Bulletin of Environmental Contamination and Toxicology最新文献

In China, rare earth mining (REEs mining) is amongst the most important anthropogenic sources of potentially toxic elements (PTEs) release into the soil. In the last few decades, many researchers have conducted studies on PTE pollution in REEs mining areas. Yet, most of those studies only focused on a small geographical area or a single REEs mining, which does not reflect the overall scenario on a national scale. The current study collected data on the concentration of 8 PTEs (Pb, Cd, Cr, Cu, Hg, As, Zn, and Ni) from various research articles published from 2008 to 2024 in six rare earth mining provinces of China, investigated the spatial distribution of PTEs, their contamination level, potential sources and human health risk associated with them. The findings revealed that the average concentration of all eight PTEs was significantly higher than both Chinese and world background values, with Pb, Cd, and Hg exceeding the GB 15618-2018 guidelines for agricultural soils also. The Nemerow composite pollution index (NCPI) results indicated substantially elevated levels of pollution in all REEs mining provinces, with Sichuan having the highest NCPI (50.8). The principal component analysis (PCA) results showed mixed anthropogenic and geogenic sources of pollution for the selected PTEs. The human health risk assessment indicated that children were more at risk than adults via exposure pathways (oral, dermal, inhalation). The carcinogenic risk assessment revealed that Cr posed a significant cancer risk in both children (CR = 4.9 × 10^-3) and adults (CR = 2.1 × 10^-3) while Cu showed no carcinogenic risk in adults (CR = 8.6 × 10^-4) but presented a carcinogenic risk in children (CR = 2.0 × 10^-3), suggesting that children are more prone to the adverse effects of PTEs in REEs mining soils. Therefore, the present study indicates that REEs mining releases PTEs into nearby soils and poses a potential health risk to the surrounding environment, and should be mitigated by the government through effective management strategies.

Neotropical aquatic ecosystems harbor a rich diversity of endemic species, many critically threatened by anthropic activities, such as the aeglid crabs. Hemolymph cell morphology and viability analyses offer diagnostic tools for evaluating the biological condition of species subjected to environmental stressors. This study investigates apoptotic cell ratios in freshwater crabs of the genus Aegla, exposed to anthropic impact. Hemocyte morphology and apoptosis levels were assessed in Aegla spp. collected from streams with different levels of disturbance across Brazil's southeast region. Water quality parameters were measured alongside concentrations of metals and surfactants. Sites exhibiting the lowest water quality presented significantly elevated apoptotic cell ratios. The integration of hemolymph analyses with environmental assessments revealed potential correlations between biotic and abiotic factors, offering an understanding of the relationship between immune status and ecological conditions in aeglid species. This integrative approach provides a valuable framework for informing conservation strategies for these freshwater organisms.

Ecotoxicological studies on the effects of harmful heavy metals including hexavalent chromium Cr(VI), on aquatic ecosystems have increased dramatically in recent years. Moreover, biological factors like species, age, and developmental stage are crucial in determining the ecotoxicological effects. This was the first-ever study to evaluate the acute toxicity (96 h-LC50) of Cr(VI) on Chanos chanos fry (average weight 2.5 ± 0.5 g, length 6.5 ± 1 cm) in freshwater. Seven Cr(VI) treatment groups and one control group (10 fry each) were tested for mortality, morphological, behavioural and histopathological alterations. The median lethal concentration (LC₅₀) was determined as 31.22 mg/L by probit analysis, and a safe concentration factor of 0.01 was applied to estimate the allowable safe level. This investigation provides valuable insights into the ecotoxicology and risk assessment of Cr(VI), with potential implications for culturing euryhaline fish in chromium-contaminated freshwater for species diversification.

Metals reach aquatic ecosystems through various anthropogenic activities, posing risks to aquatic life. This study investigated oxidative stress and detoxification biomarkers in Strandesia rondoniensis, an Amazonian ostracod, after 96 h of exposure to sublethal concentrations of CuSO₄, ZnCl₂, CdCl₂, and HgCl₂. Significant increases in superoxide dismutase, glutathione, and metallothionein activity were observed in response to Zn, Cd, and Hg, indicating the induction of reactive oxygen species (ROS). In contrast, copper exposure did not alter biomarker activity. Lipid peroxidation increased following exposure to Zn, Cd, and Hg, damaging cell membranes and leading to DNA damage, suggesting the antioxidant defense system was insufficient to counteract oxidative stress. The results demonstrate the sensitivity of S. rondoniensis to environmentally relevant metal concentrations, supporting its application as a neotropical model organism in ecotoxicological assessments. Furthermore, the findings underscore the need to revise Brazil's environmental legislation on permissible metal concentrations in aquatic environments.

This study evaluated the ecological capacity of Tianmu Lake and analyzed its water environment and pollution load using a distributed hydrological model (SWAT) with high spatial resolution and long time series. The findings indicated significant interannual variations in total phosphorus (TP) and total nitrogen (TN) loads, with high flow years exhibiting substantially higher levels (TP: 6.69 tons year^-1, TN: 328.85 tons year^-1) compared to low flow years (TP: 4.61 tons year^-1, TN: 210.69 tons year^-1). Monthly loads were elevated during wet and normal seasons, with spatial concentrations in the Zhongtian River basin and the Yangzhuang River basin. To achieve water quality targets for 2025, 2030, and 2035, TP and TN reductions are needed in the Shahe and Daxi Reservoirs. The study emphasizes the importance of integrated strategies, including spatial optimization, source reduction, and transport regulation, to enhance ecological capacity and mitigate pollution concentration.

The UV filter benzophenone-3 (BP-3) is a prevalent environmental pollutant due to its extensive use in personal care products, raising concerns about its ecological risks. This study investigated the pH-dependent oxidative stress effects of benzophenone-3 (BP-3) on Carassius auratus by measuring four key biomarkers-superoxide dismutase, catalase, glutathione, and malonaldehyde in liver tissue. The results demonstrated that BP-3 exposure led to significant oxidative stress, as evidenced by altered antioxidant levels and increased lipid peroxidation. The integrated biomarker response indicated that stress was more pronounced at higher BP-3 concentrations and varied with pH, being greatest under acidic conditions. These findings demonstrate that the toxicity of BP-3 is strongly influenced by environmental pH, highlighting the necessity of incorporating pH variations into ecological risk assessments of ionizable organic pollutants.

Benzophenone-3 (BP-3), a widely used ultraviolet filter in personal care products, has been extensively detected in aquatic environments and poses potential ecological risks. This study innovatively investigated the pH-dependent acute toxicity of BP-3 to three model aquatic organisms-Daphnia magna, Photobacterium phosphoreum, and Danio rerio-by determining the EC₅₀ and LC₅₀ values across a pH range of 5.0 to 9.0. Our results revealed that BP-3 exerted greater acute toxicity on all three tested aquatic organisms under acidic conditions (pH 5.0) than under alkaline conditions (pH 9.0). The increased toxicity with lower pH was attributed to the predominance of the more lipophilic molecular form of BP-3, emphasizing the significant influence of environmental pH on BP-3 toxicity. These findings provide essential toxicological data for assessing the ecological risks of BP-3 in diverse aquatic environments, highlighting the necessity of considering BP-3 concentration, environmental pH and exposed species in ecological risk assessments.

Dinoseb has been banned from use as a pesticide due to concerns about its environmental persistence and toxicity, but it is still used in the chemical industry as an inhibitor of styrene polymerization. In the present study, the potential risks of dinoseb in freshwater, sediments, and soil media in Korea were assessed based on conservative exposure scenario. Acute and chronic toxicity data for aquatic organisms were collected to derive predicted no effect concentration (PNEC_water). Due to the lack of toxicity data for sediment and soil organisms, PNEC_sediment and PNEC_soil were derived using the equilibrium partitioning method based on PNEC_water. Environmental concentrations were estimated using SimpleBox Korea model. The PNEC_water, PNEC_sediment, and PNEC_soil were 0.00145 mg/L, 0.0167 mg/kg dry weight, and 0.00242 mg/kg dry weight, respectively. PECs at regional scales were lower than PNEC, but HQ exceeded 1 at one local site. Soil samples near high-risk worksites were analyzed at two different time points to measure dinoseb concentrations. Dinoseb was found to be below the limit of quantification, indicating that, within the scope of the available data and assessment conditions, the current environmental risk of dinoseb is expected to be low, although continued monitoring is warranted.