From trash to tap: assessment of microplastics contamination in leachate and groundwater

Microplastic (MP) pollution in groundwater is a growing concern due to its toxic properties and harmful effects. Meanwhile, landfills and dumpsites act as storage areas for plastic materials, which gradually disintegrate into microplastics over time, leading to pollution of the surrounding environment. Knowledge of the presence of MPs in the groundwater is scarce, and it is the need of the hour. This article focuses on the MPs migration from the dumpsite to the surrounding groundwater by analyzing the MPs in leachate generated from the dumpsite and MPs found in the groundwater near the solid waste dumpsite region in Ariyamangalam, Tiruchirappalli, Tamil Nadu, India. In this study, the Nile Red staining method has been used to quantify the microplastics with sizes as small as 3.42 μm. The results indicated that the MPs abundance in groundwater is about 11 to 77 particles/L with an average size of 45.16 μm, and in leachate on average, 102 to 140 particles/L were identified with the average size of 152 μm. Based on appearance, most of the MPs are of a fragment’s nature; some films and fibers were also found in the groundwater. Meanwhile, in leachate, fragments (45%) and fibers (44%) were found to be in equal proportion, along with a smaller number of films (11%). From micro-Raman characterization, polyethylene was the dominating polymer, followed by polypropylene, polyethylene terephthalate, polystyrene, polyvinyl chloride, poly methyl methacrylate, polyamide, and polyvinyl alcohol in the groundwater. The risk assessment reveals that the groundwater near the dumpsite zone comes under risk category IV based on the polymer risk index, which means that there is a high risk due to the certain kind of highly toxic polymer present in the groundwater.