桂林市菜地土壤和蔬菜砷含量调查与健康风险评估

A survey of arsenic concentrations in vegetables and soils in Guilin and the human health risks assessment

通过对桂林市蔬菜和菜地土壤中砷含量状况的调查，研究了蔬菜和菜地土壤中的砷含量、富集特征及对人体的健康风险，并筛选出抗砷污染能力强的蔬菜品种.本研究在桂林市13个县区蔬菜种植基地和蔬菜批发市场共采集71种566个蔬菜样品，160个相对应菜地的土壤样品和32个背景土壤样品.研究发现，与背景土壤相比，桂林市菜地土壤没有明显的砷积累（平均积累指数为0.839），砷含量范围、算术均值、几何均值分别为5.55-132、23.4、21.4 mg kg-1.蔬菜（鲜重）总砷含量范围、中值和几何平均值分别为5.34-49.7、24.0、22.2 mg kg-1，均未超标，且叶菜类蔬菜中的砷含量高于根茎类和瓜果类.根据蔬菜砷富集系数的高低用层级聚类法分析，结果表明，西红柿、油麦菜、胡萝卜、生菜等18种蔬菜的抗砷污染能力最强.桂林市居民通过消费蔬菜的人均总砷摄入量为2.54 μg d-1，蔬菜消费只占总砷摄入量的7.07%左右，因此，对于大多数居民而言不存在明显的健康风险.

In order to assess the human risk posed by elevated concentrations of arsenic in vegetables and to identify pollution-tolerant vegetables varieties, a survey of arsenic levels in soil and vegetable planted or sold in Guilin was conducted. Seventy one types of 566 fresh vegetable samples were obtained from gardens and wholesale outlets in 13 regions of Guilin. In addition, 160 soil samples from gardens and fields used to grow vegetable plants and 32 background soil samples were collected. The results show that, in comparison with the arsenic contents in the background soils, the accumulation of arsenic （the average accumulation index is 0.839） in Guilin＇s vegetable soil was not remarkable, and arsenic concentrations in soil ranged from 5.55 to 132 mg kg-1, with arithmetic and geometric means of 23.4 and 21.4 mg kg-1, respectively. Moreover, concentration of arsenic in the edible plant portions in fresh mass ranged from 5.34 to 49.7 mg kg-1, with median and geometric means of 24.0 and 22.2 mg kg-1, respectively. Total arsenic concentration in all vegetable samples were not higher than the tolerance limit for the safety requirements, and arsenic contents in leaf vegetables was significantly higher than that in tubers and melons. Results of hierarchical cluster analysis on the arsenic bio-concentration factor （BCF） in vegetables indicated that 18 kinds of vegetables had strong arsenic resistance, such as tomato （Lycopersicon esculentum）, lettuce （Brassica campestris）, carrot （Daucus carota）, green salad （Romaine lettuce）, etc. The average ingestion rate of arsenic from vegetables was 2.54 μg/individual/day for people of Guilin. As vegetable consumption merely accounted for about 7.07% of arsenic intake, it would not cause obvious health risk to the local resident.