Acute toxicity of nonylphenols and bisphenol A to the embryonic development of the abalone Haliotis diversicolor supertexta

Acute toxic effects and mechanisms of two typical endocrine disrupting chemicals, nonylphenols (NPs) and bisphenol A (BPA), to the embryonic development of the abalone Haliotis diversicolor supertexta, were investigated by the two-stage embryo toxicity test. The 12-h median effective concentrations (EC₅₀) of NPs and BPA to the trochophore development were 1016.22 and 30.72 μg L^-1, respectively, and the respective 96-h EC ₅₀ values based on the completion of metamorphosis (another experimental endpoint) were reduced to 11.65 and 1.02 μg L^-1. Longer exposure time and magnified exposure concentrations in the benthic diatom, that serves as both food source and settlement substrate during the metamorphosis, via bioaccumulation, led to the higher sensitivity of metamorphosis to target EDCs compared with the trochophore development. The hazard concentrations for 5% of the species (HC₅) could be employed as the safety thresholds for the embryonic development of the abalone. The 12-h HC₅ values of NPs and BPA were 318.68 and 13.93 μg L^-1, respectively, and the respective 96-h HC₅ values were 0.99 and 0.18 μg L^-1, which were at environmentally relevant levels. Results of proteomic responses revealed that NPs and BPA altered various functional proteins in the abalone larvae with slight differences between each chemical and affected various physiological functions, such as energy and substance metabolism, cell signalling, formation of cytoskeleton and cilium, immune and stress responses at the same time, leading to the failure of metamorphosis.