Depth profiles of volatile halogenated hydrocarbons in seawater in the Bay of Bengal

Measurements were made of bromocarbons (CHBr3 and CH2Br2), iodocarbons (CH2I2 and CH2ClI), and dimethylsulfide (DMS, CH3SCH3) in seawater collected from the Bay of Bengal under tropical stratified conditions. These compounds showed different depth profiles, characteristic of each group. CH2I2 and CH2ClI showed very similar depth profiles to chlorophyll-a, suggesting their production by phytoplankton followed by rapid decay in seawater. The CH2I2 maximum at a depth a little below the CH2ClI maximum was consistent with its more significant photolytic decay. The bromocarbons were less localized in their distributions than were the iodocarbons, suggesting their longer residence time in seawater after their release from phytoplankton. Both of these profiles were different from the pattern of DMS, which had its maxima above the chlorophyll-a maximum layer near the surface.     

微波辅助光催化降解水中酚的研究

利用改装的家用微波炉和自制的无电极灯(EDL)试验了5种酚在水溶液中的微波辅助光催化降解效果.结果表明,反应30 min,微波辅助光催化作用(MW/EDL/TiO2)能去除80%以上的苯酚、间硝基苯酚、对氯苯酚和对甲酚,相应溶液的总有机碳(TOC)均减少70%以上,2-萘酚的去除率为59%,溶液TOC减少54%;微波(MW或MW/TiO2)作用对酚的去除率有一定贡献;对上述5种酚的微波辅助光催化反应动力学进行了初步研究,发现均符合准一级动力学方程.     

纳米TiO2光催化的改良及其在环境工程中的新应用

综述了近年来纳米TiO2光催化剂改良的最新技术,包括对其的改性及与其他技术的联合运用,以提高纳米TiO2的光催化效率;探讨了其在环境工程中的新应用,并就今后纳米TiO2光催化剂的研究发展方向提出了一些建议.     

Evaluation of accelerated dechlorination of p,p'-DDT in acidic paddy soil

The reductive dechlorination and behavior of p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) was investigated in a paddy soil. Treatment with 5% (w/w) metallic iron (Fe(0)) resulted in sharp decrease of p,p'-DDT, whereas there was no extra effect when 2% (w/w) aluminum sulfate (Al(2)(SO(4))(3)) was added to the Fe(0) treatment. These results suggest that Fe(0) could effectively promote the reductive dechlorination of p,p'-DDT and its metabolites while Al(2)(SO(4))(3) did not show any effect on those processes. Furthermore, p,p'-DDT and its daughter compounds inhibited holistic soil respiration greatly at first but could be metabolized by certain species of indigenous microorganisms after a period of adaptation time in the soil. When treated with Fe(0), the polluted soil produced much less CO(2) while the addition of Al(2)(SO(4))(3) counteracted its negative effect to much extent.     

Transport of rimsulfuron and its metabolites in soil columns

This paper presents a study on degradation, sorption and transport of the sulfonylurea herbicide rimsulfuron and its major metabolites in alluvial soil columns. The formulation of rimsulfuron was found to strongly affect its degradability. Hydrolysis of pure rimsulfuron takes place rapidly in distilled water (t(1/2)=2.2 days) or indeed instantaneously in alkaline solution. The formulated rimsulfuron (Titus, 25% rimsulfuron, Du Pont De Nemours) is more persistent in alluvial soil suspensions (t(1/2)=7.5 days). The study of sorption of Titus and its two major metabolites (1 and 2) revealed that these three chemicals are potentially highly mobile in the studied soil: in suspension distribution coefficients of 0.0028, 0.125 and 0.149 cm3 g(-1) were obtained respectively. Given the instability of rimsulfuron in alkaline solutions, the pH effect was evaluated with metabolite 2 in water saturated Fontainebleau sand columns at pH 6, 8 and 10. Transport was found to be strongly dependent on pH; a linear relationship was obtained between pH and the retardation factor or the dispersion coefficient. In alluvial soil columns, rimsulfuron from Titus was found to be very mobile (R=1.2) and rapidly degraded into metabolites 1 and 2, which were transported at a similar velocity. Nevertheless, the risks of groundwater contamination by rimsulfuron seem very low, as it is rapidly degraded under dynamic conditions (t(1,2)=1.4 days). On the other hand the relatively stable metabolite 2 seems likely to persist in the soil and to be transported to the groundwater. Special attention should thus be given to this compound at least as long as its harmlessness is not demonstrated.     

负载型TiO2在印染废水降解中的失活及原因分析

研究了负载型TiO2光催化剂在印染废水降解中的失活及其产生的原因.实验结果说明,催化剂活性下降的主要原因有废水中不溶于水的染料等悬浮物和催化反应中产生的无定形碳在催化剂表面的吸附;高含量的无机离子对催化剂活性位的占据或在表面的沉积;长时间的使用和反复冲洗使TiO2负载量减少.通过同时采用灼烧和酸洗的方法可以使TiO2的活性恢复到新催化剂的69.5%.     

Degradation in soil and water and ecotoxicity of rimsulfuron and its metabolites.

The degradation and ecotoxicity of sulfonylurea herbicide rimsulfuron and its major metabolites were examined in batch samples of an alluvial sandy loam and in freshwater. An HPLC-DAD method was adapted to simultaneously identify and quantify rimsulfuron and its metabolites, which was successfully validated by GC-MS analysis. In aqueous solutions, pure rimsulfuron was rapidly hydrolyzed into metabolite 1 (N-(4,6-dimethoxypyrimidin-2-yl)-N-(3-(ethylsulfonyl)-2-pyridinylurea)), which itself was transformed into the more stable metabolite 2 (N-((3-(ethylsulfonyl)-2-pyridinyl)-4,6-dimethoxy-2-pyrimidineamine)), with half-life (t(1/2)) values of 2 and 2.5 days, respectively. Hydrolysis was instantaneous under alkaline conditions (pH = 10). In aqueous suspensions of the alluvial soil (pH = 8), formulated rimsulfuron had a half-life of 7 days, whereas that of metabolite 1 was similar to that in water (about 3.5 days). The degradation of the two major metabolites was also studied in soil suspensions with the pure compounds at concentrations ranging from 1 to 10 mg l(-1). The half-life of metabolite 1 ranged from 3.9 to 5 days, close to the previous values. Metabolite 2 was more persistent and its degradation is strongly dependent on the initial concentration (C0): half-life values ranged from 8.1 to 55 days at 2-10 mg l(-1), respectively. These values are higher than those determined from the kinetics of metabolite 1 transformation into metabolite 2 (t(1/2) = 8-19 days). The ecotoxicity of the three chemicals was evaluated through their effect on Daphnia magna and Vibrio fischeri (Microtox bioassay). No effect was observed on D. magna with 24 and 48 h acute toxicity tests. Similarly, no toxic effect was observed with the Microtox test for the three chemicals in the range of concentrations tested that included the field application dose. Thus, being of low persistence and lacking acute toxicity, these chemicals present a low environmental risk. However, chronic effects should be studied in order to confirm the safety of rimsulfuron and its major metabolites.     

Semen quality as a potential susceptibility indicator to SARS-CoV-2 insults in polluted areas

Environmental Science and Pollution Research - The epidemic of the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has impacted worldwide with its infectious spread and mortality...     

Hydroxychloroquine in COVID-19: therapeutic promises,current status,and environmental implications

Environmental Science and Pollution Research - The outbreak of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected the entire world with its infectious spread and...     

TiO2光催化剂在污水处理中的应用

在污水处理方面TiO2光催化剂以其独特的氧化活性、光学性能和无机化能力引起了人们极大的关注.对TiO2光催化原理、农药、染料和环境荷尔蒙等有机污染物的分解,提高催化效率的方法以及其实用技术等方面,分别作了综合评述.     

Effects of H2O2 on growth,metabolic activity and membrane integrity in three strains of Microcystis aeruginosa

Environmental Science and Pollution Research - The application of hydrogen peroxide (H2O2) as a management tool to control Microcystis blooms has become increasingly popular due to its short...     

高盐废水盐度对中度嗜盐菌生长动力学的影响

高盐废水盐度变化是影响微生物生长的重要因素之一。研究以中度嗜盐菌Halomonassp．STSY．3为例,测定其在不同盐度下生长对数期末OD600,并以葡萄糖为限制性基质,利用Monod方程,对菌株进行生长动力学拟合。结果表明,Halomonassp．STSY-3的最适生长盐度为7％（以NaCl计）,此盐度下其OD600 为2．56,而0%和34％盐度下OD600分别为0．47和0．06;Halomonassp．STSY-3的生长动力学模型与实验数据能较好地拟合,在最适生长盐度下动力学模型参数μmax 为2．257h-1,Ks为0．0082g／L。比较不同盐度下STSY-3生长动力学参数,得出中度嗜盐菌STSY-3的生长存在3个明显分区：最适盐度区（盐度2％～9％）、嗜盐过渡区（盐度9％～20％和0．68％～1．76％）及生长抑制区（盐度≤2％或≥20％）。其中嗜盐过渡区0．68％～1．76％由于范围较小,实际意义小,忽略不计。     

Metabolism of 2-chloro-N-isopropylacetanilide (propachlor) in the rat.

Eleven urinary metabolites from [14C]propachlor were either identified or characterized by mass spectrometry. Those identified were 2-[S-(N-acetyl)cysteinyl]-N-isopropylacetanilide, 2-(methylsulfonyl)-acetanilide, 4'-hydroxy-2-(methylsulfonyl)-acetanilide, and 4'-hydroxyacetanilide. Those characterized were N-(1-hydroxyisopropyl)-2-(methylsulfonyl) acetanilide and its glucuronide, the glucuronides of 4'-hydroxy-N-isopropyl-2-(methylsulfonyl)acetanilide, N-(1-hydroxyisopropyl) aniline, 4'-hydroxy-2-(methylsulfonyl)acetanilide, and either N-(1-hydroxy-isopropyl) acetanilide or 2-hydroxy-N-isopropylacetanilide.     

Effects of biochar on nitrification and denitrification-mediated N2O emissions and the associated microbial community in an agricultural soil

Environmental Science and Pollution Research - Nitrous oxide (N2O) is a strong greenhouse gas, and it is of great significance for N2O reduction to study the effects of biochar on its production...     

Does regional energy consumption disparities assist to control environmental degradation in OBOR: an entropy approach

China launched the One Belt & One Road (OBOR) initiative to minimize the energy resource shortage. The China’s nearby countries are rich in energy resources especially Middle East and North Africa (MENA) and Asian countries which make them ideal locations to cooperate with China in terms of energy resources, as 42.8% of world energy consumption belongs to OBOR countries. The present study elaborates the spatial distribution pattern of energy consumption disparities and its impact on environment. To do this, an entropy approach is utilized to compute the energy consumption inequalities in OBOR and its regions. The spatial and Pareto analysis show that MENA, East, and Southeast Asian economies have the highest degree of energy consumption inequalities, while European and Central Asian economies show the lowest energy consumption inequalities in OBOR region. The long-run estimates indicate that energy consumption inequalities enhance the CO₂ emission in OBOR and its region except South and Southeast Asia. Financial development also has a significantly positive impact on CO₂ emission in all models for OBOR and its regions except East Asia. Based on findings, the spatial distribution analysis is applicable to maintain balance in regional energy consumption inequality within OBOR and its regions.

     

Inhibitory effects of catechol accumulation on benzene biodegradation in Pseudomonas putida F1 cultures

The influence of benzene concentration on the specific growth rate (mu), CO(2) and metabolite production, and cellular energetic content (i.e., ATP content), during benzene biodegradation by Pseudomonas putida F1 was investigated. Within the concentration range tested (5-130mg benzene l(-1)) the mu, the specific CO(2) production, and the ATP content remained constant at 0.42-0.48h(-1), 1.86+/-0.21g CO(2) g(-1) biomass, and 5.3+/-0.4x10(-6)mol ATP g(-1) biomass, respectively. Catechol accumulated during process start-up at all tested concentrations. Catechol specific production increased with increasing benzene inlet concentrations. This confirms that the transformation of this intermediate was the limiting step during benzene degradation. It was shown that catechol inhibited both the conversion of benzene to catechol and its further transformation. In addition, catechol concentrations higher than 10mgl(-1) significantly decreased both benzene and catechol associated respiration, confirming the highly inhibitory effect of this intermediate. This inhibitory threshold concentration was approximately two orders of magnitude lower than the concentrations present in the culture medium during process start-up, suggesting that cellular activity was always far below its maximum. Thus, due to its toxic and inhibitory nature and its tendency to accumulate at high benzene loading, catechol must be carefully monitored during process operation.     

A wood preservative metabolite in river water

- A previously unknown pollutant in river water was identified to be 2-mercaptobenzothiazole (2-MBT) by interpretation and simulation of its GC/LRMS spectrum. Further GC/HRMS measurement of the isotope composition of the molecular ion verified this structure. 2-MBT is a well-known agent for corrosion inhibition and a stable metabolite of several other benzothiazoles. The present 2-MBT trace was most probably a metabolite of the wood preservative TCMTB which leaked from an upstream sawmill. The metabolite had been detected earlier in urine of the sawmill workers, but now was identified in the recipient water environment for the first time.     

Photolysis of PAHs in aqueous phase by UV irradiation.

The photooxidation of polycyclic aromatic hydrocarbons (PAHs) was investigated in an aqueous ethanolic solution irradiated with a medium-pressure mercury lamp in laboratory photoreactors equipped with a quartz immersion well. Degradation photolysis of fluorene was more efficient than sensitized photolytic oxidation in the presence of TiO2 suspensions. Photolysis kinetics was dependent on molecular weight and the presence and type of substituents. During the photolytic degradation of fluorene and its derivatives, 9-fluorenone and its corresponding derivatives, which were more resistant to photolysis, were formed.     

交联壳聚糖对重金属离子的吸附性能研究

以海蟹壳为原料制备的壳聚糖在碱性条件下,经环氧氯丙烷交联制得水不溶性的交联壳聚糖,采用静态法研究交联壳聚糖对Ｃｕ＾２＋,Ｃｒ＾３＋,Ｎｉ＾２＋,Ｐｂ＾２＋,Ｚｎ＾２＋,Ｈｇ＾２＋等几种重金属离子的吸附性能及ｐＨ值对吸附性能的影响,探讨了它们的作用机理。     

Uncertainties in the role of land vegetation in the carbon cycle

Since the late 1950s the CO2 concentration of the atmosphere has been increasing by around 0.5-3 ppm per year. Understanding of carbon sinks is vital to understanding this trend and its future behaviour. Here we examine some of the factors which may affect the proportion of anthropogenic CO2 ending up in the atmosphere in the present and in the future, and variability in the CO2 increase from one year to another. We also examine the evidence for the potential of terrestrial ecosystem carbon sinks to take up or release CO2. In some cases, a careful re-examination of the research methods used to deduce present and future feedbacks may be necessary. The most advanced technology and the most complex models do not necessarily produce reliable results. They should be carefully checked against a general background knowledge of ecological processes before their results are accepted.