The toxicity of Paraquat dichloride, a herbicide, was investigated with emphasis on histopathological effects of African Catfish (Clarias gariepinus) juvenile. The fishes were exposed to 0, 20, 60, 80, 110 mg/l of Paraquat dichloride .,The lethal concentration (LC 50 ) value of Paraquat dichloride was 1.75mg/l for 96 h of exposure. Histopathology of the organs after 96 hr exposure revealed cell proliferation, lamellar fusion, lamellar cell hyperplasia, and epithelial lifting. In the liver, there was vacuolation of hepatocytes and necrosis. The changes in these tissues occur predominantly in the 96 hr exposure. Respiratory stress, erratic swimming and instant death of fish were observed in exposed fish, which varied with the concentration of the toxicant. Paraquat dichloride is highly toxic to Clarias gariepinus, therefore its use near fish farms or in areas close to aquatic bodies should not be encouraged.

Organophosphate pesticides, commonly used in large scale farming, have been found to be major contaminants in aquatic environment. Clarias gariepinus was exposed to acute and sublethal concentrations of phostoxin and DD Force to evaluate single and joint action toxicity of the organophosphates. Effects of phostoxin and DD force on antioxidant enzymes, fish organs and acetylcholinesterase levels in fingerlings and juveniles of C. gariepinus were also investigated. The lethal concentrations (96 h LC50) for phostoxin and DD Force were 0.631 and 1.759 mg/l, respectively. The results obtained from the bioassay showed that phostoxin was 2.8× more toxic than DD Force after exposure of C. gariepinus. Joint action toxicity evaluations of phostoxin and DD Force showed that the interaction between the chemicals was synergistic (RTU >1). The biochemical responses in the exposed fish differed significantly (P < 0.05) from the control fish. The result of acetylcholinesterase study revealed significant difference between acetylcholinesterase levels in the exposed fish and control, with reduction in the acetylcholineterase level in fish exposed to sublethal concentrations of phostoxin and DD Force. Haematological studies revealed an increase in WBC, RBC, PCV and platelets in the exposed fish. Histopathology of the gills showed shortened primary lamellae, loss of secondary lamellae and loss of ceratobrachial bones. In the acute toxicity studies, respiratory stress, erratic swimming and instant death of fish were observed in the exposed fish. This study reveals that changes in histopathology and acetylcholinesterase level are good biomarkers and can be successfully used to detect exposure to organophosphates pesticides in fish.

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In an 8-week feeding experiment, 32 growing buck rabbits (Oryctolagus cuniculus) of an average weight of 1366.56±37.54g, were used to assess the effects of inclusion of different ISSN 2166-0379 2015 www.macrothink.org/jas 167 dietary concentrations of Cerium oxide (CeO), a Rare Earth Element, at 0, 50, 100 and 150 ppm on fertility. The animals were randomly allotted to the four dietary groups, each consisting of eight animals per treatment. The Extra-gonadal Sperm Reserve (the sperm stored in the caput, corpus and cauda epididymis), the testes weights and the daily sperm production (DSP) were estimated. The results revealed that the extra-gonadal Sperm Reserves (ESR) were significantly (P<0.05) increased by dietary cerium oxide at 100 ppm inclusion. Sperm reserves were higher in bucks fed dietary cerium oxide compared with those fed control diet and the highest value recorded at 100 ppm level of inclusion. The results also showed that the testes weights and the daily sperm production (DSP) per testes of the buck rabbits were significantly (P<0.05) increased. The testes of the animals fed diets containing 50-150 ppm dietary cerium oxide had good and normal testicular generation and proper process of spermatogenesis. Therefore, feeding diets supplemented with cerium oxide to buck rabbits to be used for breeding would positively influence sperm production. Journal of Agricultural Studies

Any electrical or electronic equipment that is taken to no longer be capable of performing the function for which it was originally intended is an e-waste. Due to their hazardous material contents, Waste Electrical and Electronic Equipment (WEEE) may cause environmental problems during the waste management phase if it is not properly pre-treated.3 The presence of elements like lead, mercury, arsenic, cadmium, selenium and hexavalent chromium and flame retardants beyond threshold quantities in WEEE/e-waste implicates them as hazardous waste. Nigeria has emerged the most important African importing country for new and used electronic and electrical equipment (EEE), which are shipped largely from the United Kingdom (UK). In Nigeria, many e-waste fractions cannot be managed appropriately, which is resulting in the accumulation of large hazardous waste volumes in and around major refurbishing and recycling centers. Furthermore, some recycling practices – like the open burning of cables and plastic parts – cause severe emissions of pollutants such as heavy metals and dioxins. The aim of this study is to determine the concentration of heavy metals (Pb, Zn, Cd, Ni, Cr and Cu) in soil and water samples collected from and around electronic waste dumpsites in different parts of Lagos state in Nigeria (computer village (Ikeja), Alaba International Market (Ojo) and Westminister (Apapa).