Acute Toxicity of PFOA and Its Degradation Products to Chlorella sp.

Perfluorooctanoic acid (PFOA) is a typical persistent organic pollutant. Photocatalytic degradation is one of the removal approaches, but the degradation products may exert toxic effects on aquatic organisms. In this study, the acute toxicity of PFOA and its photocatalytic degradation products (DL) to Chlorella sp. was compared through a 96 h exposure experiment at environmentally relevant concentrations of 0.0001 REF and 0.05 REF (REF, Relative Enrichment Factor). Algal cell density and chlorophyll a content were measured to evaluate the effects on growth and photosynthetic system. The results showed that at 0.05 REF, both PFOA and DL significantly inhibited algal growth, with a significantly higher inhibition rate for DL (25.23%) than for PFOA (10.13%) (p < 0.05). Meanwhile, both treatments significantly reduced chlorophyll a content, and DL caused more severe damage. In conclusion, the photocatalytic degradation products of PFOA exhibit stronger acute toxicity to Chlorella sp. than the parent compound, warranting attention in environmental risk assessment.