ABSTRACT

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Vegetable fields in Katsina State are increasingly being loaded with heavy metals through various pollution sources such as agricultural activities mining and traffic. Onion bulb samples from the three senatorial zones that constitute to make up Katsina state in the North West of Nigeria were collected and the concentrations of seven heavy metals (Pb, Cd, Cr, Fe, Zn, Mn and Ni) in all the samples were determined by atomic absorption spectrometry. The health risk assessment methods developed by the United States Environmental Protection Agency (US EPA) were employed to explore the potential health hazards of heavy metals in the samples on the children and adult population. The highest mean concentration (mg/kg) was observed for Fe, followed by Pb, Zn and Mn. While Cd has the lowest concentration with the heavy metals Cr and Ni being below detection level (BDL). Overall hazard index (Hi) for the heavy metals were within the safety limit. The overall cancer risk to the adults based on pseudo-total metal concentrations exceeded the target value, mainly contributed by Pb.  Mn and Zn were the primary heavy metals posing non-cancer risks while Pb caused the greatest cancer risk. It was concluded that consumption of the onion samples from Katsina State may contribute to the population cancer burden.

Aim: To investigate the effect of Carica papaya seed extract on KBrO3 - induced nephrotoxicity in rats. Renal toxicity was induced by a single oral dose of 100 mg/kg body weight of KBrO3. Study Design: Thirty (30) male albino rats were divided into six groups, five rats per group; normal control, KBrO3 control, papaya control and KBrO3 group administered with methanol seed extract of 200 mg/kg, 400 mg/kg and 600 mg/kg body weight for 48 hours. Place and Duration of Study: Department of Biochemistry Laboratory, Faculty of Basic Medical Sciences, Bayero University Kano, Nigeria, from April 2018 to August 2018. Methodology: Serum urea, creatinine, uric acid and electrolytes were determined using kits from randox laboratories. Furthermore, activities of renal brush border membrane marker enzymes namely γ-glutamyltransferase (GGT), alkaline phosphatase (ALP), maltase (Mal) and leucine aminopeptidase (LAP) and some parameters of oxidative stress including catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), reduced glutathione (GSH) and malondialdehyde (MDA) were determined in homogenates prepared from renal cortex and medulla of the kidney of rats using colorimetric methods. Results: Administration of KBrO3 significantly (P<0.05) increases the serum levels of urea, creatinine, uric acid and all electrolytes studied in a dose-dependent fashion from 200mg/kg to 400mg/kg and 600mg/kg in that order. Furthermore, the activities of GGT, ALP, Mal and LAP decrease in renal homogenates with KBrO3 administration. Also the activities of CAT, SOD, GPx and level of GSH decreases while the level of MDA significantly (P<0.05) increases however concurrent administration of Carica papaya seed extract prevented all the KBrO3- induced changes in the biochemical parameters studied . Conclusion: It was suggested that methanol seed extract of Carica papaya possess nephroprotective effect against KBrO3 –induced renal toxicity and oxidative stress, and the most effective dose was 600 mg/kg body weight.

This study was conducted in the year 2016 to determine the heavy metal concentrations in whole fish (Clarias gariepinus) samples and water obtained from some selected Dams (Ajiwa, Zobe and Dannakola) in Katsina state Nigeria. The objectives were mainly to detect the presence of heavy metals in whole fish and water from some selected Dams in the study area, compare the concentration of heavy metals in samples from the selected Dams concerning the permissible limits specified by WHO/FAO and USEPA Standards. Eight (8) water samples were collected at 8 random points within approximately 1000 meters on each extremity and median parts of the selected dams. Fish (Clarias gariepinus) was sampled using standard methods (AOAC, 1990). The fish and water samples were collected from Ajiwa, Zobe and Dannakola Dams of Katsina state Nigeria. Nine adult fish samples, three each from Ajiwa Dam, and Dannakola were procured from fishermen. Analysis of the concentration of these heavy metals; Cr, Cd, Fe, Ni, Mn, Pb and Zn was conducted by the use of AAS (by Atomic Absorption Spectrophotometry) method. The results showed wide mean concentrations of the heavy metals in the selected dams water; iron recorded the highest level (range 0.4596 μg / g - 2.9510 μg / g) and lead (range 0.0031 μg / g -0.0323 μg / g) recorded the lowest level, for the fish samples the mean concentrations of the same heavy metals showed iron recording the highest level (range 1.8847 μg / g -10.0474 μg / g) and cadmium (0.0130 μg / g -0.0138 μg / g) recording the lowest level. Results from this study indicate that with the exception of the heavy metals Cd, Fe and Pb (from Zobe dam sample) values of  Mn, Pb (Ajiwa and Dannakola dams samples) and Zn in the water samples were generally lower than the USEPA, WHO/FAO maximum permissive limits while Ni was below the detection level (BDL) in all the samples. the results of this study showed that apart from Mn (PI range = 0.02-0.09), Zn (PI range = 0.01-0.03) and Pb for sampled water from Dannakola dam (PI= 0.77) which have no effect on the water quality, all the other heavy metals have pollution indices which suggest slightly, to moderate and strong effect on the selected dams water quality consideration for human and aquatic health. The metal indices also showed that all the heavy metals are at the threshold level (MI > 1) except for the heavy metals Mn and Zn in sampled waters from all the selected dams, Pb for water samples from Ajiwa and Dannakola dams and Cr for Zobe dam water sample. With the exception of the heavy metals Pb, Ni and Cr that were BDL in the fish samples the levels of the heavy metals all fall below the USEPA, WHO/FAO permissible limit for fish. The results from the present study suggests that the selected dams water quality is threatened by heavy metals pollution and may have adverse implication for drinking and aquatic health, in the fish samples the concentration levels of the heavy metals all fall below the USEPA, WHO/FAO permissible limit for fish.  However, the fish’s bio-accumulation factors of the metals suggest that they have high potentials to bio-accumulate some of the heavy metals to high levels and this may have adverse implication for human consumption.