The fate of chlorantraniliprole was studied in rice field ecosystem, and a simple and reliable analytical method was developed for determination of chlorantraniliprole in soil, rice straw, paddy water and brown rice. Chlorantraniliprole residues were extracted from samples with acetonitrile. The extract was cleaned up with QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method, and determined by high-performance liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The average recoveries were 76.9-82.4% from soil, 83.6-89.3% from rice straw, 95.2-103.1% from paddy water and 84.9-87.7% from brown rice. The relative standard deviation was less than 15%. The limits of detection (LODs) of chlorantraniliprole calculated as a sample concentration (S/N ratio of 3) were 0.012 μg L(-1) for paddy water, 0.15 μg kg(-1) for soil, brown rice and rice straw. The results of the kinetics study of chlorantraniliprole residue showed that chlorantraniliprole degradation in soil, water and rice straw coincided with C=0.01939e(-0.0434t), C=0.01425e(-0.8111t), and C=1.171e(-0.198t), respectively; the half-lives were about 16.0 d, 0.85 d and 3.50 d, respectively. The degradation rate of chlorantraniliprole in water was the fastest, followed by rice straw. The final residues of chlorantraniliprole on brown rice were lower than maximum residue limit (MRL) of 0.02 mg kg(-1) after 14 d Pre-Harvest Interval (PHI). Therefore, a dosage of 150 mL a.i.hm(-2) was recommended, which could be considered as safe to human beings and animals. 相似文献
Atmospheric mercury (Hg) emission from coal is one of the primary sources of anthropogenic discharge and pollution. China is one of the few countries in the world whose coal consumption constitutes about 70% of total primary energy, and over half of coals are burned directly for electricity generation. Atmospheric emissions of Hg and its speciation from coal-fired power plants are of great concern owing to their negative impacts on regional human health and ecosystem risks, as well as long-distance transport. In this paper, recent trends of atmospheric Hg emissions and its species split from coal-fired power plants in China during the period of 2000-2007 are evaluated, by integrating each plant's coal consumption and emission factors, which are classified by different subcategories of boilers, particulate matter (PM) and sulfur dioxide (SO2) control devices. Our results show that the total Hg emissions from coal-fired power plants have begun to decrease from the peak value of 139.19 t in 2005 to 134.55 t in 2007, though coal consumption growing steadily from 1213.8 to 1532.4 Mt, which can be mainly attributed to the co-benefit Hg reduction by electrostatic precipitators/fabric filters (ESPs/FFs) and wet flue gas desulfurization (WFGD), especially the sharp growth in installation of WFGD both in the new and existing power plants since 2005. In the coming 12th five-year-plan, more and more plants will be mandated to install De-NO(x) (nitrogen oxides) systems (mainly selective catalytic reduction [SCR] and selective noncatalytic reduction [SNCR]) for minimizing NO(x) emission, thus the specific Hg emission rate per ton of coal will decline further owing to the much higher co-benefit removal efficiency by the combination of SCR + ESPs/FFs + WFGD systems. Consequently, SCR + ESPs/FFs + WFGD configuration will be the main path to abate Hg discharge from coal-fired power plants in China in the near future. However advanced specific Hg removal technologies are necessary for further reduction of elemental Hg discharge in the long-term. 相似文献
The degree and extent of lead contamination of urban soils and vegetation in the vicinity of secondary lead industries are provided. These urban industries, a secondary smelter reprocessing lead from used batteries and scrap metal and a manufacturer of new storage batteries, were located near residential communities. Levels as high as 21,000 ppm of lead in the upper 5 cm of soil (based on air dried weight) and 3500 and 2700 ppm in willow foliage (not washed and washed, respectively, based on dry weight) were found adjacent to the secondary smelter, with the levels decreasing exponentially from the sources. The data on lead contamination of soils and vegetation at various distances and directions from the urban secondary lead industries were compared with levels of lead found in control urban and highway locations. In addition, arsenic levels in soil were examined as a tracer for the source of industrial lead emissions. High levels of lead found In both vegetation and soil in the vicinity of the urban industries reflected both historical and current emissions of lead in those areas. These studies were conducted for industrial abatement purposes; to assist medical related epidemiology studies; to define the areas of severe contamination for soil cleanup purposes; and to formulate guidelines for excessive levels of lead in soil and vegetation. Since lead in soil is persistent, concern arises with respect to pica for small children, contamination of edible vegetables grown in high-lead soil, and reentrainment of leaded particulate matter into the air. 相似文献
Nitrous oxide (N2O) has gained considerable attention as a contributor to global warming and depilation of stratospheric ozone layer. Landfill is one of the high emitters of greenhouse gas such as methane and N2O during the biodegradation of solid waste. Landfill aeration has been attracted increasing attention worldwide for fast, controlled and sustainable conversion of landfills into a biological stabilized condition, however landfill aeration impel N2O emission with ammonia removal. N2O originates from the biodegradation, or the combustion of nitrogen-containing solid waste during the microbial process of nitrification and denitrification. During these two processes, formation of N2O as a by-product from nitrification, or as an intermediate product of denitrification. In this study, air was injected into a closed landfill site and investigated the major N2O production factors and correlations established between them. The in-situ aeration experiment was carried out by three sets of gas collection pipes along with temperature probes were installed at three different distances of one, two and three meter away from the aeration point; named points A-C, respectively. Each set of pipes consisted of three different pipes at three different depths of 0.0, 0.75 and 1.5 m from the bottom of the cover soil. Landfill gases composition was monitored weekly and gas samples were collected for analysis of nitrous oxide concentrations. It was evaluated that temperatures within the range of 30–40°C with high oxygen content led to higher generation of nitrous oxide with high aeration rate. Lower O2 content can infuse N2O production during nitrification and high O2 inhibit denitrification which would affect N2O production. The findings provide insights concerning the production potentials of N2O in an aerated landfill that may help to minimize with appropriate control of the operational parameters and biological reactions of N turnover.
Implications: Investigation of nitrous oxide production potential during in situ aeration in an old landfill site revealed that increased temperatures and oxygen content inside the landfill site are potential factors for nitrous oxide production. Temperatures within the range of optimum nitrification process (30–40°C) induce nitrous oxide formation with high oxygen concentration as a by-product of nitrogen turnover. Decrease of oxygen content during nitrification leads increase of nitrous oxide production, while temperatures above 40°C with moderate and/or low oxygen content inhibit nitrous oxide generation. 相似文献
While phenomenological investigations of ecosystem patterns often fail to reveal underlying dynamic mechanisms, we highlight
a universal principle for pattern formation in ecosystems. We consider ecosystems to be typical complex adaptive systems that
seek an optimal process to obtain maximized flux under given constraints. An analysis of the optimal process reveals underlying
microscopic dynamic mechanisms that induce complex patterns in ecosystems. We emulate ecosystem patterns using a Self-Organization
Feature Map: an artificial neural network theoretical model by which evolution processes, structural classifications, and
the fractal growth of ecosystem patterns can be simulated. The results help us analyze the formation and dynamics of ecosystem
patterns, with attending implications for the classification, protection, and optimization of ecosystems. 相似文献