Environmental Toxicology and Chemistry最新文献

Amide herbicides (AHs) were disturbed urease (UA) activity and soil microbial community, caused soil nutrient changes. Activity of UA was inhibited by AHs via groups of chlorine, benzene ring, peptide bond (-N-/-CO-). Difference of surface charge distribution were mainly derived from position to connected -Cl, distance of -O- from ether group and -N from peptide bond, difference of structure/length for hydrocarbon chain, and different regions of negative charge enrichment. Developmental toxicity (DT) for alachlor was strongest related to smaller structure and weaker steric hindrance effect, mutagenicity for propanil was weakest could be related to missing ether group. Molecular mechanism and structural activity relationship for inhibition of AHs and UA based on functional groups, amino acids with high frequency, hydrogen bonds, hydrophobic interactions, binding area (BA) of butachlor (396.3 Å2), absolute value of binding energy (|BE|) of propanil (2.93 kJ/mol) (which as highest), quantitative structural relationship between BA and |BE|, which was negative correlation. BA for AHs and UA had negatively correlation for density with correlation coefficient (r) as -0.937 (p ≤ 0.01). |BE| for AHs and UA had positively correlation for density with r as 0.847 (p ≤ 0.05), and negatively correlation for molecular weight (MW) with r as -0.973 (p ≤ 0.001). Results provided technological support and theoretical foundation for toxic effects of SEs activity, health effects, risk regulation and control of AHs.

This review evaluates 70 published studies with R2 > 0.95 that apply the diffusion-chemisorption (D-C) model to adsorption systems. It also incorporates an experimental component to demonstrate the practical applicability of the derived characteristic curves and equations. The study introduces a new framework for classifying adsorption systems based on intraparticle diffusion, leveraging a solid-phase mass transfer index (RDC) and characteristic curves derived from the D-C kinetic model. Additionally, new equations were developed to rapidly estimate the half-time of adsorption reactions and map operating time as a function of sorbent saturation. The characteristic curves based on the published studies revealed four distinct zones for RDC ranging from 0 to infinity. Type I curves correspond to large particle sizes and highly porous adsorbents, whereas Type IV curves represent powdered and low-porosity adsorbents. The concurrence to Types I, II, III, and IV curves from the 70 published studies were 8.5%, 36%, 32.5%, and 23%, respectively. To demonstrate the usefulness of the developed equations, the adsorption of Cu(II) ions by Fomes fasciatus was successfully evaluated to elucidate the influence of intraparticle diffusion and predict adsorption performance. This type of analysis offers a valuable tool for researchers and designers to identify adsorbents for specific adsorbates and explicate transport mechanisms. Further, it minimises the need for extensive sampling and enables the comparison of adsorbent performances.

Embryotoxicity is a well-known consequence of polycyclic aromatic compound (PAC) exposure, but the molecular mechanisms of action of PAC mixtures, especially for unconventional crude petroleum types such as diluted bitumen (dilbit), remain to be fully elucidated in birds. To explore the mechanism of action of PAC in birds, the egg-injection model was used. Eggs of Domestic Chicken (Gallus gallus), Double-crested Cormorant (Nannopterum auritum), and Northern Gannet (Morus bassanus) were injected with 0.5 μL/g of average species-specific egg weight of 1:10-1:10,000 dilutions of Clearwater or Cold Lake Blend dilbits into the air cell on embryonic day 0 and were artificially incubated until the liver was formed. The injections of < 0.16-335 ng total PAC/g egg were consistent with PAC concentrations measured in wild bird eggs and in embryos exposed to dilbit through eggshell oiling. Mortality and frequency of malformations were low across treatments. The expression of genes involved in xenobiotic detoxification in both liver and chorioallantoic membrane (CAM) differed among species in response to dilbit exposure. Cytochrome P450 1a (cyp1a) in the CAM of dilbit-exposed chickens was induced to a higher fold-change at a lower PAC concentration than the liver, but this pattern was not consistent in wild birds. The expression of additional genes involved in the aryl hydrocarbon receptor activation adverse outcome pathway were variable in the Double-crested Cormorant and Northern Gannet CAMs. Our study demonstrates the usefulness of CAM as a target tissue for PAC metabolism in embryotoxicity. Future studies should address the differential CAM physiology across bird species to better understand the variation of species responses to contaminants and consider the use of CAM in addition to liver.

Pollination by honey bees (Apis mellifera) is crucial for maintaining biodiversity and crop yields. However, the widespread use of pesticides may threaten bees' survival by contaminating their resources. Lambda-cyhalothrin, a neurotoxic insecticide commonly used in agricultural pest control, poses particular risks. In insects, the midgut and fat body serve as primary barriers against xenobiotics, and exposure to these chemicals during larval development can impact adult bees. This study aimed to assess whether the residual concentration of lambda-cyhalothrin in pollen grains affects the midgut and fat body of larval A. mellifera workers after chronic exposure. The midgut epithelium of larvae exposed to a lambda-cyhalothrin-based insecticide exhibited autophagic vacuoles, apical cell protrusions, apocrine secretion, nuclear pyknosis, and high levels of polysaccharides and glycoconjugates in the cytoplasm, with smaller amounts in the brush border. Histochemical analysis revealed areas of vacuolation and damage to cell integrity in the midgut. In fat body cells, the insecticide increased polysaccharide storage and decreased lipid droplet diameter. Despite the histopathological damages, no effects were found in the larval development and adult emergence. These findings suggest the occurrence of apoptosis and autophagy in midgut cells and alterations in nutrient storage in the fat body of A. mellifera larvae exposed to the lambda-cyhalothrin-based insecticide, potentially impacting the physiology and development of this pollinator with possible effects on adult workers.

As part of the Great Lakes Restoration Initiative, chemical monitoring and surveillance efforts have detected ∼330 chemicals in surface water of Great Lakes tributaries. There were 140 chemicals for which no empirical toxicity data were available. The aim of the present study was to generate transcriptomic points of departure (tPODs) for 10 of these compounds and demonstrate how they could be applied in a screening-level prioritization. Organisms representing three trophic levels of the aquatic food-web (P. promelas, D. magna, and R. subcapitata) were exposed for 24 h to a ½-log dilution series of nominal exposure concentrations typically ranging from 66.7 to 0.021 µM of each chemical. In addition to observations of apical effects (e.g., survival and morphology), whole body transcriptomic responses (tPODs) to each chemical were evaluated with targeted analysis using TempO-seq for P. promelas and D. magna and non-targeted RNA-seq for R. subcapitata. The tPODs ranged from 0.18 to 10.8 µM for P. promelas and 0.32 to 29 µM for D. magna, with the most potent of the chemicals tested being fipronil carboxamide for both species. For R. subcapitata, the tPODs ranged from 0.04 to 1.77 µM, with gabapentin as the most potent chemical tested. Empirically derived tPODs from these data-poor chemicals were compared to concentrations detected in the Great Lakes basin. Environmental concentrations were less than the tPODs, except for R. subcapitata and 3,4-dichlorophenyl isocyanate. Similarly, tPODs from previously tested data-rich chemicals were compared with environmental concentrations, in which case tPODs from several chemicals overlapped environmental concentrations. This work demonstrates the potential utility of emerging ecological high-throughput transcriptomics assays to support screening and prioritization of data-poor environmental contaminants.

Excess metal accumulation in organisms can result in adverse impacts at the levels of the individual, population, and community. A detectable increase of metal concentrations in organisms does not necessarily imply that there are such impacts, but to our knowledge no field study has directly tested this hypothesis. To test this hypothesis, we investigated the accumulation of six elements (Cu, Zn, Cd, Pb, As, and Se) in masu salmon (Oncorhynchus masou, Salmonidae) at a total of nine study sites in a metal-contaminated river receiving mine discharge and in a nearby reference river. Multiple fish community surveys in 2018 and 2019 consistently indicated that the abundances and condition factors of the four dominant fish species, including masu salmon, were comparable in the two rivers. In contrast, despite sample sizes of only five individuals per site, statistically significant increases in the concentrations of Cu, Cd, Pb, As, and Se in the muscle of masu salmon were observed at multiple sites in the metal-contaminated river, where no detectable impacts on the abundance or condition factor of the fish were observed. The muscle concentrations of Cu, Zn, Cd, Pb, As, and Se at these sites were 1.4-2.5, 1.5-1.9, 188-520, 4.6-68.0, 1.1-3.9, and 2.8-3.5 times, respectively, the mean concentrations at the reference sites, although the increase of the Zn concentration in muscle at these metal-contaminated river sites was not significant. These results provide clear empirical evidence that a detectable increase in metal accumulation does not necessarily imply that population and community-level impacts are simultaneously occurring in the environment.

Cannabidiol (CBD) is a major non-psychoactive cannabinoid that has been detected in environmental samples, but the ecotoxicological effects remain unknown. In this study, Lumbriculus variegatus are exposed to CBD, and its metabolites 7-hydroxy-cannabidiol (7-OH-CBD) and 7-carboxy-cannabidiol (7-COOH-CBD). In this study, toxicity, tactile stimulation to elicit stereotypical behaviours and locomotor activity are measured after 24-hour exposure of L. variegatus to CBD and its metabolites. We also describe the impacts on dorsal blood vessel pulsation and oxygen consumption after 24-hour exposure to CBD and 7-OH-CBD, and the effects on regenerative capacity and total energy reserves after 72 hours of exposure to CBD and 7-OH-CBD. We observe CBD, 7-OH-CBD and 7-COOH-CBD display toxicity in 50% of test populations at 14.12 µM, 11.29 µM and 15.36 µM, respectively. 24-hour exposure to CBD decreases tactile stimulation response to elicit body reversal at ≥ 2.5 µM and helical swimming at ≥ 0.5 µM and reduces locomotor activity. L. variegatus oxygen consumption was not affected by CBD but ≥2.5 µM significantly reduced dorsal blood vessel pulse rate. We observe that exposure to 7-OH-CBD does not affect the regenerative capacity of L. variegatus while CBD is shown to reduce regeneration. Exposure to CBD also results in a significant decrease in carbohydrates, increased lipid, and no effect on protein levels in L. variegatus. We determined that CBD can reduce L. variegatus behaviours, decrease pulse rates and regenerative capacity, and disrupt energy reserves. Our findings show that CBD is toxic to this common aquatic organism and the increased availability and use of CBD, and related substances, warrants further study of their environmental impact.

Acute fish toxicity is an ecotoxicological endpoint which provides important information about a chemical's potential to elicit adverse effect(s) on fish. These effects are typically studied using in vivo tests but for animal welfare reasons as well as the quest for increased species relevance, biological coverage, mechanistic understanding of effects and throughput, there have been significant efforts in recent years to reduce or replace the use of animals in (eco)toxicological hazard assessment, by developing defined approaches (DA) or integrated approaches to testing and assessment (IATA). To this end, a novel score-based DA has been developed, which integrates three in silico predictions from freely available (Q)SARs: the VEGA Fish (KNN-Read-Across) and Fathead Minnow (KNN-IRFMN) models and the United States Environmental Protection Agency (USEPA) ECOSAR Fish 96-h LC50 model, along with in vitro RTgill-W1 data. The DA provides a categorical output aligned with the United Nations Globally Harmonized System of Classification and Labelling (GHS) framework (Acute Category 1, Acute Category 2, Acute Category 3 or Not Classified) with an overall accuracy of 80%, offering a reliable alternative to traditional in vivo testing methods for acute fish toxicity.

Per- and polyfluoroalkyl substances (PFAS) are a broad class of chemicals with high environmental persistence and growing ecological and human health concern. Perfluorooctane sulfonate (PFOS) is among the most detected PFAS in environmental sampling and is often at high concentrations and has been measured in a variety of ecological receptors from around the globe. Despite the prevalence of PFOS, there are still important data gaps with regard to toxicity. For example, while studies have confirmed PFOS accumulation in tissues of wild reptiles, reptilian laboratory toxicity data are lacking. The purpose of this study was to first develop toxicity testing protocols using the brown anole, Anolis sagrei and, second, to conduct PFOS dosing studies to generate toxicity data to support ecological risk assessment of reptiles. We conducted two studies in which subadult males and then mature males were dosed with PFOS via pseudo-gavage with maximum doses in the range of 2 mg/kg/d. Subadults were exposed for 35 days while adult males were exposed for 90 days. While no significant mortality was observed, subadult male size and growth rate were significantly affected by PFOS at 2.98 mg/kg/d with a corresponding no effect level of 0.20 mg/kg/d and corresponding 10 and 20% effect levels for growth rate of 0.22 and 0.44 mg/kg/d, respectively. There were no significant effects on size metrics of mature male anoles from the 90-day study although several metrics showed dose-dependent decreases. These data may serve as the basis for toxicity reference values (TRVs) for use in ecological risk assessments of PFAS-contaminated sites in which reptiles may be exposed.