Environmental Science and Pollution Research - Targeting the removal of Pb2+ in wastewater, sugarcane bagasse was treated with nitric acid and an alkaline solution to prepare adsorbents. On a... 相似文献
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
In vivo laboratory studies of toxicity were performed on Wistar rats using a methanol extract produced by the natural population of Cylindrospermopsis raciborskii (abundance of 2.13 × 105 trichomes mL−1) collected at Aleksandrovac Lake (Serbia). HPLC analysis showed that the extract contains 6.65 μg cylindrospermopsin (CYN) mg−1. The rats were killed 24 or 72 h after a single intraperitoneal injection of C. raciborskii extract in concentrations of 1500, 3000, 6000 and 12,000 μg kg−1 body weight (bw) and an equivalent amount of CYN as present in the highest dose of the extract (79.80 μg CYN kg−1 bw). The genotoxic effect on the livers treated with C. raciborskii was evaluated using comet assay and potential induction of oxidative stress as the toxicity mechanism associated with the presence of CYN in extract. The results from the analyses of DNA damage in the comet tail length, tail moment and percentage of DNA in the tail in the liver indicated that administration of extract and CYN present statistically significant difference when compared with the negative control group. Although an increase in the frequency of selected parameters induced by the CYN was observed in the liver, this damage was less than the damage resulting from the administration of the highest dose of extract. The changes in the biochemical parameters of the hepatic damage showed that the application of single doses of the extract and CYN did not cause serious liver damage in rats. The extract and CYN significantly increased oxidative stress in rats’ liver after a single exposure.
As a global developing tendency, the general viewpoint has been reached in the construction of the ecocities, which has produced widespread influence in the international society. Cities must enable people to live in harmony with nature and achieve sustainable development. Although more and more cities in the world are being designed and built to the ecological ones, the construction is also theoretical questions and arduous tasks. People oriented, ecocity development requires the comprehensiv… 相似文献
At urban areas in south Europe atmospheric aerosol levels are frequently above legislation limits as a result of road traffic and favourable climatic conditions for photochemical formation and dust suspension. Strategies for urban particulate pollution control have to take into account specific regional characteristics and need correct information concerning the sources of the aerosol.With these objectives, the ionic and elemental composition of the fine (PM2.5) and coarse (PM2.5–10) aerosol was measured at two contrasting sites in the centre of the city of Oporto, roadside (R) and urban background (UB), during two campaigns, in winter and summer.Application of Spatial Variability Factors, in association with Principal Component/Multilinear Regression/Inter-site Mass Balance Analysis, to aerosol data permitted to identify and quantify 5 main groups of sources, namely direct car emissions, industry, photochemical production, dust suspension and sea salt transport. Traffic strongly influenced PM mass and composition. Direct car emissions and road dust resuspension contributed with 44–66% to the fine aerosol and with 12 to 55% to the coarse particles mass at both sites, showing typically highest loads at roadside. In fine particles secondary origin was also quite important in aerosol loading, principally during summer, with 28–48% mass contribution, at R and UB sites respectively. Sea spray has an important contribution of 18–28% to coarse aerosol mass in the studied area, with a highest relative contribution at UB site.Application of Spatial Variability/Mass Balance Analysis permitted the estimation of traffic contribution to soil dust in both size ranges, across sites and seasons, demonstrating that as much as 80% of present dust can result from road traffic resuspension. 相似文献