碳酸盐对土壤中外源钕交换态及生物有效性的影响

用放射性同位素147Nd示踪法，以pH8.2的NaAc为交换态Nd的提取剂，研究了碳酸盐对土壤对外源Nd的交换态及生物有效性的影响，无论酸盐存在与否，加入土壤中的Nd,99%以上均被吸附；碳酸盐在低浓度时，能够降低土壤中交换态Nd含量，碳酸盐在高浓度时，对交换态Nd含量影响作用不明显，实验还表明碳酸盐在0．8－1.6g.kg^-1范围内有明显降低Nd植物有效性的作用，浓度升高到4．0g.kg^-1时，对植物吸收Nd的抑制作用不明显。     

Nuclear methods for food analysis at the U. S. Food and Drug Administration

An overview of radioanalytical techniques used in support of research,monitoring programs, and field assignments directed by the U. S. Food andDrug Administration's Center for Food Safety and Applied Nutrition (CFSAN)is presented. The Winchester Engineering and Analytical Center annually determinesradionuclide concentrations in 260 Total Diet Study foods, approximately 80imported foods, and a selection of domestic foods collected near U. S. nuclearpower plants. Radioanalytical techniques used at CFSAN's neutron activationanalysis laboratory at the National Institute of Standards and Technologyare discussed along with applications for research, quality control, and specialprojects.     

吉林某弹药销毁场土壤炸药污染调查及其赋存状态研究

研究吉林某军事弹药销毁场土壤炸药污染程度以及炸药在土壤中的赋存状态,为炸药和重金属污染土壤修复提供针对性策略。采集了某弹药销毁厂焚烧销毁区表层土壤样品,分析了其理化性质和常见重金属元素含量,测试了土壤全样和不同颗粒度土壤样品中炸药污染物的含量,并结合热重-傅里叶变换红外光谱(TGA-FTIR) 对炸药污染土壤样品热力学行为的表征,探讨了炸药污染物的赋存状态,炸药和重金属组合污染特征等。土壤中含有高浓度的TNT、DNT、ADNT、RDX等炸药污染物及其降解产物,并表现出土壤细颗粒富集趋势,其中土壤全样中TNT总浓度达到了1.66×104 mg·kg-1,远远高于EPA推荐的土壤TNT指导限值,RDX超过了以土壤环境为目标的指导限值;销毁活动还造成了土壤中Pb、Cu、Zn重金属浓度的升高,分别为400 mg·kg-1,318 mg·kg-1,1030 mg·kg-1。土壤中受到重金属和有机质等因素的影响,土壤中经过长期老化的炸药污染物的热解行为明显不同于自由态的炸药分子,热解温度升高、过程延长。在销毁区炸药污染土壤的修复中,应加强炸药污染物与重金属相互作用的研究,并在修复治理实践中采取协同修复的策略。     

U.S. EPA Regulatory Perspectives on the Use of QSAR for New and Existing Chemical Evaluations

Abstract

As testing is not required, ecotoxicity or fate data are available for ≈ 5% of the approximately 2,300 new chemicals/year (26,000 + total) submitted to the US-EPA. The EPA's Office of Pollution Prevention and Toxics (OPPT) regulatory program was forced to develop and rely upon QSARs to estimate the ecotoxicity and fate of most of the new chemicals evaluated for hazard and risk assessment. QSAR methods routinely result in ecotoxicity estimations of acute and chronic toxicity to fish, aquatic invertebrates, and algae, and in fate estimations of physical/chemical properties, degradation, and bioconcentration. The EPA's Toxic Substances Control Act (TSCA) Inventory of existing chemicals currently lists over 72,000 chemicals. Most existing chemicals also appear to have little or no ecotoxicity or fate data available and the OPPT new chemical QSAR methods now provide predictions and cross-checks of test data for the regulation of existing chemicals. Examples include the Toxics Release Inventory (TRI), the Design for the Environment (DfE), and the OECD/SIDS/HPV Programs. QSAR screening of the TSCA Inventory has prioritized thousands of existing chemicals for possible regulatory testing of: 1) persistent bioaccumulative chemicals, and 2) the high ecotoxicity of specific discrete organic chemicals.     

Collection and Identification of Trace Organic Compounds in Atmospheric Deposition from a Semi-Rural Site in the U.K.

Abstract

The collection of rainwater, aerosol and vapour samples at a semi-rural site in the UK was achieved using a PTFE-lined wet-only rainfall collector and a high-volume filter/adsorption trap air sampler, respectively. Analysis of atmospheric deposition revealed the presence of several hundred compounds, many of which were of anthropogenic origin, e.g.: PAH, phenols and alkylbenzenes. Amounts of compounds varied from low nanograms to tens of micrograms per litre in rainwater samples and from low picograms to high nanograms per cubic metre in aerosols. Phenolic compounds were the most abundant group of organics identified in rainwater and were present at total concentrations of >20μg1^?1 in some of the samples analysed. In the high-volume air samples most anthropogenic compounds were detected in the adsorbent rather than the filter extract. Seasonal variations in the PAH content of the adsorbent extracts were observed. The presence of siloxanes in the air samples was thought to be the result of contamination.     

Evaluation of Colilert-18 for detection and enumeration of fecal coliform bacteria in wastewater using the U.S. Environmental Protection Agency Alternative Test procedure Protocol

This study compared recovery of fecal coliform bacteria from sewage by Colilert-18 and Standard Methods 9222D (membrane-Fecal Coliform medium) in accordance with the U.S. Environmental Protection Agency (EPA) Alternative Test Protocol (ATP). Samples were collected from 10 different wastewater treatment plants in the northeastern United States and tested in a single laboratory. Twenty replicates of each sample were analyzed by each method, and 200 positive and 200 negative responses were confirmed for each method. Recovery of fecal coliforms by Colilert-18 was significantly higher than (8 of 10 sites) or statistically equivalent to (1 of 10 sites) recovery by the reference method (Standard Methods 9222D) for samples from all but one site. Both methods had low false-positive rates (< 2%); however, the false-negative rate observed with Standard Methods 9222D (21.5%) was substantially higher than that observed with Colilert-18 (7%). The accuracy rates of the two methods were calculated as 96.5 and 88.9% for Colilert-18 and Standard Methods 9222D, respectively. The results of this study demonstrate that Colilert-18 meets the acceptance criteria for alternative methods specified in the EPA ATP.     

Validation of the SL3 beta-Lactam Test for screening milk in compliance with U.S. pasteurized milk ordinance: performance tested method 040701

The SL3 beta-Lactam Test is a 3 min, receptor-based lateral flow Rapid One Step Assay (ROSA) that detects 5 of 6 beta-lactam drugs approved for dairy cattle in the United States. The method was evaluated through the AOAC Research Institute Performance-Tested Method program following a U.S. Food and Drug Administration protocol. Three combined lots detected penicillin G 4.2 parts per billion (ppb), ampicillin 8.7 ppb, amoxicillin 7.8 ppb, cephapirin 16.0 ppb, and ceftiofur (total metabolites) 51 ppb at least 90% of the time, with 95% confidence as determined by dose response probit analysis. These detection levels are less than safe level/tolerances but not more than 50% less. Lot repeatability was within 20%. Incurred residues were detected comparably or more sensitively to fortified samples due to the cumulative effect of biologically active metabolites. There were no interferences from somatic cells at 1 M/mL, bacterial cells 500 000 colony-forming units/mL, or 30 other non-beta-lactam drugs. These performances met approval conditions of the National Conference on Interstate Milk Shipments. Ruggedness conditions were incorporated into public health procedures for annual laboratory proficiency and certification.     

运动和碳酸钙联合应用对去卵巢大鼠骨矿盐代谢的影响

用测定骨矿盐含量的方法,观察了运动和碳酸钙（CaCO3）联合应用对去卵巢大鼠骨矿盐代谢的影响。将健康4月龄雌性SD大鼠30只,用抽签法随机分成5组：正常对照组,假去卵巢组,去卵巢组,去卵巢＋CaCO3组,去卵巢＋CaCO3＋运动组。去卵巢＋CaCO3组和去卵巢＋CaCO3＋运动组大鼠于切除卵巢术后第2天开始给予CaCO3灌胃[元素钙20mg／（kg·d）],持续11周;去卵巢＋CaCO3＋运动组大鼠于去卵巢术后第7天开始运动训练,每周5d,每天连续匀速跑45min,16m／min,跑道倾角0°,持续10周。结果表明,去卵巢组大鼠骨干质量、骨干质量／体质量、骨灰质量、骨灰质量／体质量、骨灰质量／骨干质量（％）均明显低于假去卵巢组;去卵巢＋CaCO3组大鼠骨干质量、骨干质量／体质量、骨灰质量、骨灰质量／体质量、骨灰质量／骨干质量（％）等指标虽然较去卵巢组增加,但骨灰质量、骨灰质量／体质量、骨灰质量／骨干质量（％）等指标仍显著低于假去卵巢组;运动和CaCO3联合应用后,上述各指标均显著回升,并且基本恢复到对照组水平。提示运动可加强CaCO3抗去卵巢大鼠骨矿盐丢失的作用。     

碳酸二甲酯和乙酸苯酯合成碳酸二苯酯的研究—焙烧温度对MoO3催化剂性能的影响

用焙烧法制备了碳酸二甲酯（DMC）与乙酸苯酯（PA）酯交换合成碳酸二苯酯（DPC）反应的正交晶系MoO3催化剂,并用N2吸附-脱附法（BET）、X射线衍射（XRD）、扫描电镜（SEM）等表征手段,考察了焙烧温度对催化剂结构和催化性能的影响．结果表明,随着焙烧温度的升高,催化剂的比表面积逐渐减小,正交晶系MoO3的（11...     

氟涂层对聚合物-钴卟啉膜氧气输送性能及其寿命的影响

采用在聚合物-钴卟啉(CoP)膜表面旋转涂覆氟涂料法,制备了氧/氮分离膜.研究表明,与未涂层膜相比,氟涂层膜中的CoP与氧表观结合平衡常数、膜的氧渗透系数和氧/氮选择性没有发生明显变化.随氟涂层厚度增加,氧渗透系数稍有降低,但水蒸汽渗透系数显著降低.由于氟涂层的憎水性,使涂层膜的水蒸汽渗透系数显著降低,氧载体CoP与氧结合寿命延长了4倍.     

ChemInform Abstract: DFT Analysis of Cubane‐Type FeIr3S4 Clusters. Dinitrogen Binding and Activation at the Tetrahedral Fe Site.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Effect of gramicidin on phospholipid-modified monolayers and on ion transfer at a liquid-liquid interface.

The interaction of hybrid lipid/gramicidin A (gA) monolayers with dextran sulfate (DS) and the effect of this interaction on ion transfer at a liquid-liquid interface is reported. The interfacial and physicochemical properties are studied with Langmuir-Blodgett (LB) and electrochemical techniques. The results obtained from compression isotherms demonstrate that the interactions between the different species in the hybrid monolayer vary according to the chemical nature of the lipid (hydrocarbon region and charge of the head group). Interfacial capacitance measured with AC voltammetry indicates that the DS chains form a rather flat and compact layer when adsorbed to either zwitterionic or negatively charged phospholipid monolayers, and that calcium, even at low concentrations, interacts with the monolayers. These results are successfully described by a model based on the solution of the Poisson-Boltzmann equation in the interfacial region. Ion transfer and interactions with the lipid/gA/DS-modified monolayers were also studied with electrochemical techniques. Admittance data show that although the studied ions are not using gA channels for the transfer through the lipid membranes, the incorporation of gA in the lipid domain and the adsorption of DS at the interface have a significant effect on ion transfer across the monolayers. This effect can be explained as a consequence of the modified surface charge and of the compactness of the lipid domain due to its interaction with gA and to calcium and DS adsorption at the interface. The ion-transfer rate, therefore, depends on the composition of the monolayer and the chemical nature of the ion.     

The U.S. Department of Energy (DOE) Sampling and Analytical Chemistry Guide: Doe Methods for Evaluating Environmental and Waste Management Samples

Abstract

DOE Methods for Evaluating Environmental and Waste Management Samples (DOE Methods) is a guidance/methods document to support sampling and analysis activities at DOE sites. DOE Methods is intended to supplement existing guidance documents (e.g., EPA's Test Methods for Evaluating Solid Waste, SW-846), which generally apply to low-level or nonradioactive samples. DOE Methods targets the complexities of DOE radioactive mixed waste and environmental samples. The document contains quality assurance (QA), quality control (QC), safety, sampling, organic analysis, inorganic analysis, and radioanalytical guidance as well as sampling and analytical methods. An addendum is distributed every six months (April and October) with updated guidance and additional methods.

DOE Methods provides a vehicle for technology transfer within the environmental restoration (ER) and waste management (WM) (collectively known as EM) community. As DOE Methods evolves, its usefulness and applicability are anticipated to grow to meet the demands of the DOE/EM mission. At the present time, DOE Methods contains methods and guidance information supplied by DOE sites. Because the EM activities in DOE are not unique to the United States, the international environmental community could benefit from the information gathered for the DOE program. This information could provide additional resources for their EM activities.     

助剂对合成碳酸二甲酯用活性炭负载Wacker催化剂结构和性能的影响

 以碱金属或碱土金属的盐或氢氧化物为助剂修饰活性炭(AC)负载的Wacker催化剂PdCl2-CuCl2. 甲醇气相氧化羰基化合成碳酸二甲酯(DMC)的反应活性评价结果表明,以乙酸钾(KOAc)为助剂的效果最好. 在KOAc/CuCl2摩尔比为1.0的条件下制备的催化剂用于该合成反应时,DMC的时空产率提高了5倍. XRD,SEM及EPR表征结果显示,在催化剂中加入适量的KOAc,有利于Cu2Cl(OH)3物相在载体表面的形成和分散,从而加快了催化剂活性物种Cu和Pd的氧化还原循环速度.