Toxic effects of DPTE on the growth, development, and reproduction of Chironomus kiiensis and its underlying mechanisms

2,3-Dibromopropyl-2,4,6-tribromophenyl ether (DPTE) is a novel brominated flame retardant (NBFR) that is widely detected in diverse environmental matrices. The ecological effects of NBFRs represent a key criterion in determining their long-term applicability. Compounds such as polybrominated diphenyl ethers (PBDEs) and other NBFRs are known to induce disruptions in physiological processes. DPTE interferes with the secretion of sex hormones in both larval and adult Chironomus kiiensis , thereby impairing reproduction and juvenile development. In this study, 48 h exposure to DPTE at concentrations ≥30 μg/L inhibited the activity of C. kiiensis larvae, and all tested concentrations of DPTE accumulated within the organism and were maternally transferred to offspring. Larval body length in the parental generation (P) was significantly reduced by all DPTE concentrations, whereas in the filial generation (F), significant reductions occurred only at 300 μg/L. Across all concentrations, DPTE delayed adult emergence and reduced developmental rates in both generations. These physiological abnormalities may be associated with disruptions in hormone, vitamin, and energy metabolism, along with fluctuations in the expression of hormone-related genes involved in ecdysteroid, juvenile hormone, and insulin signaling pathways. Our findings reveal that DPTE exerts toxic effects on freshwater organisms not only through acute immobilization but also via bioaccumulation, which subsequently impairs growth, development, and reproduction.