The purpose of this study was to determine and evaluate the spatial changes in soil salinity by using geostatistical methods. The study focused on the suburb area of Beijing, where urban development led to water shortage and accelerated wastewater reuse to farm irrigation for more than 30 years. The data were then processed by GIS using three different interpolation techniques of ordinary kriging (OK), disjunctive kriging (DK), and universal kriging (UK). The normality test and overall trend analysis were applied for each interpolation technique to select the best fitted model for soil parameters. Results showed that OK was suitable for soil sodium adsorption ratio (SAR) and Na+ interpolation; UK was suitable for soil Cl? and pH; DK was suitable for soil Ca2+. The nugget-to-sill ratio was applied to evaluate the effects of structural and stochastic factors. The maps showed that the areas of non-saline soil and slight salinity soil accounted for 6.39 and 93.61 %, respectively. The spatial distribution and accumulation of soil salt were significantly affected by the irrigation probabilities and drainage situation under long-term wastewater irrigation. 相似文献
With increasing attention paid to the recycling use of aged refuse as vegetated soil, it is important to check its possible polluting risk and probe the tolerance of plant system to its stress. For this reason, several physiological responses in Zea mays L. (maize) to the leaching samples of aged refuse in different particle-size (900-300, 300-150, 150-105, 105-90, and 90-0 microm) were investigated in the present study, including growth, lipid peroxidation, protein oxidation and activities of antioxidant enzymes. The results indicate that the aged refuse affected the growth of maize seedlings, and elevated the levels of lipid peroxidation and protein oxidation in leaf tissues in a time-dependent manner, accompanying by the changes of antioxidant status. Also, above physiological responses varied as a function of particle-size distribution of the aged refuse, and statistical growth inhibition and oxidative stress occurred after the exposure of smaller particle-size samples, which contained higher level trace metals, the characteristic pollutants in the aged refuse. The results implicate that aged refuse might cause environmental stress on plant system, but the polluting risk mainly resulted from smaller particle-size samples. Therefore, the critical point of utilizing aged refuse as vegetated soil focused on analyzing its particle-size distribution, and screening out appropriate particle-size samples. 相似文献
The role of resuspension duration on release of 16 PAHs was measured experimentally using a particle entrainment simulator (PES). Three sediment cores were resuspended for 12h at 0.2 and 0.5N m(-2). PAHs in water column and total suspended solids (TSS) were monitored at intervals. After 0.25h of resuspension, PAH release was on average 42% of their concentrations after 12h of resuspension, indicating fast release of PAHs from sediments in an initial short time. Moreover, PAHs released faster at 0.5N m(-2) than at 0.2N m(-2); low molecular weight PAHs (2-3-ring) released faster than median molecular weight (4-ring) PAHs. PAH concentrations in TSS showed generally increase with time and differences in magnitudes based on sediment type and energy. Overall, the composition of sediments is the major factor in determining the amount of released PAHs, more so than the level of resuspension energy applied. 相似文献
Environmental Science and Pollution Research - Understanding whether and how urban innovation offers a sound solution to the dilemma of urban green development is a crucial response to mitigate the... 相似文献
Environmental Science and Pollution Research - Meteorological factors, which are periodic and regular in a long run, have an unignorable impact on human health. Accurate health risk prediction... 相似文献
• The optimum SCR activity was realized by tuning the acid pretreatment.• Optimized catalysts showed NOx conversion above 90%.• The NH3 and NO adsorption capacity of Al-O3-Fe is stronger than Fe-O3-Fe.• The formation of almandine consumes Fe3+ and Al3+ and weakens their interaction. Red mud (RM), as an alkaline waste, was recently proved to be a promising substitute for the SCR catalyst. Dealkalization could improve the acidity and reducibility of red mud, which were critical for SCR reaction. However, the dealkalization effect depended on the reaction between acid solution and red mud. In this study, we realized the directional control of the chemical state of active sites through tuning the acid pretreatment (dealkalization) process. The pretreatment endpoint was controlled at pH values of 3–5 with diluted nitric acid. When the pH values of red mud were 3 and 5 (CRM-3 and CRM-5), activated catalysts showed NOx conversion above 90% at 275°C–475°C. The high initial reaction rate, Ce3+/(Ce3+ + Ce4+) ratio, and surface acidity accounted for the excellent SCR performance of CRM-5 catalyst. Meanwhile, more Fe3+ on the CRM-3 surface improved the NH3 adsorption. There was a strong interaction between Al and Fe in both CRM-5 and CRM-3 catalysts. DFT results showed that the adsorption capacity of the Al-O3-Fe for NH3 and NO is stronger than that of Fe-O3-Fe, which enhanced the NOx conversion of the catalyst. However, the almandine was formed in CRM-4, consumed part of Fe3+ and Al3+, and the interaction between Al and Fe was weakened. Also, deposited almandine on the catalyst surface covered the active sites, thus leading to lower NH3-SCR activity. 相似文献
Environmental Science and Pollution Research - The bioavailable trace metals are closely related to environmental safety and human health, which might have different source characteristics from the... 相似文献
Aiming at the problems of complex environment and serious dust pollution in large open-pit coal yards, a dust suppression gel with a dual network structure was prepared by modifying the soluble starch and sodium alginate with iron ions. The changes of functional groups, thermal stability, and morphology structure before and after the reaction were analyzed by FTIR, TG-DSC, and SEM, and the formation mechanism of the dual network was revealed by XPS. Furthermore, the water absorption and water retention experiments proved that the dual network structure is more conducive to water retention than the single-layer network. According to molecular dynamics simulations and contact angle experiments, gel and adsorbed water molecules can approach coal dust molecules on their own to contact, wet, and combine with coal dust. The adhesion test proved that the dust suppression gel with iron ions had better adhesion to dust. The anti-freezing test shows that the dust suppression gel has good anti-freezing performance. The antifreeze test shows that the dust suppression gel still has excellent freeze–thaw resistance at the test temperature of??-20℃. The mechanical property test shows that the dust suppressant gel can prevent the product from being damaged by external force. The acid and alkali resistance experiments showed that the acid and alkali resistance of the gel was improved under the condition of iron ion modification, and the flying of coal powder was effectively prevented. This research provides a new theoretical idea for coal dust control in complex environment.