石岐河水及沉积物取代芳烃的分布及评价研究

对石岐河表层水和沉积物中的20种取代芳烃进行了测定.结果表明,取代芳烃在表层水和沉积物中的含量范围分别为0.07～0.33 μg/L、ND～5.72 μg/g;水中取代芳烃的空间分布与沉积物相似,均呈现出中间高两边低的趋势.表层水中检出的取代芳烃均未超出地表水环境质量标准;与其他地区相比,石岐河表层沉积物中取代芳烃含量较低,生态风险也并不显著.     

SDS与取代芳烃多元混合体系联合毒性作用研究

测定了阴离子表面活性剂十二烷基硫酸钠(SDS)和3种取代芳烃苯酚、硝基苯、甲苯对发光菌的单一毒性,以及等浓度配比下SDS与3种取代芳烃二元、三元及四元混合体系的联合毒性效应,并基于常见的4种联合作用评价方法,对混合体系的联合毒性作用进行了评价研究.结果表明,4种不同的评价方法对SDS与苯酚、甲苯和硝基苯的联合效应评价结果具有较好的一致性,即在以SDS为底物的混合体系中,除SDS与硝基苯联合毒性表现为弱拮抗作用外,其它的二元、三元及四元混合体系的毒性均表现为不同程度的协同作用,且甲苯的协同程度最强.在选择的联合研究体系中,以毒性单位法获得参数的数值较大,判定灵敏度较高.根据发光菌发光原理、SDS的分子结构特征和芳烃类化合物取代基的不同,可对联合毒性作用的机理进行初步探讨.     

5种取代酚化合物对淡水发光菌的联合毒性

以新型淡水发光菌——青海弧菌Q67(Vibrio-qinghaiensissp.—Q67)为检验生物,以VeritasTM微孔板光度计为发光强度测试设备,分别测定了3,5-二羟基甲苯、2,3-二甲基苯酚、对氯苯酚、邻氯苯酚、2,4-二氯苯酚对淡水发光菌的发光抑制毒性及其混合物的联合毒性.结果表明,5种取代酚的剂量-效应关系都可用Weibull模型有效描述,从这些模型估算的半数效应浓度负对数值(-logEC50)分别为2.69、3.08、3.43、2.81和3.66,可知其对发光菌的毒性大小顺序为:2,4-二氯苯酚>对氯苯酚>2,3-二甲基苯酚>邻氯苯酚>3,5-二羟基甲苯.分别设计浓度等于各自之EC50和EC10的2个等效应浓度比混合物以及3个不同效应浓度比混合物进行联合毒性实验,结果发现,在所实验的浓度范围内各个混合物的剂量加和(DA)模型与独立作用(IA)模型具有相似的作用规律,其联合毒性既可用DA模型也可用IA模型进行预测.     

Biocatalytic amidation of carboxylic acids and their antinemic activity

A series of novel N-alkyl substituted amides, synthesized by enzyme catalysis, were evaluated against root-knot nematode, Meloidogyne incognita and found to have potential antinemic activity. The corresponding amides were prepared by the condensation of equimolar amounts of carboxylic acids with different alkyl amines in the presence of Candida antarctica lipase at 60–90°C in 16–20 h. The reactions were carried out in a non - solvent system without the use of any activating agents. All the products were obtained in appreciable amounts and the yields for different compounds varied between 77.4–82.3%. The synthesized compounds were characterized using spectroscopy techniques namely Infra Red (IR) and Nuclear Magnetic Resonance (NMR) (¹H and ¹³C). Nematicidal activity of synthesized amides was evaluated against J₂s of Meloidogyne incognita at 500, 250, 125 and 62.5 ppm concentrations after 24 h, 48 h and 72 h of exposure. Among all the tested compounds, N-propyl-butyramide, N-propyl-pentanamide and N-propyl-hexanamide were found to possess significant activity with LC₅₀ values of 67.46, 83.49 and 96.53 respectively. N-propyl-butyramide with LC₅₀ value of 67.46 ppm was found to be most active amide against J₂s of Meloidogyne incognita. The bioactivity study showed that an increase in alkyl chain significantly decreased the activity of amides against root-knot nematode.     

Stability of the conjugated species of environmental phenols and parabens in human serum

In humans, the metabolism of environmental phenols may include the formation of conjugated species (e.g., glucuronides and sulfates), but the free species—not the conjugated forms—are considered biologically active. Therefore, information on the concentration of these free species in blood or urine could be helpful for risk assessment. Because conjugates could hydrolyze to their corresponding free forms during collection, handling, and storage of biological specimens, information on the temporal stability of the conjugates is of interest. Previously, we reported the temporal stability of urinary conjugates of several environmental phenols, but data on the stability of phenols' conjugated species in serum, albeit critical if concentrations of free and conjugated species are compared, are largely unknown. In the present study, we investigate the stability of the conjugates of four phenols—bisphenol A, benzophenone-3, triclosan, and 2,5-dichlorophenol—and two parabens—methyl paraben and propyl paraben—in 16 human serum samples for 30 days at above-freezing temperature storage conditions (4 °C, room temperature, and 37 °C). These conditions reflect the worst-case scenarios that could occur during the short-term storage of biological samples before their long-term storage at controlled subfreezing temperatures. We found that the percentage of the conjugated species of the four detected compounds (2,5-dichlorophenol, triclosan, and methyl and propyl parabens) in these serum specimens even when stored at 37 °C for at least 30 days did not vary significantly. These preliminary data suggest that the phenols' serum conjugates appear to be more stable than their corresponding urinary conjugates, some of which started to hydrolyze within 24 h under similar storage conditions. The reported stability of these conjugated species in human serum also suggests that the free species are unlikely to have resulted from the hydrolysis of their corresponding conjugates. This information could be important for interpreting the low concentrations of free phenol species detected in serum samples of nonoccupationally exposed populations. To our knowledge, this is the first study to report on the stability of conjugated species in serum, and as such requires replication.     

Influence of combustion conditions on yields of solvent-extractable anhydrosugars and lignin phenols in chars: Implications for characterizations of biomass combustion residues

Anhydrosugars, such as levoglucosan and its isomers (mannosan, galactosan), as well as the solvent-extractable lignin phenols (methoxylated phenols) are thermal degradation products of cellulose/hemicellulose and lignin, respectively. These two groups of biomarkers are often used as unique tracers of combusted biomass inputs in diverse environmental media. However, detailed characterization of the relative proportion and signatures of these compounds in highly heterogeneous plant-derived chars are still scarce. Here we conducted a systematic study to investigate the yields of solvent-extractable anhydrosugars and lignin phenols in 25 lab-made chars produced from different plant materials under different combustion conditions. Solvent-extractable anhydrosugars and lignin phenols were only observed in chars formed below 350 °C and yields were variable across different combustion temperatures. The yields of mannosan (M) and galactosan (G) decreased more rapidly than those of levoglucosan (L) under increasing combustion severity (temperature and duration), resulting in variable L/M and L/(M + G) ratios, two diagnostic ratios often used for identification of combustion sources (e.g. hardwoods vs. softwoods vs. grasses). Our observations thus may provide an explanation for the wide ranges of values reported in the literature for these two ratios. On the other hand, the results of this study suggest that the ratios of the major solvent-extractable lignin phenols (vanillyls (V), syringyls (S), cinnamyls (C)) provide additional source reconstruction potential despite observed variations with combustion temperature. We thus propose using a property-property plot (L/M vs. S/V) as an improved means for source characterization of biomass combustion residues. The L/M-S/V plot has shown to be effective in environmental samples (soil organic matter, atmospheric aerosols) receiving substantial inputs of biomass combustion residues.     

Decolourization and removal of some organic compounds from olive mill wastewater by advanced oxidation processes and lime treatment

Background Olive mill wastewater (OMW) generated by the olive oil extracting industry is a major pollutant, because of its high organic load and phytotoxic and antibacterial phenolic compounds which resist biological degradation. Mediterranean countries are mostly affected by this serious environmental problem since they are responsible for 95% of the worldwide oliveoil production. There are many methods used for OMW treatment, such as adsorption, electro coagulation, electro-oxidation, biological degradation, advanced oxidation processes (AOPs), chemical coagulation, flocculation, filtration, lagoons of evaporation and burning systems, etc. Currently, there is no such economical and easy solution. The aim of this study was to evaluate the feasibility of decolourization and removal of phenol, lignin, TOC and TIC in OMW by UV/H₂O₂ (AOPs). The operating parameters, such as hydrogen peroxide dosage, times, pH, effect of UV and natural sunlight were determined to find the suitable operating conditions for the best removal. Moreover, there is no study reported in the literature related to the use of UV/H₂O₂ and lime together in OMW treatment. Methods OMW was obtained from an olive-oil producing plant (Muğla area of Turkey) which uses a modern production process. No chemical additives are used during olive oil production. This study was realised by using two different UV sources, while taking the time and energy consumption into consideration. These two sources were mercury lamps and natural sunlight. Before starting AOPs experiments, one litre of OMW was treated by adding lime until a pH of 7.00. Then, 100 ml was taken from each sample, and 1 to 10 ml of a 30% H₂O₂ (Riedel-deHaen) solution was added. These solutions in closed vessels were laid in the natural sunlight for a week and their compositions and colour changes were analysed daily by UV-Vis spectrophotometer. At the end of the one-week period, they were treated with lime. In this study, the effect of changes in the initial pH, times and H₂O₂ concentrations on removal was investigated. At the end of all experiments, changes in colour, phenol, lignin, TOC and TIC concentrations were analysed according to standard methods. Results and Discussion In the samples exposed to natural sunlight and having an H₂O₂/OMW ratio of 3 ml/100 ml, a significant colour removal was achieved approximately 90% of the time at the end of 7 days. When the same samples were treated with lime (pH: up to 7), 99% efficiency was achieved. When phenol and lignin removals were examined in the same concentration, phenol and lignin removal were found 99.5%, 35%, respectively. However, for maximum lignin removal, more use of H₂O₂ (10 ml H₂O₂/100 ml OMW) was found to be necessary. Under these conditions, it was found that lignin can be removed by 70%, but to 90% with lime, at the end of a seven-day period. Rate constants obtained in the experiments performed with direct UV were found to be much higher than those of the samples exposed to natural sunlight (k^a _lignin = 0.3883 ≫ k^b _lignin = 0.0078; k^a _phenol = 0.5187 ≫ k^b _phenol = 0.0146). Moreover, it should be remembered in this process that energy consumption may induce extra financial burden for organisations. Conclusions It was found, in general, that colour, lignin, total organic carbon and phenol were removed more efficiently from OMW by using H₂O₂ UV and lime OMW. Moreover, in the study, lime was found to contribute, both initially and after radical reactions, to the efficiency to a great extent. Recommendations and Perspectives Another result obtained from the study is that pre-purification carried out with hydrogen peroxide and lime may constitute an important step for further purification processes such as adsorption, membrane processes, etc.     

Assessing the steady-state [·NO<Subscript>2</Subscript>] in environmental samples

Based on available literature data of [NO₂ ⁻], steady-state [·OH], and ·OH generation rate upon nitrate photolysis in environmental aqueous samples under sunlight, the steady-state [·NO₂], could be calculated. Interestingly, one to two orders of magnitude more ·NO₂ would be formed in photochemical processes in atmospheric water droplets compared to transfer from the gas phase. The relative importance of nitrite oxidation compared to nitrate photolysis as an ·NO₂ source would be higher in atmospheric than in surface waters. The calculated levels of ·NO₂ could lead to substantial transformation of phenol into nitrophenols in both atmospheric and surface waters.     

运用QSARs方法比较和预测取代苯类化合物的毒性

本文运用ＱＳＡＲｓ方法比较了惰性化合物卤代苯和次惰性化合物硝基苯类,苯胺类化合物对金鱼的急性毒性试验,鱼肝脏内控制ＡＴＰ水解的Ｎａ＾＋、Ｋ＾＋－ＡＴＰ酶不知力试验以及发光菌毒性试验。