Bulletin of Environmental Contamination and Toxicology最新文献

Aluminum (Al) is a widely occurring element in nature and is the most abundant element in the earth's crust after oxygen and silicon. In this study, metal accumulation levels in the gills, liver and muscle tissues and liver SOD, CAT and GPx enzyme activities of liver tissue of O. niloticus were determined under the influence of 10 mg/L concentrations of micro and nano sizes of Al₂O₃ for 7 days. Aluminum levels in the tissues were measured by ICP-MS. In this study, no mortality was observed during the experiments. It was observed that there was a significant increase in the tissues examined under the effect of both forms of Al₂O₃ compared to the control. At the end of the 7 days exposure period, the following relationship was found among the tissues in accumulating under the effect of both forms of Al₂O₃ as gill > liver > muscle. It was also observed that there was a significant increase in SOD, CAT and GPx enzyme activities of liver tissue examined under the effect of both forms of Al₂O₃ compared to the control. Overall, Al₂O₃ NPs are more effective than Al₂O₃ MP in terms of liver enzyme activities.

The goal of this study was to document the presence and density of microplastics and invertebrates in the hyporheic sediments of the large Paraná River in sandbanks (Argentina). Nine species of hyporheic invertebrates were recorded and identified for the first time, with an average density of 14,164 ± 13,889 ind./m³. Isotoma sp1 (12,729 ± 19,444 ind/m³) and Aelosoma sp1 (13,889 ± 24,056 ind/m³) were the most abundant species. The average concentration of microplastic was 25,000 ± 9,129 MPs/m³. All microplastics detected were polyethylene terephthalate (PET) fibers, with sizes ranging from 693 to 1,820 μm. While the absence of comprehensive QA/QC procedures constrains the precision of absolute concentration estimates, these findings provide important baseline information for the Paraná River, in which no previous data were available. The co-occurrence of invertebrates and microplastics in the hyporheic sediments of the Paraná River highlights the potential threat that microplastics pose to the survival of hyporheic invertebrates in river ecosystems.

This study reports tissue-specific concentrations of cadmium (Cd), mercury (Hg), copper (Cu), and zinc (Zn) in two deceased Crocodylus moreletii from Southeastern Mexico. One was an adult male struck by a vehicle; the other, a severely emaciated juvenile female. Organs, plasma, and caudal scutes were analyzed using atomic absorption and voltammetry. The juvenile exhibited extremely high concentrations of Cd (137.55 µg/g) and Zn (210.27 µg/g) in kidney tissue, exceeding values reported in other crocodylian species. Scutes and plasma also reflected internal metal burdens, supporting their use as non-destructive matrices. Comparisons with published data suggest these are among the highest concentrations recorded in crocodylians, raising concern about localized environmental contamination. The findings reinforce known tissue-specific accumulation patterns and highlight the value of opportunistic sampling for internal tissue assessment in protected species. This study contributes rare toxicological data for C. moreletii and emphasizes the need for continued biomonitoring in understudied tropical freshwater habitats.

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.