喀什城郊温室土壤-蔬菜系统重金属污染特征及环境风险效应

Characteristics and Environmental Risks of Heavy Metal Pollution in Soil-Vegetable System under Greenhouse Growing Mode in Kashi Suburb

为探究喀什城郊温室土壤-蔬菜系统重金属的污染特征及环境风险效应,以喀什土壤背景值为参比,对喀什城郊土壤和蔬菜中Cu、Ni、Zn、Cr、As、Cd、Pb等7种重金属的含量进行检测,结果表明,喀什城郊土壤中Cu、Ni、Zn、As、Cd平均浓度分别超标0.09、0.11、1.75、1.80、3.07倍;地积累指数表明,土壤重金属的Igeo依次为Cd>As>Zn>Ni>Cu>Cr>Pb;潜在生态风险评价指标表明,各重金属的Er依次为Cd>As>Cu>Pb>Zn>Ni>Cr,土壤综合生态风险指数RI为165.34.喀什城郊温室蔬菜重金属平均含量均在国家食品安全标准限值内;富集系数表明,重金属在蔬菜中的富集能力依次为Cd>Zn>Cu>Ni>Cr>Pb>As;目标危险系数表明,食用研究区温室蔬菜的THQ依次为As>Cd>Pb>Cu>Zn>Ni>Cr,且成人通过饮食蔬菜摄入重金属的健康风险高于儿童.喀什城郊温室蔬菜地土壤综合生态风险程度为中等,最主要的生态风险因子Cd处于中等污染水平;蔬菜未受到重金属明显污染,但其对Cd的富集能力较强,As是健康风险最大的贡献因子,应该引起重视.

In order to explore the pollution characteristics and environmental risk effects of heavy metals in greenhouse soil-vegetable system in Kashi suburb. From October to November 2019, The contents of Cu, Ni,Zn, Cr, As, Cd and Pb in greenhouse vegetables and soil samples were investigated. The results showed that the average concentrations of Cu, Ni, Zn, as and Cd in Kashi soil exceeded the standard by 0.09, 0.11, 1.75,1.80 and 3.07 times, respectively. Geoaccumulation index showed that the Igeoof soil heavy metals decreased in the order of Cd>As>Zn>Ni>Cu>Cr>Pb;Potential ecological risk assessment showed that the single ecological risk of soil heavy metals decreased in the order of Cd>As>Cu>Pb>Zn>Ni>Cr, and the comprehensive ecological risk(RI)of soil was 154.716. The average contents of 7 heavy metals in vegetables were within the limits of national food safety standards. The enrichment coefficient showed that the enrichment ability of heavy metals in plants was Cd>Zn>Cu>Ni>Cr>Pb>As. The target risk coefficient showed that the THQ of eating vegetables in the study area was As>Cd>Pb>Cu>Zn>Ni>Cr, and the health risk of heavy metals in adults was higher than that in children. The ecological risk of greenhouse vegetable soil in Kashi suburb was moderate, and Cd was the main ecological risk factor, which was at the medium pollution level;The vegetables were not obviously polluted by heavy metals, but the enrichment ability of Cd in vegetables was strong, and As was the biggest contribution factor of health risk, which should be paid attention to.