LAUSR

To compare the toxicities of a chlorinated and a nonchlorinated organophosphorus flame retardants (OPFRs) in this study, adult Corbicula fluminea (C. fluminea) were exposed to tris(1,3-dichloro-2-propyl)phosphate (TDCIPP) and tributyl phosphate (TNBP) at 20, 200 and 2000 μg/L for 30 d. Toxicity screening using transcriptomics indicated that the apoptosis pathway was significantly affected in the groups exposed to 2000 μg/L TDCIPP and TNBP (p ≤ 0.05), and this finding was further confirmed by the protein interaction network. A TUNEL assay suggested that TDCIPP and TNBP can cause apoptosis. The significant (p ≤ 0.05) increases in the activities of caspase 3 and 8 obtained with all treatments and in those of caspase 9 obtained with the 2000-μg/L exposure treatments indicated the presence of mitochondria-dependent and mitochondria-independent apoptosis. Interestingly, a noticeable dose-dependent increase in DNA damage was observed in all treatments, resulting in apoptosis. Therefore, our results demonstrate that TDCIPP and TNBP induce DNA damage and apoptosis in C. fluminea, which indicates that these chemicals pose an ecological risk to benthic organisms. Moreover, through the similar mechanism of action in apoptosis, TDCIPP induced more serious toxicity than TNBP, which indicated that chlorination or differences in structure-specific metabolism could be key factors influencing toxicity.