Systematic literature review of heavy metal contamination of the Nigerian environment from E-waste management: associated health and carcinogenic risk assessment.

E-waste -the aftermath of large amount of electrical and electronic equipment ferried into Africa from which Nigeria receives a significant chunk, is composed of components known to be hazardous to health. Composition of series of heavy metals (HMs) in e-waste is traceable to many health conditions including cancer which is hitherto incompletely understood. This study harmonizes primary data on HMs from e-waste in different Nigerian environmental media including the air, soil, surface dust, water and plant. We estimated the possible health implications, single and aggregative soil and water pollution indices in adult and children, carcinogenic and non-carcinogenic risks secondary to HM exposure and mapped out the possible mechanism of carcinogenesis. Analysis showed that soil, water, surface dust and plant matrices in Nigerian environment are variedly but considerably contaminated with combination of HMs. The significantly high values of the hazard quotient and hazard index of both water and surface dust matrices are indicative of adverse health effect of the non-carcinogenic risk. The highest HQ is generated by Pb and Cr through dermal exposure to soil and surface dust with mean values of 1718.48, 1146.14, 1362.10 and 1794.61 respectively among Nigerian children followed by the oral exposure. This pattern of observation is similar to that obtained for adult category. HI due to Pb and Cr in soil constitutes the highest HI (2.05E+03 and 1.18E+03 respectively) followed by surface dust. However, this study precipitates the observation that children are more at health risk than adults in contaminated environment. Carcinogenic risk also follows the same pattern of expression in the Nigerian environment. We conclude that exposure to e-waste poses significant carcinogenic and non-carcinogenic health risks with the carcinogenesis and proposed that the toxicity may be mediated via DNA damage, oxidative stress and inflammatory/immune cells dysfunction in Nigerian environment.

Water contamination: A culprit of serum heavy metals concentration, oxidative stress and health risk among residents of a Nigerian crude oil-producing community.

Niger Delta has become popular for crude oil extraction for the past few decades. This uncoordinated activity has made it a hotspot for xenobiotics exposure and water bodies remain the environmental matrix significantly affected. One of the most deleterious components of crude oil is heavy metals (HMs). This study investigates HMs concentration in water and serum of humans residing in an oil-host community with the consideration of systemic effects, pollution status, carcinogenic and non-carcinogenic health risks and comparison made with residents from a non-oil-producing community. Heavy metal analysis, serum electrolytes, Urea, Creatinine, and liver enzymes were assessed using standard procedures; malondialdehyde, catalase, SOD, glutathione reductase, GPx and total antioxidant capacity (TAC) by spectrophotometry and TNF-α and 8-OHdG assessed via ELISA method. We found altered serum electrolytes; increased serum Pb and Cd levels; increased AST, ALT, ALP and lipid peroxidation; and decreased enzymes antioxidants including TAC among Ugbegugun community residents compared with control. We observed an association between environmental crude oil contamination, ecological and health risks in the community. We concluded that protracted exposure to HMs induces multi-systemic toxicities characterized by DNA damage, depletion of the antioxidant system, and increased free radical generation culminating lipo-peroxidation with significant ecological, carcinogenic, and non-carcinogenic risks characterize crude oil water contamination.

Gastroprotective and mucosa homeostatic activities of coconut milk and water on experimentally induced gastropathies in male wistar rats.

In this biphasic study, 45 male wistar rats were divided into 9 groups. In Phase 1, Group 1 was treated with normal saline and served as the overall control, group 2 was treated with 95% Ethanol and represents the ulcer control, groups 3 and 4 received coconut water (CW; 4ml/100g BWt) and milk (CM; 4ml/100g BWt) for 4weeks while group 5 received Omeprazole (Omep; 20mg/kg BWt) during terminal week. 95% Ethanol-induced ulceration followed the treatments in all except group 1. In the second phase, Group 1 was the overall control, group 2 served as ulcer control by receiving acetic acid only, group 3 received coconut milk, and group 4 received omep. CM and omep were administered post-ulcer induction for 3 and 6days twice daily. Blood collection after 1hour was through cardiac puncture for haemocytometry, and gastric tissues harvested for histopathological investigations. Results showed significantly reduced ulcer score and gastric lesion index in Omep, CW and CM groups compared to ulcer control. WBC, neutrophil, lymphocyte counts in Omep, CW and CM groups were significantly reduced compared to ulcer and overall control groups. C-reactive protein was significantly reduced in CM compared to control. Neutrophil Infiltration score reduced while mucus cell density increased significantly in Omep; CM compared to control. EGFR and CD 31 assessment revealed significantly higher expressions in coconut-milk group compared to the ulcer control. We conclude that the protective effects of coconut (water and milk) is expressed by inflammation suppression, upregulation of mucus cell population and catalyses mucosa homeostasis via angiogenesis and mucosal cell proliferation following mucosa. erosion.