1INTRODUCTIONResources and environment crisis are accompanied byincreasing economic development pressures and rapidpopulation growth in many countries of the world(RobSwart,1996).Ecological security is a hotspot.Majorityof scholars have taken in the hot discussions of ecologicalsecurity of different regions,most of which is differentfrom their background of subjects(Alex F.Mc Calla,1999;Xiao Duning,Chen Wenbo and Guo Fuliang,2002).With the development of GIS,GPS,RS and modeltechno… 相似文献
The reuse of human wastes as biofertilizer resources offers a new option for meeting the growing demand for food and addressing poor soil productivity. Feces and black water are ubiquitous human wastes that usually require proper treatment, such as composting and anaerobic digestion, to remove potentially harmful substances before they can be applied as fertilizers. As an effective treatment technology for livestock farming wastes, the ectopic fermentation bed system (EFS) provides a new means of treating human waste and producing organic fertilizer from decomposed filler. Therefore, the objective of this study was to evaluate and compare the nutrient content and fertilizer potential of decomposed fillers obtained after EFS treatment of human feces and black water under different application conditions. The results showed that the application of fillers increased the yield of pakchoi by 3.60?29.32% and nutrient uptake by 8.09?83.45% compared to the CK, which could effectively promote the growth of pakchoi. This approach also improved the quality of pakchoi and enhanced soil fertility, and differences were observed in the effects of different kinds and application amounts of fillers. Soil EC was the soil property that had the greatest effect on the growth characteristics of pakchoi in this study. These findings help to better clarify the agronomic value of human wastes, but the effects of long-term filler application need to be further explored.
Environmental Science and Pollution Research - To better understand the effects of nonionic silicones and polymers on the wetting and foaming properties of anionic and nonionic hydrocarbon... 相似文献
As one of the important elements of controlling the redox system within the hyporheic and hypolentic zone, sulfur is involved in a series of complex biogeochemical processes such as carbon cycle, water acidification, formation of iron and manganese minerals, redox processes of trace metal elements and a series of important ecological processes. Previous studies on biogeochemistry of the hyporheic and hypolentic zones mostly concentrated on nutrients of nitrogen and phosphorus, heavy metals and other pollutants. Systematic study of biogeochemical behavior of sulfur and its main controlling factors within the lake hypolentic zone is very urgent and important. In this paper, a typical desert plateau lake, Dakebo Lake in northwestern China, was taken for example within which redox zonation and biogeochemical characteristics of sulfur affected by hydrodynamic conditions were studied based on not only traditional hydrochemical analysis, but also environmental isotope evidence. In the lake hypolentic zone of the study area, due to the different hydrodynamic conditions, vertical profile of sulfur species and environmental parameters differ at the two sites of the lake (western side and center). Reduction of sulfate, deposition and oxidation of sulfide, dissolution and precipitation of sulfur-bearing minerals occurred are responded well to Eh, dissolved oxygen, pH, organic carbon and microorganism according to which the lake hypolentic zone can be divided into reduced zone containing H2S, reduced zone containing no H2S, transition zone and oxidized zone. The results of this study provide valuable insights for understanding sulfur conversion processes and sulfur biogeochemical zonation within a lake hypolentic zone in an extreme plateau arid environment and for protecting the lake–wetland ecosystem in arid and semiarid regions. 相似文献
● Increased DAAO offsets 3/4 of the decrease of DAAP in 2013–2020.● DAAO increases are mainly due to O3 concentration increase and population aging.● Health benefit from PM2.5 reduction after 2017 is larger than that before 2017.● Reducing PM2.5 concentration by 1% results in 0.6% reduction of DAAP.● Reducing O3 concentration by 1% results in 2% reduction of DAAO. PM2.5 concentration declined significantly nationwide, while O3 concentration increased in most regions in China in 2013–2020. Recent evidences proved that peak season O3 is related to increased death risk from non-accidental and respiratory diseases. Based on these new evidences, we estimate excess deaths associated with long-term exposure to ambient PM2.5 and O3 in China following the counterfactual analytic framework from Global Burden Disease. Excess deaths from non-accidental diseases associated with long-term exposure to ambient O3 in China reaches to 579 (95% confidential interval (CI): 93, 990) thousand in 2020, which has been significantly underestimated in previous studies. In addition, the increased excess deaths associated with long-term O3 exposure (234 (95% CI: 177, 282) thousand) in 2013–2020 offset three quarters of the avoided excess deaths (302 (95% CI: 244, 366) thousand) mainly due to PM2.5 exposure reduction. In key regions (the North China Plain, the Yangtze River Delta and the Fen-Wei Plain), the former is even larger than the latter, particularly in 2017–2020. Health benefit of PM2.5 concentration reduction offsets the adverse effects of population growth and aging on excess deaths attributed to PM2.5 exposure. Increase of excess deaths associated with O3 exposure is mainly due to the strong increase of O3 concentration, followed by population aging. Considering the faster population aging process in the future, collaborative control, and faster reduction of PM2.5 and O3 are needed to reduce the associated excess deaths. 相似文献