| 北江和珠江广州河段水体的三卤甲烷风险评价 |
| 摘要点击 2421 全文点击 1068 投稿时间：2014-09-23 修订日期：2014-12-03 |
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| 中文关键词 三卤甲烷 表层水 分布 风险 珠江 |
| 英文关键词 trihalomethanes surface water distribution risk the Pearl River |
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| 中文摘要 |
| 通过调查北江和珠江广州河段水体的三卤甲烷生成潜能(trihalomethane formation potential,THMFP),评价其作为水源水的风险. 为此,于2013年和2014年不同时段分别采集北江和广州河段不同地点的表层水样品254个. 254个样品经过0.45 μm滤膜过滤后,采用UFC(uniform formation condition)法对水样进行加氯消毒实验,使用气相色谱(GC-ECD)法分析THMFP,基于美国环保署(USEPA, 1997)的风险模型计算THMFP的致癌风险和非致癌风险,使用致癌风险潜能灵敏性方法寻找致癌风险因子. 结果发现,三卤甲烷(trihalomethane,THMs)的生成潜能顺序为: 三氯甲烷(chloroform,CF)>一溴二氯甲烷(bromodichloromethane,BDCM)>一氯二溴甲烷(dibromochloromethane,DBCM)>三溴甲烷(bromoform,BF),其中三氯甲烷生成总量在101.92~2590.85 μg ·L-1范围内,约占THMs总量的96.17%. 以饮用途径计算THMs非致癌风险和致癌风险,所有采样点THMs非致癌风险范围在2.03×10-7~1.00×10-5之间,均不大于1.0×10-5(USEPA推荐风险阈值),而致癌风险平均值分别为2.91×10-4(男性)和3.30×10-4(女性),所有采样点THMs的致癌风险均高于USEPA推荐的风险阈值(1.0×10-6). 两江流域不同的是,北江流域的BDCM致癌风险范围为2.50×10-5~6.37×10-4,其风险值约为CF的2倍,BDCM是北江THMs致癌风险的主要来源,而珠江广州河段的CF是致癌风险的主要来源,其风险范围处于2.26×10-5~7.22×10-4之间. 经致癌风险潜能灵敏性分析发现CF是致癌风险主要因子,以北江和珠江广州河段为饮用水源是不安全的,需要考虑预处理. |
| 英文摘要 |
| In order to investigate the risk of trihalomethane formation potential (THMFP) in finished waters as drinking water sources, 70 samples, 114 samples, and 70 samples were collected in November 2013, April 2014 and July 2014, respectively from different locations in the Beijiang River and the Pearl River. After filtration by 0.45 μm filter membrane, a total of 254 samples were chlorinated using Uniform Formation Condition (UFC) method for determining their THM Formation Potential (THMFP). The cancer risk and non-cancer risk of THMs were estimated using USEPA risk assessment model while dominant factors for total risk potential were estimated using sensitivity analysis. Among four THM species, chloroform(CF) was the highest ranging from 101.92-2590.85 μg ·L-1, followed by bromodichloromethane (BDCM), dibromochloromethane (DBCM) and bromoform (BF). Chloroform, the major THMs speciation, accounted for 96.17% of total THMs. Non-cancer and cancer risk from ingesting THMs was estimated. The result indicated that non-cancer risk of THMs level ranged from 2.03×10-7 to 1.00×10-5 and was not more than 1.0×10-5, the minimum or negligible non-cancer risk level defined by the USEPA. The average cancer risk of THMs was 2.91×10-4for male and 3.30×10-4 for female in the two rivers, respectively, exceeding the minimum or negligible risk level defined by the USEPA (1.0×10-6). The difference of cancer risk between the two rivers was that BDCM ranging from 2.50×10-5to 6.37×10-4 was approximately twice that of CF in Beijing River. BDCM played an important role in the total risk in the Beijiang River while CF played an important role in the total risk in the Pearl River, Guangzhou. Sensitivity analysis showed that CF played an important role in the estimation of total risk potential, and that the direct utilization of water sources from Beijiang River and the Pearl River Guangzhou is dangerous, thus pretreatment is necessary before chlorination. |
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