Environmental Studies Journal
Volume 4, No. 1, 2025
Pages 32-65
DOI: 10.36108/esj/5202.40.0130
Assessment of Microplastics Contamination and Soil Quality Parameters Across Farmlands in Lagos State: A Seasonal Comparative Study
* OLU Joshua1, SAMAILA Ishaya Kunden2, YUSUF, Hajara Oyiza3, SANGARI Dalhatu Usman2, HAYATU, Sa’adatu Jauro3
1HONA Tech Ltd., FCT Abuja, Nigeria
2Faculty of Environmental Science, Nasarawa State University, Keffi
3Bio entrepreneurship and Consultancy Services Department, National Biotechnology Research and Development Agency, Umaru Musa Yar’adua Expressway, Lugbe, Abuja – Nigeria
*Corresponding Author- Email: olu@lujosh.com Orcid No: https://orcid.org/0000-0002-5865-3640
Abstract
This study evaluates soil quality parameters and microplastic contamination at 0-15 cm and 15-30 cm soil depths in farmlands from four Local Government Areas (LGA); Badagry, Epe, Ikorodu, and Ojo, Lagos State, Nigeria, during the dry and rainy seasons. A total of 120 soil samples were collected, and were analyzed for physicochemical properties (used in determining soil quality index-SQI) and microplastics characteristics. Across all sites, SQI values in the dry season ranged from 0.38-0.46 (additive) and 0.39-0.47 (weighted) while the values were 0.38-0.52 (additive) and 0.38-0.57 (weighted) in rainy season. Ojo LGA exhibited the highest SQI in both seasons. Microplastics contamination showed significant level of spatial heterogeneity with Ikorodu showing the highest concentration for all parameters (146.67-184.58 particles at 0-15 cm depth). Surface soils had much higher microplastic abundances than subsurface layers indicating a low amount of vertical migration. The overall increase in microplastic concentrations was shown during the rainy season, which may indicate improved mobilization by surface runoff and infiltration. Redundancy Analysis (RDA) showed that the R2 of the full model was 88.3% to explain variance of microplastics (Adjusted R2=0.861, p<0.001), in which 53.3% unique variance was attributed to LGA and the remaining 0.95% unique variance attributed to soil physicochemical properties (mainly organic carbon and organic matter). Depth-stratified analysis revealed soil characteristics accounted for a much greater amount of variance in subsurface horizons (Adjusted R2=0.472) than in surface layers (Adjusted R2=0.172). These findings highlight the importance of coupled waste management strategies and agricultural best practices to reduce microplastics accumulation in agricultural systems in the tropics.
Keywords: Farmland, Lagos State, Microplastics, Redundancy Analysis, Soil Quality Index.
