Environmental Toxicology and Chemistry最新文献

Anthropogenic stressors, such as pollution and climate change, are altering selective pressures on natural populations, but the evolutionary consequences of chronic exposure to complex mixtures of contaminants remain poorly understood. Addressing this knowledge gap is critical to the emerging field of evolutionary ecotoxicology, which aims to understand how long-term exposure to environmental contaminants shapes adaptive evolution and genome-wide variation. In this study, we employed urban runoff sediment as complex and environmentally realistic model stressor to investigate how multigenerational exposure affects fitness and potentially drives genomic adaptation in the freshwater midge Chironomus riparius. We combined an evolutionary life-cycle test with the Evolve and Resequence (E&R) approach, exposing replicate populations over seven generations to three treatments: control and two concentrations of urban runoff sediment (0.5% and 10%). Key fitness traits, including mortality, mean emergence time (EmT50), fertility, and population growth rate (PGR), were measured, while allele frequency changes (AFC) were tracked to identify genomic signatures of selection. The results revealed distinct and non-linear fitness responses across treatments, including transgenerational effects, recovery of performance, and evidence of life-history trade-offs. Candidate haplotypes were enriched for genes involved in membrane transport, metabolism, and gene regulation, suggesting selection on general stress-response pathways consistent with polygenic adaptation. Signals of selection were also detected in control populations, underscoring the evolutionary influence of laboratory conditions. Overall, our findings demonstrate how evolutionary ecotoxicology can reveal both the potential and the constraints of rapid adaptation to realistic environmental stressors and highlight the importance of integrating evolutionary perspectives into ecological risk assessment.

Isoxazoline antiparasitic drugs are a new class of ectoparasiticides used in veterinary medicine for companion animals. Four active substances-fluralaner, (es)afoxolaner, lotilaner, and sarolaner-are marketed globally for flea and tick control. Isoxazolines exhibit long plasma half-lives in dogs and cats, with lotilaner reaching 30 days and sarolaner up to 41.5 days in cats. Their bioavailability varies with feeding; fasting significantly reduces lotilaner absorption. These drugs are primarily eliminated via the biliary/fecal route, with fluralaner showing a fecal elimination half-life of 3 to 12 days in felids and 6 to 38 days in canids. The European Medicines Agency has highlighted the risk of these substances contaminating ecosystems, though data on their environmental release are limited. Recent studies suggest that fluralaner and other parasiticides can be transferred to the environment via feces, urine, or pet hair. This study examined isoxazoline fecal elimination in dogs and cats. Elimination half-lives were determined in groups of five dogs or five cats per active substance. All animals received the drug according to label instructions. The estimated median half-lives were 15.5 and 22.0 days for fluralaner and lotilaner in cats, and 22.9, 24.6, 19.7, and 17.4 days for fluralaner, lotilaner, afoxolaner, and sarolaner in dogs, respectively. Fluralaner and lotilaner were still detected in feces after the end of the recommended treatment period. We used Monte Carlo simulations to assess the risk to nontarget arthropods. Environmental risk assessment indicated that dung-feeding insects could be highly exposed to isoxazoline parasiticides, with fluralaner and lotilaner having the greatest potential impact. These findings emphasize the need for further research on environmental contamination (pathways, quantitative estimate) and impact of veterinary parasiticides on nontarget species.

Aqueous film forming foams (AFFF) containing per- and polyfluoroalkyl substances (PFAS) have been used for decades to fight fuel-based fires. Given the known health risks of PFAS to wildlife and humans, there has been an increasing focus on developing fluorine-free foam (F3) alternatives as replacements. Before F3 alternatives are widely adopted, it is important to assess their potential ecological risk. We evaluated the reproductive and physiological effects of six F3 alternatives and one AFFF on the fathead minnow (Pimephales promelas) using 21-day chronic exposure tests. Of the tested formulations, one F3 (Naval Research Laboratory 502 W, 502 W) and the AFFF (Buckeye Platinum Plus C6 MILSPEC 3%, Buckeye) exhibited the most significant reproductive toxicity. For 502 W, daily egg production per female was 81 to 82% lower at the two highest concentrations compared to the control. For Buckeye, daily egg production per female was 78 to 97% lower and 63 to 93% fewer reproductive events occurred at the two highest concentrations compared to the control. Female gonadosomatic index (GSI) was 34% and 32% lower at the highest concentrations of 502 W and Buckeye, respectively, compared to their controls. Additionally, hepatosomatic index (HSI) of females was 45% greater at the highest concentration of Buckeye compared to the control. Male GSI decreased in one concentration of one F3 formulation and HSI increased in one concentration for three F3 formulations. Overall, our results suggest that adult fathead minnows were relatively tolerant of F3 alternatives with effects largely observed at the highest concentrations. Given that previous work has documented that larval fathead minnows are sensitive to F3 alternatives, future work conducting exposures through maturation is recommended to assess potential long-term reproductive effects.

Agricultural intensification has been followed by the increasing use of pesticides, leading to the accumulation of a mixture of residues in the soil. These may have negative impacts on non-target animals like earthworms, but little is known regarding potential effects of contaminant mixtures on these animals in Brazilian soils. Hence, we evaluated the survival and reproduction of three species, two epigeics (Eisenia andrei, Perionyx excavatus) and one endogeic (Pontoscolex corethrurus), being the latter two more typical of tropical and subtropical regions. The bioassays followed standard ecotoxicological protocols in 18 soils from native vegetation and agricultural systems in both Cerrado and Atlantic Forest biomes. Tropical artificial soil (TAS) was used as a control. Soil texture and chemical analyses accompanied the determination of 48 pesticide residues. Residues of 29 pesticides were encountered, with 14 of them present in all 18 soils, and from 16-22 active ingredients detected in each soil. Most soils (83%) had high estimated risk quotients due to the residues, and these were negatively related to P. corethrurus and E. andrei adult biomass. Although residues of selected pesticides were positively (11 pesticides) or negatively (nine) related to earthworm reproduction, differences observed in biomass and reproduction in the soils and between species appeared to be more due to soil attributes associated with higher soil fertility such as higher micronutrient, CEC, clay, silt, N and C contents, rather than to pesticide contents. Survival of P. corethrurus was high in natural soils, but all individuals died in TAS, requiring attention in the choice of control soil for future assays. Survival was high for epigeic species in both TAS and natural soils and the high reproduction of P. excavatus confirms its potential use as an alternative species for ecotoxicological assays under tropical conditions. Furthermore, reduction in bioassay duration with P. excavatus should be explored, although more efficient ways of cocoon harvesting are necessary.

Crude oil toxicity can be influenced by several physical, chemical, and biological factors including ultraviolet (UV) radiation from sunlight and chemical dispersant application. Ultraviolet radiation can increase the toxicity of polycyclic aromatic hydrocarbons (PAHs) in oil through photo-induced or photo-enhanced toxicity. Additionally, dispersants can alter the distribution of PAHs in the water column and increase the likelihood of exposure to aquatic organisms. To better understand these modifying factors of toxicity and exposure, the present study investigated the combined effects of oil, UV, and the dispersant Corexit 9500A at 3 different dispersant-to-oil ratios on larval red drum (Sciaenops ocellatus) and juvenile mysids (Americamysis bahia). Both species were sensitive to the combined effects of these stressors and exhibited pronounced decreases in survival with co-exposure to UV. Furthermore, greater dispersant application increased measured PAH concentrations, leading to greater impacts of photo-induced toxicity. The present study is the first to report the photo-induced toxicity effects of dispersed oil and UV exposure in early life stage red drum. These results demonstrate the significant effect of dispersant and UV radiation on oil toxicity in 2 Gulf of Mexico species and can be used to inform future ecological risk assessments and oil spill response planning.

Ecotoxicological tests are usually designed to measure individual-level toxicity, such as impacts on survival rate and fecundity during specific life stages. To assess population-level chemical risk, ecotoxicological test results are often incorporated into theoretical population models. However, because test duration is generally shorter than the lifespan of the test species, not all survival and reproduction parameters required for constructing population models are measured. Current test protocols may therefore overlook individual-level chemical impacts crucial for population dynamics, potentially leading to inaccurate risk assessments. In this study, we evaluated the population-level relevance of the test protocols provided by the Organisation for Economic Co-operation and Development. We first compiled matrix population models that represented the full life cycles of the test species from published papers. We then aggregated the elasticities of the population growth rate to the parameters measured in the tests. The aggregated elasticity, ranging from 0 to 1, indicates how a slight change in vital rates measured in the test affects the population growth rate, representing the population-level relevance of the test protocols. The relevance score of each test was generally below 0.4, but varied depending on the endpoint type and the taxonomic group of the target species. Notably, tests designed for terrestrial invertebrates showed low relevance, indicating a substantial limitation in capturing individual-level defects that may lead to severe population decline in terrestrial invertebrates. Multiple tests targeting the same species covered the life history complementarily, and their combined use increased the population-level relevance. This study provides the overall landscape of the relevance of current ecotoxicological tests to population-level risk assessment, highlighting key directions to better align with population conservation.

Marine sediments play a key role in the biogeochemical cycle of mercury, acting as sinks that facilitate its accumulation in marine organisms and posing a risk to the food security of coastal communities and human health. This study determined the temporal dynamics and environmental variables that influence the transfer of total mercury in dry weight from sediments to fish in artisanal fishing areas of the Pacific and Caribbean coasts of Colombia. The concentrations of total mercury in dry weight were analyzed in the sediment, seston, and muscle (dry wt) of eight fish species caught using two artisanal fishing methods (net and hook), during dry and wet seasons. Biota-sediment accumulation factor (BSAF) was calculated to estimate the transfer of mercury from the sediments to fish. All fish had a BSAF of >1, indicating accumulation of total mercury in dry weight in fish tissues, and values of >2 on average, suggesting their potential as macroconcentrators. The BSAF was higher in demersal fish (family Lutjanidae; 56.7 ± 32.3), and in the Caribbean, where it was up to four times higher than that in the Pacific. The BSAF increased during the wet season, when the lowest concentrations of mercury were in the sediments, due to an increase in bioavailability associated with organic matter. The study identified three patterns of mercury transfer between species, influenced by variables such as organic matter content, total dissolved solids, and environmental mercury concentrations. These results demonstrate a complex dynamic of mercury mobilization controlled by environmental factors and highlight the importance of considering climatic conditions, habitat, and community composition in assessing mercury risks in coastal ecosystems.

In the absence of a robust database of adverse effects to aquatic biota from pharmaceuticals introduced into the environment, alternate approaches are needed to assess risk. One such approach is the Fish Plasma Model (FPM), which can be used to prioritize pharmaceuticals as a function of potential altered biological responses for fish exposed to these chemicals in receiving waters. Other published prioritization schemes assessing various apical effects include quantitative-structure activity relationships (QSARs), cellular assays, and biochemical markers. The FPM provides another line of evidence that is complementary to these approaches. We also examined potential effects due to human Ether-à-go-go-Related Gene (hERG) activity for the active pharmaceutical ingredients (APIs) as another potentially useful and complementary approach for prioritization. In this study we used the FPM to examine predicted effects for the most commonly prescribed pharmaceuticals, which allowed us to focus on the most environmentally relevant drugs potentially toxic to fish. Drugs with Cmax values were examined with a global database of surface water concentrations to predict potential risk for fish exposed to the most biologically active compounds. To prioritize the APIs most likely to cause adverse effects for fish, we limited the list to those with a Response ratio (RR; [plasma]/1%Cmax) ≥1 (n = 57), and those APIs without exposure concentrations exhibiting a 1%Cmax value ≤0.1 ng/mL (n = 50). The majority (n = 63) of the top prioritized APIs on this list fell into six drug classes: hormones (n = 21), antidepressants (n = 13), antihistamines (n = 8), anticholinergics (4), corticosteroids (4), and antihypertensives (n = 13). The FPM is advantageous because it is based on expected low-dose in-vivo biological effects resulting from chemicals designed to interact with a specific target. Currently, the FPM is mostly limited to pharmaceuticals; however, this approach can be expanded to other chemicals with toxicity data expressed as a plasma concentration.

Methyl 2-{[1-(5-fluoropentyl)-1H-indazole-3-carbonyl]amino}-3,3-dimethylbutanoate (5F-ADB), a potent synthetic cannabinoid, induces intense euphoria, hallucinations, and addiction, posing significant risks to human health. Current drug surveillance efforts lack data to identify drug abuse, and the environmental impacts of 5F-ADB entering aquatic systems via synthesis or use remain uncharacterized. To address these gaps, a multi-level assessment system (in vitro-invertebrate-vertebrate) was established to elucidate 5F-ADB metabolic pathways and identify robust biomarkers. Human liver microsomes (HLM), Daphnia magna, and zebrafish were exposed to 5F-ADB, with metabolites profiled using high performance liquid chromatography coupled with mass spectrometry (HPLC-MS). Metabolic pathways were inferred, and metabolite toxicity was evaluated. Results revealed 9, 11, and 22 metabolites in HLM, D. magna, and zebrafish models, respectively. Dominant pathways in HLM and zebrafish included ester hydrolysis, defluorinated-hydroxylation, and combined ester hydrolysis/defluorinated-hydroxylation. D. magna metabolism primarily featured defluorinated-hydroxylation, depentylation, and ester hydrolysis coupled with hydroxylation. Glucuronidation metabolites were exclusive to zebrafish. Based on abundance and stability, H-M4 (ester hydrolysis), D-M1 (ester hydrolysis/depentylation), and Z-M15 (ester hydrolysis/condensation) were identified as key biomarkers for HLM, D. magna, and zebrafish, respectively. Toxicity assessments indicated reduced toxicity for most metabolites versus 5F-ADB. However, H-M7, D-M7, D-M11, and Z-M15 (products of ester hydrolysis/condensation or defluorinated-hydroxylation/oxidation) exhibited comparable toxicity to the parent compound. Critically, D-M7 (defluorinated-hydroxylation/oxidation) demonstrated heightened hydrophilicity and potentially elevated ecotoxicity in D. magna, warranting further ecological risk investigation. This study provides the first multi-trophic metabolic characterization of 5F-ADB, delivering critical data for tracing illicit synthesis, monitoring drug-use distribution, and evaluating environmental hazards of synthetic cannabinoids.