滹沱河冲洪积扇地下水中酞酸酯的污染现状与分布特征

Distribution Characteristics and Pollution Status of Phthalate Esters in the Groundwater of Hutuo River Pluvial Fan

2014年9月采集石家庄地区滹沱河冲洪积扇地下水水样,采用气相色谱-质谱法测定了US EPA优先控制的6种酞酸酯(PAEs),对PAEs分布特征与风险进行了分析.结果表明,研究区内51个点位仅1个点位未检出PAEs,检出的ΣPAEs范围为nd^28 873.1 ng·L^(-1),与国内其他研究区相比,研究区地下水中PAEs污染水平较重.PAEs及各组分的空间分布存在显著差异.3个地下水单元PAEs的平均污染水平总体表现为山间沟谷河谷裂隙孔隙水单元(G1)>滹沱河冲洪积扇扇顶部孔隙水单元(G2)>滹沱河冲洪积扇扇中部孔隙水单元(G3).在G2、G3单元共计39个点位中,有23个点位地下水中的PAEs以邻苯二甲酸甲酯(DMP)为主,而其余点位均因临近周边污染源,地下水中PAEs含量较高,且以邻苯二甲酸(2-乙基己基)酯(DEHP)、邻苯二甲酸丁酯(DBP)为主.研究区人群饮用受PAEs污染地下水的总非致癌风险指数和总致癌风险指数范围分别为7.6×10-9~1.1×10-2、nd^1.2×10-6,均小于US EPA推荐的可接受的水平,风险较小.

A total of 51 groundwater samples were collected from Hutuo River Pluvial Fan in September,2014,and 6 phthalate esters（ PAEs） were analyzed by gas chromatography-mass spectrometry. The distribution characteristics and health risk assessment were investigated in the present study. The results showed that the PAEs could not be detected in only one sample site. The concentration of the six total PAEs ranged between not detectable and 28 873. 1 ng·L- 1,and the PAEs pollution level of the this research area was higher than other regions reported in China. There was obvious difference in the characteristics of space distribution of PAEs constitutes among the three groundwater units. The concentration of PAEs was sequenced from large to small as follows： Gangnan reservoir valley fracture pore water unit（ G1）〉 the pore water unit of the top of Hutuo River Pluvial fan（ G2） 〉the shallow pore water unit of the middle part of Hutuo River Pluvial fan（ G3）. The results showed that the DMP was dominant in 23 sample sites among all the 39 samples within the G2 and G3 groundwater units,while the concentration of PAEs was relatively higher in the other sample points and the DEHP,DBP were the predominant components,which should be attributed to the industrial point pollution or the pollution originated from surface runoff around the sample sites. The health risk of drinking groundwater polluted by PAEs in the study area was evaluated by the recommended method by US EPA. The non-cancer risk index and the cancer risk index was lower than 1. 1 × 10- 2and1. 2 × 10- 6,respectively,which was both lower than the risk level recommended by US EPA.