Microplastics in groundwater: An overview of source, distribution, mobility constraints and potential health impacts during the anthropocene

Microplastics (MPs) have already been detected in various environmental matrices like soil, sediment, and surface water, and recently in groundwater also. The occurrence of MPs in groundwater depends up on the transportation through recharge and may controlled by source and local hydrogeology, and partly on the process of surface water-groundwater interaction (SW-GW). Based on the available studies, we intended to establish a hypothetical overview on the source and process-dependent occurrence of MPs in groundwater across terrestrial and coastal aquifers. Groundwater recharge from agricultural stagnant water, losing streams near dumping sites and agricultural fields, effluents from wastewater treatment plants, septic system failure etc. are the potential sources of MPs in groundwater. The factors like sea level rise and tidal pumping are among the major factors which may control the migration of MPs in coastal aquifer along with the physical and chemical properties of the aquifer media. These MPs have another ecological concern as they can adsorb persistent organic pollutants as well as heavy metals and transfer them to animal tissues through food chain. Studies are being conducted mainly focusing the MP contamination in surface water, marine environment and soil, and very limited studies are available to address the source of MPs in groundwater. However, no such study has been done on the existence, profusion, or environmental factors that contribute to MP pollution in the groundwater in relation to the present climate change scenario. Understanding the extent of MP contamination in groundwater systems is necessary for developing effective management strategies and minimizing their impact on the environment and human health. This study focusses on the source along with the controlling factors of the migration of MPs towards groundwater including the effect of climate change.