Microplastics Pollution in Selected Groundwater Sources in Ibadan, Nigeria

Introduction: Groundwater is an important source of freshwater, particularly in developing countries like Nigeria, where it serves as a primary source of drinking water for many households. Microplastics are emerging contaminants of concern in drinking water systems. However, information on their occurrence in groundwater sources and the environmental factors contributing to their presence remains limited in developing countries This study was conducted to investigate the occurrence and characterization of microplastics in selected groundwater sources in Ibadan, as well as to examine the environmental factors contributing to microplastic contamination.

Methods: Groundwater samples were aseptically collected from sixteen (16) dug wells and eight (8) boreholes. The samples were vacuum-filtered onto 0.45micron membrane filter and visually examined under a dissecting microscope. Microplastics were identified based on shape and colour. An observational checklist was used to collect data on environmental conditions surrounding the groundwater sources, including proximity to pollution sites, surrounding land use and the characteristics of the boreholes and wells.

Results: Microplastics were detected in all twenty-four samples, with abundances ranging from 1-120 particles/litre in dug wells and from 1-90 particles/litre in boreholes. Fragments and fibres were the dominant particle shapes, while the particles were identified in brown, orange, blue and red colours. Findings from the observational checklist indicated that stormwater runoff (62.5%), open dumpsites (25.0%) and improper trash disposal (16.7%) were the likely principal sources of microplastic contamination in the groundwater sources studied.

Conclusion: Microplastics were more abundant in dug wells than in boreholes across the studied locations, likely due to contamination from stormwater runoff and improper waste disposal practices.