北京市再生水灌区地下水中典型全氟化合物的分布现状及生态风险

陈典; 张照荷; 赵微; 李俊; 焦杏春

doi:10.15898/j.cnki.11-2131/td.202111300190

北京市再生水灌区地下水中典型全氟化合物的分布现状及生态风险

The Occurrence, Distribution and Risk Assessment of Typical Perfluorinated Compounds in Groundwater from a Reclaimed Wastewater Irrigation Area in Beijing

摘要

摘要: 全氟化合物(PFCs)是一种新型持久性有机污染物，因具有持久性、生物蓄积性和高毒性而受到广泛关注。目前关于河流、污水、湖泊等地表水体中PFCs污染状况的研究较多，而地下水PFCs的相关研究相对较少。本文以北京市再生水灌区为例，探讨了典型PFCs化合物在地下水中的含量、分布及其生态风险，并重点关注了灌区内某垃圾填埋场周边地下水PFCs的影响。使用固相萃取-高效液相色谱-串联质谱法分析了2020年5~6月采集自北京市再生水灌区的52个地下水样品，结果表明灌区地下水中不同程度地检出包括全氟羧酸(PFCAs)和全氟磺酸(PFSAs)在内的10种目标PFCs化合物，浓度范围为1.07~24.19ng/L, 其中以全氟正丁酸(PFBA)、全氟正辛酸(PFOA)和全氟丁烷磺酸(PFBS)三类单体的检出浓度最高，平均浓度分别为2.94±2.42ng/L、2.88±3.45ng/L和1.15±2.05ng/L。与来自氟化学工业园的地下水相比，本研究区地下水中∑PFCs浓度明显偏低，这与本研究区观测井多处于农田区域有关。PFCs在浅井(< 50m)与深井(>50m)中的浓度随着井深的增加有明显下降趋势。此外，从全区地下水PFCs的空间分布来看，垃圾填埋场周边的地下水PFCs浓度明显偏高，并随着与垃圾填埋场的距离增加而显著降低，说明垃圾填埋场对周围地下水PFCs的污染具有一定影响。通过计算PFOA、全氟辛基磺酸盐(PFOS)和PFBA的风险商得知，该垃圾填埋场对周边环境尚未构成生态风险，但鉴于地下水PFCs的隐蔽性与持久性，建议继续给予定期监测与评估。

Abstract:
BACKGROUND Perfluorinated compounds (PFCs) have been extensively studied in recent years due to their persistence, bioaccumulation and toxicity. However, most of the studies are concentrated in surface water with high concentration of PFCs in rivers, sewage and lakes, while few studies explore the status of PFCs pollution in groundwater.
OBJECTIVES To investigate the content, distribution and ecological risk of typical PFCs compounds in groundwater in the reclaimed water irrigation area of Beijing.
METHODS 52 groundwater samples were collected from the reclaimed water irrigation area in May to June 2020 and were analyzed by solid phase extraction and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).
RESULTS The results showed that 10 target PFCs including perfluorocarboxylic acid (PFCAs) and perfluorosulfonic acid (PFSAs) were detected in groundwater in Beijing, with a concentration of 1.07-24.19ng/L. Among them, the highest detected concentration of perfluorobutanoic acid (PFBA), perfluorooctanoic acid (PFOA), and perfluorobutane sulfonate (PFBS) averaged 2.94ng/L, 2.88ng/L and 1.15ng/L, respectively. The concentration of ∑PFCs in this study was relatively low compared to the groundwater from the fluorochemical industrial park, which was related to the mostly farmland location of the observation wells in the study area. After observing the performance of PFCs in shallow wells (< 50m) and deep wells (>50m), it was found that the concentration of PFCs decreased significantly with increasing well depth. In addition, in view of the spatial distribution of groundwater PFCs in the whole region, the concentration of groundwater PFCs around the landfill was significantly high and decreased with increasing distance from the landfill, indicating that the landfill had a certain contribution to the pollution of surrounding groundwater PFCs.
CONCLUSIONS By calculating the risk quotient of PFOA, perfluorooctane sulfonate (PFOS) and PFBA, the landfill has not posed an ecological risk to the surrounding environment. However, in view of the concealment and persistence of groundwater PFCs, it is recommended to carry out continuous regular monitoring and evaluation.

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