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At least 145 records · Page 8

ORNL Second Target Station Project: Biological & Environmental Science Workshop

Recent advances in neutron sources and instrumentation have opened up many new opportunities for the application of neutron scattering techniques in the biological and environmental sciences. Neutrons enable studies of the structure and dynamics of biological and environmental samples with a particular sensitivity to light elements, such as hydrogen, which is a key component of biological and environmental samples. Studies using neutrons are complementary to X-rays and have the unique advantage of being non-destructive and highly-penetrating. Oak Ridge National Laboratory’s upcoming Spallation Neutron Source (SNS) Second Target Station (STS) will provide high brightness cold neutron sources that significantly advance the scientific capabilities of neutron scattering instruments. The STS will advance our understanding of biological and environmental processes across spatial and temporal scales. The capabilities will enhance our ability to discover, design, and develop new materials essential for advanced sustainable technologies to address society’s most pressing needs. This report summarizes the discussions and recommendations from a joint workshop held by the STS Project and the Biological and Environmental Systems Science Directorate (BESSD) in June 2022. The purpose of the workshop was to explore science opportunities and capabilities related to biological and environmental systems that could be incorporated into both current and future STS instrument designs, as well as additional instruments at the SNS First Target Station (FTS) and High Flux Isotope Reactor (HFIR). With six breakout sessions, each with two invited plenary speakers from other institutions, the participants discussed a wide range of topics relevant to biological and environmental research. Based on the input from participants, a number of recommendations on instrumentation, sample environments, complementary multi-modal methods, data processing and analysis and sample deuteration are provided in the report. The participants also identified science opportunities that are emerging from the planned instrument capabilities at STS. Selected recommendations and science opportunities are listed in the Executive Summary.

54 ENVIRONMENTAL SCIENCES↗

Determining the Reliability of Measuring Mercury Cycling Gene Abundance with Correlations with Mercury and Methylmercury Concentrations

Methylmercury (MeHg) is a bioaccumulative toxic contaminant in many ecosystems but factors governing its production are poorly understood. Recent work has shown that the anaerobic microbial conversion of mercury (Hg) to MeHg requires the Hg-methylation genes hgcAB and that these genes can be used as biomarkers in PCR-based estimators of Hg-methylator abundance. In an effort to determine reliable methods for assessing hgcA abundance and diversity and linking it to MeHg concentrations, multiple approaches were compared including metagenomic shotgun sequencing, 16S rRNA gene pyrosequencing and cloning/sequencing hgcAB gene products. Hg-methylator abundance was also determined by quantitative hgcA qPCR amplification and metaproteomics for comparison to the above measurements. Samples from eight Hg-contaminated sites were examined over a range of total Hg (HgT; 0.03–14 mg kg-1 wet wt. soil) and MeHg (0.05–27 µg kg-1 wet wt. soil) concentrations. In the metagenome and amplicon sequencing of hgcAB diversity, the Deltaproteobacteria were the dominant Hg-methylators, while Firmicutes and methanogenic Archaea were typically ~50% less abundant. This was consistent with metaproteomics estimates where the Deltaproteobacteria were consistently higher. The 16S rRNA gene pyrosequencing did not have sufficient resolution to identify hgcAB+ species. Metagenomic and hgcAB results were similar for Hg-methylator diversity and showed a tractable relationship between Hg-methylating bacteria and soil Hg concentrations among similar environmental samples. However, clade-specific qPCR-based approaches for hgcA are only appropriate when comparing the abundance of a particular clade across various samples.

59 BASIC BIOLOGICAL SCIENCES↗

Assessing high fidelity multi-component models to facilitate safeguards at Gas Centrifuge Enrichment Plants

We report that the International Atomic Energy Agency (IAEA) inspectors routinely carry out environmental sampling (ES) as a verification method. Collection of environmental swipe samples at various locations in Gas Centrifuge Enrichment Facilities (GCEPs) is an important process in detecting misuse of a declared facility and possibly the existence of undeclared nuclear material. These samples are measured for isotopic composition in uranium containing particles by Thermal Ionization Mass Spectrometry (TIMS) or Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Even though ES is highly effective in detecting the absolute value of enrichments and their deviations from the declared values, it cannot explain the cause of those changes. Several potential explanations can serve as possibilities for particles detected above or other than the declared enrichment. These include normal and non-malicious events such as the design of the enrichment cascades, unintentional failures of the machines, or overshoot during startup of a cascade. It can also be the result of deliberate misuse by the facility operators. The primary objective of this work is to understand how these factors affect the enrichments produced by a cascade and quantify anticipated multi-isotopic concentrations for each case. The following methodology is employed to determine signatures at a particular facility. 1) Utilize a new two-dimensional multi-component diffusion code to obtain centrifuge performance data and use that information to design and perform cascade analysis. Compare and contrast the results with previous 1-D radially averaged solutions from the Pancake code. 2) Design a GCEP cascade with the production goal of 19.75% 235 U for each set of machine data above. Investigate two cascade scenarios that include enrichment of natural uranium (NU) feed to 19.75% 235U in a single cascade compared to a two-step process of NU to 5% and then 5% to 19.75%. 3) Simulate the intentional vs. unintentional off-normal scenarios in the cascades to assess the differences in isotopic concentrations. A non-ideal squared-off cascade model developed at the University of Virginia is used to calculate flow rates and isotopic concentrations of the process gas. The analysis is performed using the Rome machine model operated at 600 m/s rotor speed. The upper and lower bounds of normal and abnormal enrichments in a typical facility are used in conjunction with ES results to understand the root causes of such observations.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗

American Gut: an Open Platform for Citizen Science Microbiome Research

Although much work has linked the human microbiome to specific phenotypes and lifestyle variables, data from different projects have been challenging to integrate and the extent of microbial and molecular diversity in human stool remains unknown. Using standardized protocols from the Earth Microbiome Project and sample contributions from over 10,000 citizen-scientists, together with an open research network, we compare human microbiome specimens primarily from the United States, United Kingdom, and Australia to one another and to environmental samples. Our results show an unexpected range of beta-diversity in human stool microbiomes compared to environmental samples; demonstrate the utility of procedures for removing the effects of overgrowth during room-temperature shipping for revealing phenotype correlations; uncover new molecules and kinds of molecular communities in the human stool metabolome; and examine emergent associations among the microbiome, metabolome, and the diversity of plants that are consumed (rather than relying on reductive categorical variables such as veganism, which have little or no explanatory power). We also demonstrate the utility of the living data resource and cross-cohort comparison to confirm existing associations between the microbiome and psychiatric illness and to reveal the extent of microbiome change within one individual during surgery, providing a paradigm for open microbiome research and education. We show that a citizen science, self-selected cohort shipping samples through the mail at room temperature recaptures many known microbiome results from clinically collected cohorts and reveals new ones. Of particular interest is integrating n = 1 study data with the population data, showing that the extent of microbiome change after events such as surgery can exceed differences between distinct environmental biomes, and the effect of diverse plants in the diet, which we confirm with untargeted metabolomics on hundreds of samples.

59 BASIC BIOLOGICAL SCIENCES↗

BSSD 2019 Performance Metric Q4

The LANL SFA in Terrestrial Microbial Carbon Cycling aims to inform climate modeling and enable carbon management in terrestrial ecosystems by discovering widespread biological processes that control carbon storage and release in temperate biome soils. To achieve these goals, computational approaches are essential to analyze increasingly complex ‘omics’ data from microbial communities in environmental samples. The SFA continues to leverage advances in ‘omics' measurement technology and computation tools to decipher microbial community function in environmental samples. The computational approach is aligned with the recent shift in the SFA’s research approach. When the SFA began 10 years ago, computational approaches principally addressed “who is there” with extremely limited insight into function. Accessible ‘omics' data for complex soil communities were primarily amplicon DNA sequences of taxonomic or functional marker genes obtained by PCR, cloning, and Sanger sequencing. Computational tools for community analysis were nascent. Over the past decade, genome resources (DOE-Integrated Microbial Genomics database) and data acquisition increased 1000-fold, common computational pipelines for many analysis tasks have arisen, and the variety of ‘omics’ measurements has expanded to routinely include shotgun metagenomics, metatranscriptomics, and versions of metabolomics. The SFA is capitalizing on these advances while also developing new computational techniques to decipher how communities with different patterns of carbon cycling function from the species to ecosystem level.

54 ENVIRONMENTAL SCIENCES↗

Childhood lead poisoning from the smelter in Torreon, Mexico

Lead concentrations and isotopic compositions in blood samples of 34 children (ages 2-17 years) living within a 113 km{sup 2} area of a silver-zinc-lead smelter plant in Torreon, Mexico were compared to those of associated environmental samples (soil, aerosols, and outdoor and indoor dust) to identify the principal source(s) of environmental and human lead contamination in the area. Lead concentrations of soil and outdoor dust ranged 130-12,050 and 150-14,365 {mu}g g{sup -1}, respectively. Concentrations were greatest near the smelter, with the highest levels corresponding with the prevailing wind direction, and orders of magnitude above background concentrations of 7.3-33.3 {mu}g g{sup -1}. Atmospheric lead depositions in the city varied between 130 and 1350 {mu}g m{sup -2} d{sup -1}, again with highest rates <1 km from the smelter. Blood lead (PbB) concentrations (11.0{+-}5.3 {mu}g dl{sup -1}) levels in the children ranged 5.0-25.8 {mu}g dl{sup -1}, which is 3-14 times higher than the current average (1.9 {mu}g dl{sup -1}) of children (ages 1-5 years) in the US. Lead isotopic ratios ({sup 206}Pb/{sup 207}Pb, {sup 208}Pb/{sup 207}Pb) of the urban dust and soil (1.200{+-}0.009, 2.467{+-}0.003), aerosols (1.200{+-}0.002, 2.466{+-}0.002), and PbB (1.199{+-}0.001, 2.468{+-}0.002) were indistinguishable from each other, as well as those of the lead ores processed at the smelter (1.199{+-}0.007, 2.473{+-}0.007). Consequently, an elevated PbB concentrations of the children in Torreon, as well as in their environment, are still dominated by industrial emissions from the smelter located within the city, in spite of new controls on atmospheric releases from the facility. - Highlights: {yields} Pb contents in environmental samples evidenced chronic Pb pollution in Torreon. {yields} Pb stable isotopes evidenced contemporary emissions from the Ag-Cod-Pb-Zn smelter. {yields} Pb urban dust and soil account for most of the childhood lead poisoning in Torreon.{yields} Levels of Pub in Torreon's children are 3-14 times higher than children in the US.{yields} Children Pub concentrations are primarily attributed to emissions from the smelter.

54 ENVIRONMENTAL SCIENCES↗

Environmental RNA as a Tool for Marine Community Biodiversity Assessments

Abstract Microscopic organisms are often overlooked in traditional diversity assessments due to the difficulty of identifying them based on morphology. Metabarcoding is a method for rapidly identifying organisms where Environmental DNA (eDNA) is used as a template. However, legacy DNA is problematically detected from organisms no longer in the environment during sampling. Environmental RNA (eRNA), which is only produced by living organisms, can also be collected from environmental samples and used for metabarcoding. The aim of this study was to determine differences in community composition and diversity between eRNA and eDNA templates for metabarcoding. Using mesocosms containing field-collected communities from an estuary, RNA and DNA were co-extracted from sediment, libraries were prepared for two loci (18S and COI), and sequenced using an Illumina MiSeq. Results show a higher number of unique sequences detected from eRNA in both markers and higher α-diversity compared to eDNA. Significant differences between eRNA and eDNA for all β-diversity metrics were also detected. This study is the first to demonstrate community differences detected with eRNA compared to eDNA from an estuarine system and illustrates the broad applications of eRNA as a tool for assessing benthic community diversity, particularly for environmental conservation and management applications.

Giroux, Marissa S.↗

VAPOR PRESSURE ISOTOPE EFFECTS IN THE MEASUREMENT OF ENVIRONMENTAL TRITIUM SAMPLES.

Standard procedures for the measurement of tritium in water samples often require distillation of an appropriate sample aliquot. This distillation process may result in a fractionation of tritiated water and regular light water due to the vapor pressure isotope effect, introducing either a bias or an additional contribution to the total tritium measurement uncertainty. The magnitude of the vapor pressure isotope effect is characterized as functions of the amount of water distilled from the sample aliquot and the heat settings for the distillation process. The tritium concentration in the distillate is higher than the tritium concentration in the sample early in the distillation process, it then sharply decreases due to the vapor pressure isotope effect and becomes lower than the tritium concentration in the sample, until the high tritium concentration retained in the boiling flask is evaporated at the end of the process. At that time, the tritium concentration in the distillate again overestimates the sample tritium concentration. The vapor pressure isotope effect is more pronounced the slower the evaporation and distillation process is conducted; a lower heat setting during the evaporation of the sample results in a larger bias in the tritium measurement. The experimental setup used and the fact that the current study allowed for an investigation of the relative change in vapor pressure isotope effect in the course of the distillation process distinguish it from and extend previously published measurements. The separation factor as a quantitative measure of the vapor pressure isotope effect is found to assume values of 1.034 {+-} 0.033, 1.052 {+-} 0.025, and 1.066 {+-} 0.037, depending on the vigor of the boiling process during distillation of the sample. A lower heat setting in the experimental setup, and therefore a less vigorous boiling process, results in a larger value for the separation factor. For a tritium measurement in water samples, this implies that the tritium concentration could be underestimated by 3 - 6%.

54 ENVIRONMENTAL SCIENCES↗

Summary of the Undergraduate Mentoring Assistance Program for PNNL

Kelly Fitzgerald Kelly Fitzgerald assisted with laboratory testing for an ongoing R&D project known as Electrochemically Modulated Separation (EMS) for on-line rapid preseparations of actinides prior to mass spectrometry analysis. Ryne Burgess Ryne Burgess used SCALE 5.1 ORIGEN-ARP to predict isotope libraries for the Units 1, 2 and 3 reactors and Unit 4 spent fuel pool for comparing against measurements of environmental sampled collected at the site in order to identify the source terms of the accident. Comparison of the cesium 134/137 and cesium 136/137 ratios observed in environmental samples and ORIGEN-ARP predictions indicated that the Unit 4 Spent Fuel Pool did not significantly contribute to radionuclide release during the Fukushima Daiichi accident.

Burgess↗

Method for isolating nucleic acids

The current disclosure provides methods and kits for isolating nucleic acid from an environmental sample. The current methods and compositions further provide methods for isolating nucleic acids by reducing adsorption of nucleic acids by charged ions and particles within an environmental sample. The methods of the current disclosure provide methods for isolating nucleic acids by releasing adsorbed nucleic acids from charged particles during the nucleic acid isolation process. The current disclosure facilitates the isolation of nucleic acids of sufficient quality and quantity to enable one of ordinary skill in the art to utilize or analyze the isolated nucleic acids for a wide variety of applications including, sequencing or species population analysis.

59 BASIC BIOLOGICAL SCIENCES↗

Early Results and Spaceflight Implications of the SWAB Flight Experiment

Microbial monitoring of spacecraft environments provides key information in the assessment of infectious disease risk to the crew. Monitoring aboard the Mir space station and International Space Station (ISS) has provided a tremendous informational baseline to aid in determining the types and concentrations of microorganisms during a mission. Still, current microbial monitoring hardware utilizes culture-based methodology which may not detect many medically significant organisms, such as Legionella pneumophila. We hypothesize that evaluation of the ISS environment using non-culture-based technologies would reveal microorganisms not previously reported in spacecraft, allowing for a more complete health assessment. To achieve this goal, a spaceflight experiment, operationally designated as SWAB, was designed to evaluate the DNA from environmental samples collected from ISS and vehicles destined for ISS. Results from initial samples indicate that the sample collection and return procedures were successful. Analysis of these samples using denaturing gradient gel electrophoresis and targeted PCR primers for fungal contaminants is underway. The current results of SWAB and their implication for in-flight molecular analysis of environmental samples will be discussed.

Ott, C. Mark↗

Plutonium isotope ratio variations in North America

Historically, approximately 12,000 TBq of plutonium was distributed throughout the global biosphere by thermo nuclear weapons testing. The resultant global plutonium fallout is a complex mixture whose {sup 240}Pu/{sup 239}Pu atom ratio is a function of the design and yield of the devices tested. The average {sup 240}Pu/{sup 239}Pu atom ratio in global fallout is 0.176 + 014. However, the {sup 240}Pu/{sup 239}Pu atom ratio at any location may differ significantly from 0.176. Plutonium has also been released by discharges and accidents associated with the commercial and weapons related nuclear industries. At many locations contributions from this plutonium significantly alters the {sup 240}Pu/{sup 239}Pu atom ratios from those observed in global fallout. We have measured the {sup 240}Pu/{sup 239}Pu atom ratios in environmental samples collected from many locations in North America. This presentation will summarize the analytical results from these measurements. Special emphasis will be placed on interpretation of the significance of the {sup 240}Pu/{sup 239}Pu atom ratios measured in environmental samples collected in the Arctic and in the western portions of the United States.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗

A rapid live-cell ELISA for characterizing antibodies against cell surface antigens of Chlamydomonas reinhardtii and its use in isolating algae from natural environments with related cell wall components

Background: Cell walls are essential for most bacteria, archaea, fungi, algae and land plants to provide shape, structural integrity and protection from numerous biotic and abiotic environmental factors. In the case of eukaryotic algae, relatively little is known of the composition, structure or mechanisms of assembly of cell walls in individual species or between species and how these differences enable algae to inhabit a great diversity of environments. In this paper we describe the use of camelid antibody fragments (VHHs) and a streamlined ELISA assay as powerful new tools for obtaining mono-specific reagents for detecting individual algal cell wall components and for isolating algae that share a particular cell surface component. Results: To develop new microalgal bioprospecting tools to aid in the search of environmental samples for algae that share similar cell wall and cell surface components, we have produced single-chain camelid antibodies raised against cell surface components of the single-cell alga, Chlamydomonas reinhardtii. We have cloned the variable-region domains (VHHs) from the camelid heavy-chain-only antibodies and overproduced tagged versions of these monoclonal-like antibodies in E. coli. Using these VHHs, we have developed an accurate, facile, low cost ELISA that uses live cells as a source of antigens in their native conformation and that requires less than 90 minutes to perform. This ELISA technique was demonstrated to be as accurate as standard ELISAs that employ proteins from cell lysates and that generally require >24 hours to complete. Among the cloned VHHs, VHH B11, exhibited the highest affinity (EC50 < 1 nM) for the C. reinhardtii cell surface. The live-cell ELISA procedure was employed to detect algae sharing cell surface components with C. reinhardtii in water samples from natural environments. In addition, mCherry-tagged VHH B11 was used along with fluorescence activated cell sorting (FACS) to select individual axenic isolates of presumed wild relatives of C. reinhardtii and other Chlorphyceae from the same environmental samples. Conclusions: Camelid antibody VHH domains provide a highly specific tool for detection of individual cell wall components of algae and for allowing the selection of algae that share a particular cell surface molecule from diverse ecosystems.

54 ENVIRONMENTAL SCIENCES↗

Analysis of a Nuclear Accident: Fission and Activation Product Releases from the Fukushima Daiichi Nuclear Facility as Remote Indicators of Source Identification, Extent of Release, and State of Damaged Spent Nuclear Fuel

Measurements of several radionuclides within environmental samples taken from the Fukushima Daiichi nuclear facility and reported on the Tokyo Electric Power Company website following the recent tsunami-initiated catastrophe were evaluated for the purpose of identifying the source term, reconstructing the release mechanisms, and estimating the extent of the release. 136Cs/137Cs and 134Cs/137Cs ratios identified Units 1-3 as the major source of radioactive contamination to the surface soil close to the facility. A trend was observed between the fraction of the total core inventory released for a number of fission product isotopes and their corresponding Gibbs Free Energy of formation for the primary oxide form of the isotope, suggesting that release was dictated primarily by chemical volatility driven by temperature and reduction potential within the primary containment vessels of the vented reactors. The absence of any major fractionation beyond volatilization suggested all coolant had evaporated by the time of venting. High estimates for the fraction of the total inventory released of more volatile species (Te, Cs, I) indicated the damage to fuel bundles was likely extensive, minimizing any potential containment due to physical migration of these species through the fuel matrix and across the cladding wall. 238Pu/239,240Pu ratios close-in and at 30 km from the facility indicated that the damaged reactors were the major contributor of Pu to surface soil at the source but that this contribution likely decreased rapidly with distance from the facility. The fraction of the total Pu inventory released to the environment from venting units 1 and 3 was estimated to be ~0.003% based upon Pu/Cs isotope ratios relative to the within-reactor modeled inventory prior to venting and was consistent with an independent model evaluation that considered chemical volatility based upon measured fission product release trends. Significant volatile radionuclides within the spent fuel at the time of venting but not as yet observed and reported within environmental samples are suggested as potential analytes of concern for future environmental surveys around the site.

Schwantes, Jon M↗

Deep Diversity: Novel Approach to Overcoming the PCR Bias Encountered During Environmental Analysis of Microbial Populations for Alpha-Diversity

Alpha-diversity studies are of crucial importance to environmental microbiologists. The polymerase chain reaction (PCR) method has been paramount for studies interrogating microbial environmental samples for taxon richness. Phylogenetic studies using this technique are based on the amplification and comparison of the 16S rRNA coding regions. PCR, due disproportionate distribution of microbial species in the environment, increasingly favors the amplification of the most predominant phylotypes with every subsequent reaction cycle. The genetic and chemical complexity of environmental samples are intrinsic factors that exacerbate an inherit bias in PCR-based quantitative and qualitative studies of microbial communities. We report that treatment of a genetically complex total genomic environmental DNA extract with Propidium Monoazide (PMA), a DNA intercalating molecule capable of forming a covalent cross-linkage to organic moieties upon light exposure, disproportionally inactivates predominant phylotypes and results in the exponential amplification of previously shadowed microbial ?-diversity quantified as a 19.5% increase in OUTs reported via phylogenetic screening using PhyloChip.

phylogenetic microarray technologies↗

Environmental Swipe (ES) Streamline Protocol—ORNL Testing Fiscal Year 2016 Report

As a sub-section of the NA241 project entitled “Faster, Simpler, Lower-Cost Laboratory Analysis of Environmental Samples,” Oak Ridge National Laboratory (ORNL) was to function as a Network Analytical Laboratory (NWAL) for validation, verification, and review of analytical methods developed under the auspices of this project. ORNL would also provide technical input on alternative analytical protocols for analyzing bulk environmental samples submitted for uranium (U) and/or plutonium (Pu) determinations by the International Atomic Energy Agency (IAEA). The final ORNL task would then be to summarize findings as stated in this end-of year report.

54 ENVIRONMENTAL SCIENCES↗

The development of radioactive sample surrogates for training and exercises

The development of radioactive sample surrogates for training and exercises Source term information is required for to reconstruct a device used in a dispersed radiological dispersal device. Simulating a radioactive environment to train and exercise sampling and sample characterization methods with suitable sample materials is a continued challenge. The Idaho National Laboratory has developed and permitted a Radioactive Response Training Range (RRTR), an 800 acre test range that is approved for open air dispersal of activated KBr, for training first responders in the entry and exit from radioactively contaminated areas, and testing protocols for environmental sampling and field characterization. Members from the Department of Defense, Law Enforcement, and the Department of Energy participated in the first contamination exercise that was conducted at the RRTR in the July 2011. The range was contaminated using a short lived radioactive Br-82 isotope (activated KBr). Soil samples contaminated with KBr (dispersed as a solution) and glass particles containing activated potassium bromide that emulated dispersed radioactive materials (such as ceramic-based sealed source materials) were collected to assess environmental sampling and characterization techniques. This presentation summarizes the performance of a radioactive materials surrogate for use as a training aide for nuclear forensics.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗