Gene expression can be modified in people who are chronically exposed to high concentrations of heavy metals. The soil surrounding the Ventanas Industrial Complex, located on the coastal zone of Puchuncaví and Quintero townships (Chile), contain heavy metal concentrations (As, Cu, Pb, Zn, among others) that far exceed international standards. The aim of this study was to determine the potential association of the heavy metals in soils, especially arsenic, with the status of methylation of four tumor suppressor genes in permanent residents in those townships. To study the methylation status in genes p53, p16, APC, and RASSF1A, we took blood samples from adults living in areas near the industrial complex for at least 5 years and compared it to blood samples from adults living in areas with normal heavy metal concentrations of soils. Results indicated that inhabitants of an area with high levels of heavy metals in soil have a significantly higher proportion of methylation in the promoter region of the p53 tumor suppressor gene compared with control areas (p-value: 0.0035). This is the first study to consider associations between heavy metal exposure in humans and aberrant DNA methylation in Chile. Our results suggest more research to support consistent decision-making on processes of environmental remediation or prevention of exposure.
Semi-coking wastewater contains a rich source of toxic and refractory compounds. Three-dimensional electro-Fenton (3D/EF) process used CuFe2O4 as heterocatalyst and activated carbon (AC) as particle electrode was constructed for degrading semi-coking wastewater greenly and efficiently. CuFe2O4 nanoparticles were prepared by coprecipitation method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy disperse spectroscopy (EDS). Factors like dosage of CuFe2O4, applied voltage, dosage of AC and pH, which effect COD removal rate of semi-coking waste water were studied. The results showed that COD removal rate reached to 80.9% by 3D/EF process at the optimum condition: 4 V, 0.3 g of CuFe2O4, 1 g of AC and pH?=?3. Trapping experiment suggesting that hydroxyl radical (?OH) is the main active radical. The surface composition and chemical states of the fresh and used CuFe2O4 were analyzed by XPS indicating that Fe, Cu, and O species are involved into the 3D/EF process. Additionally, anode oxidation and the adsorption and catalysis of AC are also contributed to the bleaching of semi-coking waste water. The possible mechanisms of 3D/EF for degrading semi-coking waste water by CuFe2O4 heterocatalyst were proposed.
Journal of Polymers and the Environment - High-amylose maize starch (AS) was modified by graft copolymerization with sodium acid maleate and disodium maleate, using the KMnO4-NaHSO3 redox system,... 相似文献
In December 2009, ambient air was sampled with active high-volume air samplers at two sites: on the roof of the No. l building of Dalian Jiaotong University and on the roof of the building of Dalian Meteorological Observatory. The concentrations and the congeners between vapor phase and particulate phase of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the air were measured. Sample analysis results showed that the concentrations of PCDD/Fs in particulate phase was higher than that in gaseous phase. The ratio of PCDD to PCDF in gaseous phase and particulate phase was lower than 0.4 in all samples. The total I-TEQ value in gaseous phase and particulate phase was 5.5 and 453.8 fg/m3 at Dalian Jiaotong University, 16.6 and 462.1 fg/m3 at Dalian Meteorological Observatory, respectively. The I-TEQ value of Dalian atmosphere was 5.5-462.1 fg/m3 which was lower than international standard, the atmospheric quality in Dalian is better. 相似文献
AbstractMethane, which is an important greenhouse gas, has received less attention regarding its flux in ponds. Small ponds, whose area only occupies approximately 8.6%, comprise the bulk of CH4 efflux from lakes and ponds on a global scale. However, temporal and spatial variability, as well as consequences of CH4 fluxes from ponds, remains unknown. The aim of this study was to examine using 4 field experiments diel methane (CH4) fluxes from a subtropic eutrophic pond in different seasons. For the eutrophic pond, the mean CH4 efflux for all seasons was 1.772?mg/m2/h, and CH4 emissions in summer were approximately three-fold higher than total of winter, spring, and autumn. Methane diffusive emissions were positively correlated with water temperature, dissolved oxygen (DO) and air temperature but negatively related to pH and to the difference between water temperature and air temperature. The diel diffusive CH4 flux among different seasons varied significantly. The CH4 bubble flux did not differ markedly in winter, spring and autumn, but the quantity in summer was significantly different from all other seasons. Bubble is the main pathway for CH4 emissions. The CH4 ebullition flux accounts for 66, 71, 97 and 98% of the total in winter, spring, summer and autumn, respectively. On an annual scale, the CH4 ebullition flux accounts for 77% of the total fluxes (diffusive?+?ebullitive). Our results show that further investigations need to be carried out to probe temporal variability of CH4 fluxes in ponds located in different climate zones for better understanding of the global carbon budget, which is critical to predict future climate changes. 相似文献
