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This study aimed to reveal possible alterations to lipidomic profiles in Sydney rock oysters, Saccostrea glomerata, exposed to estrogenic mixtures (i.e., estrone, E1; 17β-estradiol, E2; estriol, E3; 17α-ethinylestradiol, EE2; bisphenol A, BPA; 4- t -octylphenol, 4- t -OP; and 4-nonylphenol, 4-NP) at "low" and "high" concentrations, typical of those detected in Australian and global receiving waters. A seven-day acute exposure window exhibited significantly lower abundances of many non-polar metabolites in digestive gland, gills, and gonads. Overall, there was a strong effect of the carrier solvent ethanol (despite a low exposure of 0.0002%), with all solvent containing treatments exhibiting lower abundances of lipidic metabolites, especially in the gill and digestive gland. No significant changes of the lipidome were exhibited in the male gonad by estrogenic exposure. However, in the female gonad, significant reductions of phospholipids and phosphatidylcholine were associated with exposure to high estrogenic mixtures. We hypothesise that the decreases in these phospholipids in the female gonad may be attributable to 1) lower algal consumption and thus lower uptake of lipidic building blocks; 2) a reduction of available substrates for phospholipid and phosphatidylcholine synthesis; and/or 3) induction of reactive oxygen species via estrogen metabolism, which may cause lipid peroxidation and lower abundance of phospholipids. [Display omitted] • Estrogenic mixtures reduced oyster soft body mass. • In the female gonad, estrogenic mixtures remarkably decreased phospholipids and phosphatidylcholine. • No significant alteration of the lipidome in the male gonad by estrogenic mixtures. • There was a strong carrier solvent (ethanol) effect on the digestive gland and gill lipidome. [ABSTRACT FROM AUTHOR]

Plastic waste is ubiquitous in marine environments. Despite the sheer volume of plastic waste, it remains relatively unknown how marine invertebrates will interact with microplastics (plastic <1 mm). Microplastics (<2 μm) were ingested by the economically and ecologically significant Sydney rock oyster Saccostrea glomerata and translocated to the haemolymph, perhaps via phagocytosis. The presence of microplastics in the haemolymph indicates that filter feeding S. glomerata can ingest and accumulate microplastics which are prevalent in the environment. This research shows microplastics can enter marine molluscs and highlights the need to monitor microplastics in the marine environment and aquaculture to safeguard the seafood industry. Unlabelled Image • Oysters are a valuable seafood yet potentially vulnerable to microplastic pollution. • Oysters (Saccostrea glomerata) were exposed to microplastics. • Oysters ingested microplastics at the size of 2 μ and 0.5 μ. • Once ingested, microplastics were translocated through the digestive gland to the hemolymph. [ABSTRACT FROM AUTHOR]