辣椒产地土壤重金属潜在生态风险评价——以贵州省百宜镇为例
Distribution and Risk Assessment of Heavy Metals in a Pepper-Growing Area——A Case Study in Baiyi, Guizhou

辣椒对土壤重金属有较强的富集性，辣椒产地土壤重金属风险评价对区域辣椒绿色生产和食品安全至关重要.选择全国著名的地方特色辣椒产地贵州省百宜镇作为研究区，采集该区辣椒耕地表层（0~20 cm）土壤样品125个，分析土壤重金属Cd，Pb，Cr，Cu和Zn质量分数，并采用单因子污染指数法、内梅罗综合污染指数法和Hakanson潜在生态危害指数法对5种重金属污染状况和潜在生态风险进行分析和评价.结果表明：研究区土壤Zn，Cr，Pb，Cu，Cd质量分数平均值分别为116.50，73.11，55.76，33.53，0.45 mg/kg，除了Cd元素，其余4种重金属平均质量分数均低于国家土壤环境质量标准（GB15618-1995）二级标准；从空间分布看，土壤Cd，Pb，Cr，Cu和Zn质量分数研究区北部高于南部，东部高于西部；以国家二级限量值为评价标准，研究区96%以上的样点土壤Pb，Cr，Cu和Zn污染均属于安全级别，79.2%的样点土壤属于Cd轻度污染级别，5种重金属综合污染程度为轻度；研究区土壤重金属潜在生态风险程度从大到小依次为Cd，Pb，Cu，Cr，Zn，5种重金属综合生态风险程度为轻度.目前，百宜镇辣椒地土壤重金属Cd，Pb，Cr，Cu和Zn污染程度较轻，潜在生态风险处于可控范围内，基本不会对当地的辣椒种植和生态环境产生影响.
Pepper has a good ability of heavy metal enrichment, and risk assessment of soil heavy metals in pepper-growing areas is of vital importance for green production and food safety. BaiYi Town in Guizhou province, a famous pepper-producing area in China, was chosen as the study area, and 125 surface soil (0-20 cm) samples were collected from a pepper plantation and the concentrations of Cd, Pb, Cr, Cu and Zn in them were analyzed. The pollution degrees and potential ecological risks of the heavy metals were evaluated with the single factor pollution index, Nemero synthesis index and Hakanson's potential ecological risk index. The results showed that the average contents of soil Zn, Cr, Pb, Cu and Cd in the study area was 116.50, 73.11, 55.76, 33.53 and 0.45 mg/kg, respectively. They were lower than the contents of Class 2 according to the Environmental quality standard for soils of China (GB15618-1995), with the exception of Cd. As for their spatial distribution, the concentrations of Cd, Pb, Cr, Cu and Zn were higher in the north and the east than in the south and the west of the study area. Evaluated with Class 2 of GB15618-1995, more than 96.0% of the soil samples were pollution-free of Pb, Cr, Cu and Zn, and 79.2% were slightly polluted of Cd. The comprehensive pollution degrees of all the 5 heavy metals in the study area were at a low level. The potential ecological risk of the heavy metals was in the sequence of Cd, Pb, Cu, Cr, Zn, and their potential ecological risks were at a low risk level. In conclusion, at present, soil heavy metals (Cd, Pb, Cr, Cu and Zn) have but a light pollution degree in the pepper-cultivated land of Baiyi, their potential ecological hazard remains in a controllable range and they will not affect the local pepper planting and ecological environment