Environmental Toxicology and Chemistry最新文献

The Organisation of Economic Co-operation and Development (OECD) 216 nitrogen transformation test is used to understand the impacts of plant protection products (PPPs) on the soil microbiome. However, there is significant interest in developing the European PPP risk assessment to include new technologies such as amplicon sequencing to assess impacts on soil microbial community composition and diversity. We have little understanding of how to generate endpoints from amplicon sequencing data sets, their robustness, and whether they provide an appropriate level of protection to the soil microbiome. Our study addresses this key knowledge gap. We conducted a dose-response OECD 216 study with two chemicals, nitrapyrin and streptomycin, and calculated traditional functional endpoints, in accordance with the OECD 216 guideline, and used amplicon sequencing techniques to generate a range of endpoints based on soil bacterial diversity, richness, dissimilarity from the control, species sensitivity distributions, and threshold indicator analysis. We show it is possible to generate a range of endpoints from amplicon sequencing data sets; however, these endpoints varied significantly based on the calculation method, with up to a 101-fold difference between the least and most sensitive endpoints. Additionally, the relative sensitivity of these endpoints compared to the currently used functional OECD 216 metrics was compound dependent, with many endpoint calculation methods unable to detect the impacts of nitrapyrin on the soil microbiome at concentrations deemed ecotoxicologically relevant by OECD 216. Our study shows amplicon sequencing methods to study soil microbial ecotoxicology did not perform consistently and reliably when considering both nitrapyrin and streptomycin treatments and in many cases did not consistently provide an enhanced degree of protection over the functional OECD 216 assessments already integrated into the PPP risk assessment.

The application of metal-organic frameworks (MOFs) towards the adsorption of antibiotics is a new and emerging area of study. The rise in use or misuse of antibiotic products has exacerbated their ongoing presence and persistence in the natural environment. Even at low concentrations, antibiotic residues exert pressure on bacterial populations, eventually leading to the emergence of resistant bacteria. Metal-organic frameworks, known for their high porosity, vast specific surface area, and ease of modification, have emerged to be a promising and sustainable antibiotic adsorbent. In an effort to advance the development of this adsorbent, this study provides a state-of-the-art review of recent research published from 2020 to the present, specifically examining the use of MOFs for removing antibiotics from aqueous solutions. Multiple MOF adsorbents were analyzed, with approximately 59% demonstrating significant adsorption capacity within the pH range of 6.0-8.0. In 75% of the instances, the adsorption system reached equilibrium in under 2 hr. Adsorption capacities compared well to other published works in the literature and exceeded conventional adsorbents in many instances. Notable cases of MOF performance were MIL-53(Al) adsorption of amoxicillin (AMX) and SA-g-P3AP@MOF(Fe)/Ag adsorption of neomycin where adsorption capacities of 758.5 and 625.0 mg/g were attained, respectively. The reusability of MOFs was extensively reported at the laboratory batch scale. Analysis of the reported studies revealed the most effective eluents were acetone, ethanol, and methanol, with mostly 3-5 cycles attainable without appreciable loss in efficiency. The recent literature confirmed that MOFs are highly efficient in the adsorption of antibiotics; however, there are some areas that warrant further development. It is intended that this work will bring recent trends to the forefront, identify knowledge gaps, and help guide future research proposals.

Atrazine (ATR) is a commonly found herbicide contaminant in water bodies across the United States. In this study, native freshwater mussels (Elliptio complanata) were investigated to determine histopathological effects and bioaccumulation of ATR under laboratory conditions. Mussels were collected from the Rice Creek Field Station, Oswego, NY, and were exposed to two different concentrations of ATR (15 and 150 μg/L) for 4 weeks. Histopathological phenotypes induced by ATR include reduced or no ciliary epithelium, ciliary cells merged or completely absent, skeletal rods and connective tissue reduced, causing malformed gill filaments; inhibition of condensation of spermatogenic cells and induced necrosis in spermatocytes in testis; disintegration of acini, oocytes, follicles, and epithelium of the duct, disintegration of the yolk and stalk connecting acini to the follicular wall in ovaries. There were no apparent ATR-mediated histopathological effects in the mantle tissue. Liquid chromatography-mass spectrometry was used to quantify the levels of bioaccumulation of ATR in the tissues where the teratogenic effects are observed from the histological analysis. Bioaccumulation of ATR was observed in gills (0.11 µg/g in the ATR 15 µg/L group and 0.51 µg/g in the ATR 150 µg/L group) and visceral tissues (0.11 µg/g in the ATR 15 µg/L group and 0.63 µg/g in the ATR 150 µg/L), correlating with the histopathological phenotypes. ATR's action mechanism is identified as induced apoptosis in the cells. Further investigation is warranted to elucidate the biochemical response and determine the derivates of ATR in this species.

In this study, a detailed analysis of 20 per- and polyfluoroalkyl substances (PFAS) was conducted, in different environmental media of the Fu River, the main sewage storage body, located near the Tianhe Airport in Wuhan, China. The PFAS included 13 perfluorocarboxylic acids (C4-C18), four perfluorosulfonic acids (C4, C6, C8, C10), and three PFAS. In the surface water samples, short-chain PFAS perfluorobutanesulfonic acid (PFBS) and perfluorobutanoic acid were the most prevalent and highest concentrations, 168 ng/L and 49.7 ng/L, respectively. However, in the sediment samples, PFBS and perfluorooctane sulfonate (PFOS) were the most prevalent and highest concentrations, 840 ng/kg and 1,510 ng/kg, respectively. In addition, PFOS was the most prevalent substance, with the highest concentrations measured at 23.3 μg/kg in egg yolk and 28.1 μg/kg in fish, accounting for proportions of 82% and 88%, respectively. Two new short-chain substitutes of PFOS, 6:2 clorinated polyfluoroalykyl ether sulfonate and 8:2 clorinated polyfluoroalykyl ether sulfonate, emerged in sediment and fish. The PFAS in eggs, fish, and vegetables of the Fu River Basin poses a potential health risk to residents according to the suggested values of the European Food Safety Agency.

Diclofenac (DCF) is a nonsteroidal anti-inflammatory drug commonly used in health care, livestock, and pharmaceuticals and widely detected in surface water environments globally. Here, we reviewed the occurrence characteristics, migration pathways, and aquatic toxicity of DCF in surface water environments. Asian and African populations are exposed to high concentrations of DCF (> 8,000 ng L-1). Wastewater discharge, livestock, and industrial pollution are the primary factors influencing the concentration and distribution of DCF. Diclofenac can cause acute toxicity, oxidative stress, and other toxic effects on aquatic organisms. We focused on China and analyzed the ecological risks of DCF in surface water environments and found low risk in the south and high risk in the north, as well as low risk during the rainy season and high risk during the dry season. Finally, we discuss the removal methods for DCF and propose the potential of metal-organic frameworks as a new material to replace conventional methods for DCF removal. This study comprehensively reveals the pollution status of DCF and the ecological risk it poses to surface water environments, providing a reference for the environmental management of DCF.

In silico methods are increasingly important in predicting the ecotoxicity of engineered nanomaterials (ENMs), encompassing both individual and mixture toxicity predictions. It is widely recognized that ENMs trigger oxidative stress effects by generating intracellular reactive oxygen species (ROS), serving as a key mechanism in their cytotoxicity studies. However, existing in silico methods still face significant challenges in predicting the oxidative stress effects induced by ENMs. Herein, we utilized laboratory-derived toxicity data and machine learning methods to develop quantitative nanostructure-activity relationship (nano-QSAR) classification and regression models, aiming to predict the oxidative stress effects of five carbon nanomaterials (fullerene, graphene, graphene oxide, single-walled carbon nanotubes, and multi-walled carbon nanotubes) and their binary mixtures on Scenedesmus obliquus cells. We constructed five nano-QSAR classification models by combining zeta potential (ζP) with the C4.5 decision tree, support vector machine, artificial neural network, naive Bayes, and K-nearest neighbor algorithms. Moreover, we constructed three classification models by integrating the features including ζP, hydrodynamic diameter (DH), and specific surface area (SSA) with the logistic regression, random forest, and Adaboost algorithms. The Accuracy, Recall, Precision and harmonic mean of Precision and Recall (F1-score) values of these models were all higher than 0.600, indicating an excellent performance in distinguishing whether CNMs have the potential to generate ROS. In addition, using the ζP, DH, and SSA descriptors, we combined decision tree regression, random forest regression, gradient boosting, and the Adaboost algorithm, and successfully constructed four nano-QSAR regression models with applicable application domains (all training and testing data points lie within 95% confidence intervals), goodness-of-fit (Rtrain2 ≥ 0.850), and robustness (cross-validation R2 ≥ 0.650) as well as predictive power (Rtest2 ≥ 0.610). The method developed would establish a fundamental basis for more precise evaluations of ecological risks posed by these materials from a mechanistic standpoint.

This study investigates the 96 hr toxicity and physiological effects of eight azole fungicides on Raphidocelis subcapitata (R. subcapitata). The findings revealed significant differences in toxicity levels among these fungicides, with the hierarchy of toxicity as follows: difenoconazole ≈ tetraconazole ≈ fuberidazole > metconazole > terrazole ≈ triflumizole > flutriafol > hymexazol. Increased concentrations of azole fungicides corresponded with decreased cellular activity and inhibited algal growth, highlighting the concentration-dependent nature of toxicity. The toxicological mechanisms involved include reduced levels of chlorophyll (Chla, Chlb) and carotenoids, disrupting the photosynthetic process. Additionally, exposure to these fungicides resulted in decreased total protein levels, increased reactive oxygen species and malondialdehyde, and elevated activity of antioxidant enzymes such as superoxide dismutase and catalase. Consequently, there was a significant rise in apoptosis rates among algal cells. These findings provide important insights for assessing the ecological impact of azole fungicides on aquatic ecosystems and aquatic life.

The early-life stage (ELS) toxicity syndrome for fish is well described and has been reported in hundreds of toxicity studies. It is generally characterized by a reduced heart rate, yolk sac and pericardial edemas, and various morphological abnormalities, the most common being spinal curvature. For many of those studies, it appears that the ELS toxicity syndrome is the result of nonspecific (baseline) toxicity that occurs at aqueous and whole-body concentrations that are just below lethal concentrations. Baseline toxicity is essentially a nonspecific response that results from chemicals accumulating in and disturbing the function of biological membranes that leads to lethality and sublethal effects at relatively high doses. The commonality of this acute ELS toxicity syndrome among highly diverse organic and inorganic chemicals is remarkable. It is important to identify baseline toxicity because it is considered minimal toxicity that acts in all tissues and cells, and it has the potential to impair all cellular functions. This means if an effect is observed around baseline-toxic concentrations, it is likely that other cellular functions are also affected (i.e., the effect is not specific). The fish ELS toxicity syndrome can also be the result of specific effects involving receptor interactions; therefore, we emphasize the importance of distinguishing between specific and nonspecific toxicity responses to provide the most relevant data for environmental risk assessment.

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds that can be toxic to aquatic life at environmentally relevant concentrations. The toxicity of some PAHs increases in the presence of ultraviolet radiation (UVR). The phototoxic target lipid model (PTLM) builds on the narcotic target lipid model and predicts acute phototoxicity by accounting for the light absorbed by PAHs. Given the lack of chronic data for PAHs exposed to UVR, an acute-to-chronic ratio (ACR) was proposed as a means for extending this model for predicting chronic toxicity. No information could be found on ACRs derived for phototoxic chemicals and therefore, this study had two objectives: (a) to generate acute and chronic toxicity data with and without exposure to UVR; and (b) to test the ability of the PTLM to predict chronic toxicity using an ACR. Acute and chronic bioassays were conducted on eight species, with each exposed to three PAHs and two light treatments: with and without UVR. Although there was a general trend of higher ACRs in UVR treatments, there was no statistical difference across all species in the ACR values for UVR treatments. Data generated herein were combined with data collated through a literature search to generate a global ACR of 11.6. Twenty of the 24 predicted phototoxic effect concentration affecting 10% of species (EC10) values calculated using the PTLM and ACR were within a factor of 10 of the observed phototoxic EC10 or lethal concentration affecting 5% of species values. This study demonstrates the capability of ACR to be applied in the context of phototoxicity and therefore proposes an unprecedented methodology to predict the chronic phototoxicity of PAHs.

Diamide insecticides, specifically chlorantraniliprole (CHL), have been rising in popularity over the past decade, becoming one of the most widely used insecticide classes globally. These insecticides target the ryanodine receptor (RyR), primarily for control of lepidopteran agricultural pests. Field studies have revealed that some lepidopteran species have developed mutations where a methionine in a particular position (e.g., I4790M) increases resistance to CHL. The toxicity data for CHL across species is limited, as is the case for many chemicals, which creates an opportunity to apply both traditional toxicity test methods and new approach methods (NAMs) to address data gaps. Here, the U.S. Environmental Protection Agency's Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS) tool was used to query the RyR to generate susceptibility predictions for species exposed to CHL to fill those data gaps. These SeqAPASS results generated testable hypotheses that were used to guide focused acute aquatic toxicity studies using Daphnia magna, Daphnia pulex, Pimephales promelas, and Danio rerio. The fish species were not sensitive to CHL, whereas D. magna and D. pulex were found to be sensitive to CHL at environmentally relevant concentrations, despite having the methionine residue in the position of the I4790M resistance mutation. Additional SeqAPASS results showed that many other species, including beneficial pollinators and Lepidoptera, are predicted as likely susceptible to CHL. This study provided multiple lines of evidence toward the unlikelihood for the I4790M mutation to be the primary cause of resistance across species, filled knowledge gaps concerning CHL toxicity across species, and generated predictions of susceptibility for nontarget species that are not generally amenable to toxicity testing. This work presents a case example that demonstrates how NAMs can be used in combination with other types of data to direct targeted testing and build confidence in predictive approaches for their use in risk assessment.