DEPARTMENT OF ENVIRONMENTAL MANAGEMENT & TOXICOLOGY

This study examines the socioeconomic impact of the ban on single-use plastics (SUPs) in Lagos State, Nigeria, with particular attention to households, small businesses, and informal sector workers. The research explores how the ban has affected economic activities, behavioural adaptation, and environmental conditions across the state. A mixed-methods approach was employed, combining quantitative data from questionnaires distributed to traders, households, and micro and small enterprises across selected local government areas with qualitative insights from interviews conducted with officials of the Lagos State Ministry of the Environment, LAWMA, and market leaders. Grounded in the Theory of Planned Behaviour, Just Transition Theory, and the Environmental Kuznets Curve, the study analyses the relationship between behavioural change, economic transition, and environmental sustainability. The findings are expected to reveal both environmental gains—such as improved sanitation and reduced pollution—and economic challenges for low-income groups, offering valuable guidance for a more inclusive and sustainable
transition away from single-use plastics in Lagos State.

This study assessed the physicochemical parameters and heavy metals content in sediments from Orhiomwon River, Edo state, Nigeria. A total of nine (9) sediment samples were collected from the sampling stations from May, 2025 to July, 2025. Physicochemical parameters of sediments were analysed following standard laboratory procedures while selected heavy metals were determined following the method of the association of analytical chemistry. The average mean concentration of physicochemical and heavy metals parameters of sediments were 5.03±0.20 (pH), 43.67±10.44 (EC), 1212.61±165.52 (Ca), 287.33±93.92
(Mg), 297.91±81.39 (K), 161.62±32.71 (Na), 0.05±0.01 (N), 0.51±0.16 (TOC), 92.18±2.39 (sand), 5.94±2.38 (clay), 1.88±0.03 (silt), 2366.74±817.55 (Fe), 18.92±4.58 (Cu), 69.20±19.63 (Zn), 0.04±0.06 (Cd), 6.66±1.48 (Pb), 33.55±23.38 (Mn), 1.49±0.47 (Cr) and
27.24±10.41 (THC) respectively. Heavy metal concentrations followed the order: sand, silt and cadmium showed no significant differences (p > 0.05) across the three stations. On the other hand, pH, electrical conductivity (EC), calcium, magnesium, total organic carbon (TOC), clay, manganese, chromium, and total hydrocarbon content (THC) exhibited significant differences (p < 0.05) while potassium, nitrogen, sodium, iron, copper, zinc and lead showed a high significant difference (p<0.01) among the sediment samples from the different stations of Orhiomwon River. Fe>Zn>Pb>Cu>Mn>Cr>Cd. The results obtained in
this study showed that natural geochemical processes remained the dominant influence on Orhionmwon River sediments as signs of human activity especially from anthropogenic activities are evident.

This study investigates the impact of urban runoff on heavy metal concentrations in Ikpoba River, focusing on water, sediment, and fish gonads. Two sampling stations, upstream and downstream, were selected to assess variations in contamination levels. In August, downstream water samples exhibited significantly elevated lead (Pb) levels (0.037 mg/L) compared to upstream (0.029 mg/L). Similarly, downstream cobalt (Co) concentrations (0.02 mg/L) were higher than upstream (0.016 mg/L). These findings indicate substantial contamination downstream, potentially from industrial sources. Sediment analysis highlighted significant downstream contamination. Lead (Pb) levels in downstream sediments (5.208 mg/kg) were markedly higher than upstream (0.362 mg/kg) in August. Cobalt (Co) also displayed elevated levels downstream (2.067 mg/kg) compared to upstream (1.718 mg/kg). Chromium (Cr) levels showed no significant difference between locations. Gonadal tissue analysis revealed alarming contamination levels. In August, pelagic fish species exhibited higher lead (Pb) concentrations (0.2818 mg/kg) compared to benthic fish (0.3943 mg/kg). Similarly, cobalt (Co) levels were elevated in pelagic fish (0.02825 mg/kg) compared to benthic fish (0.03725 mg/kg). Nickel (Ni) concentrations were also higher in pelagic fish (0.04425 mg/kg) compared to benthic fish (0.04125 mg/kg). These results underscore the vulnerability of pelagic species to heavy metal accumulation. The study reveals a substantial impact of urban runoff on Ikpoba River heavy metal contamination. Elevated lead (Pb) and cobalt (Co) levels in downstream water, sediment, and fish gonads indicate significant pollution, likely originating from industrial activities. Pelagic fish species, in particular, are more susceptible to heavy metal accumulation. Urgent pollution control measures and ongoing monitoring are imperative to protect the river’s ecosystem and the health of communities depending on it. Further research should explore the long-term consequences and potential health risks associated with these heavy metal contaminant