2-ethylhexyl-4-methoxycinnamate (EHMC), as one of the most prevalent and mass-produced organic UV filters (OUVFs), has emerged as a globally significant pollutant. The continuous release of EHMC into surface waters presents significant hazards to aquatic biota, but its toxicological effects on aquatic invertebrates remain largely unknown. In the present study, Daphnia magna neonates were exposed to 0, 0.14, 1.65, and 15.71 μg/L EHMC for 21 days to investigate potential chronic adverse impacts on the growth, reproduction, antioxidant defense, and swimming behavior, and to explore the underlying toxicological mechanisms. The results indicated that EHMC significantly inhibited D. magna growth and reproduction, reducing body length, delaying first brood, lowering offspring count, and causing severe locomotor inhibition with decreased swimming speed and distance. qPCR analysis demonstrated that EHMC interfered with the expression patterns of core genes (e75, hr3) involved in the ecdysone signaling pathway and affected the transcriptional levels of reproductive-related genes (vtg1, vtg2). Furthermore, based on elevated juvenile hormone (JH) levels and upregulated jhe expression, we speculated that disruption of JH metabolism might contribute to reproductive suppression. Additionally, high concentrations of EHMC collapsed the antioxidant defense and triggered oxidative damage. Principal component analysis (PCA) revealed a marked negative correlation between ROS level, GPx activity and growth-reproduction indicators, suggesting a potential trade-off strategy that D. magna redistributed energy against oxidative damage under EHMC stress, thereby impairing physiological functions. Collectively, these findings deepen our understanding of EHMC's toxicity to aquatic invertebrates, and provide essential scientific basis for organic UV filters pollution control in aquatic environments.
The rapid expansion of coastal wind farms raises concerns about extremely low-frequency electromagnetic fields (ELF-EMF) affecting marine organisms. Using Cyclina sinensis as a model, this study examined effects of short-term (24-h intermittent exposure, 2-h on/off, then field-free recovery to day 14) and long-term (14-d intermittent exposure, 2-h on/off) ELF-EMF exposure (15 ± 1 μT, 50 Hz) versus geomagnetic control. Physiological indices were measured at 0, 1, 14 days post exposure (dpe) with time-matched controls, transcriptomic controls existed only at 0 dpe. Survival was 100 ± 0% (Control), 95.56 ± 1.92% (Short-term), and 90.00 ± 3.33% (Long-term). Short-term exposure elevated hepatopancreatic SOD, CAT activities and reduced MDA levels, returning to baseline by 14 days after exposure ceased. Long-term exposure reduced SOD, CAT and increased MDA. Transcriptomic profiling versus 0 dpe baseline identified 5479 and 4985 differentially expressed unigenes in Short- and Long-term groups, respectively. Because no time-matched transcriptomic controls at 1 and 14 dpe were included, these comparisons are confounded by experimental time and cannot be attributed solely to ELF-EMF. Short-term enrichment of endoplasmic reticulum stress and oxidative phosphorylation agrees with a parallel study using the same exposure conditions and 14-d time-matched controls, supporting an ELF-EMF-associated early response. Other long-term transcriptomic changes including amino acid metabolism, translational changes remain exploratory. These results suggest time-associated physiological responses and provide preliminary molecular insights for ecological risk assessment of offshore wind farms and sustainable coastal management. Future studies with time-matched controls at both 1 and 14 dpe are required to validate the molecular findings.
Terrestrial soils are major sinks for nanoplastics, threatening soil-dwelling oviparous reptiles that lay permeable eggs. The present study investigated the effects of embryonic exposure to an environmentally relevant dose of polystyrene nanoplastics (PS-NPs; 1 mg/L) during incubation in the Chinese skink (Plestiodon chinensis). PS-NPs penetrated eggshells and accumulated in embryos, slowing egg growth, prolonging incubation, triggering oxidative stress, and altering immune-related responses. Crucially, the oxidative stress response was associated with different developmental stages, reflecting the lower functional capacity of early-stage antioxidant systems that rely heavily on non-enzymatic defenses. In contrast, no significant differences were detected in hatchling locomotor performance, boldness, or activity under the behavioral conditions tested. Untargeted metabolomic profiling further identified differences in several important metabolites in hatchlings exposed to PS-NPs. Collectively, these findings indicate that embryonic exposure to PS-NPs is associated with measurable changes to developmental, antioxidant and metabolic responses, while not producing detectable short-term behavioral impairment under the conditions tested in this study. Notably, this study provides the first evidence that antioxidant responses to nanoplastic exposure differ between developmental stages in reptiles. This offers novel insights into the physiological vulnerabilities of oviparous wildlife to soil pollution, and highlights the need to incorporate multiple developmental stages when conducting risk assessments for environmental contamination.
