Environment Research Institute, Shandong University, Qingdao 266237, China.
MOE Laboratory for Earth Surface Processes, College of Urban & Environmental Sciences, Peking University, Beijing 100871, China.
Sci Total Environ. 2023 Apr 20;870:161882. doi: 10.1016/j.scitotenv.2023.161882. Epub 2023 Jan 31.
The ocean is an important sink for perfluorinated alkyl acids (PFAAs), but the toxic mechanisms of PFAAs to marine organisms have not been clearly studied. In this study, the growth rate, photosynthetic activity, oxidative stress and bioaccumulation were investigated using marine algae Chlorella sp. after the exposure of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate acid (PFOS). The results showed that PFOA of <40 mg/L and PFOS of <20 mg/L stimulated algal reproduction, and high doses inhibited the algal growth. The absorbed PFOA and PFOS by algal cells damaged cell membrane and caused metabolic disorder. The photosynthesis activity was inhibited, which was revealed by the significantly reduced maximal quantum yield (Fv/Fm), relative electron transfer rate (rETR) and carbohydrate synthesis. However, the chlorophyll a content increased along with the up-regulation of its encoding genes (psbB and chlB), probably due to an overcompensation effect. The increase of ROS and antioxidant substances (SOD, CAT and GSH) indicated that PFOA and PFOS caused oxidative stress. The BCF of marine algae Chlorella sp. to PFOA and PFOS was calculated to be between 82 and 200, confirming the bioaccumulation of PFOA and PFOS in marine algae. In summary, PFOA and PFOS can accumulate in Chlorella sp. cells, disrupt photosynthesis, trigger oxidative stress and inhibit algal growth. PFOS shows higher toxicity and bioaccumulation than PFOA. The information is important to evaluate the environmental risks of PFAAs.
海洋是全氟烷基酸（PFAAs）的一个重要汇，但 PFAAs 对海洋生物的毒性机制尚未得到明确研究。在这项研究中，使用海洋藻类小球藻（Chlorella sp.）研究了全氟辛酸（PFOA）和全氟辛烷磺酸（PFOS）暴露后，生长速度、光合作用活性、氧化应激和生物累积。结果表明，<40mg/L 的 PFOA 和 <20mg/L 的 PFOS 刺激藻类繁殖，高剂量则抑制藻类生长。藻类细胞吸收的 PFOA 和 PFOS 破坏了细胞膜并导致代谢紊乱。光合作用活性受到抑制，这表现为最大量子产量（Fv/Fm）、相对电子传递率（rETR）和碳水化合物合成显著降低。然而，叶绿素 a 含量增加，同时其编码基因（psbB 和 chlB）上调，可能是由于过度补偿效应。ROS 和抗氧化物质（SOD、CAT 和 GSH）的增加表明 PFOA 和 PFOS 引起了氧化应激。海洋藻类小球藻对 PFOA 和 PFOS 的 BCF 计算值在 82 到 200 之间，证实了 PFOA 和 PFOS 在海洋藻类中的生物累积。总之，PFOA 和 PFOS 可以在小球藻细胞中累积，破坏光合作用，引发氧化应激并抑制藻类生长。PFOS 比 PFOA 表现出更高的毒性和生物累积性。这些信息对于评估 PFAAs 的环境风险非常重要。
