Hauserreed7713

Surfactant-enhanced remediation (SER) has been widely applied in decontaminating PAH-polluted soil. Most researches focus on evaluating washing efficiency without considering pollutants' mutual interaction. This study aims to investigate cosolubilization effect between phenanthrene (Phe) and pyrene (Pyr) in nonionic surfactant Triton X-100 (TX100) solution on their codesorption performance from soil. Cosolubilization experiment showed that, when cosolubilized, solubility of Phe and Pyr in TX100 increased by 15.38% and 18.19%, respectively, as quantified by the deviation ratio of molar solubilization ratio in single and binary solute solubilization systems. The synergism may be due to the enlarged micelle volume caused by PAHs solubilized in the shell region of the micelle. The cosolubilization effect was further observed in the soil washing process. The strengthened TX100 solubilization capacity towards Phe and Pyr could increase the two PAHs' codesorption efficiency from soil, accompanied by synergistic extent of 6-15%. However, synergism in codesorption was weaker than that observed in the cosolubilization system, which may be related to surfactant loss to soil and PAH partition into soil organic matter and the sorbed surfactants. The improved remediation performance during codesorption of mixed PAHs implies the significance of combining PAHs' mutual interaction into evaluating SER, which may reduce the surfactant washing concentration and save remediation cost.This study investigated sorption and desorption behaviors of airborne volatile methylsiloxanes (VMS) such as octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) on nine major primary and secondary atmospheric aerosols at a relative humidity (RH) of 30%. It was found that sorption and desorption of VMS took place via a two-phase process, which included an initial rapid step, followed by slower subsequent step. The initial rapid step was favored especially at low concentrations. Equilibrium sorption isotherms were slightly better fitted to Polanyi-Manes sorption model than Langmuir model except D4 on black carbon and D5 on sea salt. Values of apparent aerosol-air partition coefficients ranged 0.09-50.4 L/m(2) for D4 and 2.1-284 L/m(2) for D5 with carbon black having the largest values. Some of aerosols such as carbon black and sea salts reversibly interacted with D4 and D5 whereas other aerosols such as kaolinite and sulfates showed highly irreversible sorption for the VMS, especially at low concentrations. As sorption density of D4 and D5 on kaolinite was decreased from 1100 to 250 µg/m(2), the irreversible fraction was increased from 27% to 80%.The mechanism responsible for these differences is essential for a better understanding and prediction of atmospheric chemistry of VMS as affected by the presence of atmospheric aerosols.Sanitation is of crucial importance for the microbiological safety of drinking water. However, chlorination of water rich in organic material produces disinfection by-products (DBPs), many of which have been reported to be mutagenic and/or carcinogenic compounds such as haloacetic acids and trihalomethanes. Epidemiological studies have suggested a link between drinking water consumption and cancer. We previously observed that Cyprinus carpio fish exposed to DBPs, may be subject to epigenetic effects such as those referable to the up-regulation of cytochrome P450 (CYP) superfamily (ex. co-mutagenesis/co-carcinogenesis and oxidative stress) that has been associated to non-genotoxic carcinogenesis. Our goal was to study the xenobiotic metabolism in mollusks exposed in situ to surface water of Lake Trasimene (Central Italy) treated with several disinfectants such as the traditional chlorine dioxide (ClO2), sodium hypochlorite (NaClO) or the relatively new one peracetic acid (PAA). The freshwater bivalves (Dreissena polymorpha) being selected as biomarker, have the unique ability to accumulate pollutants. Freshwater bivalves were maintained in surface water containing each disinfectant individually (1-2 mg/L). Following an exposure period up to 20 days during the fall period, microsomes were collected from the mussels, then tested for various monooxygenases. Strong CYP inductions were observed. These data indicate that drinking water disinfection generates harmful DBP mixtures capable of determining a marked perturbation of CYP-supported reactions. This phenomenon, being associated to an increased pro-carcinogen bioactivation and persistent oxidative stress, could provide an explanation for the observational studies connecting the regular consumption of drinking water to increased risk of various cancers in humans.The effects of halogen-light-irradiated and non-irradiated PAHs on the grouper Epinephelus marginatus were assessed through biomarkers including morphometric parameters, liver histopathology, biliary PAH concentration, genetic alterations, and enzyme activity modulation. E. marginatus juveniles were divided into three groups control (C), non-irradiated PAHs (PAHs1), and irradiated PAHs (PAHs2). Test groups were exposed for 14 days to a 0.5 ppm PAH solution in the semi-static system. After this period, fish were anesthetized with benzocaine (2%) and peripheric blood was collected by caudal puncture. Blood smears were prepared and stained with propidium iodide. Fish livers were collected, fixed in McDowell's solution, embedded in paraplast, thin-sectioned, and stained with hematoxylin-eosin (H&E). For biochemical analyses including superoxide dismutase, catalase, and glutathione S-transferase activities, fish livers were collected and preserved in liquid nitrogen. Water samples were analyzed using gas chromatography-mass spectrometry (GC-MS) and bile synchronous fluorescence spectroscopy. Fish in the PAHs2 group had micronuclei (MN) in blood cells, as well as significant differences in nuclear morphology (NMA). Significant morphological alterations were observed in the livers from fish exposed to PAHs as well as inhibition of the catalase activity. Our results show that irradiation altered the bioavailability of PAHs, especially benzanthracene, which has great impact in aquatic ecosystems. Among the consequences of physical and chemical changes to PAHs, we observed a significant increase in NMA and MN incidence in E. marginatus erythrocytes, indicating the potential initiation of mutagenic and carcinogenic processes.Tetrabromobisphenol A (TBBPA), accounting for the largest production of brominated flame-retardants (BFRs) along the Laizhou Bay in China, is of great concern due to its diverse toxicities. In this study, we focused on the gender-specific responses of TBBPA in mussel Mytilus galloprovincialis using an integrated proteomic and metabolomic approach. After exposure of TBBPA (10 µg L(-1)) for one month, a total of 9 metabolites and 67 proteins were altered in mussel gills from exposed group. The significant changes of metabolites in female mussel gills from exposed group exhibited the disturbances in energy metabolism and osmotic regulation, while in male samples only be found the variation of metabolites related to osmotic regulation. iTRAQ-based proteomic analysis showed biological differences between male and female mussel gills from solvent control group. The higher levels of proteins related to primary and energy metabolism and defense mechanisms in male mussel gills meant a greater anti-stress capability of male mussels. Further analysis revealed that TBBPA exposure affected multiple biological processes consisting of production and development, material and energy metabolism, signal transduction, gene expression, defense mechanisms and apoptosis in both male and female mussels with different mechanisms. Specially, the responsive proteins of TBBPA in male mussels signified higher tolerance limits than those in female individuals, which was consistent with the biological differences between male and female mussel gills from solvent control group. This work suggested that the gender differences should be considered in ecotoxicology.Particulate matter (PM) has been of great concern in China due to the increasing haze pollution in recent years. In 2012, the Chinese national ambient air quality standard (NAAQS) was amended with a "more strict" regulation on the PM concentrations, i.e., 35 and 70 µg/m(3) for annual PM2.5 and PM10 averages, respectively (Grade-Ⅱ, GB3095-2012). To evaluate the potential of China to attain such new NAAQS and provide a more generalized chemical profile of PM in China, a comprehensive statistical analysis was carried out based on the published data of parallel PM2.5 and PM10 mass concentrations and chemical compositions of PM2.5 and PM10. The results show that most of the measured concentrations far exceed the new NAAQS. PM2.5 and PM10 show a strong positive correlation (R(2) = 0.87, p less then 0.01) with PM2.5 accounting for about 65% of PM10, suggesting that the abatement of PM2.5 is crucial for reducing PM pollution and hence improving air quality in China. Organic carbon (OC), sulfate and crustal species are the three major components of PM. The NO3(-)/SO4(2-) ratios are 0.43 ± 0.26 in PM2.5 and 0.56 ± 0.29 in PM10, and the OC/EC ratios are 3.63 ± 1.73 in PM2.5 and 4.17 ± 2.09 in PM10, signifying that the stationary emissions from coal combustion remain the main PM source. An evaluation of PM2.5 situation in current China was carried out and the results show that it would take about 27 years to meet the limit value of 35 µg/m(3) in the revised standard, implying a rigorous challenge in PM2.5 control in China in the future.To investigate the soil ecological effect of imidacloprid, earthworm Eisenia fetida was exposed to various concentrations of imidacloprid (0.10, 0.50, and 1.00 mg kg(-1) soil) respectively after 7, 14, 21, and 28 d. The effect of imidacloprid on reactive oxygen species (ROS) generation, antioxidant enzymes activity [superoxide dismutase (SOD) and catalase (CAT), glutathione S-transferase enzyme (GST)], malondialdehyde (MDA) content and DNA damage of the E. fetida was investigated. Significant increase of the ROS level was observed. The SOD and GST activity were significantly induced at most exposure intervals. CAT activity was inhibited and reflected a dose-dependent relationship on days 7, 14 and 21. High MDA levels were observed and the olive tail moment (OTM) as well as the percentage of DNA in the comet tail (tail DNA%) in comet assay declined with increasing concentrations and exposure time after 7 d. Our results suggested that the sub-chronic exposure of imidacloprid caused DNA damage and lipid peroxidation (LPO) leading to antioxidant responses in earthworm E. fetida.Surface drinking water sources have been threatened globally and there have been few attempts to detect point-source contamination in these waters using chromophoric dissolved organic matter (CDOM) fluorescence. To determine the optimal wavelength derived from CDOM fluorescence as an indicator of point-source contamination in drinking waters, a combination of field campaigns in Lake Qiandao and a laboratory wastewater addition experiment was used. Parallel factor (PARAFAC) analysis identified six components, including three humic-like, two tryptophan-like, and one tyrosine-like component. All metrics showed strong correlation with wastewater addition (r(2) > 0.90, p less then 0.0001). Both the field campaigns and the laboratory contamination experiment revealed that CDOM fluorescence at 275/342 nm was the most responsive wavelength to the point-source contamination in the lake. selleckchem Our results suggest that pollutants in Lake Qiandao had the highest concentrations in the river mouths of upstream inflow tributaries and the single wavelength at 275/342 nm may be adapted for online or in situ fluorescence measurements as an early warning of contamination events.