Phthalic acid esters (PAEs) are a group of compounds composed of structurally similar congeners with diverse physicochemical properties and can therefore form spatiotemporally heterogeneous mixtures in the ambient environment. Developing realistic exposure profiles of PAE mixtures, along with evaluating their combined effects on aquatic organisms, is important for effective ecological risk assessment. In this study, we first predicted the exposure profiles of 12 PAEs in rivers across Japan using the Grid-Catchment Integrated Environmental Modeling System. For shorter-chain PAEs (with alkyl side chains of C1–C6), three representative environmental profiles were selected based on their total concentrations and relative toxic potencies (expressed as dibutyl phthalate DBP equivalents), and subchronic ecotoxicity tests using these mixtures were conducted on three aquatic species: algae (Raphidocelis subcapitata), daphnids (Ceriodaphnia dubia), and fish (Danio rerio). In all tested profiles, DBP and diisobutyl phthalate together accounted for over 90% of the toxicity of the PAE mixtures. Regardless of differences in the tested profiles or test species, the observed combined effects of the mixtures generally fell within a factor of two of the predictions made by the concentration addition (CA) model. These results suggest that the combined effects of PAE mixtures can be reasonably predicted using the CA model across a range of mixing ratios. Further efforts to expand environmental monitoring and improve the accuracy of emission estimates for PAEs will be essential for reliably quantifying the ecological risks associated with their combined effects.
Oda et al. (Thu,) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: