Material In Environmental Samples Research Articles

Detection of Red-Eared Slider (Trachemys scripta elegans) using Environmental DNA with Cytochrome b Primer

Biomonitoring surveys for the presence of invasive species need effective and efficient methods. Molecular methods based on the detection of genetic material in environmental samples or environmental DNA (eDNA) provide better resolution for detection, especially in elusive species. The eDNA-based method is an approach that has been widely used for conservation and business management because it is a non-invasive method. Cytochrome b primer is a specific primer that can be used to amplify Red-Eared Slider eDNA from water samples, eDNA was amplified using qPCR. The results obtained after performing qPCR are in the form of Ct values that can be used to estimate the biomass of Red-Eared Slider.

Diversity of Wadden Sea macrofauna and meiofauna communities highest in DNA from extractions preceded by cell lysis

Metabarcoding of genetic material in environmental samples has increasingly been employed as a means to assess biodiversity, also of marine benthic communities. Current protocols employed to extract DNA from benthic samples and subsequent bioinformatics pipelines differ considerably. The present study compares three commonly deployed metabarcoding approaches against a morphological approach to assess benthic biodiversity in an intertidal bay in the Dutch Wadden Sea. Environmental DNA was extracted using three different approaches; extraction of extracellular DNA, extraction preceded by cell lysis of a sieved fraction of the sediment, and extraction of DNA directly from small amounts of sediment. DNA extractions after lysis of sieved sediment fractions best recovered the macrofauna diversity whereas direct DNA extraction of small amounts of sediment best recovered the meiofauna diversity. Extractions of extracellular DNA yielded the lowest number of OTUs per sample and hence an incomplete view of benthic biodiversity. An assessment of different bioinformatic pipelines and parameters was conducted using a mock sample with a known species composition. The RDP classifier performed better than BLAST for taxonomic assignment of the samples in this study. Novel metabarcodes obtained from local specimens were added to the SILVA 18S rRNA database to improve taxonomic assignment. This study provides recommendations for a general metabarcoding protocol for marine benthic surveys in the Wadden Sea.

Ultrasonic nebulization for the elemental analysis of microgram-level samples with offline aerosol mass spectrometry

Abstract. The elemental composition of organic material in environmental samples – including atmospheric organic aerosol, dissolved organic matter, and other complex mixtures – provides insights into their sources and environmental processing. However, standard analytical techniques for measuring elemental ratios typically require large sample sizes (milligrams of material or more). Here we characterize a method for measuring elemental ratios in environmental samples, requiring only micrograms of material, using a small-volume nebulizer (SVN). The technique uses ultrasonic nebulization of samples to generate aerosol particles (100–300 nm diameter), which are then analyzed using an aerosol mass spectrometer (AMS). We demonstrate that the technique generates aerosol from complex organic mixtures with minimal changes to the elemental composition of the organic material and that quantification is possible using internal standards (e.g., NH415NO3). Sample volumes of 2–4 µL with total solution concentrations of at least 0.2 g L−1 form sufficient particle mass for elemental ratio measurement by the AMS, despite only a small fraction (∼ 0.1 %) of the sample forming fine particles after nebulization (with the remainder ending up as larger droplets). The method was applied to aerosol filter extracts from the field and laboratory, as well as to the polysaccharide fraction of dissolved organic matter (DOM) from the North Pacific Ocean. In the case of aerosol particles, the mass spectra and elemental ratios from the SVN–AMS agree with those from online AMS sampling. Similarly, for DOM, the elemental ratios determined from the SVN–AMS agree with those determined using combustion analysis. The SVN–AMS provides a platform for the rapid quantitative analysis of the elemental composition of complex organic mixtures and non-refractory inorganic salts from microgram samples with applications that include analysis of aerosol extracts and terrestrial, aquatic, and atmospheric dissolved organic matter.

Analysis of naturally occurring radioactive materials in environmental samples using gamma spectrometry

Analysis of naturally occurring radioactive materials in environmental samples using gamma spectrometry

Extraction, separation and characterization of endotoxins in water samples using solid phase extraction and capillary electrophoresis-laser induced fluorescence

This study focuses on one of the key environmental threats, endotoxins, also known as lipopolysaccharides (LPS). A capillary electrophoresis method in combination with laser induced fluorescence (LIF) detection was developed for the analysis of endotoxins from 16 different bacterial strains. LPSs were derivatized with the amino-reactive fluorescent dye, fluorescein isothiocyanate (FITC), separated by capillary zone electrophoresis (CZE) under the optimized conditions with the use of 50 mM sodium tetraborate buffer (pH 9.30), and detected by LIF detector. To improve the sensitivity of CZE-LIF detection for the determination of trace amounts of endotoxins and to remove possible interference materials in environmental samples, a solid phase extraction (SPE) pre-concentration technique was applied successfully. The SPE targeted at polysaccharide moieties of LPSs and showed LPS enrichment effects too. CE migration time could also reveal the O-antigen chain lengths of LPSs. This CE method and SPE pretreatment showed linearity at 99.84%, and repeatabilities at 8.44% and 11.0% for endotoxins from E. Coli O55:B5 and E. Coli O26:B6. The limit of detection (LOD) could reach around 5 ng/mL at optimized condition. The method was applied successfully to the determination of LPS levels in tap water and wastewater, and demonstrated sensitive, reproducible and reliable results.

Detection limits of quantitative and digital PCR assays and their influence in presence–absence surveys of environmental DNA

A set of universal guidelines is needed to determine the limit of detection (LOD) in PCR-based analyses of low-concentration DNA. In particular, environmental DNA (eDNA) studies require sensitive and reliable methods to detect rare and cryptic species through shed genetic material in environmental samples. Current strategies for assessing detection limits of eDNA are either too stringent or subjective, possibly resulting in biased estimates of species' presence. Here, a conservative LOD analysis grounded in analytical chemistry is proposed to correct for overestimated DNA concentrations predominantly caused by the concentration plateau, a nonlinear relationship between expected and measured DNA concentrations. We have used statistical criteria to establish formal mathematical models for both quantitative and droplet digital PCR. To assess the method, a new Grass Carp (Ctenopharyngodon idella) TaqMan assay was developed and tested on both PCR platforms using eDNA in water samples. The LOD adjustment reduced Grass Carp occupancy and detection estimates while increasing uncertainty-indicating that caution needs to be applied to eDNA data without LOD correction. Compared to quantitative PCR, digital PCR had higher occurrence estimates due to increased sensitivity and dilution of inhibitors at low concentrations. Without accurate LOD correction, species occurrence and detection probabilities based on eDNA estimates are prone to a source of bias that cannot be reduced by an increase in sample size or PCR replicates. Other applications also could benefit from a standardized LOD such as GMO food analysis and forensic and clinical diagnostics.

Current status and future direction for examining engineered nanoparticles in natural systems

Environmental context The detection and characterisation of engineered nanomaterials in the environment is essential for exposure and risk assessment for this emerging class of materials. However, the ubiquitous presence of naturally occurring nanomaterials presents a unique challenge for the accurate determination of engineered nanomaterials in environmental matrices. New techniques and methodologies are being developed to overcome some of these issues by taking advantage of subtle differences in the elemental and isotopic ratios within these nanomaterials. Abstract The increasing manufacture and implementation of engineered nanomaterials (ENMs) will continue to lead to the release of these materials into the environment. Reliably assessing the environmental exposure risk of ENMs will depend highly on the ability to quantify and characterise these materials in environmental samples. However, performing these measurements is obstructed by the complexity of environmental sample matrices, physiochemical processes altering the state of the ENM and the high background of naturally occurring nanoparticles (NNPs), which may be similar in size, shape and composition to their engineered analogues. Current analytical techniques can be implemented to overcome some of these obstacles, but the ubiquity of NNPs presents a unique challenge requiring the exploitation of properties that discriminate engineered and natural nanomaterials. To this end, new techniques are being developed that take advantage of the nature of ENMs to discern them from naturally occurring analogues. This paper reviews the current techniques utilised in the detection and characterisation of ENMs in environmental samples as well as discusses promising new approaches to overcome the high backgrounds of NNPs. Despite their occurrence in the atmosphere and soil, this review will be limited to a discussion of aqueous-based samples containing ENMs, as this environment will serve as a principal medium for the environmental dispersion of ENMs.

環境試料中の単一核物質含有微粒子の分析

環境試料中の単一核物質含有微粒子の分析

In-source resonance ionization spectroscopy of high lying energy levels in atomic uranium

In-source resonance ionization spectroscopy of uranium has been carried out as preparation for the analysis of low contaminations of nuclear material in environmental samples via laser mass spectrometry. Using three-step resonance ionization spectroscopy, 86 levels of odd parity in the energy range from 37,200–38,650 cm − 1 were studied, 51 of these levels were previously unknown. Suitable excitation schemes for analytic applications are discussed.

Challenge to ultra-trace analytical techniques of nuclear materials in environmental samples for safeguards at JAERI: methodologies for physical and chemical form estimation

From a viewpoint of physical and chemical form estimation, ultra-trace analytical techniques of nuclear materials in environmental samples for safeguards have been investigated at Japan Atomic Energy Research Institute. This article deals with (1) an outline of the developed techniques for bulk and particle analyses of uranium and plutonium in the safeguards environmental samples; (2) current R&D on techniques relating to estimation of the physical and chemical form, such as SEM images and EDX spectra for fine particles of nuclear materials and fission track observation applicable to fissile materials; and (3) possible analytical methodologies, as future works, applicable to ultra-trace amounts of nuclear materials in environmental samples.

Review of Methods and Instruments for Determining Undeclared Nuclear Materials and Activities

At present time high-sensitivity nuclear environmental sampling techniques have been recognized as a power tool for the detection of undeclared activities in the context of the growing threats of nuclear proliferation and terrorism. The International Atomic Energy Agency has proved the ability of the environmental sampling and analysis techniques to support the traditional international safeguards. This article reviews the potentially promising physical methods as well as the current methods and instruments used to analyze trace amounts of nuclear materials in environmental samples. Two types of samples analysis are distinguished: the bulk analysis and particles analysis. Techniques for sample preparation and special laboratory conditions to prevent possible contamination are considered as an essential part of the sample analysis. Detection limits achieved at present in frame of considered techniques are discussed.

Establishment of a Clean Laboratory for Ultra Trace Analysis of Nuclear Materials in Safeguards Environmental Samples

The Japan Atomic Energy Research Institute has established a cleanroom facility with cleanliness of ISO Class 5: the Clean Laboratory for Environmental Analysis and Research (CLEAR). It was designed to be used for the analysis of nuclear materials in environmental samples mainly for the safeguards, in addition to the Comprehensive Nuclear-Test-Ban Treaty verification and research on environmental sciences. The CLEAR facility was designed to meet conflicting requirements of a cleanroom and for handling of nuclear materials according to Japanese regulations, i.e., to avoid contamination from outside and to contain nuclear materials inside the facility. This facility has been intended to be used for wet chemical treatment, instrumental analysis and particle handling. A fume-hood to provide a clean work surface for handling of nuclear materials was specially designed. Much attention was paid to the selection of construction materials for use of corrosive acids. The performance of the cleanroom and analytical background in the laboratory are discussed. This facility has satisfactory specification required for joining the International Atomic Energy Agency Network of Analytical Laboratories. It can be concluded that the CLEAR facility enables analysis of ultra trace amounts of nuclear materials at sub-picogram level in environmental samples.

Radiation measurement for safeguards environmental samples by Imaging Plate

In order to contribute to the strengthened safeguards system based on the Program 93+2 of the IAEA, Japan Atomic Energy Research Institute (JAERI) constructed the CLEAR facility (Clean Laboratory for Environmental Analysis and Research) and is developing analytical technology for ultra-trace amounts of nuclear materials in environmental samples. To avoid cross-contamination among the samples and contamination of the clean rooms, radioactive materials in the samples to be introduced into the CLEAR facility will be limited to a certain amount. For this purpose the authors have examined the feasibility of Imaging-plate method, which is a kind of autoradiography and is suitable for determination on distribution of low-level radioactivity in the samples. Examination with β-ray (K-40), the linearity was obtained in the range of 0.01 - 0.2 Bq. The experiments with α-ray (Sm-147) suggested the detection limit of 0.05 Bq, which was equivalent to 2 μg of natural uranium.

Development of analytical techniques for ultra trace amounts of nuclear materials in environmental samples using ICP-MS for safeguards

The authors have begun to develop analytical techniques for ultra trace amounts of nuclear materials and to prepare a clean chemistry laboratory for environmental sample analyses. The analytical techniques include bulk and particle analyses. For the bulk analysis, concentrations and isotopic ratios of U and/or Pu are determined by inductively-coupled plasma mass spectrometry (ICP-MS) and thermal ionization mass spectrometry (TIMS). In the particle analysis, isotopic ratios of U and/or Pu in each particle will be measured by secondary ion mass spectrometry (SIMS). This paper reports on the outline for the development of analytical techniques and the current situation of the development of the bulk analysis using ICP-MS is described.

Texanol Isobutyrate and Other Additive Chemicals-Environmental Contaminants or Laboratory Artifacts?

Abstract Over a period of years, trace organic analysis of Scottish river water and fish samples using gas-chromatography/mass-spectrometry (GC-MS) has often shown the presence of a component with similar elution properties to diethylphthalate and with a dominant ion in the mass spectrum at m/z 71. Closer investigation of this material has now shown it to be 2,2,4-trimethyl-1,3-pentandiol diisobutyrate (common name Texanol isobutyrate), a widely-used industrial chemical marketed as Kodaflex TXIB with applications as a plasticiser, cross-linking agent and lubriciant. The origin of TXIB in analytical samples has been traced to contamination during solvent evaporation operations and it is suggested that a possible source of the chemical might be by slow release into the laboratory atmosphere from vinyl floor coverings. A summary is given of other common contaminants which were identified in the course of these investigations. The genuine occurrence of such materials in environmental samples is not ruled out but these findings highlight the need for rigorous quality assurance in environmental trace analysis if reported levels are to be truly meaningful. A brief assessment of the environmental significance of TXIB is provided.

Pyrolysis gas chromatography-mass spectrometry of polychlorinated biphenyls on sediment

Polychlorinated biphenyls (PCBs) are common environmental contaminants which were freely employed for many years in numerous industrial applications but whose use has now been regulated. Many analytical schemes for monitoring these materials in environmental samples have been developed over the last decades, however, PCBs remain difficult analytical subjects. Most protocols rely on a combination of wet chemical pre-analytical isolation and purification whose complexity depends on the sample matrix. The time required for these manipulations may greatly hamper efforts directed towards emergency cleanup of accidental or illicit contamination of the environment. Thus, a clear need exists for methods which will allow rapid analysis of relatively intransigent samples for PCB contamination. Preliminary experiments directed to assessing the use of pyrolysis/gas chromatography/mass spectrometry in determining PCB contamination of soils and sediments are reported. In these experiments pyrolytic desorption at 1000/sup 0/C during 10 sec was used to completely replace more lengthy wet chemical manipulations.

Organochlorine Substances in Lake Superior

Published and governmental reports on Lake Superior are examined for accounts of the presence of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCs), and other material in environmental samples of water, sediments, and fish. PCBs, DDT residues, and dieldrin were most often examined for and observed, although levels of hetachlor epoxide, chlordane, lindane, endrin, and a-BHC were determined infrequently and several chlorobenzenes and chloronorbomenes were found. Levels of PCBs and DDT often exceed IJC water quality objectives. An inability to compare most of the data was a major problem in assessing the data.