Environmental Toxicology and Chemistry最新文献

As a representative agent of bicyclic antidepressants, venlafaxine (VEN) has become widely used worldwide and is frequently detected in surface waters with concentrations ranging from ng/L to µg/L. To evaluate the toxicological effects of such medications on aquatic species, studies on environmentally relevant concentrations are essential. Zebrafish were used as a model organism to assess growth and development in larvae and examine tissue accumulation, oxidative stress, and DNA methylation in adults. The results showed adverse effects, including an 18.5% decrease in embryo hatching rate and an increase in mortality by 18.5%. There was also a reduction in body length (4.5%) and eye area (12.2%) in the larvae, along with abnormal developmental issues, such as pericardial edema, yolk sac edema, and spinal curvature. Venlafaxine and its metabolites induced oxidative stress, leading to observable toxic effects. In adult zebrafish, VEN and O-desmethylvenlafaxine (ODV) accumulated primarily in the liver, followed by the brain and intestines, and caused a reduction in DNA methyltransferase activity, leading to DNA hypomethylation. VEN had the most significant impact on DNA methyltransferase 1 and altered its conformation more than ODV. Overall, venlafaxine was found to be more toxic than its metabolites, providing a scientific basis for evaluating the toxic effects and ecological risks of antidepressant residues on aquatic organisms.

Occurrence of microplastics in the environment is well studied, but our knowledge of their distribution in specific locations, such as the sandboxes, which are integral parts of popular playgrounds for children, is limited. Pioneering research on the factors affecting the microplastic pollution of sandboxes in urban residential areas was conducted within three estates in Kielce, Poland. Sand samples (Σ27) were collected from nine sandboxes and examined for the presence of microplastics, using a simple quality control methodology proposed by the authors. Microplastics were found in each sample and their contents ranged from 60 to 5,540 items/kg of sand. Fragments and fibers were the most prevalent types of microplastics in the samples. They contributed to approximately 95% of all microplastics found. Transparent fibers were the most abundant among fibers (63%) and red particles (57%) among fragments. A strong, positive, and significant correlation (rSpearman = 0.90) was found between the number of microplastic items and the location of sandboxes (above sea level). There was no correlation between the population density of the estates (rSpearman  =  0.03), the distance of the estates from the center (rSpearman  =  0.02), and the distance of the estates from main roads (rSpearman  =  0.43). Considering that sandboxes can be a potential source of microplastics for children, and assuming that sand ingestion by children is similar to the estimated daily soil ingestion rate, our results indicate that the number of microplastics ingested could be 1,106. Inhalation, dermal transport, and ingestion of microplastic particles from sandboxes pose a potential threat to children's health. However, more research is needed to better understand the health risks associated with this source of microplastics.

The pH of freshwater ecosystems affects bioavailability of various metals to various organisms, including daphnids. Although it is well known that daphnid species show interclonal variation of metal sensitivity, knowledge about interclonal variation of bioavailability effects, such as the pH effect, is scarce. Here, we compared the effect of pH on chronic copper toxicity between two clones of Ceriodaphnia dubia, within its natural pH niche, which we determined to be approximately pH 6.5-8.5 based on existing experimental and biological monitoring data. Using a Bayesian modeling approach, we found that the effect of pH was not statistically significantly different between the two clones (with a credibility > 95%). Overall, we found an approximately threefold decrease in chronic Cu toxicity with increasing pH between pH 6.5 and 8.5, with 7-day 20% effect concentration (EC20) values ranging between 11.0 and 30.9 µg/L dissolved Cu. We then calibrated a preliminary generalized bioavailability model (gBAM) using these data and found a pH-effect slope parameter SpH = -0.247, which is within the range of previously reported values for Daphnia magna (-0.056 to -0.361) and similar to the SpH value of -0.220 used in the "invertebrate gBAM" for bioavailability-based Cu risk assessment under the Registration, Evaluation, Authorisation and Restriction of Chemicals. The preliminary C. dubia gBAM captured the magnitude of the observed pH effect well (mean of 1.3-fold EC20 prediction error, n = 9). It was also able to accurately predict chronic Cu toxicity in natural waters reported in an independent dataset (mean of 1.4-fold prediction error, n = 6). Also, two D. magna gBAMs (for two clones) and the invertebrate gBAM showed comparable predictive capabilities. Collectively, our work highlights the importance of studying relations between pH and metal bioavailability within the species' natural niche. It also confirms earlier findings that biological variation of pH-bioavailability relations typically does not have a large impact on predictive capacity of bioavailability models, which is important for regulatory applications.

Plastic pollution constitutes one of the major environmental problems of our time, and in recent years, it has emerged as a significant threat to the environment and to various organisms, including bird species. In this context, this study, which provides the first data in Türkiye, aimed to determine the level of microplastic (MP) pollution in 12 bird species (Eurasian buzzard; short-toed snake-eagle; white stork; northern long-eared owl; common barn-owl; ruddy shelduck; Eurasian eagle-owl; scarlet macaw; common pheasant; Indian peafowl; common kestrel; and gray parrot). The results indicate that MPs were detected in 50% of the specimens (n = 20), with an average of one MP/item per individual. With an average of three MPs per individual, the short-toed snake-eagle was found to be the species with the highest MP accumulation. Fibers (range: 51-534 µm) were the most common type of plastic found in the gastrointestinal tract of birds, with ethylene vinyl acetate and navy blue being the most common polymer type and color, respectively. It was also found that the abundance of MPs increased with the weight of specimens, contributing to the hypothesis that there is a correlation between the size/weight of animals and increased levels of MP accumulation. These findings highlight the impact of plastic pollution on birdlife and the need for further monitoring to assess the ecological impact of pollution.

Histological evaluations of tissues are commonly used in environmental monitoring studies to assess the health and fitness status of populations or even whole ecosystems. Although traditional histology can be cost-effective, there is a shortage of proficient histopathologists and results can often be subjective between operators, leading to variance. Digital pathology is a powerful diagnostic tool that has already significantly transformed research in human health but has rarely been applied to environmental studies. Digital analyses of whole slide images introduce possibilities of highly standardized histopathological evaluations, as well as the use of artificial intelligence for novel analyses. Furthermore, incorporation of digital pathology into environmental monitoring studies using standardized bioindicator species or groups such as bivalves and fish can greatly improve the accuracy, reproducibility, and efficiency of the studies. This review aims to introduce readers to digital pathology and how it can be applied to environmental studies. This includes guidelines for sample preparation, potential sources of error, and comparisons to traditional histopathological analyses.

This study assesses the occurrence of emerging contaminants (ECs) from agricultural and livestock production activities along the Salado River (Santa Fe province, Argentina). Of the 23 ECs studied, 8 were detected and quantified in river and wastewater samples, including ciprofloxacin, enrofloxacin, chlorpyrifos-methyl, albendazole, fenbendazole, levamisole, diazepam, and thiamethoxam. In river samples, the highest concentrations corresponded to ciprofloxacin, chlorpyrifos-methyl, and enrofloxacin. In wastewater samples, albendazole, fenbendazole, ciprofloxacin, enrofloxacin, and thiamethoxam were found. The detection frequency ranged from 4.2% to 54.2% in river samples and from 11.1% to 22.2% in wastewater samples. The spatial distribution of contaminants showed different concentrations, with higher levels often found near urban and agricultural areas, suggesting anthropogenic sources. Ecological risk assessments for different organisms were conducted. Ciprofloxacin posed the highest risk, especially affecting bacteria, cyanobacteria, and algae. Diazepam also was found to pose significant risks to algae, crustaceans, and fishes. Chlorpyrifos-methyl was identified as highly hazardous to multiple living organisms, which is in agreement with the fish mortality that occurred at the sampling sites. The risk assessment in humans showed differences among children, adolescents, and adults, with infants (6 months to 1 year) being at a higher risk than adults. Children may be at a higher daily intake of contaminants than adults, raising concerns about the long-term effects of exposure. This work underscores the critical need for monitoring and regulating ECs in aquatic environments. Further studies are necessary to fully understand their impact and to develop effective strategies for mitigating their presence in water systems.

Considerable amounts of polyethylene terephthalate (PET) microplastic fibers are released into the environment by the laundering of polyester clothing. Microplastic fibers can be ingested by organisms in the environment. Therefore, it has been suggested that microplastic fibers act as vectors for adsorbed contaminants, which are subsequently desorbed in the gut of the organism. We undertook sorption isotherm experiments at pH 6, 7, and 8 to quantify the sorption of methylmercury (MeHg) to PET fibers. Sorption isotherms were fit to Langmuir, Freundlich, and Brunauer-Emmett-Teller models. Sorption decreased with increasing pH, which can be explained by physisorption on the negatively charged PET surfaces and the greater presence of neutral or negatively charged MeHg species at higher pH. We used the parameters obtained by the model fits to predict the likely concentration of MeHg on PET microplastic fibers in aquatic ecosystems with environmentally realistic MeHg concentrations. We calculated MeHg concentrations on PET microplastic fibers to be four orders of magnitude lower than previously observed concentrations of MeHg in seston (suspended particles comprising algae and bacteria) at the base of the aquatic food web. The results indicate that the presence of PET microplastic fibers in the environment do not elevate the MeHg exposure to organisms that ingest fibers in the environment.

Nanoplastics (NPs) and neonicotinoids are common pollutants in aquatic ecosystems. Although their co-occurrence is expected in multiple environments, studies assessing their combined effects are still limited. This toxicological assessment investigated the potential effects of polystyrene NPs (PSNPs), clothianidin (CLO), and their mixtures on four aquatic species: the freshwater cladoceran Daphnia magna, the duckweed Lemna minor, the green algae Chlamydomonas reinhardtii, and the cyanobacteria Microcystis aeruginosa. Toxicological tests were performed following International Organization for Standardization and Organisation for Economic Co-operation and Development protocols. Acute, chronic (multigenerational) and swimming behavior tests were performed with D. magna, and growth inhibition tests were run with L. minor, C. reinhardtii, and M. aeruginosa. Abbott's model was used to predict the toxicological interactions of the mixtures for each one of the tested species. The D. magna immobility and swimming behavior tests revealed that the combined toxicities of PSNPs and CLO are decreased when the compounds are present as a mixture. Antagonistic interactions were also observed for C. reinhardtii growth, whereas for L. minor and M. aeruginosa, interactions ranged from antagonism to additivity. Chronic multigenerational tests with D. magna revealed that neonates obtained from the exposed parental generation showed a delay in the first brood during the recovery (nonexposure) phase, but this effect disappeared at the next generation, which indicates that microcrustaceans will probably be able to recover on a long-term scale if contamination is stopped. Our results provide new insights into the combined toxicity and ecological risk of NPs and neonicotinoids toward aquatic organisms.

The objective of this study was to determine the influence of tissue morphometry on tissue total mercury concentration (THg) in male and female virile crayfish (Faxonius virilis). In 2023, 10 embryonized and nine stage IV female crayfish and 29 male virile crayfish were captured from Lake Roosevelt and the Spokane River Arm, in Washington, USA. Total mercury was analyzed in the adductor muscle, gills, and hepatopancreas for all individuals and the ovaries and eggs for females with developed ovaries and embryonized females, respectively. Tissue morphometrics and tissue THg were allometrically correlated to the clawless body mass of male virile crayfish. Furthermore, it was determined that in male size-adjusted virile crayfish, gill THg was significantly associated with hepatopancreas THg but not adductor muscle THg. In embryonized and reproductive developing female virile crayfish, there was evidence of considerable adductor muscle and hepatopancreas tissue atrophy; however, no significant differences in THg occurred. In both the adductor muscle and the hepatopancreas, THg was not bioamplified despite tissue atrophy, suggesting a net loss of mercury from the tissues into the hemolymph. Although the most plausible redistribution of mercury in females with developed ovaries would be from the hepatopancreas to the developing ovary, this redistribution does not completely explain the level of maternal transfer observed. Clearly, dietary mercury contributed to the body burden of mercury within the ovaries of the females in reproductive development.