The ubiquitous distribution of halogenated aromatic compounds(XAr) coupled with their carcinogenicity has raised public concerns on their potential risks to both human health and the ecosystem. Recently, advanced oxidation processes(AOPs) have been considered as an"environmentally-friendly" technology for the remediation and destruction of such recalcitrant and highly toxic XAr. During our study on the mechanism of metal-independent production of hydroxyl radicals(UOH) by halogenated quinones and H_2O_2, we found, unexpectedly, that an unprecedented UOH-dependent two-step intrinsic chemiluminescene(CL) can be produced by H_2O_2 and tetrachloro-p-benzoquinone, the major carcinogenic metabolite of the widely used wood preservative pentachlorophenol. Further investigations showed that, in all UOH-generating systems, CL can also be produced not only by pentachlorophenol and all other halogenated phenols, but also by all XAr tested. A systematic structure–activity relationship study for all 19 chlorophenolic congeners showed that the CL increased with an increasing number of Cl-substitution in general. More importantly, a relatively good correlation was observed between the formation of quinoid/semiquinone radical intermediates and CL generation. Based on these results, we propose that UOH-dependent formation of quinoid intermediates and electronically excited carbonyl species is responsible for this unusual CL production; and a rapid, sensitive,simple, and effective CL method was developed not only to detect and quantify trace amount of XAr, but also to provide useful information for predicting the toxicity or monitoring real-time degradation kinetics of XAr. These findings may have broad chemical, environmental and biological implications for future studies on halogenated aromatic persistent organic pollutants. 相似文献
Environmental Science and Pollution Research - As one of the low-impact development measures, bioretention plays an important role in reducing the runoff peak flow and minimizing runoff pollutants,... 相似文献
An investigative biomonitoring study was conducted along the coastal area of Laizhou Bay (China) to evaluate the impact of organic pollution on the clam Ruditapes philippinarum using bioaccumulation and multi-biomarker measurements. In addition, the polychlorinated biphenyls (PCBs), total petroleum hydrocarbons (TPHs) and nonylphenol (NP) content in surface sediment at the study sites were also analyzed. Concentrations of PCBs, TPHs and NP in the sediments of the study area were 1.90 ± 0.10 μg kg?1, 39.55 ± 2.42 mg kg?1, 9.23 ± 0.41 μg kg?1 dry weight, respectively, while the organic contaminants in the soft tissues of R. philippinarum were 14.81 ± 0.96 μg kg?1 for PCBs, 165.87 ± 5.03 mg kg?1 for TPHs and 86.16 ± 5.29 μg kg?1 for NP. Linear regression analysis on the levels of organic pollutants accumulated in R. philippinarum and in sediments showed no significant correlation. Multi-biomarkers including superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, total glutathione and lipid peroxidation were assayed in gills and digestive glands of R. philippinarum. Finally, the biomarkers in gills were selected to calculate the Integrated Biomarker Response (IBR) index and to evaluate the impact of the three organic contaminants on R. philippinarum collected from different sites. According to IBR results, the western coast and eastern coast exhibited higher environmental stress than the sampling sites along the southern coast of Laizhou Bay. Significant correlation was found between the level of organic contaminants in the sediments and IBR whereas no dependence was found between pollutants’ concentrations in sediments and separate biomarker responses. The results showed that PCBs and NP were the main organic pollutants among the three studied which have caused pollution pressure on R. philippinarum in Laizhou Bay coastal area.
Environmental Science and Pollution Research - Despite the considerable contributions of remittances to households and economic advancements, their environmental implications have received little... 相似文献
Environmental Science and Pollution Research - Adsorption of test substances on micromembrane filters during sample pretreatment before qualitative and quantitative analysis has greatly affected... 相似文献
Volatile organic compounds (VOCs) oxidation processes play a very important role in atmospheric chemistry, and the chemical reactions are expressed in various manners in chemical mechanisms. To gain an improved understanding of VOCs evolution during oxidation processes and evaluate the discrepancies of VOCs oxidation schemes among different mechanisms, we used the total VOC reactivity as a diagnostic and evaluated tool to explore the differences for six widely used chemical mechanisms. We compared the total VOC reactivity evolution under high-NOx conditions for several sets of precursors, including n-pentane, toluene, ethene, isoprene and a mixture of 57 Photochemical Assessment Monitoring Stations (PAMS) species in a 0-D photochemical box model. Inter-comparison of total VOC reactivity of individual precursor simulations showed discrepancies to different extent of the oxidation schemes among the studied mechanisms, which are mainly attributed to the different lumping approaches for organic species. The PAMS simulation showed smaller discrepancy than individual precursor cases in terms of total VOC reactivity. SAPRC07 and RACM2 performances are found to better match the MCM for simulation of total VOC reactivity. Evidences suggest that the performance in simulating secondary organic products, OH concentrations and NOx concentrations are related to the OH reactivity discrepancies among various chemical mechanisms. Information in this study can be used in selection of chemical mechanisms to better model OH reactivity in different environments. The results in this study also provide directions to further improve the ability in modelling total VOC reactivity with the chemical mechanisms. 相似文献
Historical records from the past 2000 years indicate that the vegetative cover of the Loess Plateau has declined significantly with time. The decline in vegetative cover seems closely related to increased rates of soil erosion as well as the increased frequency of natural disasters such as floods, droughts and dust storms. The condition of the environment and its relationship with development is a serious problem as the Chinese government searches for ways to improve the living standard of people in the region. The purpose of this study is to outline historical changes in the vegetation and environmental conditions of the Loess Plateau. Although we believe that current population pressure of the Loess Plateau is becoming unsustainable, our objective is not to be overly pessimistic in regards to the future development of the region. Instead, our purpose is to increase the awareness of environmental conditions in the region and to encourage the implementation of policies that will promote sustainable development of the Loess Plateau. 相似文献
Environmental Science and Pollution Research - Urban drainage pipeline systems collect and transport domestic sewage, industrial wastewater, and rainwater. They are important components of urban... 相似文献