded the highest concentration of MPs. Filamentous type and white/transparent MPs were found in higher concentrations. The MP concentration was positively correlated with population density, and volume of sewage discharged in the vicinity. Size range of abundant MPs suggests that larger copepods, ichthyoplankton and zooplanktivorous fish are more susceptible to MP ingestion and interference. This study provides an insight into the MP contamination in lower stretch of the river estuary and impacts of Kolkata city on MP pollution, which can be used as baseline information in predicting the peak contaminated stretch and appraise precise mitigation. [Display omitted] •Microplastics (MP) pollution in surface water of Bhagirathi-Hooghly River Estuary was detected.•The highest MP concentration was recorded at station within the Metropolitan city Kolkata.•White/transparent color-filamentous type were found in higher concentration.•The MP concentration increased with increasing sewage discharge volume and population density.•Copepods, ichthyoplankton and zooplanktivorous fish are more susceptible to MP ingestion.