Toxicity of organophosphate flame retardant in marine rotifers: Evidence from the population, individual, biochemical and molecular levels.

Tris (1-chloro-2-propyl) phosphoric acid (TCPP), a widely used organophosphate flame retardant, has been detected in various aquatic environments due to its extensive industrial application. TCPP is well-known to negatively impact large aquatic organisms. However, the effects of TCPP on zooplankton remain poorly understood. This study explored the ecological risk of TCPP in low-trophic marine organisms by evaluating the marine rotifer Brachionus plicatilis at the molecular, biochemical, individual, and population levels after exposure to TCPP concentrations of 14.79, 44.37, and 73.94 μM. Results showed that exposure to TCPP inhibited body size, feeding behavior, life expectancy, generation time, net reproductive rate, reproduction rate, and population growth rate of rotifers, thus impairing their growth, survival, reproduction, and population expansion. Environmental concentrations surpassing 0.031 μM and 0.23 μM adversely impact rotifer reproduction and survival, respectively. Biochemically, TCPP induced oxidative stress, increased amylase activity, decreased lipase activity, and total protein content. Transcriptome analysis revealed that TCPP could induce abnormal mitochondrial function, impaired energy metabolism, programmed cell death by generating excessive reactive oxygen species, and affect cellular DNA replication. Results indicate that TCPP disrupts homeostasis in rotifers by inducing oxidative stress, significantly suppressing individual and population parameters. These findings provide critical insights for assessing the ecological risk posed by TCPP to zooplankton and the stability of aquatic ecosystems.