垃圾焚烧源周边土壤中典型重金属的污染甄别及风险评价研究

The potential environmental pollution of five typical heavy metals (Hg, Cd, Pb, Cr and As) emitted from waste incineration sources has been of a world-wide concern. At present, there exists technical difficulties in identifing typical heavy metals from incineration sources. The fundamental study on pollution mechanism and potential environmental risk of the typical heavy metals also lacks. In this project, the technology of fingerprint similarity analysis and a comprehensive method of geography and chemistry will be first adopted to study the influence of gaseous emissions of waste incineration sources on the pollution contribution and cumulant, form transformation mechanism and ecological risk of the five typical heavy metals. The pollution contribution of waste incineration sources to the heavy metals in the soil will also be discussed. The property change of the soil and the influence of chemical properties of the heavy metals on their form conversion mechanism will be revealed. In addition, the ecological and environmental harm of the incineration sources to the soil will be illustrated. The project will provide a new method to identify the heavy metals from incineration sources and other sources. It will also provide the scientific foundation to site selection of waste incinerators, pollution control of typical heavy metals in the soil around the incinerator and technological development and management of ecological restoration for the soil polluted by the heavy metals.

垃圾焚烧源五种典型重金属（Hg、Cd、Pb、Cr和As）排放带来的潜在环境污染问题已经引起国际社会的广泛关注。目前，垃圾焚烧源典型重金属的污染甄别存在技术困难，垃圾焚烧源对周边土壤中典型重金属的污染机理及潜在环境风险缺乏相关基础性研究。本项目首次采用指纹图谱相似度分析技术、地理学与化学手段相结合的方法进行垃圾焚烧源烟气的排放对周边土壤中五种典型重金属的污染贡献辨析、累积量的估算、形态转化机制及生态风险评价的研究，探讨垃圾焚烧源对周边土壤典型重金属污染的贡献机理，揭示焚烧引起的周边土壤相关特性变化及重金属自身化学性能对焚烧源周边土壤中典型重金属形态转化机制的影响规律，阐明了焚烧源重金属对周边土壤的生态环境危害，为甄别源于垃圾焚烧与其它来源重金属污染的问题提供了新的思路，并为垃圾焚烧厂的选址、焚烧厂周边土壤中典型重金属潜在污染的控制及重金属污染土壤的生态修复技术的研发与管理决策提供科学依据

垃圾焚烧处理技术因其具有无害化、减量化和资源化的特点，近年来得到了广泛的应用。然而垃圾焚烧处理过程中会排放出二次污染物，尤其是五种典型重金属（Hg、Cd、Pb、Cr 和As）排放带来的潜在环境污染问题已经引起国际社会的广泛关注。为了解和评估垃圾焚烧厂周边土壤的重金属污染状况及垃圾焚烧源对周边土壤五种典型重金属的污染贡献，本项目以深圳市某垃圾焚烧发电厂为研究对象，利用统计学方法定量分析和地理学相结合的方法来进行焚烧源烟气的排放对周边土壤中五种典型重金属的污染来源辨析、累积量估算及生态风险评价的研究，来评估垃圾焚烧处理对周边环境可能造成的影响。研究内容包括对焚烧源周边土壤中重金属含量之间的相关性分析以及空间分布特征解析，垃圾焚烧厂与采样地点之间水平距离、风向以及高程因子等因素对重金属空间分布的影响，焚烧源周边土壤中五种典型重金属的污染生态风险评价等。研究结果表明：垃圾焚烧发电厂对周边环境土壤重金属含量产生了一定的影响，焚烧厂周边土壤重金属含量较高；同一重金属在0~15cm、16~30cm两层土壤中的含量表现为极显著正相关，土壤中铬、镉、铅、汞和砷之间也表现为极显著相关。以背景值和土壤环境质量二级标准为标准的指数评价和积累指数评价结果显示：As、Cd、Cr污染较重，Hg、Pb未有污染。本研究结果可为垃圾焚烧厂的选址、焚烧厂周边土壤中典型重金属潜在污染的控制及重金属污染土壤的生态修复技术的研发与管理决策提供科学依据。