ASSESSMENT OF MICROPLASTIC POLLUTION AND ENVIRONMENTAL HEALTH RISKS IN RURAL COMMUNITIES OF SOUTHWEST NIGERIA

Abstract

Microplastics, plastic particles smaller than five millimetres, have emerged as a pervasive and
serious environmental contaminant, detected in water, soil, air and living organisms across the
globe. This study assessed and characterised microplastic pollution and evaluated its associated
environmental and human-health risks in rural communities of Southwest Nigeria. A field-andlaboratory research design was employed, sampling water, sediment and soil from three
purposively selected rural communities across Osun, Oyo and Ogun States. Microplastics were
extracted using density separation and organic-matter digestion, with particles quantified and
characterised by abundance, size, shape and colour using stereomicroscopy, and polymer types
identified using FTIR spectroscopy. Results showed microplastic abundance in water samples
ranging from 12.4 to 28.6 particles/L (mean 18.6 ± 4.8 particles/L), sediment from 84.2 to 216.4
particles/kg (mean 142.6 ± 48.2 particles/kg), and soil from 62.8 to 184.6 particles/kg (mean 118.4
± 40.6 particles/kg). The dominant polymer types were polyethylene (PE, 38.6%), polypropylene
(PP, 28.4%) and polystyrene (PS, 16.2%). The most abundant particle sizes were 0.5-1.0 mm
(34.8%) and 1.0-2.0 mm (28.6%), with fibres (42.4%) and fragments (36.8%) being the dominant
shapes. Probable sources identified included improper waste disposal, agricultural plastic use
and domestic laundry wastewater. Human-health risk evaluation indicated moderate to high risk
from microplastic exposure through drinking water and food consumption, with children identified
as the most vulnerable group. The study provides the first integrated, multi-matrix assessment of
microplastic pollution in rural Southwest Nigeria and offers evidence-based mitigation
recommendations for protecting environmental health.