| 题名 | 短链全氟化合物分析方法及其环境行为研究 |
| 作者 | 周珍 |
| 学位类别 | 博士 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 蔡亚岐 |
| 关键词 | 短链全氟化合物 分析方法 环境行为 生物富集 人体暴露 short-chain PFASs analytical method environmental behavior bioaccumulation human exposure |
| 其他题名 | Aanlytical Methods and Environmental Behaviour of Short-Chain Perfluoroalkyl Substances |
| 学位专业 | 分析化学 |
| 中文摘要 | 全氟化合物（Per- and polyfluoroalkyl substances，PFASs）因其独特的物理化学性质，被广泛应用于日常生活和工业生产的各个领域。2009年，全氟辛基磺酸（PFOS）及其盐，以及全氟辛基磺酰氟化物（PFOSF）被列入斯德哥尔摩公约，限制其相关产品的生产和使用。而全氟碳链小于7的短链PFASs作为替代产品，已逐渐被广泛应用，并随着生产使用过程不断进入环境。但是，目前对于短链PFASs的环境行为和生态风险的研究还很少。本论文的研究工作主要围绕短链PFASs的分析方法、水环境中污染特征和迁移规律、水生生物富集和组织分布以及人体暴露健康风险展开，主要包括以下五个部分的研究内容： 1、应用液相色谱-质谱联用（HPLC-ESI-MS/MS）技术，建立和完善了水样、底泥、植物、肌肉、内脏组织、血液和尿液样品中包括6种短链PFASs在内的14种PFASs的分析方法。各种环境介质中PFASs分析方法的加标回收率和重现性均表现良好，方法检出限适用于实际样品的检测，满足环境科学研究的需求。 2、研究了中国氟化工行业主要的生产基地之一——武汉地区的10个污水处理厂进、出口污水和19个地表水样品中PFASs污染特征。结果发现，在武汉地区的污水和地表水样品中，PFASs污染均以短链同系物为主。污水处理厂进口污水和出口污水中PFASs总浓度范围分别为11.8-12700 ng/L和19.1-9970 ng/L。在城区15个湖水样品中，PFASs总浓度范围为21.0-10900 ng/L；在流经城区的4个江水样品中，PFASs总浓度范围为4.11-4.77 ng/L，比湖水样品中PFASs浓度水平低1~2个数量级。值得注意的是，我们在位于武昌的L13湖（汤逊湖）水样中检测到异常高浓度的PFASs，而湖泊L13紧邻W6污水处理厂。我们推测，污水处理厂的排污直接或者间接影响了汤逊湖水样中PFASs污染水平。 3、分析了武汉市汤逊湖水域的表层水、底泥以及生物样品（包括鱼和植物）中PFASs污染水平，研究短链等PFASs在水环境中的污染特征及其迁移规律。汤逊湖表层水中PFASs以全氟丁基磺酸（PFBS）和全氟丁酸（PFBA）为主，平均浓度分别为3660 ng/L和4770 ng/L；而底泥中PFASs以PFOS为主，平均浓度为74.4 ng/g干重。比较分析不同全氟碳链长度的PFASs泥水分配系数（Koc，有机碳含量归一化）发现，短链PFASs在底泥中吸附能力低于PFOS、全氟辛酸（PFOA）以及更长链的PFASs。PFBS和PFBA可以顺水流方向水平迁移，并可垂直渗入湖底沉积物深处。然而，水中PFOS和PFOA浓度随着水流指数下降，沉积柱中PFOS和PFOA百分比随着深度的增加逐渐下降。此外，短链PFASs在水生生物体内的生物富集系数（BCF）log值较低（< 1），表明短链PFASs在水生生物中没有富集潜能。 4、进一步分析了汤逊湖地区淡水鱼和鸭子体内各组织中PFASs污染特质。结果发现，鱼和鸭各组织中PFASs都以PFOS为主，分别占总PFASs的78%-93%和93%-97%。在不同物种的水生生物样品中，PFOS浓度水平因食性不同而不同：杂食性（鸭、鲤鱼和黄颡鱼）>食草性（草鱼和鳊鱼）>滤食性（花鲢鱼和白鲢鱼）。鱼和鸭各组织样品中，以血液PFASs浓度最高，其次是肝和肾，肌肉中PFASs浓度最低。鱼胆汁中全氟磺酸（PFSAs）浓度与血液中浓度相当，高于肾脏中浓度水平，而胆汁中全氟羧酸（PFCAs）浓度低于血液中浓度，表明不同取代基团的PFASs在生物体内运输和排泄机制不同。另外，鸭蛋中PFASs主要存在于蛋黄中（>98%），并且蛋黄中PFOS浓度与血液和肝脏中浓度水平相当，说明PFASs可以由母代传递给子代。 5、采集汤逊湖地区特殊职业人群——渔场雇工的血清和尿液，分析其中PFASs浓度和临床生化指标，研究此类特殊人群的PFASs暴露途径、累积排泄和健康风险。与普通对照人群相比（n = 9，PFOS血清浓度中位值：18.7 ng/mL），在渔场雇工血清中检测到高浓度的PFASs（n = 39，PFOS血清浓度中位值：10400 ng/mL）。通过对不同暴露途径摄入量的计算，可以推断，来自汤逊湖的淡水鱼摄入是渔场雇工血清高浓度PFASs暴露的主要来源。与普通对照人群相比，渔场雇工血清中直链PFOS的比例（78.4%）明显高于对照组（66.8%），可能与摄入含有高比例直链PFOS的鱼肉（> 90%）相关。比较不同全氟碳链长度的PFASs肾清除率，发现全氟碳链小于8的PFCAs主要通过尿液排泄，而长链PFCAs和PFSAs可能通过其它途径排泄。尽管估算得到的渔场雇工PFOS每日摄入量超过了欧洲食品安全署给出的每日耐受量参考值，但是体检结果显示，所有雇工血清生化指标均在健康参考值范围内。对于汤逊湖地区渔场雇工及其周边居民暴露于PFASs的健康风险评估，还需要更进一步的流行病学研究。 |
| 英文摘要 | Per- and polyfluoroalkyl substances (PFASs) have been widely used in industrial and household products due to their extreme thermal and chemical stability, hydro- and lipophobic properties. In 2009, perfluorooctane sulfonate (PFOS), its salts and perfluorooctane sulfonyl fluoride (PFOSF) have been listed into the Stockholm Convention, and their homolog products in industrial and consumer have been phased out and restricted by international organizations. Short-chain PFASs, which have less than seven fluorinated carbons, have been widely used as substitute compounds and discharged into the environment. However, few studies have investigated the environmental behavior and ecological risk of short-chain PFASs. The main objective of this dissertation is to develop the analytical methods for short-chain PFASs in various matrixes and investigate their transport pathway in aquatic environment, bioaccumulation and tissue distribution in aquatic organisms, and health risk in exposed people. It consists of the following five parts: First, the analytical methods were developed to measure 14 PFASs including six short-chain PFASs in water, sediment, plants, muscle, biological tissue, blood and urine samples using high performance liquid chromatography/electrospray tandem mass spectrometry (HPLC-ESI-MS/MS). The methods are reliable, showing high sensitivity, good recovery and repeatability. They are suitable for the research of PFASs in environment. Secondly, occurrence of PFASs in ten major wastewater treatment plants (WWTPs) and nineteen surface water samples from lakes and river was investigated in Wuhan which is one of the main production bases of the fluorochemical industry in China. Short-chain homologs were the dominant PFASs in wastewater and surface water samples. The total PFASs concentrations in influents and effluents were in a range of 11.8-12700 ng/L and 19.1-9970 ng/L, respectively. The total PFASs concentrations in lake water samples ranged from 21.0 to 10900 ng/L. The total PFASs levels in river water samples were 1~2 order of magnitudes lower than those in lake water samples, in a range of 4.11-4.77 ng/L. It’s worth noting that relatively high levels of PFASs were observed in L13 Lake (Tangxun Lake) which is close to W6 WWTP. It is hypothesized that the discharge from W6 WWTP were responsible directly or indirectly for the PFASs contamination in Tangxun Lake. Thirdly, water, sediment and biological samples (fish and plant) were collected and analyzed from Tangxun Lake to investigate the pollution characteristics and transport pathways of short-chain PFASs. Perfluorobutane sulfonate (PFBS) and perfluorobutanoic acid (PFBA) were the predominant PFASs in surface water, with average concentrations of 3660 ng/L and 4770 ng/L, respectively. However, perfluorooctane sulfonate (PFOS) was the most abundant PFAS in sediments, with an average concentration of 74.4 ng/g dw. The organic carbon normalized distribution coefficients (KOC) indicated that short-chain PFASs (CF2 < 7) tended to have lower adsorption potentials than PFOS, perfluorooctanoic acid (PFOA), and longer perfluoroalkyl chain compounds. PFBS and PFBA could transport to farther distance in the horizontal direction along the water flow, and infiltrate into deeper depths in vertical direction. However, levels of PFOS and PFOA in water dropped exponentially along the current, and their proportions were decreased gradually with the increasing depth in sediment cores. Furthermore, values of log bioconcentration factor (BCF) of the short-chain PFASs were all relatively low (< 1), indicating no bioaccumulation potentials for short-chain PFASs in aquatic species. Then, the levels of 14 PFASs were analyzed in tissue samples of freshwater fish and mallard from Tangxun Lake. PFOS was the dominant PFAS in fish and mallard, accounting for 8%-93% and 93%-97% of the total PFASs, respectively. The concentrations of PFOS were different among species with different feed behaviors: omnivore (mallards, common carps and yellow catfish) > herbivore (grass carps and white amur breans) > filter feeder (bighead carps and silver carps). Generally, the highest concentrations of PFASs were found in blood, followed by liver and kidney, and the lowest in muscle. Interestingly, the PFSAs levels in fish bile were comparable to those in blood and higher than those in kidney, while the PFCAs levels in fish bile were lower than those in blood, suggesting that there might be different mechanism of transport and elimination in aquatic organisms between PFSAs and PFCAs. Additionally, approximately more than 98% of the PFOS measured in mallard eggs was found in the yolk, and the concentration of PFOS in egg yolk was comparable to that in blood and liver, indicating that PFASs could transfer from mother to egg. Finally, we present a comprehensive exposure assessment of PFASs in fishery employees from Tangxun Lake to investigate the exposure pathways, elimination and health risk of PFASs in special exposed peoples. Exceptionally high serum concentrations of C4 to C12 PFASs were observed in fishery employees (n = 39, median perfluorooctane sulfonic acid (PFOS) 10400 ng/mL) compared to a reference group from the same city (n = 9, median PFOS 18.7 ng/mL). Based on the comparison of different exposure pathways it was concluded that contaminated fish from Tangxun Lake was the primary source of PFAS exposure to fishery employees. PFOS isomer profiles in fishery employees showed a significantly higher proportion of linear PFOS (78.4%) compared to the background-exposed reference group (66.8%), reflecting the highly linear PFOS isomer profile (>90%) of lake fish. Renal clearance rates (CLrenal) showed that PFCAs with less than 8 perfluoroalkyl carbons were primarily eliminated via urine, whereas other routes of excretion may have contributed to the elimination for long-chain PFCAs and PFSAs. Calculated daily PFOS exposures of fishery employees significantly exceeded tolerable daily intake limits, but clinical blood biochemical parameters were mostly within normal reference ranges. However, additional epidemiological studies are needed to address potential associations between PFAS exposure and health effects in the Tangxun Lake area. |
| 公开日期 | 2015-06-15 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/13467]  |
| 专题 | 生态环境研究中心_环境化学与生态毒理学国家重点实验室 |
| 推荐引用方式 GB/T 7714 | 周珍. 短链全氟化合物分析方法及其环境行为研究[D]. 北京. 中国科学院研究生院. 2014. |
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