Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Barcelona, Catalunya, Spain.
Department of Instrumental Analysis and Environmental Chemistry, Institute of Organic Chemistry, (IQOG-CSIC), Madrid, Spain.
Water Res. 2020 Mar 15;171:115434. doi: 10.1016/j.watres.2019.115434. Epub 2019 Dec 24.
Perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) acids are ubiquitous in the oceans, including remote regions, and are toxic to fish and mammals. The impact to the lowest trophic levels of the food web, however, remains unknown. We challenged natural bacterial communities inhabiting Antarctic coastal waters (Deception Island) with PFOS and PFOA concentrations ranging from 2 ng/L to 600 ng/L that selected for tolerant taxa. After 48 h, concentrations of PFOS decreased by more than 50% and sulfur metabolism-related transcripts were significantly enriched in the treatments suggesting desulfurization of PFOS. Conversely, no significant differences were found between initial and final PFOA concentrations. Gammaproteobacteria and Roseobacter, two abundant groups of marine bacteria, increased their relative activity after 24 h of incubation, whereas Flavobacteriia became the main contributor in the treatments after 6 days. Community activities (extracellular enzyme activity and absolute number of transcripts) were higher in the treatments than in the controls, while bacterial abundances were lower in the treatments, suggesting a selection of PFOS and PFOA tolerant community in the exposed treatments. Our results show a direct effect of PFOS and PFOA exposure on the composition and functionality of natural Antarctic marine microbial communities. While no evidence of defluorination of PFOS or PFOA was detected, probable desulfurization of PFOS depicts a direct link with the sulfur biogeochemistry of the ocean.
全氟辛烷磺酸（PFOS）和全氟辛酸（PFOA）酸在海洋中无处不在，包括偏远地区，对鱼类和哺乳动物有毒。然而，对食物网中最低营养级别的影响仍不清楚。我们用浓度范围为 2ng/L 至 600ng/L 的 PFOS 和 PFOA 挑战了栖息在南极沿海水域（欺骗岛）的天然细菌群落，这些浓度选择了耐受的分类群。48 小时后，PFOS 的浓度下降了 50%以上，处理中与硫代谢相关的转录本显著富集，表明 PFOS 的脱硫作用。相反，初始和最终 PFOA 浓度之间没有发现显著差异。海洋细菌中两个丰富的群体γ-变形菌和玫瑰杆菌在孵育 24 小时后相对活性增加，而在 6 天后，处理中黄杆菌成为主要贡献者。与对照相比，处理中的群落活性（胞外酶活性和转录本的绝对数量）更高，而处理中的细菌丰度更低，表明暴露处理中存在 PFOS 和 PFOA 耐受群落的选择。我们的结果表明，PFOS 和 PFOA 暴露对自然南极海洋微生物群落的组成和功能有直接影响。虽然没有检测到 PFOS 或 PFOA 的脱氟证据，但 PFOS 的可能脱硫作用描绘了与海洋硫生物地球化学的直接联系。
