Assessment of Plant Species and Physico-Chemical Properties of Three Landfills in Lagos, Nigeria

Abstract

Indiscriminate disposal of municipal solid waste (MSW) poses significant environmental risks due to heavy metal accumulation in soils. This study assessed phytodiversity and physicochemical properties of soils from three dumpsites in Lagos State, Nigeria (Ajelogo, Oworonshoki, and University of Lagos), alongside a control site. Soil samples were collected at 0–10cm depth using a calibrated auger at 40m intervals, while plant diversity was assessed using quadrat sampling. Physicochemical parameters and heavy metals were analysed using standard procedures, including Atomic Absorption Spectrophotometry (AAS). Data were analysed using descriptive statistics and one-way ANOVA at a 0.05 significance level. Fourteen taxa across eight families were recorded, with Poaceae and Amaranthaceae dominating. Amaranthus spinosus, A. viridis, and Commelina benghalensis were widely distributed. Soil pH ranged from 7.04 to 7.89, indicating neutral to slightly alkaline conditions. Total organic carbon (0.91–2.06%) and nitrogen (0.21–0.95%) were higher in dumpsites than in the control. Heavy metals such as Cr, Fe, and Zn were elevated across sites. Although most heavy metal concentrations were within permissible limits for compost use, their accumulation suggests potential ecological risks. Dumpsite soils supported plant growth but are unsuitable for agriculture due to contamination concerns. Improved waste management practices, including sanitary landfill development and waste segregation, are recommended to reduce environmental impact.