和龙水库水质调查与健康风险评价

Investigation and health risk assessment of the water quality of Helong Reservoir

为研究和龙水库水质状况及对人体健康产生的危害风险,采用单因子评价法和有机污染综合指数法对和龙水库20个采样点为期1 a的水质监测数据进行了评价;并采用美国环境保护局（USEPA）推荐的健康风险评价模型,对水库主体水域水体进行人体饮用健康风险评价。结果表明,和龙水库主体水域水质采样年度整体为Ⅳ类水,且春季水质为开始污染水平,其余各季节水质为一般水平。水库水体中化学物质As所产生的致癌风险为1.59×10-5~3.37×10-5a-1,远高于人体最大可接受风险（1×10-6a-1）。而由Cu、Zn、Mn和NH＋4-N所引起的非致癌风险（10-10~10-11a-1）均低于最大可接受风险（1×10-6a-1）。和龙水库周边养猪场的污水排放可能是其主要污染源,养猪场附近河段的水体全年为劣V类,属于严重污染水平;主要超标污染指标为BOD5、NH＋4-N、总磷、COD,各指标值分别是水库主体水域水体的268.49、253.15、55.81、40.38倍;猪场废水中As是导致水库主体水域As人体健康风险超标的主要原因。因此,需要加强对和龙水库周边养猪场的排污治理,以保障水库水体质量。

The present article introduces its authors＇ investigation and health risk assessment of the water quality of Helong Reservoir. In doing so,we would like to provide a description of the relationship between the pollutants and human health. For our purpose,we have collected 20 water samples from the different reservoir sites in March,2012,to February,2013,in hoping to monitor and assess the water qualities with both the single-factor method and the comprehensive index method. In our work,we have also adopted an assessment model recommended by USEPA for evaluating the health risks that are likely to be caused via drinking. The single index evaluation results show that the annual average value in the main part of Helong Reservoir proves to be fit for IV grade of the surface water environment quality standards.The evaluation results of the organic pollutants gained by using the comprehensive index method also indicate that the main part of the reservoir suffers a more serious contamination in spring though less serious in other seasons. The carcinogen risk value caused by the arsenic pollutants in the main water bodies tend to range from 1. 59 × 10- 5a- 1to 3. 37 × 10- 5a- 1,much higher than the maximum acceptable level recommended by the Swedish Environmental Protection Agency（ 1 × 10- 6a- 1）. In addition,the non- carcinogen risk values caused by Cu,Zn,Mn and NH＋4-N tend to range from 10- 10a- 1to 10- 11a- 1,much lower than the maximum acceptable levels recommended by Swedish Environmental Protection Agency（ 1 × 10- 6a- 1）. The main source of the pollution turns to come from the wastewater discharged from the surrounding pig-growing farms. Statistically speaking,the water in the discharge area of pig farm belongs to V grade according to the surface water environment quality standards. As to the main pollution factors with the pig farm waste water,BOD5,ammonium nitrogen,the total phosphorus and COD account for 268. 49,253. 15,55. 81,that is,40. 38 times as that in the main part of the water area of the reservoir. The annual average mass concentration of As in the pig farm waste water is verified significantly higher than that in the water samples collected from other sites. Therefore,there has been exiting a great need for the reservoir to control its pollution form As and some practical measures should be taken to control and reduce the pollution of the waster water discharged from the pig farm.