Environmental Toxicology and Chemistry最新文献

Fish acute toxicity testing is used to inform environmental hazard assessment of chemicals. In silico and in vitro approaches have the potential to reduce the number of fish used in testing and increase the efficiency of generating data for assessing ecological hazards. Here, two in vitro bioactivity assays were adapted for use in high-throughput chemical screening. First, a miniaturized version of the Organisation for Economic Co-operation and Development (OECD) test guideline 249 plate reader-based acute toxicity assay in RTgill-W1 cells was developed. Second, the Cell Painting (CP) assay was adapted for use in RTgill-W1 cells along with an imaging-based cell viability assay. Then, 225 chemicals were tested in each assay. Potencies and bioactivity calls from the plate reader and imaging-based cell viability assays were comparable. The CP assay was more sensitive than either cell viability assay in that it detected a larger number of chemicals as bioactive, and phenotype altering concentrations (PACs) were lower than concentrations that decreased cell viability. An in vitro disposition (IVD) model that accounted for sorption of chemicals to plastic and cells over time was applied to predict freely dissolved PACs and compared with in vivo fish toxicity data. Adjustment of PACs using IVD modeling improved concordance of in vitro bioactivity and in vivo toxicity data. For the 65 chemicals where comparison of in vitro and in vivo values was possible, 59% of adjusted in vitro PACs were within one order of magnitude of in vivo toxicity lethal concentrations for 50% of test organisms. In vitro PACs were protective for 73% of chemicals. This combination of in vitro and in silico approaches has the potential to reduce or replace the use of fish for in vivo toxicity testing.

Coal fly ash is a highly heterogeneous waste product that becomes concentrated with metals after combustion that have been shown to act as neurotoxins and/or carcinogens in both wildlife and humans. As such, increased understanding of the presence, concentrations, and potential ecosystem impacts is needed. The Chesterfield power station contains more than 15 million tons of ash and is located adjacent to the James River, which serves as a tributary to the Chesapeake Bay. Our study investigated (1) the presence and concentrations of aluminum (Al), aresnic (As), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), lead (Pb), selenium (Se), and zinc (Zn) in surface water, deep water, and sediment samples obtained from the surrounding area and (2) the presence of various teleost species, using environmental DNA (eDNA) sampling. Universal cokriging was used to estimate the spatial variability of metals in sediments and the extent of pollution interpreted using enrichment factors (EF). Little contamination was observed in water samples compared to sediment samples. Elevated concentrations of Al, As, Cd, Cr, Fe, Pb, and Zn were observed in areas immediately adjacent to the coal ash landfills. Arsenic, Cd, and Pb showed increased EF in sites adjacent to the landfills, suggesting that the contamination observed is due to anthropogenic factors. Environmental DNA analyses revealed the presence of 22 teleost species, several of which have been identified as threatened, endangered, diadromous, and/or consumed by anglers who use the James River. Collectively, our results provide novel insight regarding the impacts of coal ash on an important Chesapeake Bay watershed and guidance for future risk assessment.

Pharmaceuticals as an important group of contaminants of emerging concern (CECs) are unintentionally discharged into the aquatic environment due to lack of advanced treatment of classical wastewater treatment plants (WWTPs). Therefore, the detection and monitoring studies of pharmaceuticals and personal care products (PPCPs) in an aquatic environment are getting more important as well as the definition of their ecological risks to the aquatic ecosystem. To conduct these studies successfully, it is necessary to develop sensitive, robust, selective, and reliable methods to be able to analyze PPCPs. This study was carried out in the biological WWTP (BWWTP) of Erzurum City, Türkiye, to investigate the treatment efficiency of pharmaceuticals in the plant and to assess the ecological risks for the Karasu River where treated wastewater is discharged into it. For this purpose, a wide range of pharmaceutical classes in influent wastewater (IWW) and effluent wastewater samples taken from Erzurum BBWWTP, Türkiye was simultaneously identified and quantified with liquid chromatography coupled with tandem mass spectrometry following liquid phase extraction for sample preparation. A total of 55 active pharmaceutical groups in 25 general drug groups (29 subgroups) were detected, with the highest average ratios being 82.459%, 7.306%, 4.949%, and 2.145% for analgesic-anti-inflammatory, antiepileptic, diabetic, and antipyretic pharmaceuticals groups, respectively, in IWW. Although flurbiprofen from the analgesic-anti-inflammatory pharmaceuticals group was treated with the average efficiency of 66.13% during the 12-month treatment period, it had a high risk quotient due to the very high initial concentration in WWT in the range of 809.01-22,901.10 µg/L.

N-Nitrosamines are a class of compounds that includes the potent mutagenicity and carcinogenicity of many of its members and is distributed widely throughout the human environment. DNA alkylation by their diazonium ions formed metabolically acts as a molecular initiating event (MIE) that links molecular chemistry to mutagenicity. However, the regiochemistry for diazonium ions reacting with DNA bases is still under debate. Hence, density functional theory calculations involving SN2 alkylation of guanine (Gua) by 14 diverse diazonium ions are presented, the results of which showed the mutagenicity-related shift from GuaN7- to GuaO6-alkylation proceeds by increasing complexity of the alkylating agents, along with a greater proportion of SN1 characteristic in SN2 transition states. Hence, "high oxyphilic" and "low oxyphilic" alkylating agents may instead be "SN1" and "SN2" species, respectively. As the degree of MIE selectivity for hard-hard interactions can be quantified by hard and soft acids and bases theory, quantitative relationships were modeled between the nucleophilic index (ω-) and hydrophobicity (log P) of diazonium ions and their carcinogenic potency. Therefore, the mechanistic link from MIE to target toxicity can be bridged by computational chemistry.

Chloride concentrations in freshwater are rising, with toxic effects on aquatic life. In temperate regions with cold winters, road salt used for deicing paved surfaces is a primary cause. There is evidence that water hardness can modify salt toxicity, but data are insufficient to inform policy. Because calcium is a primary ion influencing water hardness and there is widespread calcium decline in lakes, we examined the effects of varying calcium concentrations on acute salt toxicity in three Daphnia species to gain a greater understanding of the water hardness-salt toxicity relationship. We conducted 48-hr acute sodium chloride (NaCl) toxicity tests, using chloride concentrations as our metric, on neonates less than 24 hrs old in six calcium treatments: 1.5 to 128 mg/L (hardness ∼7 to 323 mgCaCO3/L). We determined the effective concentration of chloride that was lethal to 10%, 25%, and 50% of the sample populations from each iso-female line in each calcium treatment. Acute NaCl toxicity decreased as calcium concentrations increased. The relationship between NaCl toxicity and calcium concentration differed among Daphnia, such that Daphnia catawba and Daphnia pulex were more sensitive to NaCl in lower calcium treatments and less sensitive in higher calcium treatments compared to Daphnia pulicaria. Our results provide evidence that water quality guidelines are not protective enough for aquatic life in very soft water (≤3 mg Ca2+/L, 11.3 mg CaCO3/L) because most ECxx values we found for Daphnia were significantly lower than Canada's national guidelines for short-term chloride exposure. There are already many lakes with calcium concentrations below 3 mg/L, and global widespread calcium decline may put more aquatic ecosystems at risk of experiencing NaCl toxicity.

The widespread use of acephate, a common insecticide, raises concerns about its potential impacts on nontarget soil organisms. This study investigated the chronic effects of acephate on the reproduction of two key soil fauna species, the springtail Folsomia candida and the enchytraeid Enchytraeus crypticus. We exposed these organisms to acephate in both natural Cambisol soil and tropical artificial soil (TAS) to assess potential impacts under different environmental conditions. Our results revealed significant reductions in reproduction for both species, with effects ranging from 38% to 49% (based on control and lowest observed effect concentration values). Furthermore, the observed effects were dependent on both the organism and the soil type. Springtails exhibited greater sensitivity in TAS than in Cambisol (0.09 and 15.0 mg a.i. kg-1 soil dry wt, respectively), whereas enchytraeids were more sensitive in Cambisol than in TAS (1 and 100 mg a.i. kg-1 soil dry wt, respectively). These findings highlight the importance of considering species-specific responses and soil properties when evaluating the ecological risks of pesticides on soil fauna communities.

Monitoring of genotoxic chemicals released into the water cycle or formed through transformation processes is critical to prevent harm to human health. The development of the high-performance thin-layer chromatography (HPTLC)-umu bioassay combines sample separation and detection of genotoxic substances in the low ng/L concentration range. In this study, raw, process, and drinking water samples from 11 different waterworks in Germany were analyzed using the HPTLC-umu. A genotoxic response was detected in three out of 42 samples (one raw water sample and two drinking water samples). Genotoxicity testing using the micronucleus and p53-CALUX (chemical activated luciferase gene expression) assays revealed genotoxic effects for the raw water sample and one of the drinking water samples. Fortunately, only minor genotoxic effects could be detected in the two drinking water samples, with estimated 4-nitroquinoline-N-oxide equivalency concentrations of 0.12 ng/L and 0.17 ng/L, respectively. After extraction of the genotoxic zones from HPTLC plates, identification attempts were conducted with nontarget analysis (NTA). A prioritization approach based on chlorine and bromine isotope pattern revealed several halogenated features for both drinking water samples. These tentatively identified substances were previously reported in the literature as possible carcinogens. Although the detected features could not be conclusively identified, the presence of halogenated features in the genotoxic effective zone of the HPTLC-umu assay strongly suggests that the chlorine disinfection process in both waterworks was responsible for the formation of the genotoxic substances in the drinking water samples. These findings emphasize that the HPTLC-umu in combination with additional genotoxicity assays and NTA can be used to evaluate even relatively clean samples, such as drinking water.

Pesticides are an integral part of agriculture in arable and pastoral farming and in animal and pet care, but they have been shown to have detrimental impacts on biodiversity, including of freshwater systems. The United Kingdom (UK) has the 7th highest pesticide usage per area of arable land across 30 European and African countries assessed between the years 2000 and 2012 and thus an associated higher likelihood for impacts on riverine biodiversity. In our analysis of the UK's 24-year national chemical monitoring program (WIMS database; years 2000 to 2023), we show that of the nine pesticides that pose the greatest likely threat to UK freshwater invertebrates based on concentrations measured in British rivers exceeding the lowest effect concentrations (ECs) in laboratory-based toxicity tests, seven pesticides have exceeded the ECs across England between the years 2000 and 2023. The Anglian and Midland regions of England that have the highest regional arable pesticide use recorded the greatest number of pesticides exceeding the ECs for aquatic invertebrates. However, this finding may also be influenced by the more limited sampling/monitoring bias across England, and greater sampling of southern and northwest rivers is needed to better establish the potential impact of pesticides on riverine invertebrate communities in those regions.

Endocrine-disrupting chemicals can induce metabolic alterations, resulting in diseases such as obesity, diabetes, and fatty liver disease, which can be inherited by offspring inhabiting uncontaminated environments. Bisphenol A (BPA), a well-known endocrine disruptor, can induce endocrine disruption, leading to metabolic disorders in subsequent generations without further exposure to BPA via nongenetic transgenerational inheritance. Using medaka as an animal model, we reported that ancestral BPA exposure leads to transgenerational nonalcoholic fatty liver disease (NAFLD) in grandchildren four generations after the initial exposure. It is unclear if transgenerational NAFLD developed because ancestral BPA exposure differs from that developed due to direct and continuous BPA exposure because the transgenerational disease develops in the absence of the stressor. We induced transgenerational NAFLD in medaka with ancestral BPA exposure (10 µg/L) at the F0 generation and examined transcriptional and metabolomic alterations in the liver of the F4 generation fish that continued to develop NAFLD. To understand the etiology of NAFLD in unexposed generations, we performed nontargeted liquid chromatography-mass spectrometry-based metabolomic analysis in combination with bulk RNA sequencing and determined biomarkers, co-expressed gene networks, and sex-specific pathways triggered in the liver. An integrated analysis of metabolomic and transcriptional alterations revealed a positive association with the severity of the NAFLD disease phenotype. Females showed increased NAFLD severity and had metabolic disruption involving proline metabolism, tryptophan metabolism, and bile metabolism pathways. The present results provide the transcriptional and metabolomic underpinning of metabolic disruption caused by ancestral BPA exposure, providing avenues for further research to understand the development and progression of transgenerational NAFLD caused by ancestral bisphenol A exposure.

Due to its increasing affordability and efforts to understand transcriptional responses of organisms to biotic and abiotic stimuli, transcriptomics has become an important tool with significant impact on toxicological investigations and hazard and risk assessments, especially during development and application of new approach methodologies (NAMs). Data generated using transcriptomic methodologies have directly informed adverse outcome pathway frameworks, chemical and biological read across, and aided in the identification of points of departure. Using data reporting frameworks for transcriptomics data offers improved transparency and reproducibility of research and an opportunity to identify barriers to adoption of these NAMs, especially in environmental toxicology and ecotoxicology with aquatic models. Improved reporting also allows for reexamination of existing data, limiting needs for experiment replication and further reducing animal experimentation. Here, we use a standardized form of data reporting for omics-based studies, the Organisation for Economic Co-operation and Development omics reporting framework, which specifically reports on a list of parameters that should be included in transcriptomics studies used in a regulatory context. We focused specifically on fish studies using RNA- Sequencing (Seq)/microarray technologies within a toxicology context. Inconsistencies in reporting and methodologies among the experimental designs (toxicology vs. molecular characterization) were observed in addition to foundational differences in reporting of sample concentration or preparation or quality assessments, which can affect reproducibility and read across, confidence in results, and contribute substantially to understanding molecular mechanisms of toxicants and toxins. Our findings present an opportunity for improved research reporting. We also provide several recommendations as logical steps to reduce barriers to adoption of transcriptomics within environmental toxicology and ecotoxicology.