Archives of Environmental Contamination and Toxicology最新文献

Although the toxicity of petroleum-derived microplastics (MPs) has been widely investigated, the impact of biomicroplastics (BioMPs) remains controversial, and the necroecological trophic transfer of both is still poorly understood. Our study reveals that biomicroplastics may pose ecotoxicological risks comparable to or greater than those of petroleum-derived plastics, a finding that should raise concern. We aimed to evaluate the possible translocation of polystyrene (PS) and polylactic acid (PLA) MPs from mice to the necrophagous fly Synthesiomyia nudiseta and their potential effects on the larval stage. Mice were inoculated intraperitoneally with different doses of MPs [9 (I) and 90 mg/kg (II)] and subjected to the decomposition process (for ten days), allowing colonization by larvae. Our results confirmed the translocation of MPs from mice to S. nudiseta larvae, resulting in a greater accumulation of PLA-MPs compared to PS-MPs. We observed that exposure to MPs significantly influenced biomass accumulation, with larvae from the PS-I and PLA-I groups showing increased biomass. In contrast, those from the PLA-II group exhibited lower biomass. AChE activity was modulated in a concentration-dependent manner, with an increase observed in larvae exposed to PLA-MPs, indicating a potential neurotoxic effect. In addition, there was an increased production of reactive oxygen species (ROS), especially in the groups exposed to higher concentrations of MPs, without a proportional response of antioxidant enzymes, suggesting a redox imbalance and oxidative stress. The elevated serotonin levels and reduced dopamine observed in larvae exposed to MPs indicate a possible redirection of energy resources and changes related to a metabolic adaptation to the stress imposed by MPs. Principal component analysis (PCA) showed that PC1 was strongly influenced by biomarkers such as trypsin, chymotrypsin, AChE, ROS, and dopamine activity, highlighting that PLA-MPs (at the highest concentration) induced more pronounced toxic effects than PS-MPs. This finding was corroborated by discriminant analysis, which revealed a clear separation between the experimental groups, and by multiple regression analysis, which confirmed a strong relationship between MP concentration and larval biomarker responses, indicating that the type and concentration of MPs explained approximately 65% ​​of the variation in the biomarkers evaluated. In conclusion, our study demonstrates for the first time the necroecological trophic translocation of MPs between vertebrates and invertebrates, highlighting the potential risks of biomicroplastics.

Toxic effects of herbicide atrazine (ATR) have been evaluated in various aquatic organisms, but our understanding of its potential impacts in reptile species remains limited. In this study, the functional performances, and gut microbiota and liver metabolite alterations of ATR-exposed Mauremys sinensis juveniles were measured to evaluate its potential toxic effects in turtles. ATR exposure had no impact on the growth rate, but would allow turtles to right themselves more quickly. Despite having no difference in gut microbial diversity, the microbial composition was slightly changed after ATR exposure. For example, a few bacterial genera were shown to increase in exposed turtles (e.g., Turicibacter), or only observed in higher-concentration groups (e.g., Dialister, Alistipes, Delftia). Similarly, only a few identified liver metabolites were found to change significantly (e.g., decreased levels of arginine and N-acetylneuraminate; increased levels of glutathione and isomaltose in low-concentration exposure group) after ATR exposure. Overall, minor alterations in gut microbial composition and liver metabolite indicated that ATR exposure at environmentally-relevant concentrations only produced limited impacts in turtle species, although these alterations might have potentially adverse consequences on the long-term health of exposed turtles.

Oxytetracycline (OTC) and Florfenicol (FF) are prevalent antibiotics choices in both fish production and livestock farming. A comprehensive understanding of their effects is paramount for effective control of their use and for elucidating their physiological and pharmacological implications. In our investigation, zebrafish larvae were subjected to varying concentrations of OTC, FF or a combination of OTC + FF during 96 h. We observed behavioral alterations in the group exposed to OTC + FF. These fish displayed increased mobility, spent more time in the central zone, exhibited reduced turn angles, and experienced an impaired optomotor response. Coincidentally, our data provided evidence of reduced anxiety-like behavior in zebrafish larvae treated with OTC and FF, while also demonstrating the adverse effects of antibiotics on the optomotor response. Anxiety-like behavior plays an important role in species survival, acting as a key mechanism for adaptation and protection. The absence of such behavior can increase organism vulnerability in the environment. Thus, this study showed the behavioral consequences of OTC and FF exposure in zebrafish larvae, highlighting the impact of the combined toxicity of these antibiotics.

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Aquatic systems are impacted by temperature fluctuations which can alter the toxicity of pesticides. Increased temperatures related to climate change have elevated pest activity, resulting in an escalation of pesticide use. One such pesticide class, pyrethroids, has replaced the use of several banned pesticides due to its low mammalian toxicity. The impacts of increased temperatures on the toxicity of a pyrethroid, permethrin, to fish is not yet known. In the current study, juvenile inland silversides (Menidia beryllina) were exposed to permethrin at three temperatures: 10 °C, 20 °C, and 30 °C. Inland silversides were chosen for this study because they are a species used in standardized USEPA whole effluent toxicity testing. Permethrin toxicity showed an inverse relationship with temperature. As temperatures fluctuate, fishes experience a change in respiration, biotransformation, and elimination rates, which can drive the noted difference in toxicity. Based on these findings, toxicity can be temperature-dependent and should be considered when assessing risk of exposure to pesticides in aquatic systems.

One group of elements attracting more and more attention are so-called technology-critical elements (TCEs). In comparison with legacy pollutants, the anthropogenic impact of TCEs on the environment might still be minor, but various applications introduce them to the most remote places in the world including the marine environment. One area prone to pollution is the Baltic Sea, partly due to the lack of water exchange with the North Sea. In this study, a sediment core from the German Baltic Sea was used to analyze a total of 42 elemental mass fractions. Based on radiometric dating of ²¹⁰Pb and ¹³⁷Cs, results were classified in a recent (2020–2000) and a past period (< 1920), calculating background concentrations based on the Median + 2 Median Absolute Deviation (M2MAD) and the Tukey Inner Fence (TIF). Six legacy pollutants (Ni, Cu, Zn, As, Cd, Pb) and six TCEs (Ga, Ge, Nb, La, Gd, Ta) are discussed in detail. Anthropogenic impacts of both groups were assessed, and local enrichment factors were calculated showing an increase for the legacy pollutants (past period (≤ 0.8); recent period (≥ 1.2)), but also a minor increase for Ga, Ge and Nb (past period (0.9); recent period (1.1)). Values ≥ 1.5, indicating anthropogenic impact, were found for Cu, Zn, Cd and Pb, but also for Ge. Proposed background values may be considered as baseline for future studies.

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Mining operations in Canada, including uranium mining and milling, generate by-products containing radionuclides, including radium-226 (²²⁶Ra), a long-lived, bioaccumulative calcium (Ca²⁺) analog. Despite strict discharge regulations, there is limited evidence to suggest that current thresholds for ²²⁶Ra adequately protect aquatic organisms. Furthermore, Canada lacks a federal water quality guideline for ²²⁶Ra, underscoring the need for protective limits to safeguard aquatic ecosystems. Hence, this research aimed to generate data on ²²⁶Ra toxicity to the model aquatic invertebrate Daphnia magna. For this purpose, two 21-day chronic toxicity tests with D. magna were conducted, with survival and reproduction as the endpoints, as well as a reduced water hardness experiment, a multigenerational study, and a bioaccumulation assay. These experiments demonstrated that a high activity concentration (nominal 50 Bq/L) of ²²⁶Ra can significantly impact the survival of D. magna. ²²⁶Ra was also found to bioaccumulate in D. magna with a BAF of 72.8. Since the Canadian Metal and Diamond Mining Effluent Regulations (MDMER) monthly mean effluent limit is currently set at 0.37 Bq ²²⁶Ra /L, the limit for composite samples at 0.74 Bq/L ²²⁶Ra, and the limit for grab samples at 1.11 Bq/L ²²⁶Ra, it is unlikely that toxic effects to aquatic cladocerans like D. magna from ²²⁶Ra will be observed downstream of Canadian mines and mills.

The investigation focused on Tl, Hg, As, and Sb as the targeted contaminants in the soil surrounding a thallium mining region in southwestern China. Potential sources of toxic elements were identified using correlation analysis and principal component analysis. By interpreting the results of correlation and principal component analysis, the potential sources of Tl, Hg, As, and Sb were identified to include the mining and smelting industry. Additionally, Tl, Hg, and As are influenced by agricultural activities, while Sb is also associated with the soil parent material. Various analytical methods including the Nemerow comprehensive pollution index, Hakanson potential ecological risk index and hazard quotient assessment were employed to evaluate the sources of heavy metal pollution and associated health risks to crops. Results indicated elevated exceedance rates of Tl, Hg, and Sb in the farmland soil. Approximately 37.9% and 16.7% of the sampling locations were classified as highly and moderately polluted, respectively. Furthermore, toxic elements posed significant ecological risks to the soil, particularly with substantial contributions from Hg and Tl toward the overall risk index. Crop samples collected showed elevated levels of Tl, Hg, and As, particularly in leafy vegetables compared to cereals. Notably, the hazard quotient (HQ) values for Tl in cabbage and Lotus were 1.462 and 5.511, respectively, whereas the HQ value for Hg in Allium chinense was 1.773, posing a significant threat to human health. These findings offer valuable data and theoretical foundation for further investigations into the sources and risks associated with toxic elements in farmland near thallium mining sites.

Environmental risk assessments of very hydrophobic organic compounds (VHOCs) in soils are often difficult because multiple processes (e.g., sorption, volatilization, biodegradation) can complicate the interpretation of results. A standardized soil dosing and aging procedure is presented for assessing bioavailability of VHOCs in a synthetic soil, which was used to evaluate the phytotoxicity of VHOCs. The soil preparation protocol resulted in relatively stable freely dissolved concentrations of test substance compared to bulk soil concentrations with some losses likely due to volatility and biodegradation. This dosing method was used in a chronic terrestrial plant toxicity bioassay to evaluate the potential toxicity of VHOCs on complex reproductive endpoints like inflorescence and seed bud formation. Testing included representative hydrocarbons and three very hydrophobic lubricant substances (logKow > 10). The toxicity data were used to evaluate existing predicted no-effect concentrations (PNECs) that had originally been derived with the target lipid model, which did not have these higher order chronic plant endpoints. The initial exposure concentrations were set at the PNECs to provide an independent validation of the PNEC. This evaluation was performed to expand the domain of applicability of the PNEC to VHOCs and for the chronic terrestrial plant endpoints. No effects were observed on plant biomass or inflorescence production at these low exposure concentrations, demonstrating that the established PNEC is protective of long-term plant health. The results of the present study confirm that the new dosing method is fit for purpose, and that the existing PNEC framework can be extended to chronic plant endpoints for VHOCs.

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Oil spills and tarballs are significant pollutants in marine environments, and identifying their sources is crucial for mitigating environmental impacts. This study aims to determine the primary sources of petroleum spills and tarballs along the shores of Genaveh (northwest of the Persian Gulf) by employing chemical fingerprinting techniques and biomarkers. Specifically, petroleum hydrocarbons were analyzed in 19 tarball samples, 13 surface sediment samples from the Genaveh coast, and reference oil samples from 21 offshore oil platforms located in the Bahregan, Khark, Lavan, Siri, and Hendurabi regions. Samples were extracted using the Soxhlet extraction method, followed by two-step column chromatography, and the compositions of n-alkanes, polycyclic aromatic hydrocarbons (PAHs), hopanes, and steranes were determined using gas chromatography–mass spectrometry (GC–MS). The concentration of PAHs in coastal sediment samples from Genaveh ranged from 345 (S841) to 27,374 ng/g-dw (S852), indicating moderate to very high pollution levels. The total concentration of aliphatic hydrocarbons in coastal sediment samples from Genaveh ranged from 8,694 (S842) to 27,374 µg/g-dw (S851), significantly exceeding n-alkane concentrations reported in surface sediments from many other regions worldwide, suggesting considerable pollution levels. For the 19 collected tarball samples, PAH concentrations varied from 597.5 to 10,173 ng/g-dw, while n-alkane concentrations ranged from 27,136 to 66,341 µg/g-dw, which may indicate differences in age or freshness. Diagnostic indicators, such as undifferentiated complex mixtures (UCM), a carbon preference index (CPI) close to 1 for n-alkanes, diagnostic ratios of PAHs, and ratios of hopanes and steranes, pointed to a predominantly petrogenic origin of hydrocarbons in the coastal sediments of Genaveh. The principal component analysis (PCA) results revealed a distinction between oil samples from the Lavan, Hendurabi, and Siri platforms, indicating oil leakage from the Khark oilfield pipelines (Doroud and Forouzan) and Bahregan oilfields (Bahregansar and Soroosh) as a major pollution source. This implies that both oil spills, observed in the coastal sediments of Genaveh, and episodic spills, represented by tarballs, originate from a similar, homogeneous source. Only sediment samples from stations S841 and S812 were not influenced by tarballs, suggesting pollution from a different source compared to other sediment samples.

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