基于蒙特卡洛的土壤镍污染及健康风险分析

Soil contamination and health hazard analysis of nickel based on Monte-Carlo simulation

采集天津市郊区115个土样以及相对应的19种蔬菜作物作为研究对象,检测土样和蔬菜作物中镍的污染含量,计算各类蔬菜的富集系数,并根据富集系数大小进行聚类分析。由聚类结果将蔬菜作物大致分为3类:富集系数最低的瓜果类;富集系数较高的叶菜类;玉米富集系数最大,独立为一类。利用Crystal Ball和Origin拟合土壤及蔬菜中镍质量浓度的分布特性,并对统计结果进行分析,建立土壤-作物-人体健康风险评价模型,借助Crystal Ball软件实现蒙特卡洛模拟。结果显示:瓜果根茎类健康危害系数为0.15,叶菜类健康危害系数为0.27,表明根茎瓜果类及叶菜类的镍含量不会对人体健康造成危害;玉米的健康危害系数较大为2.3,会对人体的健康造成危害,风险处于不可接受水平。为降低健康风险,该区域土壤应少种玉米类富集危害系数较高的作物,改种其他富集系数较低的蔬菜作物。

In this paper, we have collected 119 soil samples and 19 sorts of corresponding vegetables and grain produce from the suburbs of Tianjin as our case study samples for cluster analysis so as to deter- mine the nickel concentration in the crop soil and vegetable plants. Based on the cluster analysis, we have classified the vegetable crops into three kinds according to the accumulating factors. In the water- melon and fruits, the lowest concentration of the element was found with the leaves of whereas relatively higher concentration in the mel- ons and fruits. However, the strongest accumulation concentration was found in the corn grains. As we know, nickel is a kind of toxic heavy metal that is likely to cause negative health influences on the human body, trying to know what exact influences of its concentration distribution on the soil and on the vegetable crops through analyzing the Crystal Ball and Origin. The next step we have taken is to do a Monte-Carlo simulation in hoping to assess the soil-human health haz- an] and the parameter distribution. The results of analysis and simu- lation demonstrate that due to low accumulation, the health hazard quotient of the nickel distribution in water melon and fruit was merely 0.15 and that of the leaf vegetables was equal to 0.27, which sug- gests that the nickel concentration in such vegetables are not likely to bring threat to human health. However, the health hazard quotient of corn grains was 2.3, which is likely to cause much greater health threat to human body, signifying great hability of negative effects. It is thus totally unacceptable from the point of view of eco-environmen- tal protection. In order to reduce the health hazard liabilities, it is strongly suggested that this area should decrease or stop the growing of cum-hke crops instead of cultivating vegetables.