ABSTRACT
In this study, the levels oftin (Sn), antimony (Sb), iron (Fe), cadmium (Cd), lead (Pb), and zinc (Zn) in soil and vegetables were examined, as well as the potential health risks of eating vegetables obtained fromareas around second cemetery, Iyakpen, Benin City, Edo state, Nigeria.
Soil samples were collected with hand auger from 0 – 20cm depth, air-dried, powdered, and sieved. Four different vegetables(mango, orange, potato and bitter-leaf) were also were randomly collected from around the cemetery and transported to University of Benin Civil engineering laboratory, Benin City, Nigeria, for sample preparation. The vegetables were washed with distilled water to remove any traces of dirt, separated, air-dried and further dried in oven for 72 h at 65 °C to attain constant weight. The dried leaves were then pounded with a mortar and pestle and converted to powder and stored each in a plastic bag for analysis. The soil and vegetable samples were analyzed with a wavelength dispersive X-ray fluorescence spectrometer (SKYRAY INSTRUMENT EDX3600B). Health risk indication parameters (health risk index, daily intake of heavy metals and target health quotient) were evaluated.
The results obtained showed that the soil was polluted withSn, Sb, Fe, Pb, Cd and Zn. The concentration ofSn, Sb, Fe, and Zn were less than the maximum allowable limit of 200mg/kg, 36mg/kg, 20mg/kg and 300 mg/kg respectively set for soils used for crop production. The concentration of Pb and Cd were lower than the maximum allowable limits (100, 3mg/kg).The daily intake values of Sb and Sn through ingestion of these vegetables were found to be higher than the recommended oral reference doses (RfDs) of 0.0004mg/kg/day and 0.0003mg/kg/day respectively, while that of iron was lower than the RfDs for adult, but higher than the dose for children. Daily intakes of Cd and Zn were lower than the respective oral reference doses of 0.001 and 0.300 mg/kg/day, while that of Pb was higher than the oral reference dose of 0.0035mg/kg/day. The health risk index and target health quotient values were, respectively, greater than one, indicating that the ingestion of the vegetables might affect human health negatively. Children consuming vegetables from these locations in the study area were seen to be in greater danger of health risks than the adults.
