环境水质学国家重点实验室知识库

      有机磷阻燃剂（organophosphorus flame retardants, PFRs）作为一类新型有机污染物，其在环境中的暴露、来源和迁移研究受到广泛的关注；被动采样（Passive sampling）是一项具有多方面优势的新兴环境监测技术，如能测量时间加权平均浓度等。基于此，本研究应用被动采样方法进行了不同水体环境中PFRs及多类PBT（通常指具有持久性（persistence）、生物富集性（bioaccumulation）或毒性（toxicity））有机污染物的暴露、来源和迁移等方面机制研究。结合目前被动采样器无法同时应用于极性和非极性物质的现状，本研究研发了新型的极性和非极性有机物整合被动采样器，其可用于环境中如PFRs这类极性范围宽泛污染物的被动采集。在现场应用中，本研究优化了被动采样的连续流动采样装置和采样方法，改进了被动采样的质量控制、校正方法和数据分析方法，拓展了被动采样应用的范围。随着全球气候变化和PFRs越来越多的发现，PFRs在南北极环境中的暴露研究具有重要意义且亟需进行，而本研究在南北极水环境中均应用被动采样开展了PFRs及多类PBT有机污染物的暴露特性、来源和迁移等机制。取得如下主要成果：
（1） 建立了水环境中PFRs的TECAM（三油酸甘油酯-醋酸纤维素复合膜）被动采样方法和样品分析方法，在前处理、仪器分析方法和质量控制上进行了完善。
（2） 开发了能同时针对水中亲水性和疏水性有机物被动采集的新型被动采样器，HLB吸附剂-醋酸纤维素复合膜被动采样器（HECAM）；实验室模拟试验研究了包括13种PFRs在内37种不同极性污染物的HECAM被动采样富集过程，预测了其动力学参数；探究了HECAM中污染物的被动传输机制，最终发现HECAM具有巨大的吸附剂/膜比表面积和薄的膜基质，且污染物在嵌入式半透复合膜中的传输阻力较小，在这些因素的共同驱动下，HECAM对中等疏水性污染物（2.5 < log Kow < 5.5）具有高的采样速率。现场应用与验证实验表明，HECAM能有效预测河流中污染物的时间加权平均浓度，其结果与同步进行的主动采样预测结果具有较高的吻合度，其作为被动采样工具同时监测水体中亲水和疏水性污染物的前景值得期待。
（3） 应用TECAM被动采样方法监测了南极菲尔德斯半岛水体中PFRs、邻苯二甲酸酯（PAEs）、多环芳烃（PAHs）、有机氯农药（OCPs）和多氯联苯（PCBs）等PBT有机污染物的长期环境暴露和潜在生物影响；TECAM提取液用于化学分析和离体生物测试，成功检出了包括6种PFRs在内的共20种污染物，但未检出显著内分泌干扰效应和遗传毒性。基于被动采样监测的时间加权平均浓度，进行了阻燃剂和增塑剂的来源和迁移研究，以及持久性有机污染物（OCPs和PCBs）在极地的时间空间变化。最终，发现南极水体中不同PFRs和PAEs的暴露特征与当地的人为活动（污水、机场和考察站）和生物活动（企鹅、鸟类和海豹粪便）密切相关；南极菲尔德斯半岛污染物的暴露浓度明显高于其他南极地区，而OCPs和PCBs这两类持久性有机污染物在过去30年内的时间浓度变化较小。在综述对比极地有机污染物监测方法时，发现时间累积被动采样方法相对于主动采样方法在野外应用和操作上具有更大的优势。
（4） 应用船载连续被动采样的方法进行了北极大面积海域海水中PFRs和PBT污染物的暴露研究与动态分布。研发的连续流动被动式采样设备（CFISD）搭载TECAM在实验室具有稳定可靠的被动采样性能。船载TECAM被动采样的样品提取液用于目标分析PFRs和非目标筛查PBT污染物，最终发现了2种广泛受关注的PFRs和4种关注较少的PBT污染物（4-叔丁基酚，2-异丙基萘，正壬基酰苯和1,3,3-三甲基-1-苯基茚满），在北极海水中的最高检出水平可达20.83 ng L-1。基于船载被动采样的时间加权和空间（航段）加权平均浓度，分析PFRs和PBT物质的来源和归趋，发现西斯皮尔根洋流传输和北极当地人类定居、石油开采和原油泄漏等活动是导致这些污染物在北极暴露的主要原因。污染物通过西斯皮尔根向北冰洋传输通量得到预测，表明它们的环境风险应该得到关注。

      Organophosphorus flame retardants (PFRs) are a group of emerging contaminants concerned by worldwide researchers. Passive sampling techniques have been considered as robust tools for monitoring time-weighted average (TWA) concentrations (regarded as bioavailable freely dissolved fraction) of trace-level contaminants in natural and artificial aquatic systems. In this study, the occurrence, source, and transport of PFRs and PBT (persistent, bioaccumulative, toxic) contaminants were studied based on passive sampling techniques. Most PFRs can be passively sampled by triolein-embedded cellulose acetate membranes (TECAM) except for several extremely hydrophilic PFRs. Therefore, we developed a novel passive sampler to simultaneously sample both hydrophilic and hydrophobic organic contaminants in water. We also developed a continuous flow passive sampling device and methods for in situ sampling, improved the quality control, calibration and data analysis methods, and expanded the application of passive sampling. With the intensification of global climate change and increasing pollution of PFRs, it is quite necessary to investigate PFRs and PBT contaminants in polar region. Hence, we studied exposure, sources, and transport of PFRs and PBT contaminants in the Antarctic and the Arctic waters. The major findings of this research are summarized as following:
(1) The analysis method of PFRs in water was optimized. The method of passive sampling PFRs by TECAM was established.
(2) A novel passive sampler, the HECAM (hydrophilic-lipophilic balance sorbent-embedded cellulose acetate membrane) has been successfully developed, which has the applicability to simultaneous passive sampling of both hydrophilic and hydrophobic organic contaminants in water. The accumulation results of thirty-seven target chemicals (including PFRs, phenols, estrogens, organophosphorus pesticides, and triazine herbicides) with a wide polarity range (1.44 < log Kow < 9.49) in the HECAM followed first-order kinetics well and the passive sampling parameters were estimated. The HECAM exhibited high sampling rate for moderately hydrophilic and moderately hydrophobic chemicals, which is probably for the large sampling surface area-to-sorbent mass ratio and little resistance in thin membrane matrix. The field validation study in an urban river resulted in the detection of four target chemicals, which were in consistent with the measured levels found in traditional grab samples by solid-phase extraction. In summary, both the laboratory tests and field deployment showed practicable results for the HECAM passive sampling, which suggests that it is an efficient approach for simultaneous monitoring of hydrophilic and hydrophobic organic contaminants in water.
(3) In the exposure research of PFRs, phthalic acid esters (PAEs), polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), and polychlorinated biphenyls (PCBs) in Antarctic waters, an approach of coupling aquatic time-integrated passive sampling with chemical analysis and bioassays was used to assess pollution. In total, twenty pollutants (six PFRs, one PAE, two PAHs, six OCPs, and five PCBs) were quantified, and six PFRs had concentrations that ranged from ND (not detected) to 44.37 ng L-1 in Antarctic waters. The concentrations detected in the waters were generally low and insufficient to have significant in vitro endocrine disruption potential or genotoxicity. The source and transport pathways of PFRs and PAE in the Fildes Peninsula were studied, and multiple local sources (wastewater, air traffic, research stations, and animal feces) for different PFRs were proposed. A spatial and temporal analysis showed slight changes in the exposure of OCPs and PCBs in Antarctic waters. Furthermore, the comparison among a variety of Antarctic water sampling cases revealed that passive sampling could be an effective tool for aquatic time-integrated investigations in polar regions.
(4) In the study of PFRs exposure in Arctic seawaters, on-board passive sampling of organic pollutants using a self-developed device (continuous flow integrative sampling device, CFISD) coupled with TECAMs was performed during an Arctic cruise. Method stability and high sampling rate for the passive sampling method with CFISD plus TECAM were veritied in both laboratory and field experiments. The field TECAM extracts were used for target analysis of PFRs, and non-target screening of persistent, bioaccumulative, and toxic (PBT) contaminants using two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOFMS). The target and non-target analysis resulted in the discovery of six contaminants in Arctic seawaters, with the temporally and spatially integrated concentrations ranging from ND to 20.83 ng L-1; two PFRs were high-concern emerging pollutants and the other four PBT contaminants (4-tert-butylphenol, 2-isopropylnaphthalene, 1,1,3-trimethyl-3-phenylindane, and 1-phenylnonan-1-one) were low-concern chemicals. Furthermore, sources and transport of the contaminants were studied, and ocean current transport (West Spitsbergen Current, WSC) and certain local sources (including human settlement, Arctic oil exploitation, and petroleum fuel emissions) were identified mainly contributed to the presence of the different contaminants. Finally, annual transport fluxes of the contaminants from the North Atlantic to the Arctic Ocean by WSC were estimated, and the results indicate that their hazard to the Arctic should be concerned.