Contribution of isoprene to formaldehyde and ozone formation based on its oxidation products measurement in Beijing,China

The atmospheric mixing ratios of methacrolein (MACR) and methyl vinyl ketone (MVK), the two specific products from isoprene oxidation in the atmosphere, were measured in Beijing from March to November, 2006. Distinct amounts of MACR and MVK were detected during vegetable growing seasons from April to October with ambient levels of 0.11–0.67 ppbv and 0.19–1.36 ppbv, respectively. The reacted isoprene and its ozone formation potentials (OFPs) in Beijing were evaluated in the range of 0.49–3.46 ppbv and 6.4–44.7 ppbv, respectively, from April to October. OFP of the reacted isoprene accounted for 10.6–23.6% of the total OFPs of VOCs (including carbonyls and isoprene) and 6.38–29.9% of the photo-chemically produced ozone. The maximum OFP of the original emitted isoprene prior to its photo-oxidation was calculated as 56.0 ppbv in August. The contribution from the reacted isoprene in Beijing to HCHO formation was also estimated to be in the range of 0.35–2.45 ppbv from April to October, which accounted for 4.6–11.5% of ambient HCHO.     

海绵铁还原耦合活性炭吸附-微波再生技术降解甲基橙

采用海绵铁(s-Fe0)还原耦合活性炭(GAC)吸附-微波(MW)再生技术降解甲基橙(MO)溶液,重点考察了s-Fe0投加量、粒径、微波功率等因素对MO去除效果的影响。结果表明,s-Fe0投加剂量为15.0 g/L、粒径为3～5 mm、超声波功率为200 W,反应1 h,MO的去除率为94.2%。其次,采用GAC吸附-MW再生技术(800 W,照射1 min)循环处理上述脱色后的MO废水。结果表明,GAC吸附可有效降低废水的生物毒性及残留的染料、TOC和总铁离子浓度,且MW辐射可有效再生吸附饱和的GAC颗粒。因此,s-Fe0还原耦合GAC吸附-MW再生技术可以有效降解MO染料,具有处理效果好、实现资源循环利用等优点。     

垃圾渗滤液中溶解性有机物对土壤中重金属迁移的影响

垃圾渗滤液主要组分中含有重金属和大量的溶解性有机物(DOM).实验选用北方最具代表性的褐土为供试样品,通过室内土柱淋滤实验研究了垃圾渗滤液溶解性有机物对重金属Cu、Cd、Pb和Zn在土壤中的迁移行为的影响.结果显示,DOM对土壤中Cd、Zn的垂直迁移起着促进作用,而对Cu、Pb迁移起着一定的抑制作用;不同浓度的垃圾淋洗...     

Comparison of initial hydrolysis of the three dimethyl phthalate esters (DMPEs) by a basidiomycetous yeast,Trichosporon DMI-5-1, from coastal sediment

Purpose  

Dimethyl phthalate esters (DMPEs) are a group of plasticizers commonly detected in the environment with potential adverse human health impact. The degradation of DMPEs by fungal systems has been studied to a limited extent, particularly by yeasts. In this study, a basidiomycetous yeast Trichosporon DMI-5-1 capable of degrading DMPEs was obtained and the degradation pathways were investigated.     

建筑物对高架点源大气污染物扩散影响的模拟研究

运用数值方法对城市中高架点源排放大气污染物的扩散规律进行了模拟研究,在计算区域内建立了三维数学模型,并将拉格朗日法描述的颗粒轨道模型耦合到风场。本研究计算了地面风速为3 m/s时的大气流场,并模拟研究了该风场条件下气体污染物的扩散和固体颗粒污染物的运动轨迹。通过分析模拟结果,给出了高架点源中排放的气体污染物的扩散区域和固体颗粒污染物运动轨迹的变化规律。     

A mathematical model and mesh-free numerical method for contact-line motion in lubrication theory

Environmental Fluid Mechanics - We introduce a mathematical model with a mesh-free numerical method to describe contact-line motion in lubrication theory. We show how the model resolves the...     

Curcumin antagonizes inflammation and autophagy induced by arsenic trioxide through immune protection in duck spleen

Environmental Science and Pollution Research - Arsenic is a toxic heavy metal widely found in the natural environment and has adverse effects on the health of waterfowl and human. Curcumin (CUR), a...     

Spatiotemporal pattern of reference crop evapotranspiration and its response to meteorological factors in Northwest China over years 2000–2019

Agricultural irrigation water in Northwest China accounts for more than 80% of total local water consumption, which is 1.23 times that of China. However, Northwest China is the most water-scarce place in China. Water scarcity in restricts crop growth and production. Reference crop evapotranspiration (ET₀) is important for agricultural water management. Understanding the reason for ET₀ change is helpful to provide a basis for rational planning of agricultural irrigation systems to conserve water. This study investigated the temporal and spatial variation characteristics of ET₀ at 181 meteorological stations in Northwest China from 2000 to 2019. And the sensitive factors and dominant factors affecting ET₀ change were quantitatively identified based on sensitivity analysis and contribution rate evaluation. Results showed that (1) a significant increase in maximum and minimum temperature (T_max and T_min), a significant decrease in sunshine duration (SD) and relative humidity (RH), and a slight increase in wind speed at 10 m height (U₁₀) were observed. (2) Annual ET₀ had an insignificant increasing trend. Spring and autumn ET₀ contributed greatly to the growth of annual ET₀, especially in March, May, September, October, and November. ET₀ in HH (Yellow River Basin area) had decreased at annual scale, while other subregions were the opposite trend. Significant differences in monthly and seasonal changes in the spatial distribution of ET₀. (3) U₁₀ was the dominating contribution factor related to annual ET₀ variability, followed by T_min, RH, T_max, and SD. In seasonal time scale, T_min, SD, U₁₀, and RH were the most dominant factors in spring, summer, autumn, and winter respectively. (4) Spatial distribution for contribution rates of various meteorological factors showed significant diversity among various subregions. The positive contribution of U₁₀ was the major cause of the increase in ET₀ in semi-arid grassland area (BGH), the southwest of “Qice line” (QCXXN), and the southeast of “Qice line” (QCXDN); the significant increase in T_min contributed most in Qaidam Basin (CDM), Hexi inland river basin (HX), the northeast of “Qice line” (QCXDB), and the northwest of “Qice line” (QCXXB), while the contribution of decreasing SD offsets the positive effects of other factors, leading to the decrease in ET₀ in HH. Our work illustrates that water management measures should be different at different spatial and temporal scales. The effect of U₁₀ can be offset by covering, to reduce evaporation and maintain water in BGH, QCXXN, and QCXDN. And high-temperature resistant varieties are planted to adapt to temperature growth in CDM, HX, QCXDB, and QCXXB. Agricultural water management strategies should be formulated and selected according to local conditions.

     

Integrated toxicity assessment of DEHP and DBP toward aquatic ecosystem based on multiple trophic model assays

Environmental Science and Pollution Research - To comprehensively understand the toxic risks of phthalates to aquatic ecosystems, we examined the acute toxicity of di-(2-ethylhexyl) phthalate...     

自动进样气相色谱法测定气体中的非甲烷烃

用泰德拉气体采样袋采样，自动进样气相色谱法测定气体中的非甲烷烃含量。甲烷、总烃的线性范围分别为0～2439，0—2066mg／m^3。进样量为1mL时，检出限为0．02mg／m^3（信噪比为3）。对3种不同浓度甲烷与丙烷混合标准气进行测定，重复性相对标准偏差为0．4％-1．0％。对4种不同性质的试样进行加标回收实验，加标回收率为96．7％-102．0％。5名实验人员分别用自动进样法及手动进样法分析4种不同性质的试样，自动进样法的重现性相对标准偏差为1．2％～1．8％，优于手动进样法的6．5％～8．3％。该法可一次连续测定21个试样，精密度高、重现性好、分析效率高。