关键词: DOM PFAS freshwater natural foam surface microlayer

Mesh : Water Pollutants, Chemical Fresh Water / chemistry Fluorocarbons Surface-Active Agents / chemistry Lakes / chemistry Environmental Monitoring Rivers / chemistry

来  源:   DOI:10.1021/acs.est.4c02285

Abstract:
Per- and polyfluoroalkyl substances (PFAS) are surfactants that can accumulate in the surface microlayer (SML) and in natural foams, with potential elevated exposure for organisms at the water surface. However, the impact of water chemistry on PFAS accumulation in these matrices in freshwater systems is unknown. We quantified 36 PFAS in water, the SML, and natural foams from 43 rivers and lakes in Wisconsin, USA, alongside measurements of pH, cations, and dissolved organic carbon (DOC). PFAS partition to foams with concentration ranging 2300-328,200 ng/L in waters with 6-139 ng/L PFAS (sum of 36 analytes), corresponding to sodium-normalized enrichment factors ranging <50 to >7000. Similar enrichment is observed for DOC (∼70). PFAS partitioning to foams increases with increasing chain length and is positively correlated with [DOC]. Modest SML enrichment is observed for PFOS (1.4) and FOSA (2.4), while negligible enrichment is observed for other PFAS and DOC due to low specific surface area and turbulent conditions that inhibit surfactant accumulation. However, DOC composition in the SML is distinct from bulk water, as assessed using high-resolution mass spectrometry. This study demonstrates that natural foams in unimpacted and impacted waters can have elevated PFAS concentrations, whereas SML accumulation in surface waters is limited.
摘要:
全氟烷基和多氟烷基物质(PFAS)是可以在表面微层(SML)和天然泡沫中积累的表面活性剂,对水面生物的潜在暴露增加。然而,水化学对淡水系统中这些基质中PFAS积累的影响尚不清楚。我们量化了水中的36个PFAS,SML,来自威斯康星州43条河流和湖泊的天然泡沫,美国,除了测量pH值,阳离子,和溶解的有机碳(DOC)。在具有6-139ng/LPFAS(36种分析物的总和)的水中,PFAS分配至浓度范围为2300-328,200ng/L的泡沫,对应于钠归一化富集因子范围<50至>7000。对于DOC观察到类似的富集(~70)。PFAS向泡沫的分配随着链长度的增加而增加,并且与[DOC]呈正相关。观察到全氟辛烷磺酸(1.4)和FOSA(2.4)的SML富集适度,而对于其他PFAS和DOC,由于比表面积低和湍流条件抑制表面活性剂积累,观察到的富集可忽略不计。然而,SML中的DOC组成与散装水不同,如使用高分辨率质谱评估。这项研究表明,未受影响和受影响的水域中的天然泡沫可以具有升高的PFAS浓度,而SML在地表水中的积累是有限的。
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