| 某区生活垃圾焚烧发电厂周边及厂区内土壤中重金属元素的污染特征及评价 |
| 摘要点击 2077 全文点击 854 投稿时间：2018-10-09 修订日期：2018-11-26 |
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| 中文关键词 生活垃圾焚烧发电厂 表层土壤 重金属元素 污染特征 潜在生态风险评价 汞 |
| 英文关键词 municipal solid waste incineration power plant surface soil heavy metal pollution characteristics potential ecological risk mercury |
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| 中文摘要 |
| 为了解与评价生活垃圾焚烧电厂周边土壤重金属元素的污染状况，按照点源扇形布点原则，在生活垃圾焚烧电厂周边和厂区内布点采样，以远离电厂区域为对照点，共采集29个土壤样品，分析检测了Cr、Mn、Ni、Cu、Zn、As、Ag、Cd、Hg和Pb等10种重金属元素的含量.结果显示，生活垃圾焚烧发电厂周边和厂区内土壤中各重金属元素的含量水平均满足国家《土壤环境质量》（GB 15618-2018）和（GB 36600-2018）中土壤污染风险筛选值要求；仅有Mn、Cu和As的平均含量高于安徽省土壤平均背景值，其中As是背景值的1.03倍，Cu是1.07倍；与对照点对比，Cr、Ni、Cd、Cu和As含量低于对照点，差异有统计学意义（P≤0.05）.电厂周边土壤中Hg在空间分布上的差异较明显，其余重金属元素空间分布差异不明显、呈现较均匀，在常年主导下风向和次主导下风向500 m土壤中最高，之后随着距电厂的距离增大而逐渐下降，最后低于对照点的水平.电厂周边和厂区内土壤中各重金属元素的污染程度为轻度污染，内梅罗综合污染指数（PI）为1.1~1.2，对照点也为轻度污染（PI为1.5）；潜在生态风险为轻微，多种重金属元素的综合潜在生态风险指数（RI）为60.2~67.7，Hg和As对RI的贡献率较大，对照点为中等生态危害（RI为116.8）.基于主成分分析的结果，综合考虑土壤中各重金属元素的含量和空间分布特征以及相关性分析和聚类分析结果，将10种重金属元素分为3类：①Ni、Cr、As和Mn；②Cu、Zn、Ag、Cd和Pb；③Hg.其中Ni、Cr、As和Mn来源主要受土壤母质影响；Cu、Zn、Ag、Cd和Pb来源主要受土壤母质和多种人类活动共同影响；Hg则很可能源于生活垃圾焚烧烟气的扩散沉降及其在土壤中的累积.在研究表明，生活垃圾焚烧发电厂周边和厂区内表层土壤中Hg具有独特的环境污染特征，在生活垃圾焚烧发电厂周边的土壤重金属污染调查中，Hg污染应受到重点关注. |
| 英文摘要 |
| To investigate and evaluate the pollution levels of heavy metals in the soil around a large Municipal Solid Waste Incineration power plant (MSWIPP), a total of 29 soil samples were collected around the MSWIPP and away from the power plant area. The contents of 10 selected heavy metals (Cr, Mn, Ni, Cu, Zn, As, Ag, Cd, Hg, and Pb) were analyzed. The results showed that the content of each heavy metal element did not exceed the values for Soil Environmental Quality of Risk Control Standard for Soil Contamination of Agricultural Land (GB15618-2018) and Development Land (GB 36600-2018). The mean contents of Mn, Cu, and As were higher than their respective background values of Anhui Province, where As was 1.03 times the background value, and Cu was 1.07 times. Compared with the control points, the contents of Cr, Ni, Cd, Cu, and As were lower than the control points, and the difference was statistically significant (P ≤ 0.05). The spatial distribution of Hg was more obvious in the soil around the power plant, and other heavy metals were not obvious and uniform. The content of Hg was the highest in the 500 m soil of perennial dominant downwind and sub-dominant downwind. With increasing distance from the power plant, the content gradually decreased and it was lower than the level of the control point. The pollution degree of heavy metal elements in the soil around the power plant and in the plant area was mild. The Nemero comprehensive pollution index (PI) was 1.1-1.2, and the control point had also mild pollution (PI was 1.5). The potential ecological risk was slight, and the comprehensive potential ecological risk index (RI) of various heavy metal elements was 60.2-67.7. The contribution rate of Hg and As to RI were large, and the control point had medium ecological risk (RI was 116.8). Based on the results of principal component analysis, accompanied with the content, spatial distribution characteristics, Pearson's correlation, and hierarchical cluster analysis results, three groups of heavy metals with different spatial distribution were identified:①Ni, Cr, As, and Mn originated from lithological sources; ②Cu, Zn, Ag, Cd, and Pb affected by both lithological and human sources (e.g. agricultural and traffic sources); ③Hg likely originated from the diffusion sedimentation of MSWI flue gas and its accumulation in the soil. The above results indicated that the unique pollution characteristics of Hg deserve serious attention in pollution monitoring in soils surrounding solid waste incinerator. |
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