Over the last two decades, nonylphenols (NPs) have become to be known as a priority hazardous substance due primarily to its estrogenicity and ubiquitous occurrence in the environment. Nonylphenols ...are commonly treated as a single compound in the evaluation of their environmental occurrence, fate and transport, treatment or toxicity. However, technical nonylphenols (tNPs) are in fact a mixture of more than 100 isomers and congeners. Recent studies showed that some of these isomers behaved significantly differently in occurrence, estrogenicity and biodegradability. The most estrogenic isomer was about 2 to 4 times more active than tNP. Moreover, the half lives of the most recalcitrant isomers were about 3 to 4 times as long as those of readily-biodegradable isomers. Negligence of NP's isomer specificity may result in inaccurate assessment of its ecological and health effects. In this review, we summarized the recent publications on the analysis, occurrence, toxicity and biodegradation of NP at the isomer level and highlighted future research needs to improve our understanding of isomer-specificity of NP.
•Isomer selectivity exists in occurrence, toxicity and biodegradation of nonylphenol.•Isomers with bulky α-substituents are recalcitrant to biodegradation.•Bulkiness at β and γ carbons increases the estrogenicity of nonylphenol isomers.•Two dimensional GC methods may substantially increase nonylphenol isomer separation.
•The image subtraction method was used to process the IRR image on the rock surface.•The evolution characters of IRR was used to analyse the precursor of rock failure.•The temperature variations were ...evaluated in different regions of rock surface.•The temperature variations were regarded to cause by the rock stress concentration.•The proposed stress-strength ratio of predicting points were 85.2% and 89.5%.
Nonylphenol (NP), a well-known environmental estrogen with numerous isomers, is frequently found in surface water and sediments. Recent studies showed that NP isomers exhibited different ...estrogenicity. However, at present little information is available on its isomer-specific degradation in the bed sediment, which is the primary sink of NP in surface aquatic systems. In this study, we investigated the biodegradability of 19 NP isomers in two river sediments under oxic and anoxic conditions. Under oxic conditions, the half-lives of NP isomers in an upper river sediment ranged from 0.9 to 13.2 d. Under reduced conditions, the persistence of NP isomers generally increased, with negligible dissipation under strongly reduced conditions. In the well-aerated sediment, NP isomers with short side chain and/or bulky α-substituents were found to be more recalcitrant to degradation. Moreover, when a total of 57 molecular descriptors were examined, the degree of branching as quantified by I DWbar was found to result in the best linear correlation with half-lives of NP isomers (R 2 = 0.88). These results indicated that the isomer-specificity of NP in environmental processes should be considered, and that simple molecular descriptors may be used to identify the more recalcitrant isomers, thus allowing prioritization in the evaluation of environmental fate and risks of NP isomers.
Pyrethroids are a class of commonly used insecticides and are ubiquitous in the aquatic environment in various regions. Aquatic toxicity of pyrethroids was often overestimated when using conventional ...bulk chemical concentrations because of their strong hydrophobicity. Over the last two decades, bioavailability has been recognized and applied to refine the assessment of ecotoxicological effects of pyrethroids. This review focuses on recent advances in the bioavailability of pyrethroids, specifically in the aquatic environment. We summarize the development of passive sampling and Tenax extraction methods for assessing the bioavailability of pyrethroids. Factors affecting the bioavailability of pyrethroids, including physicochemical properties of pyrethroids, and quality and quantity of organic matter, were overviewed. Various applications of bioavailability on the assessment of bioaccumulation and acute toxicity of pyrethroids were also discussed. The final section of this review highlights future directions of research, including development of standardized protocols for measurement of bioavailability, establishment of bioavailability-based toxicity benchmarks and water/sediment quality criteria, and incorporation of bioavailability into future risk assessment and management actions.
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•Tenax extraction and SPME were most used to assess pyrethroid bioavailability.•It can be used to better estimate the exposure and toxicity of pyrethroids in benthic invertebrates.•It should be incorporated into pyrethroid risk assessment and management actions.
Employing the "Green Credit Guidelines" implemented in 2012 as the basis for a quasi-natural experiment, this study applies the method of Difference-in-Differences(DID) to investigate the influence ...of the Green Credit Policy on both the quantity and quality of enterprise innovation. The outcomes of our analysis reveal that the policy has significantly boosted both the quantity and quality of innovation among enterprises identified as heavy polluters. It is noteworthy that the policy's positive impact on innovation quantity surpasses its positive effect on innovation quality. This substantiates that the Green Credit Policy effectively generates incentivizing outcomes for innovation among the heavy polluters, thereby verifying Porter's hypothesis within the domain of green credit in China. Furthermore, we find that the positive impact is more significant for enterprises with lower innovation capabilities, large-scale enterprises, state-owned enterprises, and those situated in both the Eastern and Western regions. Through these findings, this study illuminates a novel perspective on the interplay between the Green Credit Policy and enterprise innovation dynamics in China.
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The study of pesticide metabolism in crops is critical for assessing the mode of action and environmental risks of pesticides. However, the study of pesticide metabolism in crops is ...usually complicated and it is often a daunting challenge to accurately screen the metabolites of novel pesticides in complex matrices. This study demonstrated a combined use of high-specific activity carbon-14 labeling and high-resolution mass spectrometry (HSA-14C-HRMS) for metabolism profiling of a novel neonicotinoid cycloxaprid in rice. By generating the characteristic radioactive peaks on the liquid chromatogram, the use of 14C can eliminate the severe interference of complex matrices and quickly probe target compounds; by producing ion pairs with unique abundance ratios on HRMS, high-specific activity labeling can effectively exclude false matrix positives and promote the elucidation of metabolite structure. The structures of 15 metabolites were identified, three of which were further confirmed by authentic standards. Based on these metabolites, a metabolic profile of cycloxaprid was established, which includes denitrification, demethylation, imidazolidine hydroxylation and ring cleavage olefin formation, oxidation and carboxylation reactions. The strategy of combining high-specific activity 14C labeling and HRMS offers unique advantages and provides a powerful solution for profiling unknown metabolites of novel pesticides in complex matrices, especially when traditional non-labeling methods are not feasible.
Veterinary antibiotics in agricultural soil are a growing concern, as they pose risks to soil quality and food safety. An analysis approach that covers a broad spectrum of target substances and has ...low detection limits is required for a comprehensive risk assessment. In this study, we developed a method for simultaneously analyzing 34 antibiotics (tetracyclines, sulfonamides, macrolides, and quinolones) in agricultural soil. The soil was extracted using an organic solution of acetonitrile and methanol (v:v, 1:1) with 0.2% formic acid followed by the addition of Na
2
EDTA-McIlvaine buffer. Dispersive and solid-phase extractions (SPE) were compared for cleanup. Ultra-performance liquid chromatography-tandem mass spectrometry with matrix-matched calibration was used for quantification. The results of this study showed that SPE was more appropriate for determining multi-class antibiotics. The SPE approach proved better recoveries (56–98%) than dispersive SPE (d-SPE) (28–121%). The matrix effects obtained by SPE (46–299%) were more reasonable than that by d-SPE (3–4036%). The method detection limits by SPE were in the range of 0.007–1.400 μg/kg with relative standard deviations < 18%. This optimized method was then applied to 55 agricultural soil samples. The total concentrations of veterinary antibiotics ranged from blow method detection limits to 1448 μg/kg. Tetracyclines were the dominant antibiotics, particularly in soil applied with swine manure. This method can be used to screen for and accurately determine the presence of veterinary antibiotics in soil, which will aid their risk assessment and regulation of these antibiotics in the agroecosystem.
Due to their potent estrogenicity and ubiquitous occurrence, non-ionic surfactant metabolites nonylphenol (NP) and octylphenol (OP) are of significant concern. Abiotic chemical oxidation by naturally ...abundant metal oxides may be an important route of their environmental attenuation, but is poorly understood. We investigated the reaction kinetics and pathways of NP and OP with MnO2. At pH 5.5 and 100 mg/L δ-MnO2, 92, 84 and 76% of 4-n-NP, 4-tert-OP and technical nonylphenol (tNP) was transformed in 90 min, respectively. A further experiment using a Mn-containing soil and Mn-removed soil confirmed that soil MnO2 caused NP removal. Multiple reaction products, including hydroquinone, hydroxylated products, dimers and trimers were identified through fragmentation analysis by GC–MS/MS and UPLC–MS/MS, allowing the construction of tentative pathways. This study suggested that abiotic oxidation by MnO2 may contribute to the dissipation of tNP, 4-n-NP, 4-tert-OP and their analogues in the natural environment.
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•The oxidation of nonylphenol and octylphenol by manganese dioxide was efficient and pH dependent.•The importance of soil MnO2 was further confirmed by experiment using Mn-containing soil.•The reaction in environment is substantially slower than with synthetic MnO2.•The oxidation was inhibited by metal ions and enhanced by humic acids.•Reaction pathway is proposed based on reaction intermediates identified.
Naturally occurring MnO2 may contribute significantly to the attenuation of nonylphenol and octylphenol in soil, water and sediment.
Coal burst is a dynamic failure phenomenon that is caused by a sudden release of strain energy during mining. It is extremely difficult to predict coal burst accurately. In this study, experimental ...tests were performed under uniaxial cyclic load-unload conditions using a microcomputer-controlled electrohydraulic servo stiffness compressor with acoustic emission (AE) monitoring. The experiments data, such as the AE energy, AE energy ratio and load-unload energy response ratio, were obtained. The Y value of the load-unload response ratio (LURR) was calculated based on these data. The results show that variation characteristics of the AE energy release can be related to the failure of coal specimens. The concentrated release of AE energy occurs at the beginning of the plastic deformation stage. Then, AE energy was accumulated before coal specimens' failure. The variation characteristics of the LURR (Y1) and Benioff strain (Y2) were obtained. The fluctuation of Y1 and Y2 values was exhibited to coincide with the AE energy accumulation, which allowed predicting coal failures. The predicting time point where the Y1 and Y2 values were both close to 1 could be defined as the predicting key point of coal specimens' failure. These results of experimental investigation show a meaningful attempt for predicting coal failure.
•Y value of the load-unload response ratio (LURR) was calculated for rock bursts prediction.•Variation characteristics of AE energy release and Y value can be related to coal specimens failure.•Y1 and Y2 values were close to 1 could be defined as the predicting key point of coal failure.
Bisphenol F (BPF), an environmental estrogen, is used as a monomer in plastic industry and its environmental fate and decontamination are emerging concern. This study focused on the kinetics, ...influencing factors and pathways of its oxidation by MnO2. At pH 5.5, about 90% of BPF was oxidized in 20min in a solution containing 100μM MnO2 and 4.4μM BPF. The reaction was pH-dependent, following an order of pH 4.5>pH 5.5>pH 8.6>pH 7.5>pH 6.5>pH 9.6. Humic acids inhibited the reaction at low (≤pH 5.5) and high pH (≥pH 8.6) at high concentrations. In addition, metal ions and anions also suppressed the reaction, following the order Mn2+>Ca2+>Mg2+>Na+ and HPO42−>Cl−>NO3−≈SO42−, respectively. A total of 5 products were identified, from which a tentative pathway was proposed.
► Manganese dioxide oxidizes bisphenol F rapidly at ambient temperature. ► pH and co-solutes such as humic acids, metal ions and anions affect the reaction. ► Identification of 5 reaction intermediates points to a tentative pathway involving free radicals. ► The commonly occurring MnO2 may be important in the natural attenuation of bisphenol F or used for its decontamination.
The commonly occurring MnO2 shows a high reactivity toward bisphenol F, which may account for its natural attenuation and suggest a beneficial use of MnO2 for managed removal of bisphenol F.
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