High Levels of Heavy Metals in Blood of the Urban Population in Nigeria

Two hundred and forty blood samples were collected from children, women and men in urban area of Enugu State. The samples were analyzed for nickel, manganese and chromium by atomic absorption spectrophotometer after wet digestion using 1:3 concentrated perchloric and nitric acid. The results of the analysis in ppm show the range and % detectable values as Ni(0.007-0.850)57.08%, Mn(0.006-0.861) 84.60% and Cr(0.006-0.829) 47.00%. The concentrations of the heavy metals were very high as most exceeded the World Health Organization permissible limit. The sample population was classified as pregnant women/nursing mothers and other women, according to age groups (,12, 13-25 and >25 years), sex, occupationally and non occupationally exposed and also as those exposed/or not exposed to some probably risk factors to be associated with the heavy metals. This was done to find out if there is a trend with the different categories which will help in identifying toxicity risk groups of the heavy metals in the country using complete randomized design (ANOVA) and t-test. Children (,12 years) had the highest mean concentrations of nickel and chromium. Males also had higher mean concentrations for nickel and chromium, while pregnant women/nursing mothers had lower mean concentrations than the other women for the heavy metals. There were significant differences between the responses for some of the factors. However, no risk factor could be pinpointed since, this study was not based on any pollution point source rather, on various diffuse (non-point) sources.