Concentration level of heavy metals in wheat grains and the health risk assessment to local inhabitants from Baiyin, Gansu, China

摘要

In the present study, concentrations of heavy metals (Cu, Zn, Pb, Cd) in soil and wheat grains of the agricultural areas around Baiyin, a non-ferrous metals mining and smelting base, were detected. Meanwhile, the potential health risk of the heavy metals to adult males, adult females and children was estimated using non-carcinogenic health risk assessment model: Hazard Quotient (HQ) and Hazard Index (HI). The results showed that only the level of Cd in all soil samples exceeded the permissible limit of the environmental quality standard for soil, and its average level surpassed the standard value by 4 times. In wheat grains, the levels of Pb and Cd were 50 times and 8 times of the limited values of hygienic standard for grain respectively, while Cu and Zn concentrations did not surpass the standard value. The potential health risk due to single heavy metal for all the three investigated populations followed the sequence of HQ_(Pb)>HQ_(Cd)>HQ_(Cu)>HQ_(Zn)>l (assumed the local inhabitants wholly food on wheats), suggesting that each of the four heavy metals were making negative effect on population health, of which the situation of Pb and Cd should be paid more attention due to their significant adverse effect. The total potential health risk due to the four heavy metals followed the sequence of HI_(Children)>HI_(males)>HI_(females)>1 (assumed that the health risk due to the four heavy metals is additive), suggesting that the heavy metals were producing adverse effect on population health, and were especially hazardous for children. According to the research results, the government is suggested to strictly control the quality of irrigation water and remove the heavy metals from agricultural soil in order to ensure the safety of foodcrop production and local inhabitants.