Toxicology Centre, University of Saskatchewan, Saskatoon, SK, S7N 5B3, Canada; Research Centre for Contaminants in the Environment, Pavilion 29 Masaryk University, Brno, Czech Republic.
Department of Civil and Materials Engineering (MC 246), University of Illinois at Chicago 842 West Taylor Street, Chicago, IL 60607-7023, USA.
Environ Pollut. 2018 May;236:373-381. doi: 10.1016/j.envpol.2018.01.065.
Current and historical concentrations of 22 poly- and perfluorinated compounds (PFASs) in sediment collected from Lake Superior and northern Lake Michigan in 2011 and Lake Huron in 2012 are reported. The sampling was performed in two ways, Ponar grabs of surface sediments for current spatial distribution across the lake and dated cores for multi-decadal temporal trends. Mean concentrations of the sum of PFASs (∑PFASs) were 1.5, 4.6 and 3.1 ng g dry mas (dm) in surface sediments for Lakes Superior, Michigan and Huron, respectively. Of the five Laurentian Lakes, the watersheds of Superior and Huron are the less densely populated by humans, and concentrations observed were typically less and from more diffuse sources, due to lesser urbanization and industrialization. However, some regions of greater concentrations were observed and might indicate more local, point sources. In core samples concentrations ranged from <LOQ to 46.6 ng g dm among the three lakes with concentrations typically increasing with time. Distributions of PFASs within dated cores largely corresponded with increase in use of PFASs, but with physiochemical characteristics also affecting distribution. Perfluoroalkyl sulfonates (PFSAs) with chain lengths >7 that include perfluoro-n-octane sulfonate (PFOS) bind more strongly to sediment, which resulted in more accurate analyses of temporal trends. Shorter-chain PFASs, such as perfluoro-n-butanoic acid which is the primary replacement for C8 PFASs that have been phased out, are more soluble and were identified in some core layers at depths corresponding to pre-production periods. Thus, analyses of temporal trends of these more soluble compounds in cores of sediments were less accurate. Total elemental fluorine (TF) and extractable organic fluorine (EOF) indicated that identified PFASs were not a significant fraction of fluorine containing compounds in sediment (<0.01% in EOF).
本文报告了 2011 年在苏必利尔湖、密歇根湖北部和 2012 年休伦湖中采集的沉积物中 22 种多氟和全氟化合物（PFASs）的当前和历史浓度。采样采用两种方式进行，即用 Ponar 抓斗采集表层沉积物以了解湖泊的当前空间分布，以及采集有年代记录的沉积物芯以了解多十年的时间趋势。苏必利尔湖、密歇根湖和休伦湖表层沉积物中∑PFASs 的平均浓度分别为 1.5、4.6 和 3.1ng/g 干重。在这五个大湖中，苏必利尔湖和休伦湖的流域人口密度较低，由于城市化和工业化程度较低，因此观察到的浓度通常较低且来源较为分散。然而，在一些浓度较高的地区可能存在更多的局部点状污染源。在核心样本中，三个湖泊的浓度范围从 <LOQ 到 46.6ng/g dm，浓度通常随时间增加。在有年代记录的核心样本中，PFASs 的分布与 PFASs 的使用增加基本一致，但物理化学特性也会影响分布。链长>7 的全氟烷基磺酸盐（PFSAs），包括全氟辛烷磺酸（PFOS），与沉积物的结合力更强，因此更准确地分析了时间趋势。短链 PFASs，如全氟丁烷酸，是已被淘汰的 C8 PFASs 的主要替代品，其溶解度更高，在一些核心层的深度与生产前时期相对应的位置被检测到。因此，在沉积物核心中对这些更易溶解的化合物进行时间趋势分析的准确性较低。总元素氟（TF）和可提取有机氟（EOF）表明，所鉴定的 PFASs 不是沉积物中含氟化合物的重要组成部分（EOF 中<0.01%）。
