Bioaccumulation and toxicity of perfluorooctanoic acid and perfluorooctanesulfonate in marine algae Chlorella sp. br

The ocean is an important sink for perfluorinated alkyl acids (PFAAs), but the toxic mechanisms of PFAAs to marine organ-isms have not been clearly studied. In this study, the growth rate, photosynthetic activity, oxidative stress and bioaccumu-lation were investigated using marine algaeChlorella sp.after the exposure of perfluorooctanoic acid (PFOA) andperfluorooctane sulfonate acid (PFOS). The results showed that PFOA of<40 mg/L and PFOS of<20 mg/L stimulatedalgal reproduction, and high doses inhibited the algal growth.The absorbed PFOA and PFOS by algal cells damaged cellmembrane and caused metabolic disorder. The photosynthesis activity was inhibited, which was revealed by the signifi-cantly reduced maximal quantum yield (Fv/Fm), relative electron transfer rate (rETR) and carbohydrate synthesis. How-ever, the chlorophyllacontent increased along with the up-regulation of its encoding genes (psbBandchlB), probablydue to an overcompensation effect. The increase of ROS and antioxidant substances (SOD, CAT and GSH) indicated thatPFOA and PFOS caused oxidative stress. The BCF of marine algaeChlorella sp.to PFOA and PFOS was calculated to be be-tween 82 and 200, confirming the bioaccumulation of PFOA and PFOS in marine algae. In summary, PFOA and PFOS canaccumulate inChlorella sp.cells, disrupt photosynthesis, trigger oxidativestress and inhibit algal growth. PFOS shows highertoxicity and bioaccumulation than PFOA. The information is important to evaluate the environmental risks of PFAAs