Environmental Toxicology and Chemistry最新文献

Traditional approaches for monitoring aquatic pollution primarily rely on chemical analysis and the detection of pollutants in the aqueous environments. However, these methods lack realism and mechanistic insight and, thus, are increasingly supported by effect-based methods, which offer sensitive endpoints. In this context, daphnids, a freshwater species used extensively in molecular ecotoxicology, offer fast and noninvasive approaches to assess the impact of pollutants. Among the phenotypic endpoints used, feeding rate is a highly sensitive approach because it provides evidence of physiological alterations even in sublethal concentrations. However, there has been no standardized method for measuring feeding rate in daphnids, and several approaches follow different protocols. There is a diversity among tests employing large volumes, extensive incubation times, and high animal densities, which in turn utilize measurements of algae via fluorescence, radiolabeling, or counting ingested cells. These tests are challenging and laborious and sometimes require cumbersome instrumentation. In the present study, we optimized the conditions of a miniaturized fast, sensitive, and high-throughput assay to assess the feeding rate based on the ingestion of fluorescent microparticles. The protocol was optimized in neonates in relation to the concentration of microplastic and the number of animals to increase reproducibility. Daphnids, following exposures to nonlethal concentrations, were incubated with microplastics; and, as filter feeders, they ingest microparticles. The new approach revealed differences in the physiology of daphnids in concentrations below the toxicity limits for a range of pollutants of different modes of action, thus proving feeding to be a more sensitive and noninvasive endpoint in pollution assessment. Environ Toxicol Chem 2024;43:2211–2221. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Energy content, moisture content, and energy assimilation efficiency are essential parameters in the food intake rate (FIR) and exposure calculations for bird and mammal risk assessments. The updated European Food Safety Authority guidance document on risk assessment for birds and mammals summarizes these parameters for different food items. For seed treatments, values for cereal seeds are proposed as surrogates for other crops. Oil-containing seeds are expected to have a higher energy content than cereal seeds. This would result in lower FIR and, thus, exposure from consuming such seeds. To be able to calculate reliable exposure values for risk-assessment purposes, we conducted a systematic literature review to collect information on these three parameters for oil-containing seeds (sunflower, oilseed rape, soybean, peanut, sesame, safflower, linseed [flax], white mustard, and castor bean). The search yielded 401 papers, of which 151 contained values for at least one of the parameters of the crops in focus. The overall average energy content value of oil-containing seeds was 24.25 kJ/g (n = 124, SD = 3.00), whereas that for moisture content was 6.57% (n = 296, SD = 1.15). Energy assimilation values were only available for peanut, oilseed rape, soy, linseed, and sunflower for a limited number of bird and mammal species. Mean energy assimilation efficiency for mammals was 82.69% (n = 4, SD = 1.55), whereas values for birds were 57.54% (n = 2, SD = 6.77) for Galliformes and 79.25% (n = 2, SD = 1.82) for Passeriformes. The values presented can be used to calculate appropriate FIR values for future bird and mammal risk assessments. Environ Toxicol Chem 2024;43:2080–2085. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Legacy brominated flame retardants, including polybrominated diphenyl ethers (PBDEs), have been classified as persistent organic pollutants and replaced with novel brominated flame retardants (NBFRs). The octanol–water partition coefficients (log K_OW) of NBFRs have been computationally estimated, but the log K_OW values provided by these methods can differ by 1 to 3 orders of magnitude. Given the importance of this parameter in fate and toxicity models, we indirectly measured the log K_OW values of eight NBFRs by their capacity factor (k′) on a reversed-phase high-performance liquid chromatography (HPLC) C18 column by isocratic elution and compared these measured values with those estimated by nine computational models. Log K_OW values were obtained for the NBFRs 1,2-bis(2,4,6-tribromophenoxy) ethane, pentabromobenzene, pentabromoethylbenzene, pentabromotoluene, 2-ethylhexyl 2,3,4,5-tetrabromobenzoate, allyl 2,4,6-tribromophenylether, 2,3-dibromopropyl-2,4,6-tribromophenyl ether, and bis(2-ethylhexyl) tetrabromophthalate. A training set of phthalates, polychlorinated biphenyls, PBDEs, and halogenated benzenes were chosen to obtain the log k′–log K_OW calibration for the NBFRs. The computational models KowWIN, XLogP3, EAS-E Suite, COSMOtherm, DirectML, and Abraham polyparameter linear free energy relationships all predicted the log K_OW values of the calibration compounds to within 1 order of magnitude without significant bias. The median of these models predicted log K_OW values for the calibration compounds that were close to those known in the literature with root mean square error (RMSE) = 0.224 and for the NBFRs that were close to those measured by HPLC (RMSE = 0.334). Environ Toxicol Chem 2024;43:2105–2114. © 2024 SETAC

Salamanders serve as bioindicators of mercury (Hg) in both terrestrial and aquatic habitats and are an important link in the food web between low-trophic prey and higher-trophic predators. We investigated the drivers of methylmercury (MeHg) exposure in three common plethodontid salamander species in New York State, USA, including comparisons among regions, habitat types (terrestrial and semiaquatic), and color morphs of Plethodon cinereus (striped and unstriped). Nonlethal tail samples were collected from one terrestrial species (P. cinereus) and two semiaquatic species (Eurycea bislineata and Desmognathus spp.) in the Adirondack Mountains (ADK) and the Finger Lakes National Forest (FLNF) regions. Samples were analyzed for MeHg and stable isotopes, including δ¹⁵N and δ¹³C which are proxies of trophic position and diet, respectively. Despite elevated biota Hg concentrations typically found in the ADK, salamander MeHg concentrations did not differ by region in the terrestrial species and one of the semiaquatic species. In addition, diet and trophic level did not explain MeHg exposure in salamanders. Semiaquatic salamanders exhibited higher MeHg concentrations than terrestrial salamanders in the FLNF only. Within species, only snout–vent length predicted MeHg concentrations in E. bislineata with few other variables significant as predictors of MeHg concentrations in path models. Among P. cinereus individuals in the FLNF, the striped morph had greater MeHg concentrations than the unstriped morph, and food web tracers were not different between morphs. Overall, New York State salamander Hg concentrations were elevated compared to other locations where these species are present. The present study establishes baseline Hg data in salamanders for future assessments of changes in Hg bioavailability to forests of New York State. Environ Toxicol Chem 2024;43:2045–2057. © 2024 SETAC

Acetochlor, as a commonly used pre-emergent herbicide, can be toxic to crops and affect production if used improperly. However, the toxic mechanism of acetochlor on plants is not fully understood. The present study used a combination of transcriptomic analysis and physiological measurements to investigate the effects of short-term (15-day) exposure to different concentrations of acetochlor (1, 10, 20 mg/kg) on the morphology, physiology, and transcriptional levels of pea seedlings, aiming to elucidate the toxic response and resistance mechanisms in pea seedlings under herbicide stress. The results showed that the toxicity of acetochlor to pea seedlings was dose-dependent, manifested as dwarfing and stem base browning with increasing concentrations, especially at 10 mg/kg and above. Analysis of the antioxidant system showed that from the 1 mg/kg treatment, malondialdehyde, superoxide dismutase, peroxidase, and glutathione peroxidase in peas increased with increasing concentrations of acetochlor, indicating oxidative damage. Analysis of the glutathione (GSH) metabolism system showed that under 10 mg/kg treatment, the GSH content of pea plants significantly increased, and GSH transferase activity and gene expression were significantly induced, indicating a detoxification response in plants. Transcriptomic analysis showed that after acetochlor treatment, differentially expressed genes in peas were significantly enriched in the phenylpropane metabolic pathway, and the levels of key metabolites (flavonoids and lignin) were increased. In addition, we found that acetochlor-induced dwarfing of pea seedlings may be related to gibberellin signal transduction. Environ Toxicol Chem 2024;43:2005–2019. © 2024 SETAC

In 2019, there was an environmental catastrophe in Brazil, when more than 5000 tons of unknown origin crude oil invaded beaches and mangroves. Two years later, two monitoring areas were selected to study seahorses’ offspring: Massangana River estuary (apparently healthy area) and Cocaia Island (affected area). Thirty-six reproductive events of Hippocampus reidi (Syngnathidae) couples from these two areas were monitored to analyze the offspring. At the apparently healthy area, no newborns with malformations were found. However, the offspring from Cocaia Island showed a mean of 19.73% (±5.23) malformations in newborns. It is argued that the toxic/teratogenic effects of polycyclic aromatic hydrocarbons have affected the population in two ways: directly through the induction of mutations in the germ cells of the species and through a drastic reduction of the population (bottleneck effect) whose density observed today recovered through consanguineous couplings, potentiating deleterious genotypes in the offspring. Environ Toxicol Chem 2024;43:1996–2004. © 2024 SETAC

Although ecotoxicological and toxicological risk assessments are performed separately from each other, recent efforts have been made in both disciplines to reduce animal testing and develop predictive approaches instead, for example, via conserved molecular markers, and in vitro and in silico approaches. Among them, adverse outcome pathways (AOPs) have been proposed to facilitate the prediction of molecular toxic effects at larger biological scales. Thus, more toxicological data are used to inform on ecotoxicological risks and vice versa. An AOP has been previously developed to predict reproductive toxicity of silver nanoparticles via oxidative stress on the nematode Caenorhabditis elegans (AOPwiki ID 207). Following this previous study, our present study aims to extend the biologically plausible taxonomic domain of applicability (tDOA) of AOP 207. Various types of data, including in vitro human cells, in vivo, and molecular to individual, from previous studies have been collected and structured into a cross-species AOP network that can inform both human toxicology and ecotoxicology risk assessments. The first step was the collection and analysis of literature data to fit the AOP criteria and build a first AOP network. Then, key event relationships were assessed using a Bayesian network modeling approach, which gave more confidence in our overall AOP network. Finally, the biologically plausible tDOA was extended using in silico approaches (Genes-to-Pathways Species Conservation Analysis and Sequence Alignment to Predict Across Species Susceptibility), which led to the extrapolation of our AOP network across over 100 taxonomic groups. Our approach shows that various types of data can be integrated into an AOP framework, and thus facilitates access to knowledge and prediction of toxic mechanisms without the need for further animal testing. Environ Toxicol Chem 2024;00:1-14. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Both microplastics and antibiotics are commonly found contaminants in aquatic ecosystems. Microplastics have the ability to absorb antibiotic pollutants in water, but the specific adsorption behavior and mechanism are not fully understood, particularly in relation to the impact of microplastics on toxicity in aquatic environments. We review the interaction, mechanism, and transport of microplastics and antibiotics in water environments, with a focus on the main physical characteristics and environmental factors affecting adsorption behavior in water. We also analyze the effects of microplastic carriers on antibiotic transport and long-distance transport in the water environment. The toxic effects of microplastics combined with antibiotics on aquatic organisms are systematically explained, as well as the effect of the adsorption behavior of microplastics on the spread of antibiotic resistance genes. Finally, the scientific knowledge gap and future research directions related to the interactions between microplastics and antibiotics in the water environment are summarized to provide basic information for preventing and treating environmental risks. Environ Toxicol Chem 2024;43:1950–1961. © 2024 SETAC