Need of groundwater microplastics study: insights from India

Dependence on groundwater as a freshwater resource is increasing worldwide, yet the study of microplastics (MPs) contamination in groundwater remains limited.Infiltration from landfills, urban runoff, seawater and river discharge through soil pores, fractures and joints in rocks, along with disintegration of the MPs in aquifers, significantly contributes to groundwater contamination by the MPs.The strong hydrophobicity of MPs combined with chemical additives can lead to trace metal enrichment, which may eventually enter groundwater systems.Despite groundwater being a major source of freshwater across the country, research on MPs in groundwater in India began in 2019 and to date, has been largely confined to the state of Tamil Nadu.Existing studies indicate the presence of small-sized MPs, primarily composed of polyethylene and polypropylene, with fibres and fragments being the dominant shapes.Current research is focused on coastal zones and landfill sites, where sampling has been carried out using pumping and filtration techniques.The characterization and quantification of MPs have primarily relied on optical microscopy, infrared spectroscopy, and electron microscopy.However, future research should focus on comprehensive monitoring efforts, identifying MP hotspots, understanding the subsurface migration mechanisms, and investigating behaviour and reactivity at the soil-groundwater interface.