The effect of natural organic matter on bioaccumulation and toxicity of chlorobenzenes to green algae

•NOM-CB interaction and its effect on bioaccumulation and algal toxicity were studied.•The NOM-CB interaction increased with increasing Cl-substitutions in CBs.•NOM increased cell surface hydrophobicity of algae exposed to CBs.•NOM increased BCFs and accumulations of CBs in algae.•The effect of SRNOM on the algal toxicity of CBs varied with Cl-substitutions.