A novel low-cost detection method for screening of arsenic in groundwater

In the present work, a novel and simple detection system for As inorganic species contained in groundwater is presented. To reach the required detection limit, the proposed methodology is based on two steps: first is the transport and preconcentration of the inorganic arsenic species using a polymer inclusion membrane (PIM) system and second is the formation of a coloured complex, the  absorbance of which is measured. Different parameters related to the membrane composition and the transport kinetics have been studied, and it was found that membranes made of polyvinyl chloride (PVC) as a polymer, and Aliquat 336 as a carrier, ensured efficient arsenic transport when the carrier content was at least 31 % (w/w). The implementation of the designed PIM in a special device that contained only 5 mL of the stripping solution (0.1 M NaCl) allowed As preconcentration from a 100-mL water sample, thus facilitating its detection with the colorimetric method. The new method developed here was validated, and its analytical figures of merit were determined, i.e. limit of detection of 4.5 μg L^?1 at 820 nm and a relative standard deviation within the range 8–10 %. Finally, the method was successfully applied to the analysis of different water samples from Catalonia region with naturally occurring As.     

Application of Delphi method in screening of indexes for measuring soil pollution value evaluation

Environmental Science and Pollution Research - Soil pollution is one of the most important issues in environmental governance at present. Using scientific and reasonable methods to estimate the...     

The weight method: a new screening method for estimating pesticide deposition from knapsack sprayers in developing countries

Investigations of occupational and environmental risk caused by the use of agrochemicals have received considerable interest over the last decades. And yet, in developing countries, the lack of staff and analytical equipment as well the costs of chemical analyses make it difficult, if not impossible, to monitor pesticide contamination and residues in humans, air, water, and soils. A new and simple method is presented here for estimation of pesticide deposition in humans and soil after application. The estimate is derived on the basis of water mass balance measured in a given number of high absorbent papers under low evaporative conditions and unsaturated atmosphere. The method is presented as a suitable, rapid, low cost screening tool, complementary to toxicological tests, to assess occupational and environmental exposure caused by knapsack sprayers, where there is a lack of analytical instruments. This new method, called the “weight method”, was tested to obtain drift deposition on the neighbouring field and the clothes of the applicator after spraying water with a knapsack sprayer in one of the largest areas of potato production in Colombia. The results were confirmed by experimental data using a tracer and the same set up used for the weight method. The weight method was able to explain 86% of the airborne drift and deposition variance.     

A screening method for preliminary assessment of risk to groundwater from land-applied chemicals

A simple mathematical model for initial screening is presented that can aid in evaluating the relative risk to groundwater from applying nonpolar synthetic organic chemicals to soil. The basic premise is that the magnitude of the quotient of the chemical concentration of the water entering the aquifer and the maximum allowable concentration (as established by EPA or Health Departments) represents the health risk of a chemical. The chemical concentration of the soil water is estimated based on conservative, simplifying assumptions and requires only readily available data such as: basic soil properties (organic matter and saturated hydraulic conductivity), organic chemical properties (octanol-water partition coefficient and degradation rate) and environmental factors (recharge rate and depth to groundwater).The methodology was applied to assess the relative risk of organic chemicals in municipal sewage sludge and pesticides applied to agricultural land. The results are realistic.     

水质总氮在线检测的光谱数据校正方法

由于受光纤灯源光能波动和一些外界干扰的影响,微型光谱仪检测到的光谱数据存在波动现象,这将直接影响水质总氮在线检测的精确性。在采用均值法去除随机噪声干扰的基础上,针对光能波动的问题基于支持向量机提出了一种光谱数据校正方法,并建立了吸光度与浓度的线性关系。实验结果表明,该方法提高了光谱数据的稳定性,检测相对误差从校正前的12%提高到5%以内,满足水质总氮的分析测试要求。     

海水中邻苯二甲酸二乙酯的快速检测方法建立

为构建海水中邻苯二甲酸二乙酯(DEP)快速检测方法,采用胶体金酶联免疫层析技术,利用抗DEP单克隆抗体杂交瘤细胞株进行腹水制备。以邻苯二甲酸单乙酯(MEP)-OVA为包被抗原,羊抗鼠IgG为二抗,优化抗原抗体配对组合和胶体金-抗体标记条件,最后组装获得快速检测DEP胶体金免疫层析试纸条。利用包括DEP在内的12种邻苯二甲酸酯类化合物标准溶液检测试纸条的灵敏度和特异性,并利用人造海水作为稀释溶剂检测试纸条的海水环境适应性。结果显示：纯化后抗体效价最高可以达到1∶30 000以上,胶体金溶液与抗体最佳标记条件为pH=7.2,抗体最佳标记量为6 μL·mL-1;所制备胶体金酶联免疫层析(GICA)试纸条对DEP的检测特异性较高,在人造海水条件下试纸条对DEP的检测限可达20 μg·L-1,适用于海水中DEP的快速检测。     

Evaluation of a multiresidue method for pesticides in cereals using supercritical fluid extraction and gas chromatographic detection

Supercritical fluid extraction (SFE) was evaluated to be applied for residue analysis of 22 gas chromatography/electron capture detector-nitrogen phosphorus detector (GC/ECD-NPD) amenable pesticides in rice, wild rice and wheat. Samples were extracted with supercritical carbon dioxide at 200 atm pressure and 50°C temperature, using methanol as a static modifier. Mean recoveries obtained with the proposed SFE method at two spiking levels with four replicates per level are compared with those obtained with an ethyl acetate-based solvent extraction/gel permeation chromatography (GPC) clean up method. Both methods gave consistent high recoveries for almost all the pesticides from all the commodities with overall mean recoveries higher than 70% with relative standard deviations lower than 20%. Remarkable exceptions were captafol and dimethoate, for which low and/or non-reproducible recoveries were obtained with the SFE method. Residue levels determined with both methods in nine different incurred samples of wheat, containing some of the studied pesticides, were very similar, but, in all cases, slightly higher levels were determined with the SFE method.     

Environmental labeling of car tires--toxicity to Daphnia magna can be used as a screening method

Car tires contain several water-soluble compounds that can leach into water and have toxic effects on aquatic organisms. Due to tire wear, 10,000 tonnes of rubber particles end up along the Swedish roads every year. This leads to a diffuse input of emissions of several compounds. Emissions of polyaromatic hydrocarbons (PAHs) are of particular concern. PAHs are ingredients of the high aromatic oil (HA oil) that is used in the rubber as a softener and as a filler. The exclusion of HA oils from car tires has started, and an environmental labeling of tires could make HA oils obsolete. The toxicity to Daphnia magna from 12 randomly selected car tires was tested in this study. Rubber from the tread of the tires was grated into small pieces, to simulate material from tire wear, and the rubber was equilibrated with dilution water for 72 h before addition of test organisms. The 24-h EC50s of the rubber pieces ranged from 0.29 to 32 gl-1, and the 48-h EC50s ranged from 0.0625 to 2.41 gl-1. Summer tires were more toxic than winter tires. After the 48-h exposure, the daphnids were exposed to UV-light for 2 h, to determine if the tires contained compounds that were phototoxic. After UV-activation the EC50s ranged from 0.0625 to 0.38 gl-1. Four of the 12 tires had a very distinct photoactivation, with a toxicity increase of >10 times. This study has shown that the used method for toxicity testing with Daphnia magna according to ISO 6341 could be used as a basis for environmental labeling of car tires.     

Rapid PCDD/PCDF screening method for fly ash with ion trap MS/MS

A rapid screening method for the polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF) in fly ash has been developed. The screening is done in two steps: (a) the extraction by the accelerated solvent extraction and (b) the quantitative measurement by ion trap tandem mass spectrometer (MS/MS). Anhydrous sodium sulfate was added to the fly ash containing activated carbon in order to increase the extraction efficiency. The selectivity of the ion trap MS/MS was confirmed with 13C-labelled internal standard. Then the results of the screening method were compared with those obtained by the conventional analytical method using high-resolution mass spectrometer (HRMS).     

Application of photocatalysis as a post treatment method of a heterotrophic-autotrophic denitrification reactor effluent

The aim of this study is the application of photocatalysis as an effective post treatment scheme for the removal of the organic matter and bacteria released by an innovative biological denitrification process referred to as heterotrophic-autotrophic denitrification, which combines heterotrophic and autotrophic denitrification processes. Photocatalytic treatment was applied using TiO2 as a photocatalyst in the loading range of 0.25-2.00 g l(-1) for irradiation periods up to 60 min using a black light fluorescent lamp with an intensity of I(0)=1309 microW cm(-2). The photocatalytic inactivation data were modelled to pseudo first order kinetics as well as by the areal rates to evaluate the photocatalyst loading effect. Chlorination was used as a final disinfection step to attain an overall inactivation of total coliforms as well as to the formation of very low level of trihalomethanes.     

Development and verification of a screening model for surface spreading of petroleum

Overflows and leakage from aboveground storage tanks and pipelines carrying crude oil and petroleum products occur frequently. The spilled hydrocarbons pose environmental threats by contaminating the surrounding soil and the underlying ground water. Predicting the fate and transport of these chemicals is required for environmental risk assessment and for remedial measure design. The present paper discusses the formulation and application of the Oil Surface Flow Screening Model (OILSFSM) for predicting the surface flow of oil by taking into account infiltration and evaporation. Surface flow is simulated using a semi-analytical model based on the lubrication theory approximation of viscous flow. Infiltration is simulated using a version of the Green and Ampt infiltration model, which is modified to account for oil properties. Evaporation of volatile compounds is simulated using a compositional model that accounts for the changes in the fraction of each compound in the spilled oil. The coupling between surface flow, infiltration and evaporation is achieved by incorporating the infiltration and evaporation fluxes into the global continuity equation of the spilled oil. The model was verified against numerical models for infiltration and analytical models for surface flow. The verification study demonstrates the applicability of the model.     

A cost-effective screening method for pesticide residue analysis in fruits, vegetables, and cereal grains

This paper reports the results of studies performed to investigate the potential of applying thin layer chromatography (TLC) detection in combination with selected extraction and cleanup methods, for providing an alternative cost-effective analytical procedure for screening and confirmation of pesticide residues in plant commodities. The extraction was carried out with ethyl acetate and an on-line extraction method applying an acetone-dichloromethane mixture. The extracts were cleaned up with SX-3 gel, an adsorbent mixture of active carbon, magnesia, and diatomaceous earth, and on silica micro cartridges. The Rf values of 118 pesticides were tested in eleven elution systems with UV, and eight biotest methods and chemical detection reagents. Cabbage, green peas, orange, and tomatoes were selected as representative sample matrices for fruits and vegetables, while maize, rice, and wheat represented cereal grains. As an internal quality control measure, marker compounds were applied on each plate to verify the proper elution and detection conditions. The Rf values varied in the different elution systems. The best separation (widest Rf range) was achieved with silica gel (SG)--ethyl acetate (0.05-0.7), SG--benzene, (0.02-0.7) and reverse phase RP-18 F-254S layer with acetone: methanol: water/30:30:30 (v/v) (0.1-0.8). The relative standard deviation of Rf values (CV(Rf)) within laboratory reproducibility was generally less than 20%, except below 0.2 Rf, where the CVRf rapidly increased with decreasing Rf values. The fungi spore inhibition, chloroplast inhibition, and enzyme inhibition were found most suitable for detection of pesticides primarily for confirming their identity or screening for known substances. Their use for determination of pesticide residues in samples of unknown origin is not recommended.     

Application of an ELISA for PCB 118 to the screening of dioxin-like PCBs in retail fish

A commercially available enzyme-linked immunosorbent assay (ELISA) kit was evaluated for the determination of toxic equivalents (TEQs) of dioxin-like polychlorinated biphenyls (PCBs) in retail fish. The ELISA was highly specific for 2,3',4,4',5-pentachlorobiphenyl (PCB 118), which is generally the most abundant dioxin-like PCB isomer found in fish. The quantitative limit of the ELISA (using 3,3',4'-trichloro-4-methoxybiphenyl as a surrogate standard for PCB 118) was 10 ng ml(-1) (125 pg assay(-1)) in the standard curve, corresponding to 50 pg PCB 118 g(-1) in the tested sample. Good recoveries of PCB 118 (78.7-112.3%) were obtained for spiked purified fish extracts according to the ELISA. Good linearity was also obtained in dilution tests using purified fish extracts. No significant interference of the matrix was observed in the ELISA when this purification procedure was used. Recovery tests in which PCB 118 was added to fish samples also resulted in acceptable recoveries (60.2-82.3%) in the ELISA following purification. The ELISA results for fish samples correlated well with the TEQ concentrations of dioxin-like PCBs obtained by high-resolution gas chromatography/high-resolution mass spectrometry (r = 0.92, n = 26). These data indicate that the ELISA kit is suitable for screening retail fish for the TEQs of dioxin-like PCBs.     

PCR-酶切技术在石油烃降解菌筛选鉴定中的应用

将以原油驯化所得的纯培养微生物菌株作为模板,采用PCR(聚合酶链式反应)法,用扩增细菌16S rDNA的一对通用引物(8 f,1492 r)对模板扩增,并用限制性内切酶R saI和M spI对PCR产物进行ARDRA多态性分析。聚类去除重复菌株后60株菌株可分为11种不同分类操作单元(OTU),同时得出每个分类操作单元的数量。实验结果表明,此方法可快速去除重复菌株并反映出菌株间的系统进化关系;同时实验数据可构建成库,使后续分离菌株的筛选工作只需比对数据即可完成。     

生物强化系统微生物分子诊断技术的应用及新发展

现代分子生物技术的飞速发展及其在环境研究领域的应用,为生物强化技术的研究和发展提供了新方法和新思路.本文从生物强化系统特异微生物检测及定量化技术、生物强化系统微生物群落结构组成及动态演替规律研究、生物强化作用机制的分子生物学解析、生物强化菌的基因工程构建、生物强化系统微生物的安全释放及控制技术几方面,对生物强化系统微生物分子诊断技术的应用和发展作了较为全面的综述.     

生物强化系统微生物分子诊断技术的应用及新发展

现代分子生物技术的飞速发展及其在环境研究领域的应用，为生物强化技术的研究和发展提供了新方法和新思路。本文从生物强化系统特异微生物检测及定量化技术、生物强化系统微生物群落结构组成及动态演替规律研究、生物强化作用机制的分子生物学解析、生物强化菌的基因工程构建、生物强化系统微生物的安全释放及控制技术几方面，对生物强化系统微生物分子诊断技术的应用和发展作了较为全面的综述。     

Application of a permethrin immunosorbent assay method to residential soil and dust samples

A low-cost, high throughput bioanalytical screening method was developed for monitoring cis/trans-permethrin in dust and soil samples. The method consisted of a simple sample preparation procedure [sonication with dichloromethane followed by a solvent exchange into methanol:water (1:1)] with bioanalytical detection using a magnetic particle enzyme-linked immunosorbent assay (ELISA). Quantitative recoveries (83–126 %) of cis/trans-permethrin were obtained for spiked soil and dust samples. The percent difference of duplicate ELISA analyses was within ± 20 % for standards and ± 35 % for samples. Similar sample preparation procedures were used for the conventional gas chromatography/mass spectrometry (GC/MS) analysis except that additional cleanup steps were required. Recoveries of cis/trans-permethrin ranged from 81 to 108 % for spiked soil and dust samples by GC/MS. The ELISA-derived permethrin concentrations were highly correlated with the GC/MS-derived sum of cis/trans-permethrin concentrations with a correlation coefficient (r) of 0.986. The ELISA method provided a rapid qualitative screen for cis/trans-permethrin in soil and dust while providing a higher sample throughput with a lower cost as compared to the GC/MS method. The ELISA can be applied as a complementary, low-cost screening tool to prioritize and rank samples prior to instrumental analysis for exposure studies.