垃圾焚烧发电已经成为很多国家处理城市垃圾的主要方式,但垃圾焚烧的烟气汞污染问题突出,由于甲基汞毒性远大于汞,垃圾焚烧发电厂汞排放引发的甲基汞污染问题更加值得关注。为了研究大型垃圾焚烧发电厂汞排放对周边地区的影响,选取广州李坑垃圾焚烧发电厂为研究对象,在分析该厂周边土壤、农作物、水体中甲基汞浓度水平及空间分布特征的基础上,评估了其甲基汞污染对周边环境的影响。结果表明:冬季焚烧厂周边环境土壤甲基汞浓度为145.8-978.3ng/kg,夏季为19.5~791.5ng/kg,平均值分别为532.3ng/kg和117.0ng/kg,均表现为中度污染;风向、地形特征、土地利用类型对焚烧厂周边土壤甲基汞的浓度分布影响较大;周边水体沉积物甲基汞含量为84.1~2216.0ng/kg,平均值为1000.3ngkg,污染水平与周边工业发展水平密切相关;冬季焚烧厂周边植物甲基求含量为20.4~147.4ng/kg,夏季为38.5—224.8ng/kg,平均值分别为64.5ng/kg和63.8ng/kg;不同植物叶片对甲基汞的吸收能力不同,细叶榕最强,香蕉最弱,有4个采样点植物富集率超过了100%。
Power generation by waste incineration has become the principal way to treat municipal soli.d waste (MSW) in many countries. However the problem about gaseous-mercury pollution is serious as a result of trash burning all the time. The emission of methylmercury from waste incineration power plant draws more attention due to higher toxicity of methylmercury than mercury. In order to study the influence of mercury discharge from waste incineration power plant on the surrounding areas, Waste Incineration Power Plant (WS1PP) of Li-Keng in Guangzhou was chosen as the study area. On the basis of ana- lyzing the density and spatial distribution of methylmercury in soil, drops and water around, the influence of methylmercury discharge on the surrounding areas was estimated. Results showed that the concentrations of methylmercury in soils were 145.8- 978.3 ng/kg in winter and 19.5-791.5 ng/kg in summer, with average as 532.3 ng/kg and 117.0 ng/kg respectively, indicating that they were all in a state of moderate pollution. Factors of wind direction, terrain and topographical features and land-using types had great influence on methylmercury concentration distribution in surrounding area. Methylmercury in peripheral water body sediments was 84.1-2 216.0 ng/kg, with average as 1 000.3 ng/kg, indicating that the pollution level had a strong bear- ing on the around industrial development level. Methylmercury in plants around was 20.4-147.4 ng/kg in winter, and 38.5- 224.8 ng/kg in summer, with average as 64.5 ng/kg and 63.8 ng/kg respectively. Absorption capacities of different plant leaves for methylmercury varied greatly, for instance,the taro and Chinese Banyan tree were stronger than banana tree, and accumulation ratios of plants were more than 100% in 4 sampling points.