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Bioaccumulation and Human Health Risk of Heavy Metals from Pesticides in Some Crops Grown in Plateau State, Nigeria
* 1 , 2 , 2 , 2 , 3
1  Department of Biological Sciences, Bayero University Kano, Nigeria.
2  Department of Applied Ecology Abubakar Tafawa Balewa University, P.M.B. 0248, Bauchi, Nigeria
3  Aminu Saleh college of education, Azare Bauchi State, Nigeria


The health risk assessment of heavy metals in food crops fumigated with pesticides as the only source of contamination are mostly overlooked. This study determined the concentrations of heavy metals (Cd, Pb, Cr, Cu and Zn) in some food crops and soil fumigated with pesticides from agricultural farms and their health risk in human. The mean concentrations of heavy metals in different parts of the crops ranged from 0.12-2.03, 1.73 -23.34, 1.60-1150.50, 0.67 -19.50, 0.09 -6.14-mg/kg for Zn, Pb, Cu, Cr, and Cd respectively. The concentrations of Cd, Pb, and Cr in the investigated crops were above the WHO, (2011) permissible limits. Heavy metals concentration varied significantly in different parts of most of the studied crops and were in decreasing trend of Cu>Pb>Cr>Cd>Zn . The mean concentration of heavy metals in the corresponding soils of all the crops fumigated with pesticides from agricultural farms were higher than adjacent control soil which has not been fumigated with pesticides. Most of the crops showed bio accumulation factor (BAF) >1 values for Cd, Pb and Zn and BAF value was maximum for copper (141.75) in Oryza sativa. Pollution indices showed all the investigated crops were contaminated for Cd, Pb and Cr and are likely to pose potential health risk to humans. The estimated daily intake for Cd, Pb had exceeded the USEPA, (2006) oral reference dose daily limit. Hazard Quotient >1 was observed only from the consumption of Oryza sativa (3.504) for Cu and could likely cause potential health risk in human. More so, Hazard Index showed that the inhabitants may experience adverse health risk through the consumption of Oryza sativa (4.666), Zea mays (1.475), capsicum annuum (1.132) for all the studied metals. Therefore, the need for monitoring of heavy metals in the edible part of crops and soil to see if they exceed the permissible limits. Indiscriminate use of these chemical pesticides most be regulated and use of bio pesticides cannot be overemphasized.

Keywords: Bioaccumulation factor, Hazard quotient, Hazard Index, Heavy metals, Pesticides