Environmental Toxicology and Chemistry最新文献

Phthalate esters (PAEs) are typical industrial and agricultural chemicals that are readily released into the environment. Due to their endocrine-disrupting properties, PAEs pose considerable ecological risks in different environmental matrices. However, current standards for evaluating ecological risks of PAEs focus primarily on environmental quality thresholds and do not account for criteria based on native species. This study integrated the species sensitivity distribution (SSD) modeling, interspecies correlation estimation (ICE), and acute-chronic ratio (ACR) calculations using toxicity data for 7 representative PAEs (dimethyl phthalate [DMP], diethyl phthalate [DEP], dibutyl phthalate [DnBP], butyl benzyl phthalate [BBP], dis (2-ethylhexyl) phthalate [DEHP], diisodecyl phthalate [DIDP], and dihexyl phthalate [DnHP]) from native species in freshwater. Short- and long-term predicted no-effect concentrations (PNECs) were estimated and applied to the ecological risk assessment (ERA) for these PAEs in freshwater and sediment across major basins of China. The PNECs for DIDP and DnHP were derived for the first time. The values of PNECs for the remaining PAEs were generally lower than previously reported value. The freshwater ERA results indicated a consistent risk ranking of DEHP > DnBP > BBP > DEP > DMP (DnHP) for both acute and chronic exposure. For sediment, the short- and long-term risk rankings differed, with acute risks following DnBP > DEP (DMP) > DEHP > BBP > DnHP, and chronic risks following DEHP > DnBP > DEP > DMP > BBP > DnHP. The DEHP should be warranted particular concern in sediments, as its ecological risk increased over time.

To provide insights into the potential impacts of releases of oil sands process affected water (OSPW) into the environment, chronic toxicity tests on early-life stage rainbow trout (ELS-RBT) were conducted. The objective of the testing was to better characterize the effects of OSPW from the Alberta Oil sands on swim-up fry mortality, development (fish length and width, yolk sac development), and deformities (skeletal, craniofacial, finfold, and edemas) as a function of OSPW dilution (%) and ∑O2-naphthenic acid concentrations. More than 95% mortality in ELS-RBT was observed in the range of 22 to 100% OSPW. Lethal concentrations of 50% of the test population (LC50) values expressed in terms of OSPW dilutions were 13.7 (SE 0.7), 10.6 (SE 0.5), and 12.7 (SE 0.5) % for OSPW collected in 2019, 2021, and 2022, respectively. Corresponding LC50 values for ∑O2-naphthenic acids concentrations were 2.8 (SE 0.14), 2.0 (SE 0.11), and 2.2 (SE 0.09) mg/L, respectively. Primary sublethal effects included delayed development, craniofacial defects, and evidence of cardiovascular toxicity, including pericardial and yolk sac edema and hemorrhaging. Evidence of sublethal developmental effects was observed at OSPW dilutions above 10% and corresponding ∑O2-naphthenic acid concentrations above 1.69 mg/L. The only exception was for 17.1 (SE 3.3) % craniofacial deformities at OSPW concentrations of 3.2% and corresponding ∑O2-naphthenic acid concentrations of 0.66 mg/L, but only for OSPW collected in 2019. The results from this indicate that a 20-fold or greater dilution (or a corresponding removal of OSPW) of the tested OSPW from the Kearl site is sufficient to negate the chronic toxicity in Rainbow trout investigated in this study.

Micro(nano)plastics (MNPs) are both pollutants and carriers of other toxic pollutants, which produce complex combined effects with co-exposed pollutants. Tris (1,3-dichloro-2-propyl) phosphate (TDCIPP), a widely used organophosphate ester (OPE) plasticizer and flame retardant in plastics, was selected to examine how microplastics (MPs) and nanoplastics (NPs) modulate its bioaccumulation and toxicity in zebrafish embryos. The results indicated that MPs did not significantly affect the bioaccumulation or toxicity of TDCIPP in embryos. In contrast, NPs increased the accumulation of TDCIPP in embryos, thereby enhancing adverse effects on hatching, development and survival. Toxicokinetic (TK) and toxicodynamic (TD) models were further applied to validate the influence of MPs and NPs on the bioaccumulation and toxicity of co-existing pollutants. The TK-TD modeling revealed that MPs had no significant effect on the bioconcentration factor (BCF) or internal threshold concentration (CIT) of TDCIPP, whereas NPs significantly increased BCF and decreased CIT. Moreover, the ratio CIT/BCF was found to explain the differential toxicity effects of TDCIPP in the presence of MPs and NPs. This study quantified the disparate effects of MPs and NPs at environmental concentrations on the bioaccumulation and toxicity of TDCIPP from the TK-TD perspective, contributing to a better understanding of the toxicity mechanism of the mixture.

Hyalella azteca is a North and Central American amphipod used worldwide to evaluate the toxicity of sediments and water matrices. While current evaluation procedures extensively use H. azteca standard life-cycle tests, there are no protocols specifically designed in this species to assess contaminant effects on reproductive processes and embryonic development at the individual level. Based on a methodology available in European gammarids, this study aims to initiate the development of a chronic test, leveraging an advanced knowledge of the female reproductive cycle in these amphipods. Parameters such as molting advancement, embryonic development in marsupium, and realized fecundity are the fundamental endpoints of the proposed 2-week biotest. First, females were monitored between two egg-laying events at three temperatures (16 °C, 20 °C, 24 °C) to describe the molting process and the embryonic development. Afterwards, we proposed a biotest consisting in exposing couples for one reproductive cycle (10 days at 24 °C) starting with females in AB molting stage (post-molting time <24 hr). Molting impairment and embryonic development are assessed at a first time of observation (Day 6), followed by a measurement of realized fecundity at Day 13 (three days post-laying in clean water), that is, embryo number in the maternal pouch for the second reproductive cycle. Four control experiments and one exposure test to cadmium (at 1 and 5 µg L-1) validated the robustness and the sensitivity of the method. As in other amphipods, cadmium inhibited the molting and embryonic development in Hyalella. The proposed Hyalella reprotoxicity test offers a rapid tool for specifically assessing reproductive impairments caused by chemicals and environmental matrices, complementing the standardized life-cycle tests available in this species for population-level toxicity assessment.

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.

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.