Biomonitoring of Heavy Metals in Blood and Urine of African Children from OwerriMetropolis, Eastern Nigeria

Abstract

Childhood illnesses have been linked to elevated heavy metals in children's bodies. Such studies are lacking in developing countries despite the fact that African children could be most exposed to heavy metals. This study determines the concentrations of heavy metals in blood and urine of children in selected schools within Owerri metropolis. Consent and due process were followed to obtain blood and urine samples from 60 children. Samples were digested with nitric and hydrochloric acids for 6 hours at 90^o C and analyzed using Perkin Elmer 400 A analyst atomic absorption spectrometer. Mean concentrations in blood was Pb (4.517±1.599 mgl^-1); Cd (1.04±0.671 mgl^-1); Ni (5.612±1.237 mgl^-1); Mn (7.198±4.705 mgl^-1) and Cr (0.288 ±0.412 mgl^-1). In urine; Pb (1.912±1.219 mgl^-1); Cd (0.39±0.138 mgl^-1); Ni (3.988±1.230 mgl^-1); Mn (3.099±0.990 mgl^-1) and Cr (20.773 ±10.449 mgl^-1) were generally lower than concentrations in blood. Maximum metals concentrations in blood were higher than values for USA Academy of pediatrics. Except at WBP, Cr was highest concentrations within each school. Order of prevalence (%) was Pb> Ni > Cr >Mn> Cd in blood and Cd >Mn>Pb> Ni > Cr in urine. Variability revealed moderate to high with Cr (143%) as highest for blood while Pb (63.76%) was highest in urine. There was low relationship between metal in blood and urine as R² values ranged between manganese (0.006) to nickel (0.216). The prominent trend of metal was Mn - Cr as highest and lowest concentrations respectively. Metal diagnostic ratios revealed very undesirable values for Cd (4.05) and Mn (3.545) in blood. Currently no standards for metals in blood and urine for African children, metal concentrations in the present study were elevated. Government agencies and policy makers need to act in time to reduce the potential danger in the near future.