Chemosphere最新文献

Pine needle, pine bark, and soil samples were collected from various regions in South Korea, considering the suitability of vegetation samples as passive samplers. A total of 27 organochlorine pesticides (OCPs) were analyzed using a gas chromatograph/high-resolution mass spectrometer (GC/HRMS). The total concentrations of OCPs ranged between 650 and 3652 pg/g dw in soil, 215 and 1384 pg/g ww in pine needles, and 456 and 1723 pg/g ww in pine bark. Metabolites such as endosulfan sulfate, p,p'-DDE, and p,p'-DDD were dominant in the soil samples, whereas parent compounds were more prevalent in the pine needles. Diagnostic ratios and compositional profiles suggested that potential OCP sources were primarily related to historical use, atmospheric transport, and unintentional byproducts. OCPs that were never used or registered in South Korea were also detected in all sample types, indicating atmospheric transport from source regions. Sites closer to North Korea and China showed higher concentrations of OCPs, with levels gradually decreasing from west to east in the soil, suggesting long-range atmospheric transport from the source regions. Fugacity fractions indicated net volatilization for most compounds, while net deposition was observed for others, suggesting a dynamic equilibrium. This study concludes that atmospheric transport plays a predominant role in the distribution and fate of OCPs in the environment, with no evidence of current local sources.

Activated carbon adsorption is a widely used technology for the removal of per- and polyfluoroalkyl substances (PFAS). However, the rapid breakthrough of PFAS in activated carbon filters poses a challenge to meet the very low allowable PFAS concentrations in drinking water, leading to high operational costs. In this study, we conducted batch isotherm and kinetic adsorption experiments using nine different types of PFAS molecules at concentrations typically found in water sources used for drinking water production (0.1-100 ng/L). The isotherm experiments at these low concentrations reveal that the maximum adsorption capacity of several PFAS is much lower than reported in literature. The estimated isotherms were included in a dynamic model that includes mass transport based on surface diffusion. This model effectively describes the experimental kinetic data, and the obtained surface diffusion coefficients indicate a very slow PFAS surface mobility. Additionally, our findings indicate that PFAS surface mobility decreases in scenarios with more available adsorption sites. Notably, mesoporous activated carbon, with its higher adsorption capacity, exhibits lower PFAS surface mobility than microporous carbon with lower PFAS adsorption capacity. Moreover, for both carbons, we observed a decrease in PFAS surface mobility at higher carbon loadings when the surface is less saturated with PFAS. Our findings suggest potential inherent limitations in activated carbon technology for PFAS removal under environmentally relevant conditions, as we observed lower adsorption capacities than previously reported at higher concentrations, and a decrease in PFAS surface mobility with more available adsorption sites.

Cyanobacterial blooms are prevalent globally and present a significant threat to water security. Titanium salt coagulants have garnered considerable attention due to their superior coagulation properties and the absence of metal residue risks. This paper explored the influencing factors in the coagulation process of titanium xerogel coagulant (TXC), the alterations in cell activity during floc storage, and the release of cyanobacterial organic matters, thereby determining the application scope of TXC for cyanobacterial water treatment. The findings indicated that at a TXC dosage of 8 mg Ti/L, the removal rate of Microcystis aeruginosa (M. aeruginosa) exceeded 86% across a pH range of 5-9. The coagulation performance with anions HCO₃^-, CO₃^2- and H₂PO₄^-/HPO₄^2- was unsatisfactory at concentrations of 10, 20, and 50 mg/L, with corresponding chlorophyll a (Chl-a) levels of 168, 129, and 196 μg/L, respectively. While the presence of Cl^-, NO₃^-, SO₄^2-, K⁺, NH₄⁺, Ca²⁺ and Mg²⁺ had little influence on the removal efficiency. At sodium alginate (SA) concentration of 6 mg/L, the Chl-a content was 116 μg/L, with humic acid (HA) not affecting M. aeruginosa removal but hindering turbidity reduction, leaving a residual turbidity of 11 NTU. Following TXC treatment, a floc storage study with cyanobacteria-laden surface water showed a decrease in microcystins (MCs) content. The low residual titanium concentration post-TXC coagulation (<0.06 mg/L) and MCs reduction contributed to reduced effluent toxicity, indicating TXC's versatile applicability for treating cyanobacterial-contaminated waters.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies/article-withdrawal). .

Following a decline in the production and use of polychlorinated naphthalenes (PCNs) and the restrictions introduced by the Stockholm Convention, dietary intake represents the most significant pathway of human exposure to these dioxin-like contaminants. PCNs occur ubiquitously in foods, originating from the legacy of historical production that is now globally redistributed, as well as from ongoing industrial and domestic combustion sources which have a stronger influence on occurrence patterns in countries where they were not produced. Recent studies have benefited from a wider set of available PCN reference standards, enabling more accurate reporting of a diverse range of congeners. Combining the available information on food occurrence with relative potency (REP) data, an initial selection of twenty PCN congeners are presented here for monitoring of foodstuffs. The selection is expected to provide a good indication of the overall dioxin-like toxic equivalence (TEQ) associated with food occurrence, particularly in industrialised countries and regions where both, historical production and current combustion processes are significant sources. The selection also appears to be representative of the vast majority of PCN TEQ reported in human tissues despite the limited amount of reliable data. Future studies will benefit from the increasing availability of new PCN standards and provide a broader spectrum of occurrence data in foods and human tissues. They will also support toxicological studies on a wider range of congeners and biological effects, enhancing our understanding of PCN-mediated toxicity. Both these information strands will allow refinement and expansion of the proposed selection of congeners, if required.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies/article-withdrawal). .

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies/article-withdrawal). .

Ciguatera poisoning (CP) is one of the most prevalent non-bacterial seafood-borne illnesses worldwide, caused by the consumption of fish contaminated with ciguatoxins (CTXs). Even though its prevention largely relies on avoidance of certain fishes and geographic regions, the development of rapid and user-friendly bioanalytical methods for effective CP management and surveillance is still necessary. In this work, four simplified strategies of a magnetic bead (MB)-based sandwich immunoassay were proposed for the rapid and highly sensitive detection of CTXs in fish. The one consisting of a single step was selected, which allowed the detection of CTXs in a fish extract in only 40 min at levels as low as 0.01 μg CTX1B equivalents/kg of fish, which is the safety guidance level proposed by the United States Food and Drug Administration (FDA). In this strategy, all components were incubated simultaneously with the sample, only requiring a subsequent washing and substrate incubation step before signal measurement, reducing the complexity and the time required for analysis in contrast with the classical sequential sandwich immunoassays. The ease of experimental handling, added to the short analysis time and appropriate sensitivity make this single-step immunoassay a promising tool for CP risk assessment and management.

The uneven distribution of lead (Pb) in rice and soil across the primary rice-growing regions of southern China has led to challenges in assessing rice quality and associated health risks. Therefore, it is crucial to develop a fast and precise method for forecasting the accumulation of Pb in soils and rice to evaluate the environmental risks of heavy metals. We utilized eight machine learning models to fit the training data and find the optimal model based on 1,396 pairs of soil-rice samples collected during field surveys in Guizhou Province. Among them, the random forest model achieved higher prediction accuracy (rice: R² = 0.486; soil: R² = 0.518) and was further optimized using a Bayesian optimizer to enhance its performance (rice: R² = 0.662; soil: R² = 0.718). The importance of characteristics showed that annual precipitation and soil effective state were the main factors affecting rice Pb accumulation; distance to the nearest mine and annual rainfall were the main factors affecting total soil Pb. The area with higher risk of Pb accumulation in soil was located in the western part of Bijie, while the area with higher risk of Pb accumulation in rice was located in the southern part of Tongren. There were some differences between the two. About 88% of the areas in Guizhou Province are classified as priority protected areas regarding safe planting zoning, with safe utilization areas accounting for about 10%. However, areas in the eastern part of Qiandongnan, the southeastern part of Tongren, and the western part of Bijie require strict control. Our study attach great importance to the prevention of high Pb accumulation in rice as well as in soils in major rice growing areas.

Methyl 2-{[1-(5-fluoropentyl)-1H-indazole-3-carbonyl]amino}-3,3-dimethylbutanoate (5F-ADB), which is classified as an illicit drug in China and most European countries, is susceptible to abuse. The abuse of 5F-ADB must avoid entering the water environment. However, the aquatic toxic effects of 5F-ADB remain unclear. In this study, Daphnia magna (D. magna) was used to investigate the potential toxicity of 5F-ADB at concentrations of 0, 0.01, 1, and 100 μg/L. The results showed that 5F-ADB caused significant developmental, reproductive, and neurodevelopmental toxicity in D. magna. Compared with the control group, exposure to 5F-ADB significantly reduced daphnia body length, weight, heartbeat, total number of offspring, while increased daphnia respiratory rate, and swimming behavior. Superoxide dismutase (SOD) activity increased significantly, while catalase (CAT) activity decreased, indicating that the exposed daphnia suffered obvious oxidative damage. 5F-ADB also triggered the inhibition of the serotonergic and noradrenergic systems, which ultimately stimulated the swimming behavior of D. magna. This study demonstrates that 5F-ADB has a significant toxic effect on the vital activity of D. magna upon entering aquatic environments, and that synthetic cannabinoid analogs such as 5F-ADB may pose potential ecological risks to organisms in aquatic ecosystems.