间接竞争ELISA方法测定水中2，4-D的研究

以2,4-D-BSA为包被抗原,采用自行制备的2,4-D单克隆特异性抗体6D11建立了水中2,4-D的间接竞争 ELISA检测方法．本研究比较了包被抗原2,4-D-BSA浓度分别为240ng·mL-1、120ng·mL-1和60ng·mL-1的反应体系和竞争反应时间为60min和15min的间接竞争ELISA剂量-反应曲线,确定了当包被抗原浓度为60 ng·mL-1、竞争反应时间为15min时,剂量-反应曲线的IC50值较低．采用上述实验条件分别测定了由PBS缓冲溶液、饮用水、清华大学地下水和圆明园福海地表水配制的2,4-D标准溶液的剂量．反应曲线,发现实际水样的基质效应对检测结果的影响较大;采用实际水样和PBS缓冲溶液配水在含有5％乙醇的PBS缓冲体系中反应的方法,基本上消除了基质效应对检测结果的干扰．采用上述优化试验条件,测定2,4-D浓度分别为0．5mg·L-1、0．125mg·L-1和0．03mg·L-1的加标样品,测定数据的准确度符合痕量有机污染物定量检测对准确度的要求,但是平行样品测定数据之间的变异系数较大,需要进一步改进检测方法,用于实际水样的检测．     

酶联免疫吸附法测定麻疯树核糖体失活蛋白

建立了一种检测麻疯树核糖体失活蛋白(Curcin)的简便、快速的酶联免疫吸附测定法(ELISA).ELISA条件优化试验结果显示:最佳条件为costar酶标板在紫外线下照射45 min后进行包被;抗原最适稀释度为1:640倍(2.5μg/mL);curcin抗血清最适稀释度为1:12 800倍;2%封闭用山羊血清封闭120 min;二抗最适稀释度为1:5 000倍.在此试验条件下检测curcin含量,得到回归方程y=31.722x+106.88,相关系数R2=0.993 3.Curcin浓度在0.08～11μg/mL之间,曲线呈良好的线性关系.本方法的最低检测限为0.08μg/mL.高、中、低3个浓度的添加回收率分别为95.56%、102.27%、98.40%,平均回收率为98.74%.板内和板间的平均变异系数分别为4.78%和6.71%.Curcin抗血清与2种大戟科同类蛋白均无交叉反应.利用本方法成功检测了麻疯树种仁及脱毒饼粕中的curcin含量.     

Removal of cadmium(II), lead(II), and chromium(VI) ions from aqueous solution using clay

Removal of cadmium(II), lead(II), and chromium(VI) from aqueous solution using clay, a naturally occurring low-cost adsorbent, under various conditions, such as contact time, initial concentration, temperature, and pH has been investigated. The sorption of these metals follows both Langmuir and Freundlich adsorption isotherms. The magnitude of Langmuir and Freundlich constants at 30°C for cadmium, lead, and chromium indicate good adsorption capacity. The kinetic rate constants (K _ad) indicate that the adsorption follows first order. The thermodynamic parameters: free energy change (ΔG ^o), enthalpy change (ΔH ^o), and entropy change (ΔS ^o) show that adsorption is an endothermic process and that adsorption is favored at high temperature. The results reveal that clay is a good adsorbent for the removal of these metals from wastewater.     

Sorption of tetracycline to sediments and soils: assessing the roles of pH,the presence of cadmium and properties of sediments and soils

Batch sorption experiments were conducted to evaluate the sorption behavior of tetracycline (TC, H₃L) on sediments and soils in the presence and absence of cadmium (Cd), as affected by pH and properties of sediments and soils. The results indicated stronger nonlinearity and higher capacity of TC sorption on sediments than on soils. Sorption of TC also strongly depended on environmental factors and sediment/soil properties. Lower pH facilitated TC sorption through a cation exchange mechanism, which also took place at pH values above 5.5, where TC existed as a zwitterion (H₂L⁰) or anions (HL^- and L^2-). When pH was above 7, however, ligand-promoted dissolution of TC might occur due to TC weakening the Al-O bond of aluminum oxide and the Fe-O bond of iron oxide. Natural organic matter (NOM) plays a more important role in TC sorption than cation exchange capacity (CEC) and clay contents. The presence of Cd (II) increased TC sorption on both sediments and soils, which resulted from the decrease of equilibrium solution pH caused by Cd²⁺ exchange with H⁺ ions of sediment/soil surfaces. The increase of TC sorption was also related to the formation of TC-Cd complexes, where Cd²⁺ acted as a bridge between the sediment/soil and TC.     

梯度薄膜扩散技术(DGT)与传统化学方法评估黑麦草吸收Cd的对比

为研究不同方法评估黑麦草吸收Cd的效果,采集了16个不同理化性质实际Cd污染土壤,盆栽试验种植黑麦草,采用梯度薄膜扩散技术(DGT)测定黑麦草根际土Cd的生物有效性,并与离心法采集土壤溶液、乙酸(HAc)和乙二胺四乙酸二钠(EDTANa2)3种传统提取方法所提取土壤有效态Cd含量进行比较,研究其与黑麦草地上部和地下部Cd含量的相关关系.结果表明,DGT提取的土壤有效态Cd含量与黑麦草中Cd含量的相关性显著高于化学提取法.运用多元统计分析研究土壤pH、阳离子交换量(CEC)、有机质(OM)和土壤颗粒组成等理化指标的影响,提取出两种主成分因子,建立了多元回归模型.第一主成分与OM和黏粒(clay)之间呈显著相关,定义为土壤中影响重金属生物有效性的"有机指标",第二主成分则与土壤pH和CEC相关程度较高,定义为土壤中影响重金属生物有效性的"无机指标".研究表明,第二主成分显著影响了3种化学方法构建的预测模型,而DGT技术综合了两种主成分对土壤有效态Cd含量的影响,所构建的模型几乎不受土壤基本理化性质的影响,说明DGT分析法是一种预测黑麦草吸收Cd的较好方法.     

A simple ligandless microextraction method based on ionic liquid for the determination of trace cadmium in water and biological samples

A simple and efficient ionic liquid-based ligandless microextraction method has been developed for preconcentration of cadmium ions (Cd²⁺) as a step prior to its determination by flame atomic absorption spectrometry (FAAS) with a micro-sample introduction system. In this approach, the ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate [C₄mim][PF₆] and ethanol were used as extractant and dispersive solvents to preconcentrate the Cd²⁺ in different waters, acid digested scalp hair, and nail samples. Some analytical parameters influencing the extraction efficiency of Cd²⁺ and its subsequent determination, including pH, IL volume, dispersant solvent volume, sample volume, temperature, incubation time, and matrix effect, were optimized. Under optimal conditions, the limit of detection (LOD), limit of quantification (LOQ), and enhancement factor (EF) were 0.4 μg L^?1, 1.3 μg L^?1, and 50, respectively. The relative standard deviation (RSD) of 100 μgL^?1 Cd²⁺ was 4.3% (n = 6). The validity of the proposed method was checked by determining Cd²⁺ in certified reference material (TM-25.3 fortified water) and standard addition; the results showed sufficient recovery (>98%) of Cd²⁺ within the certified value. The method was applied for preconcentration and determination of cadmium in waters and biological samples.     

Granulation of gibbsite with inorganic binder and its ability to adsorb Mo(VI) from aqueous solution

In this study, we prepared a new adsorbent and evaluated its ability to adsorb Mo(VI). Gibbsite was granulated with colloidal alumina or colloidal silica. The amount of Mo(VI) adsorbed onto granular gibbsite with a binder, effect of contact time and pH on the adsorption of Mo(VI), and column experiments were investigated. The amount of Mo(VI) adsorbed was greater in the order of ST12 (colloidal silica, 12%)?相似文献   

High cadmium pollution risk on vegetable amaranth and a selection for pollution-safe cultivars to lower the risk

A pot experiment was carried out by growing 29 different genotypes (Amaranthus spp.) of vegetable amaranth under low- (0.12 mg·kg^-1) and middle- (0.40 mg·kg^-1) cadmium (Cd) exposure. The result showed that amaranth was vulnerable to cadmium (Cd) contamination in soil. Variations of Cd concentrations in both roots and edible parts among genotypes were significant (P<0.001) in both treatments. Cd concentrations in edible parts of the tested genotypes grown under low- and middle-Cd levels were significantly correlated (p<0.01), implying that Cd-accumulating property of amaranth is genotype-dependent. Differences in Cd chemical forms between cv. Nanxingdayemashixian (cv. Nan), a selected typical pollution-safe cultivar (Cd-PSC), and cv. Pennongjianyexian (cv. Pen), a selected typical non-Cd-PSC, under different Cd exposure conditions were compared. It was found that the alternation of Cd in F_NaCl (Cd form extracted by 1 mol·L^-1 NaCl) may be a key factor in regulating Cd accumulation of different amaranth genotypes and that the protein-binding Cd is considered to be associated with Cd translocation. The results indicated that amaranth is capable of enduring high level of Cd pollution when grown as vegetable crop, and accordingly, consuming vegetable amaranth would bring high health risk. Therefore, adopting Cd-PSC strategy would help reducing the risk of Cd pollution in amaranth. In this study, cv. Nan was identified as a Cd-PSC and recommended to be applied production practice.     

The effects of exposure to zinc and cadmium separately and jointly on the free amino acid pool of Gammarus pulex (L.)

Effects of the heavy metals zinc and cadmium on the free amino acid (FAA) pool of Gammarus pulex were studied at different metal concentrations and combinations as well as different exposure times. The dominant effect of these two metals was the reduction of most free amino acids and the whole FAA pool, except in the 10‐day low zinc and cadmium concentration exposures which resulted in a rise of free amino acid pool.

Among the free amino acids, the most sensitive to zinc exposure, were alanine, glutamic acid, arginine, and taurine; valine, leucine, asparagine, and isoleucine were among the most sensitive to cadmium. No predictable changes of individual free amino acids were shown in the mixed metals exposures. Elevation of taurine concentration was constant in seven of the eight treatments, it is suggested that this elevation may be related to the hepatopancreatic damage observed and induced synthesis of metallothioneins.     

Utilization of aluminum hydroxide waste generated in fluoride adsorption and coagulation processes for adsorptive removal of cadmium ion

Although Al-based coagulation and adsorption processes have been proved highly efficient for fluoride (F) removal, the two processes both generate large amount of Al(OH)₃ solid waste containing F (Al(OH)₃-F). This study aimed to investigate the feasibility of utilizing Al(OH)₃-F generated in Al(OH)₃ adsorption (Al(OH)₃-F_ads) and coagulation (Al(OH)₃-F_coag) for the adsorption of cadmium ion (Cd(II)). The adsorption capacity of Al(OH)₃-F_ads and Al(OH)₃-F_coag for Cd(II) was similar as that of pristine aluminum hydroxide (Al(OH)₃), being of 24.39 and 19.90 mg·g^–1, respectively. The adsorption of Cd(II) onto Al(OH)₃-F_ads and Al(OH)₃-F_coag was identified to be dominated by ion-exchange with sodium ion (Na⁺) or hydrogen ion (H⁺), surface microprecitation, and electrostatic attraction. The maximum concentration of the leached fluoride from Al(OH)₃-F_ads and Al(OH)₃-F_coag is below the Chinese Class-I IndustrialWastewater Discharge Standard for fluoride (<10 mg·L^–1). This study demonstrates that the Al(OH)₃ solid wastes generated in fluoride removal process could be potentially utilized as a adsorbent for Cd(II) removal.     

Preparation and application of a phosphorous free and non-nitrogen scale inhibitor in industrial cooling water systems

A novel environmentally friendly type of calcium carbonate, zinc (II) and iron (III) scale inhibitor Acrylic acid- allylpolyethoxy carboxylate copolymer (AA-APEL) was synthesized. The anti-scale property of the AA-APEL toward CaCO₃, zinc (II) and iron (III) in the artificial cooling water was studied through static scale inhibition tests. The observation shows that both calcium carbonate, zinc (II) and iron (III) inhibition increase with increasing the dosage of AA-APEL. The effect on formation of CaCO₃ was investigated with combination of scanning electronic microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) analysis and fourier transform infrared spectrometer, respectively. The results showed that the AA-APEL copolymer not only influenced calcium carbonate crystal morphology and crystal size but also the crystallinity. The crystallization of CaCO₃ in the absence of inhibitor was rhombohedral calcite crystal, whereas a mixture of calcite with vaterite crystals was found in the presence of the AA-APEL copolymer. Inhibition mechanism is proposed that the interactions between calcium or iron ions and polyethylene glycol (PEG) are the fundamental impetus to restrain the formation of the scale in cooling water systems.     

基于氮掺杂碳量子点的制备及其对Hg2+的响应

以乙二胺和抗坏血酸为原料,通过一步水热法制备了水溶性的氮掺杂碳量子点(N-CQDs).研究了N-CQDs的形貌特征、光学性能和应用分析.表征结果说明,N-CQDs形态为均匀分散的球形,有明显的晶格条纹,抗光漂白性能良好,表面富有含氧官能团,具有良好的水溶性.此外发现N-CQDs还具有优良的荧光性能和荧光稳定性,量子产率可以高达12.29%.分析得出,Hg²⁺对N-CQDs在1.0—120μmol·L^-1范围内有一定的猝灭效应,可作为Hg²⁺的荧光探针,检出限达230 nmol·L^-1.     

活性污泥动力学模型的建立及在完全混合式污泥系统中的应用

首先建立了微生物衰减系数和污泥浓度、底物浓度的函数关系式,带入Lawrence-McCarty第一方程式得到了Logistic方程形式的微生物生长方程式.在分析污泥泥龄和污泥停留时间关系基础上,引入Monod方程建立了活性污泥动力学模型,推导证明了Lawrence-McCarty方程式是模型静态条件下的表达形式.用建立的活性污泥动力学模型对完全混合式污泥系统进行了模拟,并分析了水力停留时间Hydraulic retention time(HRT)和污泥停留时间Sludge retention time(SRT)对完全混合式污泥系统的影响,表明模型能很好地对活性污泥系统的动态过程进行模拟.根据模型编程画出了污泥系统相关变量关于HRT和SRT变化的三维曲面图,通过编程将复杂模型看作一定输入输出的函数,使得模型更易于应用和推广.     

A new regeneration approach to cation resins with aluminum salts: application of desalination by its mixed bed

A novel method for the regeneration of cation exchange resins by aluminum (Al) salts was investigated in order to improve the regeneration efficiency of resins and reduce the dosage of regenerant. The influences of Al³⁺ concentration and the pH of regeneration solution on resin transformation had been studied. The desalination experiments were carried out to evaluate the characteristics of the Al form resins. Experimental results showed that the regeneration rate of resins was strictly dependent on Al3+ concentration and the pH of the solution. Compared to the conventional regeneration method, the Al form mixed bed exhibited the same desalination capability as the H form mixed bed (MB), and the total organic carbon (TOC) removal was up to 90%, clearly higher than that of the H form. Al salt solution could be utilized repeatedly to regenerate Al form resins.     

锰氧化物-阳离子交换树脂复合材料的制备及其对水中重金属的吸附性能

采用原位沉淀-空气氧化法将锰氧化物负载于大孔强酸性阳离子交换树脂D001上,制备出一种新型锰氧化物-阳离子交换树脂复合材料Mn-D001,并对该材料吸附水中Pb2+、Cd2+、Cu2+的性能进行了深入研究.TEM、XRD以及XPS的分析结果表明,负载的锰氧化物以MnO2的形态存在.基于单一金属离子静态吸附的一元体系实验表明,Mn-D001比D001对Pb2+、Cd2+、Cu2+具有更高的吸附选择性,在高浓度竞争离子Ca2+、Mg2+、Na+共存的情况下,仍能保持较高的重金属去除率;Mn-D001对Pb2+、Cd2+、Cu2+的吸附行为符合准一级动力学模型(R2>0.99)和Langmuir吸附等温线模型(R2>0.99).在温度为303 K时,Mn-D001对3种重金属的饱和吸附容量可分别达到476.19 mg.g-1、243.90 mg.g-1及196.08 mg.g-1,优于原有树脂D001.基于复合重金属离子竞争吸附的二元、三元体系的实验表明,Mn-D001对3种重金属的吸附能力顺序为Pb2+>Cu2+>Cd2+,吸附能力由原有树脂D001以及负载的锰氧化物的性质共同决定.     

Biogeochemical model (BGC-ES) and its basin-level application for evaluating ecosystem services under forest management practices

It is important for humans to live in harmony with ecosystems. Evaluation of ecosystem services (ES) may be helpful in achieving this objective. In Japan, forest ecosystems need to be re-evaluated to prevent their degradation due to lack of forest management.In order to evaluate the effects of forest management on forest ES, we developed a process-based biogeochemical model to estimate water, carbon, and nitrogen cycles in forest ecosystems (BGC-ES). This model consists of four submodels: biomass, water cycle, carbon-nitrogen (CN) cycles, and forest management. The biomass submodel can calculate growth of forest biomass under forest managements.Several parameters of the model were calibrated using data from observations of evapotranspiration flux and quality of stream flow in forests. The model results were compared with observations of runoff water from a dam catchment site and with carbon flux observations.Our model was coupled with a basin-level GIS database of forests. Evaluations under various forest management scenarios were carried out for forests in a basin contained in the Ise Bay basin (Chubu region, Japan), where plantations (artificial forests) seemed to have degraded from poor forest management.Comparing our simulation results with those of forests without management in the basin, we found that the amounts of absorbed carbon and runoff were larger in managed forests. In addition, the volume of harvested timber was larger and its quality (diameter) was better in managed forests. Changes of ES within the various scenarios were estimated for their economic value and were compared with the cost of forest management.     

受体报告基因实验及其在维甲酸和维甲酸X受体干扰物监测中的应用

受体报告基因实验具有快速、经济、灵敏、方便等诸多优势,在高通量筛选类或抗雌雄激素等通过核受体起作用的环境内分泌干扰物方面得到了广泛的应用。环境中的维甲酸和维甲酸X受体干扰物如有机锡等有着类似的作用机制,研究者也开始采用受体报告基因实验的方法对该类污染物进行筛选与监测。本文综述了受体报告基因实验的技术方法,包括报告基因和宿主细胞的选择,并介绍了该方法在人工合成的维甲酸和维甲酸X受体干扰物筛选以及环境样品中该类污染监测中的应用。综述总结了应用受体报告基因实验检测环境内分泌干扰物研究中的不足并对该方法的未来发展进行了展望,希望为该方法在环境监测和评估中的应用提供新的思路。     

Determination of cadmium in water and herbal medicine by Penicillium chrysogenum immobilized on silica gel for flame atomic absorption spectroscopy

Penicillium chrysogenum was immobilized on silica to develop a simple and cost effective method for solid phase extraction of Cd(II) and determination using flame atomic absorption spectrometry (FAAS). The sorbent was characterized by Fourier transform infrared spectroscopy and packed into a column. The conditions for quantitative sorption and desorption of Cd(II) were optimized. The preconcentration factor was 100 while detection limit was 0.61 µg L^?1 with a relative standard deviation of 1.0%. The method was applied for determination of Cd in herbal medicine and tap water.     

An early warning method of landscape ecological security in rapid urbanizing coastal areas and its application in Xiamen, China

Based on the Pressure-State-Response (P-S-R) approach, an index system for landscape ecological security (LES) was suggested using three dimensions, six factors, and three weights. The indicators in the system were divided into two groups: spatial interpolation (acquired by the remote sensing data) and non-spatial interpolation (acquired by consultation with experts). According to data of 2003 and 2006, coupled with current tendencies, the early warning method was classified into four categories: security and degradation, sub-security and slow degradation, sub-security and rapid degradation, and insecurity. Our research with early warning method finds three interesting phenomena: (1) mean value of LES in 2003 was 0.586, indicating medium security; while in 2006 it was 0.650, an upper medium security. The LES level within each districts of Xiamen in 2006 was better than the level in 2003. In terms of LES, the comprehensive condition within each district of Xiamen in 2006 was enhanced compared with 2003. Overall, there was improvement in 80.5% of areas from 2003 to 2006, showing promising signs of positive development. (2) The LES of Xiang’an District and Jimei District were in stages of high early warning given that the percentage of land in these districts that showed symptoms of insecurity and degradation was 41.03 and 34.89%, respectively. (3) On the whole, the areas that showed notable signs of insecurity and rapid landscape, and which can already be identified as early warning areas requiring immediate attention, correspond closely with the distribution of coastal industrial parks in these regions. In conclusion, the consequences of rapid industrialization and urbanization are far reaching and affect local and regional ecological security.     

有机污染物对水生生物毒性作用机理的判别及影响因素

有机污染物对水生生物急性毒性作用机理的判别及影响因素是定量结构与活性相关研究的基础,对准确预测有机污染物对水生生物的毒性具有重要的意义.本文根据目前国内外在该领域的研究现状和本课题组在该领域的研究成果,系统地总结了有机污染物对水生生物的急性毒性作用机理、毒性作用机理的判别方法、及影响毒性作用机理判别的因素.有机污染物对水生生物的急性毒性作用机理可分为非极性麻醉型、极性麻醉型、反应型和特殊作用型;化合物的毒性比率、毒性临界值和结构警示是目前判别毒性作用机理的主要方法;有机化合物的生物富集、非生物转化、生物代谢、离子化率和溶解度是毒性作用机理判别的主要影响因素.