In order to monitor heavy metal pollution in agricultural soils and assess the corresponding health risk in the Yellow River irrigation area, this study applied the Nemero index and the health risk index to evaluate heavy metal pollution in wheat grains and the health risks for residents in the lower reaches of the Yellow River. Four towns in Kaifeng, which are within the lower reaches of the Yellow River, were selected as the study area. The examination of wheat samples revealed that the average contents of Cd, Cr, Pb, Cu, Zn, Ni, and Hg in the wheat grains were 0.034, 0.428, 0.279, 5.363, 29.605, 0.305, and 0.003 mg·kg-1, respectively. Among the heavy metals, Pb and Zn exceeded the national food hygiene standards. The pollution indices of Pb and Zn in the wheat grains contributed significantly to the comprehensive pollution index, as each was greater than 1 (1.985), although the pollution indices of the other heavy metals were less than 1. The comprehensive pollution index of wheat in each town ranged from 1.116 to 1.847. The health risk indices of non-carcinogenic heavy metals (Pb, Cu, Zn, and Hg) for adults and children were 1.0558 and 0.5450, respectively. The health risk indices of carcinogenic heavy metals (Cd, Cr, and Ni) for adults and children were higher than the maximum acceptable risk level (1×10-4) recommended by the USEPA, which suggests that residents of the study area have a high risk of developing various forms of cancer.
Keywords: Yellow River irrigation area; health risk; heavy metal; pollution characteristics; wheat.