关键词: 重金属, 暴露评估, 目标危害系数, 层次分析法, 风险权重

Abstract: This paper is focused on assessing the health risk associated with dietary intake of heavy metals from vegetables and fruits in the Tanggu district of Tianjin. A microwave digestion system was used to digest food samples for the determination of the concentrations of Cr, As, Cd, Hg and Pb by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that heavy metal contents of some samples exceeded the standard limits. The over-standard rates of Pb in vegetables and fruits were higher than 10%. In order to accurately assess the contribution rates of hazardous heavy metals to health risk, the analytic hierarchy process (AHP) was introduced to determine their risk weights. The exposure assessment and the target hazard quotient (THQ) were used to quantify the risk. Based on the THQ value combined with the overstandard rates of heavy metals, the risk weight was calculated. The results showed that the risk weights of Cr, As, Cd, Hg, and Pb were 0.141 1, 0.157 0, 0.341 1, 0.040 4 and 0.320 4, and the risk levels decreased in the order of Cr, Pb > As, Cr > Hg at the average exposure level. The contribution rates of these metals to health risk based on the daily intake and the overstandard rates was determined. This study may provide a new method for evaluating the risk levels of multiple hazardous substances in foods.

Key words: heavy metals, exposure assessment, target hazard quotient, analytic hierarchy process, risk weight