Evaluation of the Toxicological Implication of Consuming Carrots ( Daucus carota L) Cultivated Along River Galma Basin Around Dakace Industrial Layout, Zaria, Nigeria

摘要

Carrot (Daucus carota L), is a root vegetable rich in bioactive compounds having significant health-promoting properties. The enormous health benefits of the vegetable notwithstanding, consumption of contaminated edible portion of the plant could pose serious toxicological risk. In this study, Lead (Pb), Chromium (Cr), Nickel (Ni) and Manganese (Mn) contents of edible carrots roots from River Galma basin around Dakace industrial area, Zaria were thoroughly assessed to evaluate the potential risk of consuming root vegetables from the area and by implication, the impact of Dakace industrial area on the environment. The assessment was carried out by atomic absorption spectrophotometry using Shimadzu atomic absorption spectrophotometer (model AA-6800, Japan) after wet digestion. The overall mean concentrations of the metals were: 1.05±0.5 mg/kg for lead, 1.51±0.9 mg/kg for chromium, 3.74±1.89 mg/kg for nickel and 1.21±2.72 mg/kg for manganese. Lead and chromium concentrations were found to be above WHO/FAO permissible levels. Average values of Estimated Daily Intake (EDI) were higher compared to Recommended Daily Intake (RDI) and Upper Tolerable Daily Intake (UL) for all the metals. Target Hazard Quotient (THQ) for lead and nickel were found to be above the safe limit of unity. Hazard Index (HI) used to evaluate the potential risk to human health due to the combined effect of the four heavy metals was 2.84. The relative contributions of these metals to the aggregated risk were 59.86%, 0.21%, 38.03% and 1.76% for Pb, Cr, Ni, and Mn respectively. Consumption of edible carrots roots from the study area thus poses a serious toxicological risk. Average values of the contaminants in the study area were found to be significantly (p < 0.05) higher than the control suggesting that the industrial estate exerts a significant adverse impact on the environment. Implications of these findings to public health are fully discussed.