生活垃圾重金属对环卫工人身体健康影响研究

Study on influencing of heavy metal in municipal solid waste on health of sanitation workers

以珠江三角洲5市(广州、深圳、佛山、惠州和肇庆)生活垃圾为研究对象,分析了55个生活垃圾样品的干基组分及典型重金属(As、Cd、Hg、Cr和Pb)的含量,采用主成分因子分析探论重金属的主要影响因素及可能来源,并结合人体健康风险评价模型,用蒙特卡洛模拟定量评价生活垃圾收运、分类及处理各环节环卫工人的健康风险.结果表明,珠江三角洲5市生活垃圾中As、Cd、Hg、Cr和Pb的浓度分别为(4.49±1.18),(1.95±1.96),(0.41±0.60),(147.28±160.48)和(121.59±199.42)mg/kg;生活垃圾中Hg和Pb可能主要来源于金属制品和镀金材料;Cd和Cr可能主要来源于金属制品、镀金材料、快餐垃圾和包装垃圾;As可能主要来源于生活垃圾中的沙土和草木组分.生活垃圾的收运、分类及处理环节,街道清扫保洁工人、分类收运工人和填埋处理工人的非致癌风险基本不用考虑,但致癌风险很高,致癌风险指数最高可达安全阈值的6倍,主要风险暴露途径为手-口摄入(非食物途径);垃圾焚烧处理工人的非致癌风险和致癌风险均很高,非致癌风险和致癌风险指数最高值分别约为安全阈值的11倍和90倍,主要风险暴露途径为手-口摄入和呼吸吸入;相同暴露环境下,女环卫工人的非致癌风险和致癌风险概率均略高于男环卫工人.因此,生活垃圾收运、分类及处理环节需做好安全防范措施,对重金属人体暴露途径进行阻隔.

The As, Cd, Hg, Cr, and Pb contents (on a dry weight basis) of 55 municipal solid waste (MSW) samples from five cities (Guangzhou, Foshan, Huizhou, Shenzhen, and Zhaoqing) in the Pearl River Delta were determined. Principal component analysis was performed to assess the factors affecting the heavy metal concentrations and possibly identify the sources of the heavy metals. The health risks posed to sanitation workers exposed to heavy metals while collecting, sorting, and disposing of MSW were assessed using a combined health risk assessment model and Monte Carlo simulation. The mean As, Cd, Hg, Cr, and Pb concentrations in the MSW samples were (4.49±1.18)mg/kg,(1.95±1.96)mg/kg,(0.41±0.60)mg/kg,(147.28±160.48)mg/kg, and (121.59±199.42)mg/kg, respectively. Hg and Pb in MSW were probably mainly derived from metalware and materials with metallic coatings. Cd and Cr were derived from metalware and metallic coatings and also from fast food and packaging waste. Element As was probably main derived from soil and grass. Non-carcinogenic risks for workers during waste collection, sorting, and disposal to landfill could be ignored, but carcinogenic risks were very high. The highest carcinogenic risk index was about six times the safety threshold. The highest risks were posed through ingestion after hand-to-mouth contact (not through ingestion of food and drink). Non-carcinogenic and carcinogenic risks were both high for waste incineration workers, the highest non-carcinogenic and carcinogenic risk indices being 11 and 90 times, respectively, the safety thresholds. The highest risks were posed through ingestion after hand-to-mouth contact and inhalation. Non-carcinogenic and carcinogenic risks were slightly higher for female than male workers for the same exposure situations. Precautions must therefore be taken to decrease the exposure of workers to heavy metals during waste collection, sorting, and disposal.