Distribution, Sources, and Heavy Metal Interactions of Microplastics in Groundwater and Sediment of Semi‐Arid Regions of Northwest India
Sunil Kumar, Ameen Musfir, S. Kaushal, Kumar Ajay, Vijay pal Meena, Balasubramanian Karthick, Ambili Anoop
Abstract
ABSTRACT Microplastic (MP) pollution is a growing public health concern, yet its presence in groundwater, a critical potable water source, remains underexplored. This study investigates MPs in groundwater from open and closed well systems, as well as in sediment samples, in the semi‐arid region of Didwana‐Kuchaman, Rajasthan, Northwest India. The MPs, identified using a fluorescence microscope, were ubiquitous at all sampling sites, with groundwater concentrations ranging from 3 to 122 particles/L (average = 35.46 particles/L) and sediment abundance ranging from 170 to 1140 particles/kg (average = 505.52 particles/kg). Morphologically, beads/pellets within the 20–200 μm size range dominated the MP samples, while polyethylene and polystyrene were identified as the dominant polymer types. A significant positive correlation ( r = 0.65) between MP concentration in the sediment and open‐well samples was noted, with the highest values observed near landfills and agricultural areas. Heavy metals (HMs) concentrations (ppb) in groundwater samples were ranked in the following order: As (396.11) > Mn (280.18) > Zn (184.67) > Co (71.8) > Ni (60.56) > Pb (24.24) > Cr (1.26). The hazard quotient derived for both children and adults indicates As > Mn > Pb > Co, significantly above the acceptable threshold (HQ > 1), suggesting a considerable contamination risk. Although no significant correlation was observed between MPs and HMs in the water samples, SEM–EDX analysis revealed the adherence of HMs, including Ni, As, Co, Cr, Zn, Mn, and Pb, to MP surfaces, suggesting potential interactions and co‐transport mechanisms. The results underscore the concerning co‐occurrence of MPs and HMs in groundwater, raising alarming concerns about potential synergistic health effects. This study highlights the urgent need for comprehensive risk assessments and mitigation strategies addressing MP and HM contamination in critical groundwater resources.