Toxic effects of disinfection by-products on Pseudokirchneriella subcapitata and co-cultured algae community

Abstract

The widespread use of disinfectants in response to the COVID-19 pandemic may increase the concentration of disinfection by-products (DBPs) in surface water, posing ecological risks. This study assessed the acute toxicity of haloacetic acids and halophenols DBPs to Pseudokirchneriella subcapitata, and evaluated the impact of environmental concentrations of DBPs on co-cultured algae communities. The results showed that after exposure to disinfection by-products, the photosynthetic pigments of Pseudokirchneriella subcapitata were significantly reduced, and the MDA content and antioxidant enzyme activity were increased. The results of the ecological risk assessment showed that the RQ values of TBAA, 2,4-DBP, and 2,6-DBP were >0.1, with medium and high ecological risks. Despite this, the three DBPs with the highest risk values had little effect on the community structure of co-cultured algae. In contrast, the disinfection by-products with low ecological risk had a greater impact on the community structure and greatly promote the growth of cyanobacteria, which may cause new ecological risks. Therefore, not only high-risk disinfection by-products need to be paid attention to, but the impact of low-risk disinfection by-products cannot be ignored.