Determinaton of micro plastic from freshwater environment: lentic environment

Abstract

ABSTRACT: “Micro plastics”, defined as plastics with a diameter of less than 5 mmwhether originating directly from industrial and household products or from the degradation of larger plastics, can have extremely negative effects on the public health and ecosystem and are now frequently found in various water bodies.An additional concern is the ability of microplastics to adsorb inorganic and organic pollutants and subsequently liberate them into marine and freshwater systems. Therefore, the aim of the present study is to estimate microplastic concentration of different urban lentic fresh waterbodies and determine the correlation between different water quality parameters with microplastic concentrations. The present study has been carried out for two seasons (i.e., post-monsoon and pre-monsoon) from 2021-2022. The water bodies identified for the present study are situated within the municipal boundary of Kolkata, West Bengal. In this study, different ponds within the Kolkata Municipal Corporation area were evaluated for the presence of micro plastics in terms of their characterization of water samples, correlation of micro plastics concentration with other water quality parameters, and classification of micro plastics using machine learning technique. . Microplastic abundance in water is measured as items/𝑚3.For determining Pearson correlation coefficient, SPSS-2025 has been used. For morphological classification of microplastic support vector machine (SVM) and MATLAB R-2020a has been used. The highest percentage for microplastic based on the shape were obtained as fibres (58 %), followed by films (11 %), fragments (5.0%), others (22%) and pellets (3.0 %) in post monsoon season.For pre-monsoon seasons out of total 419 microplastic particles collected the main type of plastics observed were fibres (59 %), followed by films (14 %), fragments (9.0%), others (14%), foam (2%) and pellets (2.0 %). No significant differences were found between the post monsoon and pre monsoon seasons based on the abundance, but significantly varied based on size and shape. To study correlation between water quality parameters and microplastics six water quality parameters were considered viz. pH, turbidity, TDS, DO, BOD5 and total coliform count. All the water quality parameters are obtained significantly correlated with microplastic concentration at 90% or 95% significance level. DO concentration is negatively correlated with microplastic where BOD5 and total coliform count are positively correlated with microplastic. Microorganisms are attached with microplastics and consume more DO therefore BOD5 increases while DO decreases with microplastic concentration.The overall accuracy of support vector machine (SVM) for morphological classification is 89 %. Keywords: Micro plastics, lentic environment, water quality