Bioaccumulation and effects of novel chlorinated polyfluorinated ether sulfonate in freshwater alga Scenedesmus obliquus

摘要

AbstractChlorinated polyfluorinated ether sulfonate (Cl-PFESA) is a novel alternative compound for perfluorooctane sulfonate (PFOS), with its environmental risk not well known. The bioaccumulation and toxic effects of Cl-PFESA in the freshwater alga is crucial for the understanding of its potential hazards to the aquatic environment.Scenedesmus obliquuswas exposed to Cl-PFESA at ng L−1to mg L−1, with the exposure regime beginning at the environmentally relevant level. The total log BAF of Cl-PFESA inS. obliquuswas 4.66, higher than the reported log BAF of PFOS in the freshwater plankton (2.2–3.2). Cl-PFESA adsorbed to the cell surface accounted for 33.5–68.3% of the total concentrations. The IC50 of Cl-PFESA to algal growth was estimated to be 40.3 mg L−1. Significant changes in algal growth rate and chlorophylla/b contents were observed at 11.6 mg L−1and 13.4 mg L−1of Cl-PFESA, respectively. The sample cell membrane permeability, measured by the fluorescein diacetate hydrolyzation, was increased by Cl-PFESA at 5.42 mg L−1. The mitochondrial membrane potential, measured by Rh123 staining, was also increased, indicating the hyperpolarization induced by Cl-PFESA. The increasing ROS and MDA contents, along with the enhanced SOD, CAT activity, and GSH contents, suggested that Cl-PFESA caused oxidative damage in the algal cells. It is less possible that current Cl-PFESA pollution in surface water posed obvious toxic effects on the green algae. However, the bioaccumulation of Cl-PFESA in algae would contribute to its biomagnification in the aquatic food chain and its effects on membrane property could potentially increase the accessibility and toxicity of other coexisting pollutants.Graphical abstractDisplay OmittedHighlights•Bioaccumulation and cellular effects of Cl-PFESA were evaluated inScenedesmus obliquus.•Total log BAF of Cl-PFESA was 4.66, with 33.5–68.3% adsorbed to the cell surface.•Cl-PFESA increased cell membrane permeability and mitochondrial membrane potential.•Cl-PFESA induced oxidative stress inS. obliquus.•Cl-PFESA showed higher accumulation and toxic potency than PFOS.The novel alternative chlorinated polyfluorinated ether sulfonate showed higher accumulation and toxic potency than PFOS in the freshwater algaScenedesmus obliquus.