硝基苯和西维因在活性炭上的吸附效果及动力学研究

测定分析了活性炭的孔隙结构、表面性质及化学组成,研究了硝基苯和西维因在活性炭上吸附的等温线及动力学特征,结果表明Polanyi-Manes模型和二级动力学方程具有较高的拟合相关系数,说明吸附可能是以色散力为主的多过程复杂反应,活性炭对西维因的吸附容量及吸附速率略小于硝基苯,快速吸附过程与慢速吸附过程的差距较为明显,说明吸附质分子大小和吸附剂孔隙结构是影响吸附的重要因素;溶液Na+浓度对吸附的影响很小,可能由于介质离子强度对分子间色散力的影响较小.     

急性毒性藻红外测试中联合作用的评价方法（Evaluation Method for Combined Toxicity Effects in the Measure of Alage Infrared Radiation for Acute Toxicity）

藻红外测试中联合作用的评价方法是急性毒性藻红外测试法的重要组成,为建立其评价方法,用敏感藻和重金属、有机药品、农药开展了探索性实验.首先确定联合作用系数θ的计算式和总均偏差系数f,用其构建联合偏差系数法;再用实验得到的f=0.06调整相加作用的θ理论值(θ=1),联合偏差系数θi分别在大于、等于、小于1+0.06或1-0.06时,评价联合作用类型;最后进行二元药品对敏感藻联合作用的验证实验,验证联合偏差系数法的可行性.结果发现,4种重金属6种混合对短线脆杆藻(Fragilaria brevistriata)的联合作用为:3次拮抗作用,2次独立作用,1次相加作用;4种有机药品6种混合对羊角月牙藻(Selenastrum capricornutum)的联合作用为:2次协同作用,3次独立作用,1次拮抗作用;8种农药12种混合对水华鱼腥藻、纤细裸藻的联合作用为:9次拮抗作用,3次独立作用;一组验证实验包括藻液加药、测试、计算和评价,共需要60min,而用光密度、细胞数、叶绿素含量、细胞干重作为测试指标进行藻类急性毒性实验,需要24h～96h.对验证结果分析可知,用所构建的联合偏差系数法评价二元药品对敏感藻的联合作用,具有可行、快速、简便的优势.     

城市加油站苯系物污染状况

在重庆地区利用苏马罐系统和气相色谱质谱分析方法对加油站及其周边空气中苯系物进行了初步监测。结果发现,几种苯系物均有检出,各监测点苯系物总体浓度介于0.34-11.33 mg/m3之间,其中苯浓度最高,各点浓度为0.07-3.57 mg/m3,二甲苯其次,苯乙烯最低。从不同监测点来看,卸油区和加油区苯系物浓度普遍较高,环境敏感点相对较低。     

开封市城区冬季大气挥发性有机物污染特征及来源解析

为探究开封市冬季大气挥发性有机物(VOCs)的污染特征及来源,基于2021年12月至2022年1月开封市生态环境局(城区)在线监测站获取的大气VOCs组分数据,阐述其VOCs污染特征和二次有机气溶胶生成潜势(SOAP),利用PMF模型解析出VOCs的来源.结果表明,冬季开封市ρ(VOCs)平均值为(104.71±48.56)μg·m^-3,其质量分数最高为烷烃(37.7%),其次为卤代烃(23.5%)、芳香烃(16.8%)、 OVOCs(12.6%)、烯烃(6.9%)和炔烃(2.6%).VOCs对SOA的贡献平均值为3.18μg·m^-3,其中芳香烃贡献率高达83.8%,其次为烷烃(11.5%);开封市冬季VOCs的最大人为排放来源为溶剂使用(17.9%),其次为燃料燃烧(15.9%)、工业卤代烃排放(15.8%)、机动车排放(14.7%)、有机化学工业(14.5%)和LPG排放(13.3%);溶剂使用源对SOAP的贡献率达到32.2%,其次是机动车排放(22.8%)和工业卤代烃排放(18.9%).可见,降低溶剂使用、机动车排放和工业卤代烃排放的...     

小麦秸秆生物碳质吸附剂从水中吸附硝基苯的机理

在炭化温度为300℃下,以小麦秸秆为材料制备生物碳质吸附剂,采用批量平衡试验,研究了其对水中硝基苯的吸附特性,并从动力学及热力学角度探讨其吸附硝基苯的作用机理.结果表明,硝基苯在生物碳质上的吸附过程符合拉格朗日假二级动力学方程,反应活化能为12.2 kJ/mol;吸附行为可用Freundlich吸附等温方程描述,饱和吸附容量为91.58 mg/g.由吸附热力学方程计算得到的等量吸附焓变(ΔH)<0,吸附自由能变(ΔG)<0,吸附熵变(ΔS)>0,表明生物碳质对硝基苯的吸附为放热和熵减少的自发过程.      

多溴二苯醚类化合物干扰人雌激素受体alpha活性机理的理论研究

基于分子对接方法探讨了多溴二苯醚(PBDEs)类化合物与人雌激素受体α亚型间的分子作用机理.对多溴二苯醚类化合物是否具有拟雌激素功能的研究得出:可通过对接打分值和化合物结构特征来推测PBDEs母体化合物是否具有拟雌激素活性;对HO-PBDEs,与氨基酸残基GLU53和/或ARG394形成氢键可能是影响其拟雌激素活性的重要因素;对MeO-PBDEs,疏水MeO-位于结合腔的疏水中部有利于拟雌激素活性.从结构及构象分析得出,邻位疏水基(Br-、MeO-)有利于PBDEs类化合物的拟雌激素活性.同时对多溴二苯醚类化合物是否具有抗雌激素功能的结合特征研究发现,表现出抗雌激素活性的部分PBDEs类化合物伸进通常被雌激素受体拮抗剂雷洛昔芬和4-羟基它莫西芬的烷基胺侧链占据的通道,而大多数未表现出抗雌激素活性的PBDEs类化合物的结合模式类似雌激素受体激动剂17β-雌二醇,位于结合腔,没有伸进通道.本研究从化合物结构及化合物在受体内结合的构象特征上解释化合物活性不同的原因,以期能够利用构象分析得到的结果进行筛选.     

Monitoring of heavy metals and butyltin compounds in coastal waters of Ligurian Sea: Results of a mussel watch project

From December 1994 up to October 1995 a “Mussel Watch Project”; was carried out to assess the quality of water of the Ligurian Sea and to identify the possible sources of heavy metal pollution. Several metals and organotin compounds were measured in mussels (Mytilus galloprovincialis, Lam) transplanted in different months from a marine farm to eight sites of the Ligurian coast.

Spatial differences and temporal trends in tissue concentrations of Zn, Cu, Ni, Cr, Fe, Al, V, Cd and Mn were evaluated. Concentrations resulted in the same range as those obtained in a previous Mussel Watch Project carried out in the same area. In general, areas of known pollution display high concentrations of these metals, but also some areas not greatly influenced by human activities showed high concentrations of some metals.

Data from this study show little evidence of any overall seasonal pattern except for Cu, Zn and V, concentrations of which were a function not only of sampling site, but also of reproductive cycle.

Organotin compounds show differences in terms of both concentration and speciation between the investigated sites.     

Effects of Cr(III) organic compounds on Lactobacillus plantarum

Biotransformation of Cr(VI) to less toxic Cr(III) has been known to produce insoluble Cr(III) compounds and soluble Cr(III) organic complexes. However, recent research reports have indicated that Cr(III) organic complexes are relatively stable in the environment. Little has been reported on the fate and toxic effects of Cr(III) organic compounds on organisms. In this study, the toxic effects of the soluble Cr(III) organic complexes [Cr(III) citrate, Cr(III) histidine, Cr(III) lactate and Cr(III) glutamate] to a local strain of Lactobacillus plantarum isolated from sauerkraut was investigated. Growth inhibition, viable cell count and lactic acid inhibition were measured to determine the toxicity potential of the test compounds. The EC₅₀ values of Cr(III) citrate, Cr(III) histidine, Cr(III) lactate, and Cr(III) glutamate, calculated from the percent growth inhibition were found to be 56 mg L^?1, 70 mg L^?1, 81 mg L^?1, and 85 mg L^?1, respectively. Similar trend was observed in the viable cell counts and lactic acid production. Cr(VI) was observed to be more toxic than the Cr(III) organic compounds, while inorganic Cr(III) was the least toxic. The severity seemed to increase with increase in chromium compounds’ concentration. The results showed that Cr(III) citrate was the most toxic Cr(III) organic compound, while Cr(III) glutamate was the least.     

Isolation of petroleum and chlorinated hydrocarbons from the same extract

Sequential analysis is an extremely powerful technique for complex samples analysis. For determination of petroleum and chlorinated hydrocarbons, the same sample is divided into two parts. One part is utilized to extract the petroleum hydrocarbons and the second part is used to extract the organochlorine compounds because petroleum hydrocarbons usually appear in higher concentrations and interfering with organochlorine compounds. This analysis method required more solvent, time, and more sample volume. The analytical strategy, in this paper, involves the use of effective and efficient but simple techniques for petroleum hydrocarbons and chlorinated hydrocarbons separation. A clean‐up procedure is presented, by which these compounds are isolated from aliphatic as well as polyaromatic hydrocarbons through a combination of HPLC and adsorption chromatography on a florisil microcolumn. Mass spectrometric identification was used as confirmation method. GLC equipped with ECD and FID for organochlorine and petroleum compounds analysis, respectively.     

A preliminary study of temporal differences in serum concentrations of perfluoroalkyl acids,among New York anglers,in the absence of known changes in manufacturing practices

Perfluorinated compounds have been manufactured in large quantities and used in myriad industrial processes and commercial applications. The aim of this preliminary study was to generate hypotheses with regard to differences in body burdens of perfluoroalkyl acids, among a sub-sample of participants from the New York State Angler Cohort Study, over a time interval during which no known substantial changes occurred in US manufacturing practices or commercial use. Paired serum specimens, collected from 15 subjects in 1993–1994 (time 1), and in 1995–1997 (time 2), with a minimum interval of 2.5 years, were assayed for PFDA, PFHpA, PFHxS, PFNA, PFOA, PFOS, PFOSA and PFUnDA using HPLC with ES-MS/MS. By subject, differences in concentrations between time 1 and time 2 were estimated, employing paired t-tests, correlations, and multivariable linear regression to accommodate heterogeneity in duration between specimens, and in time 1 concentrations. A statistically significant (P < 0.05) adjusted mean decrease of 0.16 ng mL^?1 (18.8%) between time 1 and 2 was detected for PFNA, and an adjusted mean increase of 0.54 ng mL^?1 (56.8%) was detected for PFOA. The results of this study may be indicative of short-term changes in human body burdens of PFNA and PFOA in association with local exposure sources.