Assessment of ecological and human health risks of cu, zn and pb accumulation in agricultural soils and okra

Abstract

Emission from Vehicles manufacturing and processing industries have caused accumulation of heavy metals insoils and food crops, which could be harmful to public health and the environment. Heavy metals accumulate in foods as a result of their uptake by crops. This research was conducted to investigate Cu, Zn and Pb concentrations in soils and okra from two farmlands in Cape Coast; to assess the ecological and health risk and the relation between the metal transfer factor and soil properties, pH and organic matter. Twenty composite top soil samples were collected in the dry season from each farm. The concentrations (mg/kg) of Cu, Zn and Pb in soils from UCC farm were respectively11.6, 18.24 and 4.88; the corresponding levels measured in the soils from Amamoma were 9.33, 14.83 and 4.65 respectively. The concentrations of the metals in the soils were significantly higher than corresponding levels found in the okra samples. The TF values ranged between 0.08 and 0.41. For all the metals TF < 1, suggesting that translocation of the metals from the soil solution to the okra were less effective. The uptake capabilities of heavy metals from soil to okra was in the order of Zn < Cu < Pb. Organic matter correlated negatively and insignificantly with TF of Cu and Pb. It, however, correlated significantly and positively with TF of Zn. pH correlated positively with TF values of all the three metals Cu, Zn and Pb; but only Zn showed significant correlation. the Enrichment Factor (EF), Contamination Factors (CF), Pollution Load Index (PLI), mean enrichment quotient (MEQ); and Geoaccumulation Index (Igeo) suggest the sites are not enriched and are practically unpolluted with the three metals. Consumption of okra from the farms was considered safe