Sodium borohydride reduction of individual polybrominated diphenyl ethers

Many chemicals in use today lack appropriate documentation on their environmental properties, fate, and effects. To counteract this lack of documentation it is vital to thoroughly investigate a compound’s fate in the environment before it comes into use. The present study is describing a novel method for assessing the reduction potential of polybrominated diphenyl ethers (PBDEs), as a part of a project aimed to create an experimental model for determination of chemical persistence. The reductive transformation of 15 PBDE congeners using sodium borohydride was determined. Pseudo-first-order reaction rate constants of the transformations were determined by monitoring the disappearance of the investigated congeners. The reductions lead primarily to formation of lower brominated PBDEs. Each PBDE congener was tested in a total of ten replicates which showed a relative standard deviation of 31% or less. The decaBDE, BDE-209 was approximately 3 times as prone to reductive transformation as BDE-207. The three nonaBDEs, BDE-206, BDE-207, and BDE-208, showed similar reductive potential. The reactivity of the tested octaBDEs was quite variable, from 5% to 24% of the reactivity of BDE-209 for BDE-196 and BDE-198, respectively. The heptaBDEs studied were in the range of the less reactive octaBDEs, except for BDE-181 which was as high as 13% of the reactivity of BDE-209. The results presented give a method for measuring the propensity of PBDEs, and possibly similar compounds, to undergo reductions. They indicate a potential route to a vital piece of information in the assessment of environmental persistence of chemicals.     

沈阳市地表水持续稳定达标关键措施与对策探讨

对沈阳市地表水环境特征及水质达标现状进行了分析,论述了地表水变化趋势,提出了实现地表水持续稳定达标的技术路径,要实现地表水环境质量持续稳定达标,必须采取优化经济结构及布局,持续推进污水集中控制,强化污染源治理,实施农村环境综合整治,提升河流生态环境质量和水体自净能力,强化水环境政策制度建设及环境监管等有效措施。     

Use of Fe/Al drinking water treatment residuals as amendments for enhancing the retention capacity of glyphosate in agricultural soils

Fe/Al drinking water treatment residuals (WTRs), ubiquitous and non-hazardous by-products of drinking water purification, are cost-effective adsorbents for glyphosate. Given that repeated glyphosate applications could significantly decrease glyphosate retention by soils and that the adsorbed glyphosate is potentially mobile, high sorption capacity and stability of glyphosate in agricultural soils are needed to prevent pollution of water by glyphosate. Therefore, we investigated the feasibility of reusing Fe/Al WTR as a soil amendment to enhance the retention capacity of glyphosate in two agricultural soils. The results of batch experiments showed that the Fe/Al WTR amendment significantly enhanced the glyphosate sorption capacity of both soils (p < 0.001). Up to 30% of the previously adsorbed glyphosate desorbed from the non-amended soils, and the Fe/Al WTR amendment effectively decreased the proportion of glyphosate desorbed. Fractionation analyses further demonstrated that glyphosate adsorbed to non-amended soils was primarily retained in the readily labile fraction (NaHCO₃-glyphosate). The WTR amendment significantly increased the relative proportion of the moderately labile fraction (HCl-glyphosate) and concomitantly reduced that of the NaHCO₃-glyphosate, hence reducing the potential for the release of soil-adsorbed glyphosate into the aqueous phase. Furthermore, Fe/Al WTR amendment minimized the inhibitory effect of increasing solution pH on glyphosate sorption by soils and mitigated the effects of increasing solution ionic strength. The present results indicate that Fe/Al WTR is suitable for use as a soil amendment to prevent glyphosate pollution of aquatic ecosystems by enhancing the glyphosate retention capacity in soils.     

地埋式无动力生活污水处理装置调查及技术探讨

介绍了目前无锡的部分宾馆，饭店、疗养院地进式无动力生活污水处理装置的运行情况及处理效果。对该装置如何解决完善调节池出水水量的稳定和提高氧化沟内废水的溶解氧提出了一些改进意见和设想。     

砷形态水样贮存方法及稳定性研究

设计了不同试样、不同浓度、不同酸度、不同温度以及不同容器条件的贮存方案，对含砷形态化合物水样的贮存和砷形态稳定性进行了研究。认为，人为酸化水样不利于砷形态的稳定；塑料瓶作容器、低温对砷形态水样的保存有利。本研究为水质监测砷形态提供了必要依据。     

A New Mathematical Approach in Environmental and Life Sciences: Gene–Environment Networks and Their Dynamics

An important research area in life sciences is devoted to modeling, prediction, and dynamics of gene-expression patterns. As clearly understood in these days, this enterprise cannot become satisfactory without acknowledging the role of the environment. To a representation of past, present, and most likely future states, we also encounter measurement errors and uncertainties. This paper surveys and improves recent advances in understanding the foundations and interdisciplinary implications of the newly introduced gene–environment networks, and it integrates the important theme of carbon dioxide emission reduction into the networks and dynamics. We also introduce some operational and managerial issues of practical working and decision making, expressed in terms of sliding windows, quadrants (modules) of parametric effects, and navigating (controlling) between such effects and directing them. Given data from DNA microarray experiments and environmental records, we extract nonlinear ordinary differential equations that contain parameters that have to be determined. For this, we employ modern (Chebychevian) approximation and (generalized semi-infinite) optimization. After this is provided, time- discretized dynamical systems are studied. A combinatorial algorithm with polyhedra sequences allows to detect the region of parametric stability. Finally, we analyze the topological landscape of gene–environment networks with its structural (in)stability. By embedding as a module and investigating CO₂ emission control and figuring out game theoretical aspects, we conclude. This pioneering work is theoretically elaborated, practically devoted to health care, medicine, education, living conditions, and environmental protection, and it invites the readers to future research.      

The stability of sarin and soman in dilute aqueous solutions and the catalytic effect of acetate ion

Abstract

The hydrolysis of aqueous solutions of organophosphonate compounds such as sarin and soman is a critical factor in biochemical and therapeutic studies. The ability to dilute and transport these compounds with assurance of their purity is imperative to the integrity of such studies. An enzymic method has been used to measure low levels of organophosphonates. Maximum stability data were determined in aqueous and isotonic saline solutions. Acetate ion was found to significantly accelerate hydrolysis.¹     

弹塑性极限平衡法分析复杂岩质边坡的稳定性

笔者采用弹塑性极限平衡法来研究分析复杂岩质边坡的稳定性 ,即以塑性极限理论为基础 ,应用逐渐降低材料强度来逼近系统的极限平衡 ,并以屈服区的贯通来表征系统的极限平衡状态。此时 ,系统达到临界平衡状态时所对应的材料强度降低倍数即为整体最小安全系数 ,临界平衡状态定义为边坡内的塑性屈服区能够形成潜在的滑移通道时的状态。以城门山露天矿南帮边坡为研究对象 ,通过自行改编的NCAP -FS程序进行了数值分析 ,结果表明 ,南帮边坡现阶段是安全稳定的 ,与现场观测结果一致。     

评估固体废弃物堆肥腐熟和稳定的研究

用化学方法、生物活性及植物毒性分析等技术，从腐熟和稳定两个方面对堆肥成熟的评估方法作了综述，推荐了几种常用，有用的评估堆肥腐熟和稳定的方法，包括微生物、ＣＯ２的产和玫Ｏ２的吸收、植物发芽实验、水溶性有机Ｃ／Ｎ比和腐殖质等化合物的组分的变化，随着分析技术和微生物技术发展，先进、快捷的堆肥评估方法，不断出现，堆肥的生产和使用者可根据实际情况，选择合适的评估方法     

Construction of Ag2CO3/BiOBr/CdS ternary composite photocatalyst with improved visible-light photocatalytic activity on tetracycline molecule degradation

Photocatalytic degradation was considered as a best strategy for the removal of antibiotic drug pollutants from wastewater. The photocatalyst of ABC (Ag₂CO₃/BiOBr/CdS) composite synthesized by hydrothermal and precipitation method. The ABC composite used to investigate the degradation activity of tetracycline (TC) under visible light irradiation. The physicochemical characterization methods (e.g. scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution-transmission electron microscopy (HR-TEM), ultraviolet visible spectroscopy (UV), photoluminescence (PL) and time resolved photoluminescence (TRPL) clearly indicate that the composite has been construct successfully that enhances the widened visible light absorption, induces charge transfer and separation efficiency of electron – hole pairs. The photocatalytic activity of all samples was examined through photodegradation of tetracycline in aqueous medium. The photocatalytic degradation rate of ABC catalyst could eliminate 98.79% of TC in 70 min, which is about 1.5 times that of Ag₂CO_3, 1.28 times that of BiOBr and 1.1 times that of BC catalyst, respectively. The role of operation parameters like, TC concentration, catalyst dosage and initial pH on TC degradation activity were studied. Quenching experiment was demonstrated that ·OH and O₂^·− were played a key role during the photocatalysis process that was evidently proved in electron paramagnetic resonance (EPR) experiment. In addition, the catalyst showed good activity perceived in reusability and stability test due to the synergistic effect between its components. The mechanism of degradation of TC in ABC composite was proposed based on the detailed analysis. The current study will give an efficient and recyclable photocatalyst for antibiotic aqueous pollutant removal.