Sources and Factors Influencing Microplastic Concentration during Monsoon Season in Ganga River, Bihar, India

Abstract The aquatic ecology is becoming more and more vulnerable to the harmful effects of microplastic (MP) pollution. One of India's longest rivers, the Ganga, is home to an enormous variety of wildlife. The Ganga River receives untreated residential and industrial waste from major Indian cities situated on its banks, in addition to traffic trash that is mostly responsible for the occurrence of MP. The purpose of this study is to clarify the distribution of MP in the Ganga at sampling sites (S1 to S3) in the Patna area during the monsoon season based on their size, shape, and kind. All surface water samples along the Ganga were found to contain MP, with the greatest concentrations (946.5 ± 48.7 particles per m3) found in S2 of Patna city. In the surface water, the average MP concentration across the three sites was 858.5 ± 224.34 (SD) particles per m3 (1.05 particles L-1). Moreover, fiber and fragment particles dominated the MP distribution. The concentration of MP showed a positive correlation with both the number of drains in the Ganga River that discharged untreated and runoff water (r = 0.62; p < 0.05) and the population density in the area (r = 0.87; p < 0.05). With a buffer radius of two kilometers, MP were positively correlated with both urbanization and precipitation; the correlation coefficients in the buffer were (0.49; p < 0.05 and 0.92; p < 0.05, respectively). This study provides fresh insights into the effects of heavily urbanized cities on MP pollution and increases our understanding of MP pollution in the Ganga. These insights can be utilized as baseline data to assess specific mitigation strategies.