Bulletin of Environmental Contamination and Toxicology最新文献

A Reversed-Phase High-Performance Liquid Chromatography (RP-HPLC) method was developed and validated to simultaneously quantify six contaminants of emerging concern (CECs) in the context of microalgae bioremediation. RP-HPLC was chosen for its ability to separate substances of differing polarities, its use of cost-effective and low-toxicity mobile phases, and the capacity to selectively adjust pH for enhanced sample resolution. To validate this method, standard guidelines were followed to evaluate system suitability, linearity, accuracy, precision, recovery, limits of detection and quantification, selectivity and specificity. Limits of detection and limits of quantification were, respectively, 0.017 and 0.051 µg mL^-1 for paracetamol (PAR), 0.024 and 0.072 µg mL^-1 for methylparaben (MP), 0.008 and 0.027 µg mL^-1 for imidacloprid (IMID), 0.014 and 0.041 µg mL^-1 for bisphenol A (BPA), 0.023 and 0.069 µg mL^-1 for triclosan (TCS) and 0.016 and 0.048 µg mL^-1 for ibuprofen (IBU). Precision and accuracy values assessed inter-day and intra-day were all within the acceptance limits of relative standard deviation (%RSD) and %bias of less than 15%. Percentage recovery was determined to be within the acceptable range of 80-120%, except for TCS due to low solubility. Applicability was demonstrated by assessing the effect of contaminant exposure to microalgae cells, and contaminant removal. The developed method is linear, precise and accurate and has been successfully applied to the quantification of the six contaminants during microalgae bioremediation.

Amide herbicides (AHs), commonly applied in agriculture, are now known to inhibit the activity of alkaline phosphatase (AKP), subsequently disturbing the soil microbial community and spurring significant shifts in soil nutrient dynamics. The complex mechanisms governing the interaction between AHs and AKP, along with the impact of halogen substituents in AHs on AKP function and this study sets out to investigate these interactions. By integrating computational docking techniques with Spearman correlation analysis and focusing on seven typical AHs, we probed the mechanisms of the AHs-AKP complex and aimed to clarify the structure-activity relationship between these herbicides and AKP. Our findings disclose that within the AKP-AHs complex, the proportion of neutral amino acids peaked at 48.41%. The chief interaction patterns between AKP and AHs hinged on hydrogen bonding and hydrophobic interactions. Among the AHs, butachlor exhibited the largest binding area (BA ≈ 452.61 Ų), implying stronger binding than its counterparts. In contrast, propanil manifested the maximum absolute value of binding energy (|BE|) at 2.94 kJ/mol, indicating that it may possess stronger binding characteristics despite the larger BA of butachlor. This discrepancy may be attributed to the chlorine atom content of propanil relative to the other AHs, which enhances its interaction with AKP through increased hydrophobicity and specific interactions. Moreover, our analysis reveals a negative correlation between the molecular weight (MW) of the AHs and their corresponding |BE| values, signifying that as MW rises, the binding energy of the AHs-AKP interaction declines. This suggests a potential inverse relationship. In sum, these findings provide critical technological insights and foundational theory for understanding the harmful impacts of AHs via the halogen effect (Cl) on soil enzyme inhibition, with implications for health risk management and regulation. These insights are crucial for understanding the environmental impact of AHs and informing risk management strategies.

Previous health risk assessments of particulate polycyclic aromatic hydrocarbons (PAHs) have ignored the size distributions and respiratory tract deposition rates, resulting in significant bias. To calculate the health risks of depositing PAHs, this study investigates the size-resolved dynamics of particulate PAHs and associated deposition fluxes in Baoding, a representative inland city in China's Beijing-Tianjin-Hebei air pollution corridor. Size-segregated aerosol sampling (n = 20 batches) across four seasons revealed: coarse particles (> 2.1 μm) dominated PM mass in spring (67%), summer (60%), and autumn (60%), while winter exhibited fine particle (< 2.1 μm) dominance (62% of TSP). All PAHs demonstrated bimodal size distributions with accumulation (0.43-0.65 μm) and coarse modes (4.7-5.8 μm). Low-molecular-weight PAHs show more significant volatility-driven migration to coarse particles than high-molecular-weight PAHs. The deposition fluxes of size-segregated PM and PAHs were calculated by multi-path particle dosimetry model. Compared with adults, children have a 32-40% higher flux of coarse PM deposition. In addition, the deposition fluxes of coarse PM is higher than fine PM. These findings challenge conventional fine PM-centric risk frameworks, highlighting the necessity to reconsider coarse PM toxicity for child-specific exposure in northern China's inland cities.

There have been reports confirming the presence of microplastic pollution in rice fields, which have potential negative effects on rice cultivation. In this article, the growth characteristics and oxidative stress levels of rice seeds were analyzed in the presence of polystyrene microplastics with different particle sizes (50 μm, 50 nm) and concentrations (0-1500 mg/L), as well as their co-exposure to 2,4-epibrassinolide. The micro-particles had no significant effect on the growth of rice seeds, however, the nano-plastic had an inhibitory effect on the growth of rice seed and the effect was the strongest at high concentration. The addition of brassinolide alleviated the inhibitory effect of the nano-plastics on rice seed. The oxidative stress level results indicated that the addition of brassinolide weakened the oxidation induction effects of microplastics, improved the antioxidant capacity of rice seeds under microplastics stress.

This study investigated the distribution, sources, and ecological toxicity of polycyclic aromatic hydrocarbons (PAHs) in surface sediments along the Mekong River, from its entry into Vietnam to its outflow into the East Sea. The results showed that total PAH concentrations ranged from 53.66 to 1205.35 ng/g dry weight, with an average of 281.08 ± 391.13 ng/g dry weight. Among the 16 PAH compounds analysed, Pyrene (Pyr) and Fluoranthene (Flu) were detected in all sediment samples. Naphthalene (Nap) had the highest concentration among the detected PAHs. Diagnostic ratio and principal component analyses indicated that PAHs originated from mixed sources, including traffic emissions, coal and biomass combustion, petroleum leakage, and wastewater discharge. Based on the risk quotient (RQ), PAHs posed low to moderate ecological risks. Both adults and children in the study area may be exposed to cancer risks due to the presence of carcinogenic PAHs in sediment samples.

The usage of biodegradable plastics as a substitute for traditional plastics is increasing yearly. However, the toxicity of biodegradable microplastics to freshwater microalgae is still unclear compared to traditional microplastics; In addition, the toxic release effects of different aging methods on biodegradable plastics are also unknown. Taking polyethylene (PE) and polylactic acid (PLA) as the research objects, the acute toxicity (96 h) of Microcystis aeruginosa under high temperature aging (HT) and ultraviolet aging (UV) conditions was investigated. Results showed that more cracks appeared on the surface of aged PLA, and the inhibition effect on microalgae was greater than that of aged PE. Moreover, the inhibition rate of microplastics on microalgae after UV aging (PLA: 39.64%, PE: 32.66%) was higher than that of HT aging (PLA: 30.95%, PE: 26.36%). In addition, the reactive oxygen species (ROS) levels in the treatment groups subjected to UV aging (PLA: 7-45%, PE: 3-28%) increased more than those subjected to HT aging (PLA: 6-31%, PE: 2-20%). This study revealed the toxicity difference between PLA and PE on Microcystis aeruginosa under different aging conditions, which provided a theoretical basis for studying the effects of aging biodegradable plastics on freshwater microalgae.

This study assesses the histological abnormalities induced by graphene nanosheets in Cirrhinus mrigala fish (Mrigal) treated orally with plant extracts of Tamarix aphylla and Albizia lebbeck. In 1st phase of experiment LC₅₀ of graphene nanosheets was determined as 81.22 mg/kg over 96 h. In 2nd phase of experiment fish were exposed to 15th, 10th, and 5th fraction of the LC50 for 28 days exhibited liver and intestinal abnormalities, including vacuolation, necrosis, villous atrophy, and crypt hyperplasia. In 3rd phase of experiment co-treatment with Tamarix aphylla and Albizia lebbeck (5, 10, and 15 mg/kg) for 56 days reversed these changes. Graphene nanosheets increased oxidative stress parameters (glutathione, malondialdehyde, catalase, and lipid peroxidase), but the effect is considerably reversed by treatment with plant extracts. Raman and TEM analyses confirmed graphene nanosheet characterization, while GCMS and HPLC analysis of plant extracts revealed antioxidant properties. The study concludes that graphene nanosheets induce oxidative stress and histological damage in Cirrhinus mrigala (Mrigal), mitigated effectively by Tamarix aphylla and Albizia lebbeck extracts.

This study assessed the herbicides atrazine (ATZ) and glyphosate (GLP) concentration in water and sediment of Argentine Pampas shallow lakes with agriculture activity (AA) mainly transgenic crops of soybeans and corn on the coast near the water (Cochicó and Guaminí), and in a lake with extensive cattle activity (CA) close to their coasts (La Salada de Monasterio). Also, the concentration of ATZ in the muscle and the frequency of testicular histopathological lesions (THL) of pejerrey fish (Odontesthes bonariensis) were studied. In the water, maximum concentrations of ATZ (0.279 µg l^- 1) and GLP (0.015 µg l^- 1 were found in Guaminí and Cochicó shallow lakes. For sediments, the maximum concentrations were 32.6, 45.2, and 14.9 µg kg^- 1 for ATZ, GLP, and its metabolite aminomethylphosphonic acid (AMPA), respectively in the same shallow lakes. The results showed that 30.6% of the pejerrey sampled had THL being fish from Guaminí (60%) the most affected. Of the pejerrey analyzed for ATZ, 80.82% of them had this herbicide in the muscle. The highest percentage of THL was found again in pejerrey from Guaminí (68.75). with sterility as dominant (59.38%). These findings suggest a possible adverse effect on the gonads related to the herbicides identified in the water, sediments and in muscle which is an alarm signal in using agrochemicals and protecting the fish biota.

Microplastics, which decompose from large pieces of plastic and cause water pollution, are becoming an increasing environmental problem due to their stable structure, high mobility, and ease of interaction with organic compounds in the environment. Large amounts of microplastics enter surface waters through wastewater and stormwater. Therefore, it is necessary to develop simple and accessible methodologies as a foundation for establishing reliable and effective strategies for microplastic removal from aquatic environmental samples. In this study, the removal of microplastics (< 1 mm) at laboratory scale using synthetic microplastics is investigated by three methods: filtration, centrifugation and flocculation. For this purpose, polypropylene-based microplastic particles are prepared and turbidity is used to measure removal. In this study, all three methods are investigated to determine a more effective method for the removal of microplastic particles. Among the three methods studied, the centrifuge method showed higher removal efficiency than the filtration and flocculation methods for the removal of microplastic particles from aqueous solution. The removal efficiency of microplastic particles by the centrifugation method reached 95.6% and was 90.6% by the filtration method. The flocculation method has a lower removal efficiency of microplastic particles than the centrifugation and filtration methods, ranging from 75.6 to 81.8%. In general, the results show that centrifugation is the more suitable and efficient method to remove microplastic particles from aqueous solution.

In aquatic arthropods, molting is essential for normal development. An earlier study showed that 3-phosphoglycerate (3PG) and phosphoenolpyruvate (PEP), which are present in the exoskeleton, play important roles in its calcification. Under normal culture conditions, we found higher levels of 3PG and PEP at the pre-molt stage than that at the post-molt stage in the carapace of kuruma prawn juveniles (Penaeus japonicus). In subsequent experiments, exposure of environmentally relevant concentrations of fipronil (0.1, 0.05, and 0.025 µg L^-1) for 24-96 h resulted in significant decreases in 3PG and PEP in the exposure group. Furthermore, we found higher internal insecticide concentrations in molted prawns than those in unmolted prawns. Given that molting requires a higher amount of energy, these changes are indicative of the allocation of more and less energy for detoxification and molting, respectively, which may contribute to the mitigation of fipronil bioconcentration.