Enzymatic reaction of the immobilized enzyme on porous silicon studied by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry

Desorption/ionization on silicon mass spectrometry (DIOS-MS) is a matrix-free technique that allows for the direct desorption/ionization of low-molecular-weight compounds with little or no fragmentation of analytes. This technique has a relatively high tolerance for contaminants commonly found in biological samples. DIOS-MS has been applied to determine the activity of immobilized enzymes on the porous silicon surface. Enzyme activities were also monitored with the addition of a competitive inhibitor in the substrate solution. It is demonstrated that this method can be applied to the screening of enzyme inhibitors. Furthermore, a method for peptide mapping analysis by in situ digestion of proteins on the porous silicon surface modified by trypsin, combined with matrix-assisted laser desorption/ionization-time of flight-MS has been developed.

Ten Years of the Relative Risk Model and Regional Scale Ecological Risk Assessment

It has been 10 years since the publication of the relative risk model (RRM) for regional scale ecological risk assessment. The approach has since been used successfully for a variety of freshwater, marine, and terrestrial environments in North America, South America, and Australia. During this period the types of stressors have been expanded to include more than contaminants. Invasive species, habitat loss, stream alteration and blockage, temperature, change in land use, and climate have been incorporated into the assessments. Major developments in the RRM have included the extensive use of geographical information systems, uncertainty analysis using Monte Carlo techniques, and its application to retrospective assessments to determine causation. The future uses of the RRM include assessments for forestry and conservation management, an increasing use in invasive species evaluation, and in sustainability. Developments in risk communication, the use of Bayesian approaches, and in uncertainty analyses are on the horizon.

Remediation of Persistent Organic Pollutants (POPs) in Two Different Soils

Persistent organic pollutants (POPs) are a set of chemicals that are toxic, persist in the environment for long periods of time, and biomagnify as they move up through the food chain. The most widely used method of POP destruction is incineration, which is expensive and could result in undesirable by-products. An alternative bioremediation technology, which is cheaper and environ-mentally friendly, was tested during this experiment. Two different soil types containing high and low organic matter (OM) were spiked with 100 mg/kg each of pyrene and Aroclor 1248 and planted with three different species of grasses. The objective of the study was to determine residue recovery levels (availability) and potential effectiveness of these plant species for the remediation of POPs. The results showed that recovery levels were highly dependent on the soil organic matter content—very low in all treatments with the high OM content soil compared to recoveries in the low OM soil. This indicates that availability, and, hence, biodegradability of the contaminants is dependent on the organic matter content of the soil. Moreover, the degree of availability was also significantly different for the two classes of chemicals. The polyaromatic hydrocarbon (PAH) recovery (availability) was extremely low in the high organic matter content soil compared to that of the polychlorinated biphenyls (PCBs). In both soil types, all of the plant species treatments showed significantly greater PCB biodegradation compared to the unplanted controls. Planting did not have any significant effect on the transformation of the PAHs in both soil types; however, planting with switchgrass was the best remedial option for both soil types contaminated with PCB.

Early Embryonic Exposure to Polychlorinated Biphenyls Disrupts Heat-Shock Protein 70 Cognate Expression in Zebrafish

Polychlorinated biphenyls (PCBs) are persistent environmental contaminants that have documented neurological effects in children exposed in utero. To better define neuronally linked molecular targets during early development, zebrafish embryos were exposed to Aroclor 1254, a mixture of PCB congeners that are common environmental contaminants. Microarray analysis of the zebrafish genome revealed consistent significant changes in 38 genes. Of these genes, 55% (21) are neuronally related. One gene that showed a consistent 50% reduction in expression in PCB-treated embryos was heat-shock protein 70 cognate (Hsc70). The reduction in Hsc70 expression was confirmed by real-time polymerase chain reaction (PCR), revealing a consistent 30% reduction in expression in PCB-treated embryos. Early embryonic exposure to PCBs also induced structural changes in the ventro-rostral cluster as detected by immunocytochemistry. In addition, there was a significant reduction in dorso-rostral neurite outgrowth emanating from the RoL1 cell cluster following PCB exposure. The serotonergic neurons in the developing diencephalon showed a 34% reduction in fluorescence when labeled with a serotonin antibody following PCB exposure, corresponding to a reduction in serotonin concentration in the neurons. The total size of the labeled neurons was not significantly different between treated and control embryos, indicating that the development of the neurons was not affected, only the production of serotonin within the neurons. The structural and biochemical changes in the developing central nervous system following early embryonic exposure to Aroclor 1254 may lead to alterations in the function of the affected regions.

农业污染物在多孔介质中迁移的研究进展

为有效地预测和控制农业污染物对土壤及地下水资源的污染 ,需要建立相应的数学模型。在数学模型的应用中 ,模型参数的确定是关键。本文简要回顾了农业污染物在多孔介质迁移模型研究的进展 ,指出了各自的适用条件及存在的问题。

细颗粒泥沙絮凝-分散在水土保持中的应用

简要介绍了细颗粒泥沙絮凝 -分散对土壤渗透性、土壤可蚀性以及污染物迁移的影响 ,以期有效防治水土流失和由此带来的非点源污染。

Spatial distribution of soil heavy metal pollution estimated by different interpolation methods: Accuracy and uncertainty analysis

Mapping the spatial distribution of contaminants in soils is the basis of pollution evaluation and risk control. Interpolation methods are extensively applied in the mapping processes to estimate the heavy metal concentrations at unsampled sites. The performances of interpolation methods (inverse distance weighting, local polynomial, ordinary kriging and radial basis functions) were assessed and compared using the root mean square error for cross validation. The results indicated that all interpolation methods provided a high prediction accuracy of the mean concentration of soil heavy metals. However, the classic method based on percentages of polluted samples, gave a pollution area 23.54-41.92% larger than that estimated by interpolation methods. The difference in contaminated area estimation among the four methods reached 6.14%. According to the interpolation results, the spatial uncertainty of polluted areas was mainly located in three types of region: (a) the local maxima concentration region surrounded by low concentration (clean) sites, (b) the local minima concentration region surrounded with highly polluted samples; and (c) the boundaries of the contaminated areas. (C) 2010 Elsevier Ltd. All rights reserved.

Accumulation of petroleum hydrocarbons and heavy metals in clams (Ruditapes philippinarum) in Jiaozhou Bay, China

Accumulation and distributions of aliphatic and polyaromatic hydrocarbons (PAHs) and heavy metals were measured in tissues of the clam Ruditapes philippinarum collected from 5 sites in Jiaozhou Bay, Qingdao, China. The concentrations of total aliphatic hydrocarbon and PAHs ranged from 570 to 2 574 ng/gdw (gram dry weight) and from 276 to 939 ng/gdw, in the most and least polluted sites, respectively. The bio-accumulation of hydrocarbons and PAHs in the clams appeared to be selective. Aliphatic hydrocarbons were predominantly represented by short chain (< nC(23)) n-alkanes, suggesting that petroleum hydrocarbons were likely the major contamination source. The selective uptake of 3 and 4 ring PAHs, such as naphthalene, fluorene, phenanthrene, fluoranthene and pyrene, by the clams was probably related to the physiological and bio-kinetic processes that were energetically favorable for uptake of compounds with fewer rings. Accumulation of the metals Cd, Cu, Zn, Pb, Cr, Hg, and As in the clam tissues also showed high variability, ranging from 0.043 to 87 A mu g/gdw. Among the 7 detected metals, Zn, Cd, Cu, and As had a particularly high potential of accumulation in R. philippinarum. In general, a positive correlation was found between the tissue concentrations and sediment concentrations of hydrocarbons and of some metals. Our study suggests that moderate contamination with polyaromatic hydrocarbons, and low to moderate contamination with metals, currently exists for clam R. philippinarum in Jiaozhou Bay, in comparison with other regional studies. A long-term monitoring program is certainly needed for assessment of the potential ecological influence and toxicity of these contaminants of R. philippinarum in Jiaozhou Bay.

Organochlorine micropollutants in the Jiulong River Estuary and Western Xiamen Sea, China

Organochlorine contaminants including 12 polychlorinated biphenyl (PCB) congeners and 18 insecticides were determined in water, pore water and sediments of the Jiulong River Estuary and Western Xiamen Sea, China. The results showed that the levels of the total PCBs ranged from non-detectable to 1500 ngl(-1) in water, from 209 to 3870 ngl(-1) in pore water, and from 2.78 to 14.8 ng g(-1) dry weight in sediments. Total organochlorine insecticide concentrations were from below the limit of detection to 2480 ngl(-1) in water, from 267 to 33400 ngl(-1) in pore water, and from 4.22 to 46.3 ng g(-1) dry weight in sediments. Concentrations of PCBs and insecticides in pore water were significantly higher than those in surface water, due to the high affinity of these hydrophobic compounds for sediment phase. The PCB congeners with the highest concentrations were CB153, CB180 and CB194, which together accounted for 68-87% of total PCBs in water, pore water and sediment. Among the hexachlorocyclohexane (HCH) compounds, beta-HCH was found to be a major isomer. Analysis of 1,1,1-trichloro-2,2-bis-chlorophenyl-ethane (DDT) and its metabolites showed that 1, 1-dichloro-2[o-chlorophenyl]-2[p-chlorophenyl]-ethylene (DDE) was dominant in the group. In comparison to a 1998 study in the Western Xiamen Sea, levels of organochlorines were enhanced due probably to recent inputs and changes in sediments. (c) 2004 Elsevier Ltd. All rights reserved.

南堡油田测试资料综合评价及试油配套工艺技术研究与应用

A series of significant oil-gas exploration progresses have been achieved in Nanpu depression with 1.02 billion ton oil-gas reserves have been proven. It has been confirmed that Nanpu beach has a geologic condition to be a major field based on exhaustive research. This finding, which is integrated reservoir，great reserves, thick oil layer and high productivity in Nanpu depression, is the most excited success in Chinese oil-gas exploration in recent years. This abundant oilfield found is significant to the strategy of oil production stability in the east of China. Nanpu depression exploration is also a crucial exploration project for Petrochina. Based on the comprehensive research on Nanpu formation testing data, we reevaluate and analyze the reservoir property and the structure characteristics, and propose a series of testing technique that are suitable for Jidong oil field development. The results are summarized as follows: 1. The reservoir parameters and characters are defined by formation test data interpretation and systemic dynamic-static data comparison. 2. Based on sources analysis and statistical research related to formation contaminants, some technique measures, which can not only prevent or reduce invasion damage for different formations but also can effectively improve completion efficiency, are proposed. 3. By selecting the testing pressure drawdown, optimum working regulation and flow /shut-in duration, and adopting dynamic-static flow parameters correlation analysis to predict production, an optimum research on working regulation and flow /shut-in duration was accomplished. Optimization formation test principles suitable for any kinds of Nanpu oilfield are established, which can improve test quality, construction efficiency and data recording quality. 4. By reasonable selection of perforating gun and penetrating charge, the perforation penetration has been improved effectively and the flow channel of the oil gas have been expanded, so that the communication between formations and the wellbore is improved better. 5. One joint working procedure which combining formation test, perforation, unloading and stimulation treatment has become the dominant testing technology in the Nanpu offshore Oilfield. This combination technique can implement several procedures using one pipe string, and achieve rapid testing purpose.

天然溶解有机质和环境污染物的相互作用--以铜、汞离子和卡马西平为例

天然溶解有机质（natural dissolved organic matter，DOM）是由动植物残体经过复杂的物理、化学和生物过程形成的高分子有机混合物，它广泛分布于水体、土壤和沉积物中。DOM的结构十分复杂，分子量从几百到几十万不等，元素组成和化学结构随时空和来源不同而变化。腐殖物质是DOM的主要组成部分，以溶解有机碳计约占DOM总量的50%~80%。腐殖物质可以分为：富里酸（fulvic acid， FA任何pH值条件下都溶于水），腐殖酸（humic acid，HA在pH 1时不溶于水）和胡敏素（humin，任何pH条件下都不溶于水）。 DOM能影响许多生物地球化学过程。例如DOM是一个重要的碳汇，它能影响微生物的食物链和全球碳循环；DOM和营养元素含量、食物链结构等一起决定水生生态系统的属性和发展动态；它还能吸收自然光，从而影响紫外线在水中的穿透能力和浮游植物的光合作用；DOM含有多种弱酸和弱碱官能团，是天然水体pH的调节剂和控制因素；DOM和痕量金属离子或有机污染物发生作用，从而影响它们的形态、毒性、迁移转化和生物有效性；在饮用水消毒过程中，DOM能生成致癌物三卤甲烷和其它消毒副产物。 天然水体中的痕量金属离子（如Cu2+和Hg2+）主要以DOM络合态存在。在海水中DOM控制铜的主要存在形态；在淡水中 90%以上的铜离子与DOM发生配位。通过配位作用DOM能抑制浮游生物对Hg的吸收，增加鱼类对Hg的蓄积。目前，人们对金属离子在环境中的迁移转化机理的理解还不够深入，尤其是对有机质参与下的有毒重金属循环还缺乏必要地认识。条件稳定常数是描述重金属离子与DOM配位能力的基本参数。前人运用多种手段对DOM与金属离子的结合能力进行了研究，主要包括：离子选择性电极法、溶出伏安法、超滤及荧光淬灭滴定法等。紫外吸收滴定法可用于研究单一有机化合物和金属离子的相互作用，在这一领域的应用尚未报道。本文首次将紫外吸收滴定法应用于测定DOM与Cu2+和Hg2+的条件稳定常数。实验表明紫外吸收滴定法迅速、简便、可望成为研究DOM和痕量金属离子相互作用的有力工具。 药品和个人护理品（pharmaceuticals and personal care products，PPCPs）在环境中普遍存在。有证据表明，环境中的有些PPCPs能对生物体产生影响，如改变生物体的性别比例，影响植物生长，动物幼虫的孵化，甚至具有明显的致畸效应。卡马西平（Carbamazepine，CBZ）是一种常用的抗癫痫、止痛药物和抗抑郁药。毒理学实验表明，环境中的CBZ能严重影响鱼、蚌等水生生物的免疫和循环系统。CBZ使用量大，在环境中含量高，在地下水渗透过程和常规污水处理中保持稳定，因此CBZ成为衡量人类活动和污水处理工艺效率的标志物。但是目前人们对CBZ的环境地球化学循环知之甚少。DOM能与许多有机污染物发生相互作用，从而影响它们的生物环境地球化学行为，但DOM对CBZ的影响尚未见报道。本论文利用三维荧光光谱技术和同步荧光光谱技术，研究了DOM与CBZ的结合强度、结合类型、影响因素，并且初步总结了DOM对CBZ环境地球化学循环的影响。为理解其它PPCPs的生物地球化学循环，预测它们的迁移转化、归宿和环境毒性提供参考。 本文运用紫外吸收滴定法和荧光淬灭滴定法研究了不同来源的DOM和金属离子（Cu2+和Hg2+）的相互作用，运用三维荧光光谱法和同步扫描荧光光谱法研究了DOM和卡马西平的相互作用。主要成果简述如下： 1、本文首次将紫外吸收滴定法应用于测定金属离子和DOM的条件稳定常数，结果表明紫外吸收滴定法操作更简便、测定迅速、仪器普及率高，可在DOM含量很低（约10-5 ~ 10-7 mol/L）的情况下也可以直接进行测定，不必进行复杂的预富集。可望成为DOM和痕量有毒重金属离子相互作用的有力工具。 2、重金属离子（Hg2+和Cu2+）与DOM的羧基和酚羟基等基团配位。配位后电子的离域性增加，导致紫外吸收增加。与此同时配位后分子极性的改变和铜离子顺磁性作用，引起DOM荧光淬灭。在Cu2+和Hg2+的滴定过程中，紫外吸光度和荧光强度之间呈极显著线性负相关关系（R2=0.99，P<0.001）。这说明荧光和紫外从不同侧面揭示了DOM和金属离子的配位作用。 3、紫外吸收滴定法和荧光淬灭滴定法测定其条件稳定常数（log K）一致，介于3.5 ~ 5.5之间。强配位作用是DOM影响有毒重金属离子环境地球化学行为的根源。研究还表明配位作用的强弱受DOM来源和体系pH的影响。 4、 CBZ和DOM能发生强烈的相互作用，结合常数（log K）介于3.41 ~ 5.04之间。DOM能明显减少游离态CBZ的浓度，提高CBZ溶解度和迁移转化能力。这对认识CBZ和其它PPCPs的环境地球化学循环及其影响因素具有指导意义。 5、荧光光谱研究表明CBZ对DOM发射的荧光具有明显的猝灭作用，其猝灭机理为静态猝灭。疏水作用是CBZ和DOM之间的主要作用力。DOM-CBZ受pH值的影响不大， Cu2+对CBZ和DOM的结合有一定的影响。

疏水性有机污染物的非线性吸附过程及滞后现象的研究

该论文测定了疏水性有机污染物在地质吸附剂上的吸附-解吸等温线,选用合适的模型拟合了这些等温线,并且研究了非线性吸附过程、解吸滞后现象与壤/沉积物异质性之间的关系;得到以下几点认识:1、利用红外光谱仪和核磁共振谱仪研究了土壤/沉积物有机质、土壤胡敏酸的组成.2、测定了菲、蔡、1,3,5-三氯苯在土壤/沉积物及处理样品上的吸附等温线.所有地质吸附剂上的吸附等温线表现出明显的非线性.Freundlic上模型能很好的拟合了有机物的吸附等温线,双区位反应模型(DRDM)能很好的拟合有机物在部分土壤/沉积物及处理样品上的吸附等温线,并且DRDM模型清楚的反映出有机物在低浓度和高浓度下不同的吸附特征.3、对相同土壤/沉积物样品,萘的吸附等温线要比菲的吸附等温线的线性要好些,这与它们的物化性质有关.4、对碱提取后残留土壤测定了菲、茶、1,3,5-三氯苯的吸附-解吸等温线.5、菲和萘在土壤/沉积物及处理样品上的吸附-解吸过程存在明显的滞后现象.