广西南丹土壤-玉米重金属积累特征及其健康风险

Characteristics of Heavy Metal Accumulation in Soil-Corn System Contents and Their Health Risks in Nandan,Guangxi

  • 摘要: 为了探讨矿业活动对有色金属之乡——南丹县粮食作物玉米籽粒的影响,采集当地玉米籽粒和对应土壤各139份,并分析其Cd、Pb、As、Cu和Zn含量。结果表明,南丹县玉米地土壤Cd、Pb、As、Cu和Zn的平均含量分别为1.205、79.31、29.42、27.91和132.4 mg·kg-1;依据GB 2762-2012《食品中污染物限量》,玉米中Cd、Pb和As的超标率分别为8.4%、28.3%和3.0%。相关性检验结果表明,南丹县土壤和玉米中Cd、Zn、As含量存在显著相关性(P<0.05),通过玉米及对应土壤重金属含量对耕地土壤环境质量评价得出,综合质量影响指数均值为2.70,土壤质量状态为轻度超标。人体健康风险评价表明,玉米中单一重金属Cd、Pb、As、Cu、Zn的风险系数和多金属综合风险系数均小于1,且食用玉米的年健康风险也低于国际辐射防护委员会(ICRP)推荐的最大年健康风险水平,表明长期摄入当地玉米对居民的健康不会造成明显影响,可安全食用。

     

    Abstract: Nandan is famous for its mining of nonferrous metals. In order to investigate effects of the mining activities on the soil and corn, the staple grain crop of this county, a total of 139 soil samples and 139 corn samples were collected for analysis of concentrations of Cd, Pb, As, Cu and Zn. Results show that the mean concentration of Cd, Pb, As, Cu and Zn in the soil samples was 1.205, 79.31, 29.42, 27.91 and 132.4 mg·kg-1, respectively. The over-standard rate of Cd, Pb and As in the corn was calculated to be 8.4%, 28.3% and 3.0% respectively, by GB 2762-2012 "Thresholds for Pollutants in Food". Correlation analysis shows that the corn was significantly related to the soil in concentration of Cd, Zn and As (P<0.05), but not so much in concentration of Pb and Cu. Environmental quality evaluation of the farmland soils based on the above analysis of heavy metal concentrations in the corn and soil shows that ⅡCQ was 2.70 on average, indicating that the soil was slightly over the standard. Human health risk assessment shows that both HQ (single element risk coefficient) and HI (multi-element integrated risk coefficient) were below 1; and the annual health risk of corn consumption to people in Nandan County was also lower than the highest level recommended by the International Commission on Radiological Protection (ICRP), which suggests that long term ingestion of locally produced corn will not have any significant health risk. The corn is a safe food in the area.

     

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