The Experts below are selected from a list of 66411 Experts worldwide ranked by ideXlab platform
James R Ehleringer - One of the best experts on this subject based on the ideXlab platform.
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isolation of strontium pools and Isotope Ratios in modern human hair
Analytica Chimica Acta, 2013Co-Authors: Brett J Tipple, Thuan H Chau, Lesley A Chesson, Diego P Fernandez, James R EhleringerAbstract:Abstract The elements of human hair record specific information about an individual's health, diet, and surrounding environment. Strontium Isotope Ratios of human hair have attracted interest as they potentially record an individual's environment. Yet, separating the external environmental signals from the internal dietary indicators has remained a challenge. Here, we examined the effects of five different hair-cleaning methodologies to determine the extent that internal and external strontium signals can be isolated from human hair. In the first study of its kind, we employed an in-line strontium purification methodology and a multi-collector inductively coupled plasma mass spectrometer to obtain high-precision strontium Isotope ratio of human hair and of leachates of the different washing treatments. We found that the different applications of an individual treatment removed a consistent amount of strontium from hair and that replicate analyses showed each treatment altered the strontium Isotope Ratios of hair consistently. A mass-balance approach was applied to demonstrate that strontium was quantitatively removed and was accounted for in either the treated hair or the leachate. We observed that strontium Isotope ratio varied as a function of treatment aggressiveness so as to suggest that there was a fine-scale structuring of strontium within hair (transverse cross-sectional variations); these variations existed as differences in strontium concentrations and Isotope Ratios. As a result, the Sr Isotope ratio of hair and hair leachates treated with the most aggressive cleaning methods reflected the Isotope Ratios of the interior and total exterior strontium signatures, respectively. The results of this study indicate that external environmental strontium signals can be distinguished from the internal signals and therefore permit the application of strontium Isotope Ratios of modern human hair for geospatial applications.
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forensic applications of light element stable Isotope Ratios of ricinus communis seeds and ricin preparations
Journal of Forensic Sciences, 2013Co-Authors: Helen Kreuzer, Jason B West, James R EhleringerAbstract:Seeds of the castor plant Ricinus communis are of forensic interest because they are the source of the poison ricin. We tested whether stable Isotope Ratios of castor seeds and ricin preparations can be used as a forensic signature. We collected over 300 castor seed samples worldwide and measured the C, N, O, and H Isotope Ratios of the whole seeds and oil. We prepared ricin by three different procedures, acetone extraction, salt precipitation, and affinity chromatography, and compared their Isotope Ratios to those of the source seeds. The N Isotope Ratios of the ricin samples and source seeds were virtually identical. Therefore, N Isotope Ratios can be used to correlate ricin prepared by any of these methods to source seeds. Further, stable Isotope Ratios distinguished >99% of crude and purified ricin protein samples in pairwise comparison tests. Stable Isotope Ratios therefore constitute a valuable forensic signature for ricin preparations.
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Forensic Applications of Light-Element Stable Isotope Ratios of Ricinus communis Seeds
2012Co-Authors: Helen W Kreuzer, Jason B West, James R EhleringerAbstract:Seeds of the castor plant Ricinus communis are of forensic interest because they are the source of the poison ricin. We tested whether stable Isotope Ratios of castor seeds and ricin preparations can be used as a forensic signature. We collected over 300 castor seed sam- ples worldwide and measured the C, N, O, and H Isotope Ratios of the whole seeds and oil. We prepared ricin by three different procedures, acetone extraction, salt precipitation, and affinity chromatography, and compared their Isotope Ratios to those of the source seeds. The N Isotope Ratios of the ricin samples and source seeds were virtually identical. Therefore, N Isotope Ratios can be used to correlate ricin prepared by any of these methods to source seeds. Further, stable Isotope Ratios distinguished >99% of crude and purified ricin protein samples in pairwise comparison tests. Stable Isotope Ratios therefore constitute a valuable forensic signature for ricin preparations.
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hydrogen and oxygen stable Isotope Ratios of milk in the united states
Journal of Agricultural and Food Chemistry, 2010Co-Authors: Lesley A Chesson, Thure E Cerling, Luciano O Valenzuela, Shannon P Ogrady, James R EhleringerAbstract:Models of hydrogen and oxygen incorporation in human tissues recognize the impact of geographic location on the isotopic composition of fluid intake, but inputs can include nonlocal beverages, such as milk. Milk and cow drinking water were collected from dairies, and commercially available milk was purchased from supermarkets and fast food restaurants. It was hypothesized that milk water δ2H and δ18O values record geographic location information. Correlations between milk water Isotope Ratios and purchase location tap water were significant. However, the amount of variation in milk δ2H and δ18O values explained by tap water was low, suggesting a single estimation of fluid input Isotope Ratios may not always be adequate in studies. The δ2H and δ18O values of paired milk and cow drinking water were related, suggesting potential for geographical origin assignment using stable Isotope analysis. As an application example, milk water δ18O values were used to predict possible regions of origin for restaurant sam...
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hydrogen and oxygen Isotope Ratios in human hair are related to geography
Proceedings of the National Academy of Sciences of the United States of America, 2008Co-Authors: James R Ehleringer, Lesley A Chesson, Gabriel J Bowen, Adam G West, David W Podlesak, Thure E CerlingAbstract:We develop and test a model to predict the geographic region-of-origin of humans based on the stable Isotope composition of their scalp hair. This model incorporates exchangeable and nonexchangeable hydrogen and oxygen atoms in amino acids to predict the δ2H and δ18O values of scalp hair (primarily keratin). We evaluated model predictions with stable Isotope analyses of human hair from 65 cities across the United States. The model, which predicts hair isotopic composition as a function of drinking water, bulk diet, and dietary protein Isotope Ratios, explains >85% of the observed variation and reproduces the observed slopes relating the isotopic composition of hair samples to that of local drinking water. Based on the geographical distributions of the Isotope Ratios of tap waters and the assumption of a “continental supermarket” dietary input, we constructed maps of the expected average H and O Isotope Ratios in human hair across the contiguous 48 states. Applications of this model and these observations are extensive and include detection of dietary information, reconstruction of historic movements of individuals, and provision of region-of-origin information for unidentified human remains.
Chi-gyu Lee - One of the best experts on this subject based on the ideXlab platform.
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Accurate determination of minor Isotope Ratios in individual plutonium–uranium mixed particles by thermal ionization mass spectrometry
Elsevier, 2018Co-Authors: Chi-gyu Lee, Jinkyu Park, Sang Ho LimAbstract:Isotopic analyses of plutonium and low-enriched uranium mixtures with particle sizes of 0.6–3.3 μm were performed using thermal ionization mass spectrometry with a continuous heating method to verify its effectiveness for the accurate analysis of minor Isotopes without sample pretreatment. The mixed particles used in this study were prepared from a mixed solution of plutonium (SRM 947) and uranium (U010, 235U 1% enriched) reference materials. The Isotope Ratios for plutonium in the individual mixed particles, including 238Pu/239Pu, 241Pu/239Pu as well as 240Pu/239Pu, and 242Pu/239Pu, were in good agreement with the certified values despite the isobaric interference of 238U and 241Am. The Isotope Ratios for uranium in the mixed particles also agreed well with the certified values within the range of error. However, the Isotope Ratios for minor Isotopes, such as 234U and 236U, in the particles with diameters of less than approximately 1.8 μm could not be measured because numbers of 234U and 236U atoms in analyzed particles are too low. These results indicate that thermal ionization mass spectrometry with a continuous heating method is applicable for the analysis of trace amounts of plutonium Isotopes, including 238Pu and 241Pu, despite the presence of the respective isobars 238U and 241Am in the microsamples
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accurate determination of minor Isotope Ratios in individual plutonium uranium mixed particles by thermal ionization mass spectrometry
Nuclear Engineering and Technology, 2017Co-Authors: Chi-gyu Lee, Jinkyu Park, Sang Ho LimAbstract:Abstract Isotopic analyses of plutonium and low-enriched uranium mixtures with particle sizes of 0.6–3.3 μm were performed using thermal ionization mass spectrometry with a continuous heating method to verify its effectiveness for the accurate analysis of minor Isotopes without sample pretreatment. The mixed particles used in this study were prepared from a mixed solution of plutonium (SRM 947) and uranium (U010, 235 U 1% enriched) reference materials. The Isotope Ratios for plutonium in the individual mixed particles, including 238 Pu/ 239 Pu, 241 Pu/ 239 Pu as well as 240 Pu/ 239 Pu, and 242 Pu/ 239 Pu, were in good agreement with the certified values despite the isobaric interference of 238 U and 241 Am. The Isotope Ratios for uranium in the mixed particles also agreed well with the certified values within the range of error. However, the Isotope Ratios for minor Isotopes, such as 234 U and 236 U, in the particles with diameters of less than approximately 1.8 μm could not be measured because numbers of 234 U and 236 U atoms in analyzed particles are too low. These results indicate that thermal ionization mass spectrometry with a continuous heating method is applicable for the analysis of trace amounts of plutonium Isotopes, including 238 Pu and 241 Pu, despite the presence of the respective isobars 238 U and 241 Am in the microsamples.
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comparison of icp ms and sims techniques for determining uranium Isotope Ratios in individual particles
Talanta, 2009Co-Authors: Fumitaka Esaka, Chi-gyu Lee, Masaaki Magara, S. Sakurai, S. Usuda, Nobuo ShinoharaAbstract:Abstract The determination of uranium Isotope Ratios in individual particles is of great importance for nuclear safeguards. In the present study, an analytical technique by inductively coupled plasma mass spectrometry (ICP-MS) with a desolvation sample introduction system was applied to Isotope ratio analysis of individual uranium particles. In ICP-MS analysis of individual uranium particles with diameters ranging from 0.6 to 4.2 μm in a standard reference material (NBL CRM U050), the use of the desolvation system for sample introduction improved the precision of 234 U/ 238 U and 236 U/ 238 U Isotope Ratios. The performance of ICP-MS with desolvation was compared with that of a conventionally used method, i.e., secondary ion mass spectrometry (SIMS). The analysis of test swipe samples taken at nuclear facilities implied that the performance of ICP-MS with desolvation was superior to that of SIMS in a viewpoint of accuracy, because the problems of agglomeration of uranium particles and molecular ion interferences by other elements could be avoided. These results indicated that ICP-MS with desolvation has an enough ability to become an effective tool for nuclear safeguards.
Thure E Cerling - One of the best experts on this subject based on the ideXlab platform.
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hydrogen and oxygen stable Isotope Ratios of milk in the united states
Journal of Agricultural and Food Chemistry, 2010Co-Authors: Lesley A Chesson, Thure E Cerling, Luciano O Valenzuela, Shannon P Ogrady, James R EhleringerAbstract:Models of hydrogen and oxygen incorporation in human tissues recognize the impact of geographic location on the isotopic composition of fluid intake, but inputs can include nonlocal beverages, such as milk. Milk and cow drinking water were collected from dairies, and commercially available milk was purchased from supermarkets and fast food restaurants. It was hypothesized that milk water δ2H and δ18O values record geographic location information. Correlations between milk water Isotope Ratios and purchase location tap water were significant. However, the amount of variation in milk δ2H and δ18O values explained by tap water was low, suggesting a single estimation of fluid input Isotope Ratios may not always be adequate in studies. The δ2H and δ18O values of paired milk and cow drinking water were related, suggesting potential for geographical origin assignment using stable Isotope analysis. As an application example, milk water δ18O values were used to predict possible regions of origin for restaurant sam...
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hydrogen and oxygen Isotope Ratios in human hair are related to geography
Proceedings of the National Academy of Sciences of the United States of America, 2008Co-Authors: James R Ehleringer, Lesley A Chesson, Gabriel J Bowen, Adam G West, David W Podlesak, Thure E CerlingAbstract:We develop and test a model to predict the geographic region-of-origin of humans based on the stable Isotope composition of their scalp hair. This model incorporates exchangeable and nonexchangeable hydrogen and oxygen atoms in amino acids to predict the δ2H and δ18O values of scalp hair (primarily keratin). We evaluated model predictions with stable Isotope analyses of human hair from 65 cities across the United States. The model, which predicts hair isotopic composition as a function of drinking water, bulk diet, and dietary protein Isotope Ratios, explains >85% of the observed variation and reproduces the observed slopes relating the isotopic composition of hair samples to that of local drinking water. Based on the geographical distributions of the Isotope Ratios of tap waters and the assumption of a “continental supermarket” dietary input, we constructed maps of the expected average H and O Isotope Ratios in human hair across the contiguous 48 states. Applications of this model and these observations are extensive and include detection of dietary information, reconstruction of historic movements of individuals, and provision of region-of-origin information for unidentified human remains.
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stable Isotope Ratios of tap water in the contiguous united states
Water Resources Research, 2007Co-Authors: Lesley A Chesson, James R Ehleringer, Gabriel J Bowen, Erik E Stange, Thure E CerlingAbstract:[1] Understanding links between water consumers and climatological (precipitation) sources is essential for developing strategies to ensure the long-term sustainability of water supplies. In pursing this understanding a need exists for tools to study and monitor complex human-hydrological systems that involve high levels of spatial connectivity and supply problems that are regional, rather than local, in nature. Here we report the first national-level survey of stable Isotope Ratios in tap water, including spatially and temporally explicit samples from a large number of cities and towns across the contiguous United States. We show that intra-annual ranges of tap water Isotope Ratios are relatively small (e.g., <10‰ for δ2H) at most sites. In contrast, spatial variation in tap water Isotope Ratios is very large, spanning ranges of 163‰ for δ2H and 23.6‰ for δ18O. The spatial distribution of tap water Isotope Ratios at the national level is similar to that of stable Isotope Ratios of precipitation. At the regional level, however, pervasive differences between tap water and precipitation Isotope Ratios can be attributed to hydrological factors in the water source to consumer chain. These patterns highlight the potential for monitoring of tap water Isotope Ratios to contribute to the study of regional water supply stability and provide warning signals for impending water resource changes. We present the first published maps of predicted tap water Isotope Ratios for the contiguous United States, which will be useful in guiding future research on human-hydrological systems and as a tool for applied forensics and traceability studies.
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Stable hydrogen and oxygen Isotope Ratios of bottled waters of the world
Rapid communications in mass spectrometry : RCM, 2005Co-Authors: Gabriel J Bowen, Thure E Cerling, David A. Winter, Howard J. Spero, Robert A. Zierenberg, Mathew D. Reeder, James R EhleringerAbstract:Bottled and packaged waters are an increasingly significant component of the human diet. These products are regulated at the regional, national, and international levels, and determining the authenticity of marketing and labeling claims represents a challenge to regulatory agencies. Here, we present a dataset of stable Isotope Ratios for bottled waters sampled worldwide, and consider potential applications of such data for regulatory, forensic and geochemical standardization applications. The hydrogen and oxygen Isotope Ratios of 234 samples of bottled water range from -147 per thousand to +15 per thousand and from -19.1 per thousand to +3.0 per thousand, respectively. These values fall within and span most of the normal range for meteoric waters, indicating that these commercially available products represent a source of waters for use as laboratory working standards in applications requiring standardization over a large range of Isotope Ratios. The measured values of bottled water samples cluster along the global meteoric water line, suggesting that bottled water Isotope Ratios preserve information about the water sources from which they were derived. Using the dataset, we demonstrate how bottled water Isotope Ratios provide evidence for substantial evaporative enrichment of water sources prior to bottling and for the marketing of waters derived from mountain and lowland sources under the same name. Comparison of bottled water Isotope Ratios with natural environmental water Isotope Ratios demonstrates that on average the isotopic composition of bottled water tends to be similar to the composition of naturally available local water sources, suggesting that in many cases bottled water need not be considered as an isotopically distinct component of the human diet. Our findings suggest that stable Isotope Ratios of bottled water have the power to distinguish ultimate (e.g., recharge) and proximal (e.g., reservoir) sources of bottled water and constitute a potential tool for use in the regulatory monitoring of water products.
Lesley A Chesson - One of the best experts on this subject based on the ideXlab platform.
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isolation of strontium pools and Isotope Ratios in modern human hair
Analytica Chimica Acta, 2013Co-Authors: Brett J Tipple, Thuan H Chau, Lesley A Chesson, Diego P Fernandez, James R EhleringerAbstract:Abstract The elements of human hair record specific information about an individual's health, diet, and surrounding environment. Strontium Isotope Ratios of human hair have attracted interest as they potentially record an individual's environment. Yet, separating the external environmental signals from the internal dietary indicators has remained a challenge. Here, we examined the effects of five different hair-cleaning methodologies to determine the extent that internal and external strontium signals can be isolated from human hair. In the first study of its kind, we employed an in-line strontium purification methodology and a multi-collector inductively coupled plasma mass spectrometer to obtain high-precision strontium Isotope ratio of human hair and of leachates of the different washing treatments. We found that the different applications of an individual treatment removed a consistent amount of strontium from hair and that replicate analyses showed each treatment altered the strontium Isotope Ratios of hair consistently. A mass-balance approach was applied to demonstrate that strontium was quantitatively removed and was accounted for in either the treated hair or the leachate. We observed that strontium Isotope ratio varied as a function of treatment aggressiveness so as to suggest that there was a fine-scale structuring of strontium within hair (transverse cross-sectional variations); these variations existed as differences in strontium concentrations and Isotope Ratios. As a result, the Sr Isotope ratio of hair and hair leachates treated with the most aggressive cleaning methods reflected the Isotope Ratios of the interior and total exterior strontium signatures, respectively. The results of this study indicate that external environmental strontium signals can be distinguished from the internal signals and therefore permit the application of strontium Isotope Ratios of modern human hair for geospatial applications.
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hydrogen and oxygen stable Isotope Ratios of milk in the united states
Journal of Agricultural and Food Chemistry, 2010Co-Authors: Lesley A Chesson, Thure E Cerling, Luciano O Valenzuela, Shannon P Ogrady, James R EhleringerAbstract:Models of hydrogen and oxygen incorporation in human tissues recognize the impact of geographic location on the isotopic composition of fluid intake, but inputs can include nonlocal beverages, such as milk. Milk and cow drinking water were collected from dairies, and commercially available milk was purchased from supermarkets and fast food restaurants. It was hypothesized that milk water δ2H and δ18O values record geographic location information. Correlations between milk water Isotope Ratios and purchase location tap water were significant. However, the amount of variation in milk δ2H and δ18O values explained by tap water was low, suggesting a single estimation of fluid input Isotope Ratios may not always be adequate in studies. The δ2H and δ18O values of paired milk and cow drinking water were related, suggesting potential for geographical origin assignment using stable Isotope analysis. As an application example, milk water δ18O values were used to predict possible regions of origin for restaurant sam...
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hydrogen and oxygen Isotope Ratios in human hair are related to geography
Proceedings of the National Academy of Sciences of the United States of America, 2008Co-Authors: James R Ehleringer, Lesley A Chesson, Gabriel J Bowen, Adam G West, David W Podlesak, Thure E CerlingAbstract:We develop and test a model to predict the geographic region-of-origin of humans based on the stable Isotope composition of their scalp hair. This model incorporates exchangeable and nonexchangeable hydrogen and oxygen atoms in amino acids to predict the δ2H and δ18O values of scalp hair (primarily keratin). We evaluated model predictions with stable Isotope analyses of human hair from 65 cities across the United States. The model, which predicts hair isotopic composition as a function of drinking water, bulk diet, and dietary protein Isotope Ratios, explains >85% of the observed variation and reproduces the observed slopes relating the isotopic composition of hair samples to that of local drinking water. Based on the geographical distributions of the Isotope Ratios of tap waters and the assumption of a “continental supermarket” dietary input, we constructed maps of the expected average H and O Isotope Ratios in human hair across the contiguous 48 states. Applications of this model and these observations are extensive and include detection of dietary information, reconstruction of historic movements of individuals, and provision of region-of-origin information for unidentified human remains.
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stable Isotope Ratios of tap water in the contiguous united states
Water Resources Research, 2007Co-Authors: Lesley A Chesson, James R Ehleringer, Gabriel J Bowen, Erik E Stange, Thure E CerlingAbstract:[1] Understanding links between water consumers and climatological (precipitation) sources is essential for developing strategies to ensure the long-term sustainability of water supplies. In pursing this understanding a need exists for tools to study and monitor complex human-hydrological systems that involve high levels of spatial connectivity and supply problems that are regional, rather than local, in nature. Here we report the first national-level survey of stable Isotope Ratios in tap water, including spatially and temporally explicit samples from a large number of cities and towns across the contiguous United States. We show that intra-annual ranges of tap water Isotope Ratios are relatively small (e.g., <10‰ for δ2H) at most sites. In contrast, spatial variation in tap water Isotope Ratios is very large, spanning ranges of 163‰ for δ2H and 23.6‰ for δ18O. The spatial distribution of tap water Isotope Ratios at the national level is similar to that of stable Isotope Ratios of precipitation. At the regional level, however, pervasive differences between tap water and precipitation Isotope Ratios can be attributed to hydrological factors in the water source to consumer chain. These patterns highlight the potential for monitoring of tap water Isotope Ratios to contribute to the study of regional water supply stability and provide warning signals for impending water resource changes. We present the first published maps of predicted tap water Isotope Ratios for the contiguous United States, which will be useful in guiding future research on human-hydrological systems and as a tool for applied forensics and traceability studies.
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stable Isotope Ratios as a tool in microbial forensics part 3 effect of culturing on agar containing growth media
Journal of Forensic Sciences, 2005Co-Authors: Helen W Kreuzermartin, Lesley A Chesson, Michael J Lott, James R EhleringerAbstract:Stable Isotope Ratios of hydrogen and oxygen in microbes have been shown to be functions of the corresponding Isotope Ratios of the water with which the culture medium was prepared, and thus to contain a potential geographic signal. Water can evaporate from agar (solid) media during culturing, changing its Isotope Ratios. Here we describe the effect of drying on the Isotope Ratios of water extracted from agar media and the H and O stable Isotope Ratios Ratios of Bacillus subtilis spores cultured on agar. The δ 2 Hv sδ 18 O relationship of water in Petri dish agar was surprisingly constant during evaporation regardless of the ambient relative humidity, making it possible to calculate the approximate Isotope Ratios of the original water, even in significantly evaporated agar. The H stable Isotope Ratios of spores cultured on agar remained relatively unchanged as the agar dried, but the O ratio became significantly enriched.
Gabriel J Bowen - One of the best experts on this subject based on the ideXlab platform.
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mechanistic model predicts tissue environment relationships and trophic shifts in animal hydrogen and oxygen Isotope Ratios
Oecologia, 2019Co-Authors: Sarah Magozzi, Hannah Vander B Zanden, Michael B Wunder, Gabriel J BowenAbstract:Statistical regression relationships between the hydrogen (H) and oxygen (O) Isotope Ratios (delta(2)H and delta(18)O, respectively) of animal organic tissues and those of environmental water have been widely used to reconstruct animal movements, paleoenvironments, and diet and trophic relationships. In natural populations, however, tissue-environment isotopic relationships are highly variable among animal types and geographic regions. No systematic understanding of the origin(s) of this variability currently exists, clouding the interpretation of Isotope data. Here, we present and apply a model, based on fundamental metabolic relationships, to test the sensitivity of consumer tissue H and O Isotope Ratios, and thus tissue-environment relationships, to basic physiological, behavioral, and environmental parameters. We then simulate patterns in consumer tissue isotopic compositions under several 'real-world' scenarios, demonstrating that the new model can reproduce-and potentially explain-previously observed patterns in consumer tissue H Isotope Ratios, including between-continent differences in feather-precipitation relationships and (2)H-enrichment with trophic level across species. The model makes several fundamental predictions about the organic O Isotope system, which constitute hypotheses for future testing as new data are obtained. By highlighting potential sources of variability and bias in tissue-environment relationships and establishing a framework within which such effects can be predicted, these results should advance the application of H and O Isotopes in ecological, paleoecological, and forensic research.
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hydrogen and oxygen Isotope Ratios in human hair are related to geography
Proceedings of the National Academy of Sciences of the United States of America, 2008Co-Authors: James R Ehleringer, Lesley A Chesson, Gabriel J Bowen, Adam G West, David W Podlesak, Thure E CerlingAbstract:We develop and test a model to predict the geographic region-of-origin of humans based on the stable Isotope composition of their scalp hair. This model incorporates exchangeable and nonexchangeable hydrogen and oxygen atoms in amino acids to predict the δ2H and δ18O values of scalp hair (primarily keratin). We evaluated model predictions with stable Isotope analyses of human hair from 65 cities across the United States. The model, which predicts hair isotopic composition as a function of drinking water, bulk diet, and dietary protein Isotope Ratios, explains >85% of the observed variation and reproduces the observed slopes relating the isotopic composition of hair samples to that of local drinking water. Based on the geographical distributions of the Isotope Ratios of tap waters and the assumption of a “continental supermarket” dietary input, we constructed maps of the expected average H and O Isotope Ratios in human hair across the contiguous 48 states. Applications of this model and these observations are extensive and include detection of dietary information, reconstruction of historic movements of individuals, and provision of region-of-origin information for unidentified human remains.
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stable Isotope Ratios of tap water in the contiguous united states
Water Resources Research, 2007Co-Authors: Lesley A Chesson, James R Ehleringer, Gabriel J Bowen, Erik E Stange, Thure E CerlingAbstract:[1] Understanding links between water consumers and climatological (precipitation) sources is essential for developing strategies to ensure the long-term sustainability of water supplies. In pursing this understanding a need exists for tools to study and monitor complex human-hydrological systems that involve high levels of spatial connectivity and supply problems that are regional, rather than local, in nature. Here we report the first national-level survey of stable Isotope Ratios in tap water, including spatially and temporally explicit samples from a large number of cities and towns across the contiguous United States. We show that intra-annual ranges of tap water Isotope Ratios are relatively small (e.g., <10‰ for δ2H) at most sites. In contrast, spatial variation in tap water Isotope Ratios is very large, spanning ranges of 163‰ for δ2H and 23.6‰ for δ18O. The spatial distribution of tap water Isotope Ratios at the national level is similar to that of stable Isotope Ratios of precipitation. At the regional level, however, pervasive differences between tap water and precipitation Isotope Ratios can be attributed to hydrological factors in the water source to consumer chain. These patterns highlight the potential for monitoring of tap water Isotope Ratios to contribute to the study of regional water supply stability and provide warning signals for impending water resource changes. We present the first published maps of predicted tap water Isotope Ratios for the contiguous United States, which will be useful in guiding future research on human-hydrological systems and as a tool for applied forensics and traceability studies.
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Stable hydrogen and oxygen Isotope Ratios of bottled waters of the world
Rapid communications in mass spectrometry : RCM, 2005Co-Authors: Gabriel J Bowen, Thure E Cerling, David A. Winter, Howard J. Spero, Robert A. Zierenberg, Mathew D. Reeder, James R EhleringerAbstract:Bottled and packaged waters are an increasingly significant component of the human diet. These products are regulated at the regional, national, and international levels, and determining the authenticity of marketing and labeling claims represents a challenge to regulatory agencies. Here, we present a dataset of stable Isotope Ratios for bottled waters sampled worldwide, and consider potential applications of such data for regulatory, forensic and geochemical standardization applications. The hydrogen and oxygen Isotope Ratios of 234 samples of bottled water range from -147 per thousand to +15 per thousand and from -19.1 per thousand to +3.0 per thousand, respectively. These values fall within and span most of the normal range for meteoric waters, indicating that these commercially available products represent a source of waters for use as laboratory working standards in applications requiring standardization over a large range of Isotope Ratios. The measured values of bottled water samples cluster along the global meteoric water line, suggesting that bottled water Isotope Ratios preserve information about the water sources from which they were derived. Using the dataset, we demonstrate how bottled water Isotope Ratios provide evidence for substantial evaporative enrichment of water sources prior to bottling and for the marketing of waters derived from mountain and lowland sources under the same name. Comparison of bottled water Isotope Ratios with natural environmental water Isotope Ratios demonstrates that on average the isotopic composition of bottled water tends to be similar to the composition of naturally available local water sources, suggesting that in many cases bottled water need not be considered as an isotopically distinct component of the human diet. Our findings suggest that stable Isotope Ratios of bottled water have the power to distinguish ultimate (e.g., recharge) and proximal (e.g., reservoir) sources of bottled water and constitute a potential tool for use in the regulatory monitoring of water products.