Modeling methyl isothiocyanate soil flux and emission ratio from a field following a chemigation of metam-sodium

Metam-sodium had become the most heavily used soil fumigant in recent years as the deadline approached for methyl bromide to phase out in January 2005. After application, metam-sodium decomposes rapidly to methyl isothiocyanate (MITC), a highly toxic compound capable of killing a wide spectrum of soil-borne pests. Inhalation risk of MITC ranked high among airborne agricultural pesticides in California. Information about off-gassing intensity and percentage of emission is essential for exposure risk assessment and mitigation measures, but is limited, especially for new application methods such as drip chemigation. Air concentrations of MITC were monitored around a field treated with metam-sodium through surface drip irrigation system. The field was tarped with plastic films before the chemigation. The air concentrations at receptor locations were simulated for the period of air monitoring with the Industrial Source Complex (ISC3) Dispersion Model, and soil flux density of MITC at various periods after chemigation was estimated through a back-calculation procedure. The estimated soil flux density of MITC showed a diurnal pattern, with the daytime flux stronger than nighttime. However, the average air concentration at nighttime was higher than that at daytime. Soil flux density peaked at 4.30 microg m-2 s-1 in the first 12-h period after chemigation, then declined with time. The MITC emission percentage in the first 60-h was 2.65% of applied mass, of which 57% occurred in the first 24-h after chemigation. The study indicated that the tarped bed drip application method of metam-sodium had a relatively good control of MITC emission from soil.     

A multi-emission analysis of organic and inorganic pollutants during the combustion of sludge with high and low calorific value coals

Environmental Science and Pollution Research - To achieve allowable gas emission limits and eliminate the high cost and challenges associated with pre-treatment of sludge before incineration, a new...     

铜川斜坡变形与作用因素分析

斜坡变形与失稳活动是黄土高原突出的地质地貌现象．它有较强的致灾性。本文通过陕西铜川斜坡变形的现场实际调查，研究了该地斜坡的形态、物质组成、变形形式以及作用因素等。本研究对厚层黄土区斜坡变形灾害的防治有较重要意义。     

一体化间歇曝气完全混合活性污泥法

一体化间歇曝气完全混合活性污泥法处理装置采取特殊的沉淀区构造,改变了活性污泥的循环流动方式,通过间歇曝气,反应区交替处于好氧/缺氧状态,达到了有机物高效去除、高效硝化反硝化及控制污泥膨胀的效果.该方法具有出水水质好、运行稳定、能耗低、流程简洁和操作管理方便的特点,是一种很有发展潜力的一体化中小型生活污水、城市污水处理系统.     

Impacts of hydrologic variations on chemical weathering and solute sources in the Min River basin,Himalayan–Tibetan region

Environmental Science and Pollution Research - Feedback between hydrologic variations and chemical weathering is thought to play a crucial role in modulating global carbon cycling. The mechanisms...     

3种染料化合物在UV-TiO2/H2O2和UV-TiO2体系中的光催化降解研究

采用自制的TiO2膜和平板式固定床型光催化氧化反应装置,对甲基橙、茜素红和罗丹明B 3种含有不同生色基团的染料化合物进行了TiO2光催化氧化降解研究,通过对照测定降解过程中吸光度、电导率、pH的变化,分析了在加入和不加入H2O22种情况下降解过程的异同,比较了3种染料化合物脱色的难易程度,揭示了降解产物中无机离子的变化规律及某些可能的产物类型.     

Impact of land use on shallow groundwater quality characteristics associated with human health risks in a typical agricultural area in Central China

Environmental Science and Pollution Research - Groundwater pollution seriously threatens water resource safety due to high-intensity land use throughout the world. However, the relationship between...     

以pH和ORP作为脉冲SBR工艺的实时控制参数

为了实现脉冲SBR深度脱氮的实时控制，以某污水处理厂市政污水为处理对象，考察了脉冲SBR在深度脱氮过程中pH及ORP的变化规律。试验结果表明，pH及ORP的变化规律与脉冲SBR有机物去除、硝化与反硝化过程存在较好的相关关系。可以根据pH和ORP变化曲线上的特征点对脉冲SBR进行实时控制。并考察了污水C／N（COD／NH4^＋-N）对pH及ORP的变化规律的影响。在硝化过程中，C／N对pH及ORP曲线变化点的出现没有影响；在反硝化过程中，应结合pH值“硝酸盐峰”和ORP“硝酸盐膝”来判断低C／N污水反硝化的终点。在该试验中，出水TN低于2mg／L，TN去除率可达到96％以上。     

Trends of ischemic heart disease mortality attributable to household air pollution during 1990–2019 in China and India: an age-period-cohort analysis

Environmental Science and Pollution Research - Cardiovascular diseases (CVD) caused by household air pollution (HAP) have sparked widespread concern globally in the recent decade. Meanwhile,...     

Combined application of chemical fertilizer with green manure increased the stabilization of organic carbon in the organo-mineral complexes of paddy soil

Environmental Science and Pollution Research - The influence of the combined application of chemical fertilizer with green manure on the stabilization of organic carbon (C) was explored in the...