广州饮用水水源地多环芳烃分布、来源及人体健康风险评价

Distribution,Sources,and Health Risk Assessment of PAHs in Water Supply Source Regions of Guangzhou

饮用水源水体中残留微量多环芳烃(PAHs)对人体健康存在危害.以广州饮用水水源地为研究对象,采集广州部分水厂水源水体及底泥样品,考察了样品中16种PAHs含量及分布,采用美国环保署(USEPA)的RAGS风险评估模型,对水体中PAHs人体健康风险进行了评估.结果表明,广州饮用水水源地水体中PAHs的质量浓度未超过相应的水质标准限值,水体悬浮颗粒物和底泥中ΣPAHs含量处于低至中等水平.水源地水体PAHs暴露的单项非致癌风险指数和总非致癌风险指数均小于1,非致癌风险可以忽略.水源地水体PAHs单项致癌风险和总致癌风险在5. 53×10^-7~5. 34×10^-6,可能存在致癌风险但低于最大可接受风险水平.水源地PAHs为混合型污染源输入,包括石油泄漏、石油燃烧和木材、煤以及生物质的不完全燃烧.水体中PAHs与底泥中PAHs含量密切相关,PAHs在两相间的分布存在平衡分配.

Trace polycyclic aromatic hydrocarbons (PAHs) in drinking water sources have significant harmful effects on human health.Water and sediment samples from water source regions of three water treatment plants in Guangzhou were collected and the distributions of 16 kinds of PAHs were analyzed. The human risk of PAHs in the water samples was also evaluated using the Risk Assessment Guidance for Superfund( RAGS) of the United States Environmental Protection Agency (USEPA). The results showed that PAHs in the samples from the three water source regions did not exceed the corresponding standard limit for water quality,and the content of Σ PAHs in suspended solids and sediments was below the medium level. The non-carcinogenic risks (HQ and HI) of PAHs in the water samples were less than 1,and the non-carcinogenic risk was negligible. In addition,Riskingest,Riskdermal,and RiskTfor the waters were all in range of 5. 53 × 10^-7 to 5. 34 × 10^-6,indicating that a carcinogen risk was possible but acceptable. The results of the isomer ratio method indicated that the PAHs in the water sources of the three water plants had a mixed input of pollution,including petroleum discharge,petroleum combustion,and incomplete combustion of wood,coal,and biomass. The total organic carbon (TOC)content of the water and sediment samples was positively correlated with the accumulation and enrichment of low-ring PAHs,and there was a significant positive correlation between PAHs and similar molecules in the sediments. The Σ PAHs in the water and sediment samples were also strongly correlated.