Lead, cadmium and mercury pollution and health risk assessment for main marketed grain and its products in Qingpu District of Shanghai

ObjectiveTo investigate heavy metal contamination situation of grains in Qingpu, evaluating the health risks of heavy metals intake from grains consumption.

MethodsA total of 342 grain samples were collected in Qingpu using random sampling method, and the contents of Pb, Cd, Hg detected.Then the single factor pollution index and Nemerow multi-factor index were used to evaluate the levels of heavy metals in grains.In addition, combined with the data on dietary consumption in residents of Shanghai during 2012－2013, the dietary risk and carcinogenic risk of heavy metals were evaluated by USEPA health risk assessment model.

ResultsThe mean contents of Pb, Cd, Hg in grains were 0.0197, 0.0081, 0.0025 mg/kg, respectively.In addition, the single factor contamination indexes and the Nemerow multi-factor indexes of heavy metals in 3 kinds of grains were found to be less than 0.7, which indicated that the pollution status of heavy metals were at the level of safety.The average daily intake of Pb, Cd, Hg from grains were estimated to be 0.044 2, 0.012 1 and 0.068 7 μg/kg, accounting for 5.31%, 2.12% and 1.92% of PTWI(provisional tolerable weekly intake); and the higher daily intake (P₉₅) were estimated to be 0.085 3, 0.023 7 and 0.141 9 μg/kg, accounting for 10.24%, 4.14% and 3.97% of PTWI.The average and higher individual health risk of heavy metal pollution were both 10^－6/a, less than the standard of ICRP(5.0×10^－5/a).The average and higher LIE caused by the heavy metals was 20.22 min and 38.99 min.

ConclusionDietary exposure of heavy metal in grains is in a safety level in Qingpu District.