AUTHOR: ILO, ELOCHUKWU CAJETAN
DEPARTMENT: APPLIED MICROBIOLOGY AND BREWING
AFFILIATION: NNAMDI AZIKIWE UNIVERSITY, AWKA
The rat sub-chronic toxicity study (dose-response relationship) and the assessment of Antimony concentration in Nigerian bottled water samples (exposure assessment) were the two complimentary studies that sought to estimate the Antimony risk in Nigeria via drinking water. The rat sub-chronic toxicity study that lasted for four months was done by inducing toxicity in 128 male albino rats, with Antimony Potassium tartrate (APT). The rats were 8 weeks old at the time of acclimatization with average weight of 115g. Each group has eight rats housed in a cage (A, B, C and D) exposed to 5mg APT/L (A), 50mgAPT/L (B) and 500mg APT/L (C) and the unexposed group (D) respectively. The APT was dissolved in drinking water that served as the only source of water for 3 months, the fourth month of study was the wash out period. There was a monthly control group that was not exposed to APT. At the end of each month of study, a total of 32 rats were sacrificed. Blood collection via cardiac puncture was facilitated with Ether sedation. Blood for toxicological analysis sought to establish toxicological end points (TEP) or point of departure (POD) with some biochemical, Heamatological, Semen and weight changes. The tissues of the right kidney, liver and right testis were harvested for histopathological analysis. The data for the rat study was analyzed with graph pad prism version 5.03 that displayed the descriptive statistics (mean, standard deviation, median and graphs) while the inferential statistics employed the unpaired t test and Mann Whitney for two comparisons when control was compared to the 5, 50 and 500mg monthly. Then 1 way ANOVA was used to compare all the groups together. The significant change occurs when p<0.05. The toxicological end points(TEP) in the first month occurred in the following parameters: Thiobarbituric reactive substances mg5 and 500mg groups, Total protein 5mg and 500mg, groups, Albumin 5mg group, sluggish sperm and non motile sperm count 500mg groups reduced weight gain, relative liver weight and Glutathione 5mg group were compared to their respective controls with p value of 0.01,0,02,0.0016,0.0024,0.004,0.02,.0.028, 0.03,0.025 0.01. In the second month the TEP occurred when urea 5mg group, Creatinine 50mg and 500 mg groups, Total anti oxidant capacity 50 and 500mg groups, relative kidney weight 5mg and 50mg groups and relative liver weight 5mg, 50mg and 500mg groups and liver weight 500mg group were compared to their respective controls with p value of 0.02,0.008,0.01,0.026,0.0082,0.045,0.03, 0.028,0.043,0.007 and 0.03. While the TEP in the third month occurred when total sperm count for 5mg, 50mg and 500mg groups were compared with control with p value of 0.02, 0.02 and 0.028 respectively. There was no TEP for the Total white blood count, Neutrophil, Lymphocytes and Packed cell volume comparison to their respective controls. Antimony concentration was estimated with Atomic Absorption spectrophotometer (AAS) of the Biotechnology Department of Nnamdi Azikiwe University, Awka. The Antimony concentration in bottled water data were analyzed with single t test with a Mean of 3.08ppm, standard deviation of 0.07 and SEM of 0.014.The gross histopathology showed that liver was the only organ severally affected by focal piece meal and lobular necrosis by as low as 5mg APT/l after 3 months. The point of departure (POD) or lowest observed adverse effect level (LOAEL) therefore is 5mg/l corresponding to a no observed adverse effect level (NOAEL) of 0.5mg/l and a reference dose (RfD) OF 0.005mg/l. The relative source contamination (RSC) is 0.001. In conclusion the results of this study showed that Antimony is toxic to rats (by extrapolation to man) and the bottled water content of Antimony in Nigeria was higher than expected normal. Therefore it suggests that man may be at the risk of Antimony toxicity from consumption of bottled water in Nigeria.
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Tags: Acute Toxicity, Anti-oxidant Status, Antimony Potassium Tartrate, Antimony Water Sources, Chemical Risk Assessment, Clinical Chemistry., Dead Rats, Environmental Exposure, Exposure Assessment, Exposure Model Equation, Glutathione Assay, Haematology, Hazard Identification, Human Exposure, Indole Test, Kidney Histology, National Toxicology Program, Necropsy, Pharmaceutical Sciences, Pharmacology and Therapeutics-PhD-2014, Photomicogrphs, Plasma Creatinine Estimation, Plasma Urea Nitrogen Estimation, Relative Source Contribution, Sperm analysis, Sub-chronic Toxicity, Subchronic Toxicity, Sudden Infant Death Syndrome, Thiobarbituric Acid Reactive Substance, Total Anti-Oxidant Capacity, Total White Blood Count, Valency, Voges Proskauer