Bulletin of Environmental Contamination and Toxicology最新文献

Landfill mining (LFM) is increasingly adopted in India as a strategy to reclaim land and recover materials from legacy municipal solid waste (MSW) dumpsites. The study evaluates the contamination levels of soil-like material (SLM: < 4.75 mm fine fraction) recovered from the Anantapur dump yard in South India, with the aim of evaluating its potential for reuse potential and environmental risks. Samples were analysed for organic content, total soluble solids, leachate characteristics, and heavy metal concentrations, using pollution indices such as the contamination Factor (C_f), geo-accumulation index (I_geo), and enrichment factor (EF) were applied to determine contamination severity. The organic content in SLM ranged from 14-17%, significantly exceeding typical thresholds for engineering reuse. Total soluble solids (800-1000 mg/L) and leachate sulphate and chloride concentrations, surpassed national water quality standards. Heavy metals such as lead and copper exhibited extreme contamination, while zinc and manganese show moderate to high contamination. The findings highlight that while landfill mining aids in waste reduction and land reclamation, the high contamination levels in SLM necessitate proper remediation before reuse. The findings contribute to growing knowledge on LFM and provide site-specific data critical for sustainable landfill reclamation in semi-arid regions.

Lower-tier toxicity assessments of chemicals, such as metals and pesticides, are typically focused on a few standard test species representing different taxonomic levels. Invertebrate taxa most frequently used are the crustacean and insect larvae. In recent years, some species of Oligochaeta have received increasing attention as test organisms, although the number of taxa evaluated so far is still limited. In previous studies, we successfully used the indigenous tropical oligochaete Allonais inaequalis to assess the acute toxicity of metals (cadmium, copper, mercury, and manganese) and pesticides (diuron and carbofuran). The aim of the present study was therefore to assess the sensitivity of this species to chronic (12d) exposure to these compounds. The order of chronic toxicity was the same as that denoted in the acute tests: copper (mortality 12d-EC10 2.22 µg Cu²⁺/L) > mercury (22.29 µg Hg²⁺/L) > cadmium (138.59 µg Cd²⁺/L) > manganese (5650 µg Mn²⁺/L) and carbofuran (46.32 µg/L) > diuron (6751.42 µg/L). Chronic toxicity did not increase significantly compared to the acute toxicity tests. Growth, measured as body length, was hindered after exposure to the metal and pesticides due to an energy reallocation needed to cope with the chemical stress.

Information about perfluoroalkyl substances (PFASs) like perfluoroalkyl carboxylic acids (PFCAs) and sulfonates (PFSs) in settled dust from emerging and developing countries is still limited, partly due to the lack of efficient analytical methods. In this study, a reliable, simple, and cost-effective analytical procedure was developed and validated to determine 12 PFCAs and 4 PFSs in dust samples. The samples were ultrasonicated with methanol, followed by a dispersive sorbent clean-up step with graphitized carbon and quantification by liquid chromatography with tandem mass spectrometry (LC-MS/MS) method. The analytical method exhibited adequate recovery (80-120% for native standards and 50-130% for labeled standards), precision (relative standard deviations < 25%), and detection limits (0.010-0.10 ng/g). The validated method was applied to analyze PFAS concentrations in settled dusts collected from Hanoi, Vietnam. PFASs were frequently detected in the Vietnamese dust samples at relatively low concentrations (median 4.15, max 27.4 ng/g).

Weeds growing in crops contribute to the maintenance of soil biodiversity; for example, they are a source of organic matter and nutrients for soil invertebrates. However, little is known about the impact of glyphosate-contaminated weeds on the behavior and survival of earthworms. The objective of this study was to evaluate the behavior and survival of the earthworm Eisenia andrei upon exposure to glyphosate-contaminated weed compost. The study employed standardized avoidance and acute tests to assess the repellency and mortality of E. andrei earthworms at four doses of the commercial herbicide (Faena Fuerte® 360): 0, 259, 398 and 437 mg/kg/ha. The avoidance essay results indicated that earthworms with similar biomass did not avoid glyphosate-contaminated weed composts, with avoidance rates < 80%. Furthermore, the acute test showed that commercial dose of glyphosate was not associated with growth and mortality. Consequently, it was concluded that weed composts with glyphosate not exert a sublethal and lethal toxic effect on E. andrei. It is recommended that future studies focus on the microbiota associated with native endogenous earthworms in the decomposition of the weed and the degradation of the herbicide.

Cadmium (Cd) is a heavy metal, and chlorpyrifos (CPF) is a widely used organophosphorus insecticide, which are widespread environmental pollutants. These two chemicals can induce the production of reactive oxygen species (ROS) in mammals and cause oxidative damage. However, the mechanism of their combined toxicity in invertebrates and especially insects has not been well documented. In this study, we investigated the combined toxicity of Cd and CPF by using Drosophila S2 cell as a test model. We found that cell viability and antioxidant enzyme activities were reduced and the lipids and proteins peroxidation as well as ROS were induced after the treatment. Cd and CPF displayed an antagonistic interaction in the induction of oxidative damage and the reduction of cell viability. The results indicated that Cd and CPF interfere with the toxicity of each other in the cells, which implies that Cd could influence the effect of CPF used for pest insects control.

Hexavalent chromium (Cr⁶⁺) is a known carcinogen that has been listed as a priority pollutant by the Environmental Protection Agency (EPA). The toxic effects of Cr⁶⁺ in some organisms, especially aquatic animals have received considerable attention over the years but not much is known about the adverse effects of Cr⁶⁺ in terrestrial insects despite their potential exposure to Cr⁶⁺ through ingestion of contaminated food and water. Therefore, this study aimed at investigating the effects of Cr⁶⁺ on the survival, growth and development of the blowfly, Chrysomya chloropyga. The eggs of C. chloropyga that were collected from laboratory stock were exposed to dietary Cr⁶⁺ at different concentrations; 0, 4, 8, 12, 16, and 20 mg/mL and the eggs were monitored throughout the developmental stages till adult emergence, during which growth (length, width, and weight at larval and pupal stages) and developmental parameters (duration of development at different stages, egg hatchability, pupation, and adult emergence) were measured. Exposure to Cr⁶⁺ prolonged the developmental period in the blowflies with total developmental period reaching 231.00 ± 1.45 h in the insects that were treated with 20 mg/mL Cr⁶⁺ compared with 217.91 ± 1.16 h in the control. The percentage hatchability, pupation rate and number of emerged adults reduced significantly in groups exposed to Cr⁶⁺ (especially at 20 mg/mL) compared to the control. The mean length, width and weight decreased significantly in insects exposed to dietary Cr⁶⁺ at all the immature stages. The results of this study showed that dietary Cr⁶⁺ exposure have adverse effects on the growth and development of C. chloropyga.

Biochar is extensively used in environmental remediation, but the effects of aging on the immobilization of cadmium (Cd) in contaminated soils treated with biochars containing various endogenous Cd is unclear. This study investigated the effects of simulated acid rain (SAR) aging on the bioavailability of Cd in soil amended with two rice straw biochars (RSBs, marked as RS1 and RS2) and two sludge biochars (SSBs, marked as SS1 and SS2) under flooding condition. Results showed that SSBs had higher specific surface area, ash, silicate contents, and more functional groups than those of RSBs. The total Cd in the biochars followed the order of RS1 > RS2 > SS1 > SS2. SSBs applications significantly decreased soil CaCl₂-extractable and acid-soluble Cd by 51.3%-78.6% and 4.51%-5.44% after a 30-day incubation with 70% water holding capacity than the control. SAR aging significantly decreased the soluble, CaCl₂-extractable, and acid-soluble Cd in all treatments compared with those before aging. This may be due to the decreased effects from the formation of insoluble Cd sulfide and the adsorption of Cd by Fe-Mn (oxidro)oxides under continuous flooding condition was outweighed the increase in soluble Cd caused by SAR accumulation. Moreover, the soluble, CaCl₂-extractable, and acid-soluble Cd in RSBs treated soils were significantly higher than those of SSBs after SAR aging. The study indicated that the RSBs with high endogenous Cd posed greater environmental risks, thus the long-term effects of biochar application in soil need further study.

The heavy metal contamination of Bohai Sea, the largest inland sea and a major fishing ground in China, has raised wide public concern in recent years and may pose serious threats to human health and ecological system. However, the sedimentary records of heavy metals in Bohai Sea were still relatively rare. In this study, we sampled a sediment core B13 in the central Bohai Sea, investigated the levels and vertical distributions of heavy metals, assessed the pollution history and ecological risks. Our results indicated that the vertical distributions of heavy metals showed a steady increasing trend towards the surface and the sediment profile B13 showed slight pollution with As, Sb and Pb. Moreover, the As, Sb and Ni may also have non-negligible ecological risks. Based on comprehensive analysis of the above results, the vertical distributions of these proxies may reflect the potential fingerprints of anthropogenic impact intensities over the past few decades. Our results provide valuable information for understanding the heavy metal pollution records and its potential influence of human activities in Bohai Sea.

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.