G. E. Eriyamremu

This study aimed to determine metal analysis on the soil, weight changes, antioxidant defense systems, level of malondialdehyde, lipid content, the phospholipids profile, the activity for two weeks of energy and some enzymes in energy metabolism, and the lipid profile in tadpoles exposed to effluents from automobile workshops. Tadpoles were obtained from runoff water containing effluents used in automobile workshops from two different sites (Evbarake and Uwelu) in Benin City, Nigeria were used in this study. A total of 60 tadpoles were divided into three Groups with each group containing 20 tadpoles. Group 1 served as the control. Group 2 Evbarake site. Group 3 Uwelu site. Soil samples were collected from Capitol University of Benin Control group and automobile workshops (Exposed groups) respectively. The animals were maintained for the study period of two weeks with their requisite sample soil/water from the respective sites. Metal analysis on the soil, weight changes, antioxidant defense systems, level of malondialdehyde, lipid content, the phospholipids profile, the activity for two weeks of energy and some enzymes in energy metabolism, and the lipid profile were analyzed using standard methods. The data from Table 4.1 show that the heavy metal analysis were significantly (p < 0.05) higher than the control. The malondyaldehyde levels were significantly (p < 0.05) higher in tadpoles from both sites compared to the control group. The Evbarake site showed a significant (p < 0.05) increase in catalase activity compared to the control, while the Uwelu site showed a slight decrease. The glutathione peroxidase activity was significantly increased in tadpoles from both test sites when compared to the control. Aldehyde oxidase activity was significantly higher in tadpoles from both contaminated sites compared to the control. The results demonstrated that the exposure led to a significant (p < 0.05) increase in total lipids, triacylglycerol, low density lipoproteins and high density lipoproteins in a site-dependent manner. The exposure led to a significant increase in glucose levels. It was also observed that the exposure of tadpoles within the test sites decreased the weight of tadpoles and final weight of head region in tadpoles from the Uwelu site showed a significant decrease when compared to those from the control site (p < 0.05). Overall, this study provides important insights into the potential health risks associated with effluents exposure including alteration in glucose metabolism, antioxidant enzymes activity, and lipid peroxidation in the presence of effluents which may cause oxidative stress in the test sites. Further research is needed to fully elucidate the underlying mechanisms and potential longterm effect of this exposure.

The presence of petroleum-derived compounds in the soil constitutes a significant threat to soil health and agricultural productivity. In the search for the environmentally friendly approach in the bioremediation strategies for restoration of soil health, cassava mill effluent (CME) provides an accessible, available and affordable nutrient-rich organic biowaste of cassava processing for the application of organic amendment and a sustainable biostimulant for restoration of soil health. This study investigated the efficiency of CME as a source of organic nutrients in the biorestoration of hydrocarbon degraded soil for a sustainable bioremediation strategy. This was achieved by polluting clean soil, collected and weighed into containers, with spent lubricating oil (SLO) as the source of petroleum hydrocarbon at 10% (w/w), amended with CME at 2.5% (v/w) at different frequency of daily, weekly, monthly and once for a period of six months but the control soil was not treated. The percentage changes in the quality of the amended soil were monitored at 3 and 6 months periods. Cowpea (Vigna unguiculata) were grown on the amended soils at the end of the treatment to evaluate recovery of soil quality and function. Baseline data were collected at the start of the study, and others at 3 and 6 months. For physicochemical changes in the soil, the following parameters were analysed: Soil texture, pH, cation exchange capacity (K+, Na+, Ca2+, Mg2+, Al3+), electrical conductivity (EC), total petroleum hydrocarbon (THC), and metals (Fe, Zn, Pb). Nitrogen (N2) and Phosphorus (P) contents, total organic carbon (TOC) and organic matter (OM) were also analysed. The biological activities assessed include the activities of soil enzymes (urease, phosphatase, dehydrogenase, fluorescein diacetate hydrolase and glucosidase), and microbial load