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At least 127 records · Page 7Linked to original sources
USGS1997

Time series of trace element concentrations calculated from time series of suspended solids concentrations and RMP water samples: Summary and conclusions

The supply and fate of trace elements in San Francisco Bay, which are partially dependent upon particulate matter in the Estuary, are important management issues. San Francisco Bay receives many waste water discharges, especially in areas south of the Dumbarton Bridge, that contain trace elements that accumulate in benthic organisms (Luoma et al., 1985; Brown and Luoma, 1995). Trace elements tend to adsorb particulate matter (Kuwabara et al., 1989), so the fate of trace elements is partly determined by the fate of suspended solids. Concentrations of dissolved trace elements are greater in the South Bay than elsewhere in San Francisco Bay, and bottom sediments are believed to be a significant source (Flegal et al., 1991). The concentration of suspended particulate chromium in the Bay appears to be controlled primarily by sediment re-suspension (Abu-Saba and Flegal, 1995). Water quality standards for trace elements in the Bay are written in terms of total or near-total trace element concentrations (TEC). This summary has two objectives. The first is to demonstrate the relationship between suspended solids concentration (SSC) and TEC by developing equations relating SSC to total (or near-total) concentrations of trace elements based on Regional Monitoring Program (RMP) data collected during 1993 and 1994. The second objective is to demonstrate the temporal variability of TEC that are linearly correlated (LCTEC) with SSC by presenting time-series information on LCTEC based on nearly continuous SSC measurements collected during the 1995 water year (October 1, 1994 to September 30, 1995) and the SSC-LCTEC equations.

California↗
USGS1952

Topical index and bibliography of U.S. Geological Survey Trace Elements and related reports

Part 1, the topical index, lists the titles of reports prepared from 1941 to December 1952, in conjunction with the Geological Survey's program of uranium and other elements of related interest. It includes not only completed Trace Elements reports and those now in preparation, but also Survey publications, publications by Survey personnel in scientific journals, and open-fie releases. The titles are grouped topically under the headings listed in the table of contents. Entries in each category are listed alphabetically, by author, and numbered consecutively. Many of the reports have been cross-indexed, where appropriate. The classification of the Trace Elements reports, insofar as it is known, has been indicated after the title of the report. The classification of some of the earlier Trace Elements reports is uncertain. The Geological Survey does not have additional copies of most of the reports listed, but copies of some of the completed reports can be loaned on request to organizations officially cooperating with the Atomic Energy Commission. Many Trace Elements reports have been made available to the public, either by open-file release, reproduction by Technical Information Service, Oak Ridge (referred to as TIS), by publication as a Geological Survey circular or bulletin or by a publication in a scientific journal. This information is given, following the title of the report. If the abstract of a Trace Element report has been published in Nuclear Science Abstracts, it is noted by the initials NSA following the title of the report. Part 2 is a reference guide to information on the Trace Elements program that is available to the public. This information is categorized according to the type of publication or release.

Trace Elements Investigations↗
USGS1987

The effects of sample preparation on measured concentrations of eight elements in edible tissues of fish from streams contaminated by lead mining

The influence of sample preparation on measured concentrations of eight elements in the edible tissues of two black basses (Centrarchidae), two catfishes (Ictaluridae), and the black redhorse, Moxostoma duquesnei (Catostomidae) from two rivers in southeastern Missouri contaminated by mining and related activities was investigated. Concentrations of Pb, Cd, Cu, Zn, Fe, Mn, Ba, and Ca were measured in two skinless, boneless samples of axial muscle from individual fish prepared in a clean room. One sample (normally-processed) was removed from each fish with a knife in a manner typically used by investigators to process fish for elemental analysis and presumedly representative of methods employed by anglers when preparing fish for home consumption. A second sample (clean-processed) was then prepared from each normally-processed sample by cutting away all surface material with acid-cleaned instruments under ultraclean conditions. The samples were analyzed as a single group by atomic absorption spectrophotometry. Of the elements studied, only Pb regularly exceeded current guidelines for elemental contaminants in foods. Concentrations were high in black redhorse from contaminated sites, regardless of preparation method; for the other fishes, whether or not Pb guidelines were exceeded depended on preparation technique. Except for Mn and Ca, concentrations of all elements measured were significantly lower in cleanthan in normally-processed tissue samples. Absolute differences in measured concentrations between clean- and normally-processed samples were most evident for Pb and Ba in bass and catfish and for Cd and Zn in redhorse. Regardless of preparation method, concentrations of Pb, Ca, Mn, and Ba in individual fish were closely correlated; samples that were high or low in one of these four elements were correspondingly high or low in the other three. In contrast, correlations between Zn, Fe, and Cd occurred only in normallyprocessed samples, suggesting that these correlations resulted from high concentrations on the surfaces of some samples. Concentrations of Pb and Ba in edible tissues of fish from contaminated sites were highly correlated with Ca content, which was probably determined largely by the amount of tissue other than muscle in the sample because fish muscle contains relatively little Ca. Accordingly, variation within a group of similar samples can be reduced by normalizing Pb and Ba concentrations to a standard Ca concentration. When sample size ( N ) is large, this can be accomplished statistically by analysis of covariance; when N is small, molar ratios of [Pb]/[Ca] and [Ba]/[Ca] can be computed. Without such adjustments, unrealistically large N s are required to yield statistically reliable estimates of Pb concentrations in edible tissues. Investigators should acknowledge that reported concentrations of certain elements are only estimates, and that regardless of the care exercised during the collection, preparation, and analysis of samples, results should be interpreted with the awareness that contamination from external sources may have occurred.

Missouri↗
USGS1997

Assimilation efficiencies and turnover rates of trace elements in marine bivalves: A comparison of oysters, clams and mussels

Assimilation efficiencies (AEs) and physiological turnover-rate constants ( k ) of six trace elements (Ag, Am, Cd, Co, Se, Zn) in four marine bivalves ( Crassostrea virginica Gmelin, Macoma balthica Linnaeus, Mercenaria mercenaria Linnaeus, and Mytilus edulis Linnaeus) were measured in radiotracer-depuration experiments. Egestion rates of unassimilated elements were highest during the first 24 h of depuration and declined thereafter. Significant egestion of unassimilated Co, however, continued for up to 5 d in Macoma balthica , Mercenaria mercenaria and Mytilus edulis . With the exception of the extremely low values for 110 m Ag, 109 Cd, and 65 Zn in C. virginica , physiological turnover-rate constants ( k ) showed no general pattern of variation among elements, bivalve species or food types, and were relatively invariant. Values from  ≤0.001 to 0.1 d −1 were observed, but excluding those for Co, most values were  ≤0.04 d −1 . In all four species, the AEs of Ag, Am, and Co were generally lower than those of Cd, Se, and Zn. The AEs of Ag, Cd, Se, and Zn in these bivalves are directly related to the proportion of each element in the cytoplasmic fraction of ingested phytoplankton, indicating that >80% of elements in a prey alga's cytoplasm was assimilated. C. virginica , Macoma balthica , and Mercenaria mercenaria assimilated ∼36% of the Ag and Cd associated with the non-cytoplasmic (membrane/organelle) fraction of ingested cells in addition to the cytoplasmic fraction. The ratio of AE: k , which is proportional to the consumer–prey trace-element bioaccumulation factor (concentration in consumer:concentration in prey) was generally greater for Cd, Se, and Zn than for Ag, Am, and Co. This ratio was lowest in Mytilus edulis , suggesting that this bivalve, the most widely employed organism in global biomonitoring, is relatively inefficient at accumulating important elements such as Ag, Cd, and Zn from ingested phytoplankton.

Marine Biology↗
USGS2018

Watershed ‘chemical cocktails’: forming novel elemental combinations in Anthropocene fresh waters

In the Anthropocene, watershed chemical transport is increasingly dominated by novel combinations of elements, which are hydrologically linked together as ‘chemical cocktails.’ Chemical cocktails are novel because human activities greatly enhance elemental concentrations and their probability for biogeochemical interactions and shared transport along hydrologic flowpaths. A new chemical cocktail approach advances our ability to: trace contaminant mixtures in watersheds, develop chemical proxies with high-resolution sensor data, and manage multiple water quality problems. We explore the following questions: (1) Can we classify elemental transport in watersheds as chemical cocktails using a new approach? (2) What is the role of climate and land use in enhancing the formation and transport of chemical cocktails in watersheds? To address these questions, we first analyze trends in concentrations of carbon, nutrients, metals, and salts in fresh waters over 100 years. Next, we explore how climate and land use enhance the probability of formation of chemical cocktails of carbon, nutrients, metals, and salts. Ultimately, we classify transport of chemical cocktails based on solubility, mobility, reactivity, and dominant phases: (1) sieved chemical cocktails (e.g., particulate forms of nutrients, metals and organic matter); (2) filtered chemical cocktails (e.g., dissolved organic matter and associated metal complexes); (3) chromatographic chemical cocktails (e.g., ions eluted from soil exchange sites); and (4) reactive chemical cocktails (e.g., limiting nutrients and redox sensitive elements). Typically, contaminants are regulated and managed one element at a time, even though combinations of elements interact to influence many water quality problems such as toxicity to life, eutrophication, infrastructure corrosion, and water treatment. A chemical cocktail approach significantly expands evaluations of water quality signatures and impacts beyond single elements to mixtures. High-frequency sensor data (pH, specific conductance, turbidity, etc.) can serve as proxies for chemical cocktails and improve real-time analyses of water quality violations, identify regulatory needs, and track water quality recovery following storms and extreme climate events. Ultimately, a watershed chemical cocktail approach is necessary for effectively co-managing groups of contaminants and provides a more holistic approach for studying, monitoring, and managing water quality in the Anthropocene.

Biogeochemistry↗
USGS1957

Systematic variation of rare-earth elements in cerium-earth minerals

In a continuation of a study reported previously, rare-earth elements and thorium have been determined in monazite, allanite, cerite, bastnaesite, and a number of miscellaneous cerium-earth minerals. A quantity called sigma (∑), which is the sum of the atomic percentages of La, Ce, and Pr, is proposed as an index of composition of all cerium-earth minerals with respect to the rare-earth elements. The value of ∑ for all of the minerals analysed falls between 58 and 92 atomic per cent. Monazites, allanites, and cerites cover the entire observed range, whereas bastnaesites are sharply restricted to the range between 80 and 92 atomic per cent. The minimum value of ∑ for a cerium-earth mineral corresponds to the smallest possible unit-cell size of the mineral. In monazite, this structurally controlled minimum value of ∑ is estimated to be around 30 atomic per cent. Neodymium, because of its abundance, and yttrium, because of its small size, have dominant roles in contraction of the structure. In the other direction, the limit of variation in composition will be reached when lanthanum becomes the sole rare-earth element in a cerium-earth mineral. Cerium-earth minerals from alkalic rocks are all characterized by values of ∑ greater than 80 atomic per cent, indicating that the processes that formed these rocks were unusually efficient in fractionating the rare-earth elements—efficient in the sense that a highly selected assemblage is produced without eliminating the bulk of these elements. Analyses of inner and outer parts of two large crystals of monazite from different deposits show no difference in ∑ in one crystal and a slightly smaller value of ∑ in the outer part of the other crystal compared to the inner part. The ∑ of monazites from pegmatites that intrude genetically related granitic rocks in North Carolina is found to be either higher or lower than the ∑ of monazites in the intruded host rock. These results indicate that the fractionation of the rare-earth elements is not a simple unidirectional process. When a cerium-earth mineral undergoes replacement, its rare-earth elements may be fractionated into two parts, one forming a new mineral with ∑ that is smaller, and the other a second new mineral with ∑ that is larger than that of the original mineral. The complete analysis of a cerium-earth mineral to determine its ∑ is time consuming. The discovery of a direct relationship between ∑ and the Ce/(Nd + Y) atomic ratio in cerium earth minerals allows a rapid determination of ∑ from spectrograms obtained in a previously described method for determining thorium in these minerals.

Geochimica et Cosmochimica Acta↗
USGS2014

Biochar application to hardrock mine tailings: Soil quality, microbial activity, and toxic element sorption

Waste rock piles from historic mining activities remain unvegetated as a result of metal toxicity and high acidity. Biochar has been proposed as a low-cost remediation strategy to increase soil pH and reduce leaching of toxic elements, and improve plant establishment. In this laboratory column study, biochar made from beetle-killed pine wood was assessed for utility as a soil amendment by mixing soil material from two mine sites collected near Silverton, Colorado, USA with four application rates of biochar (0%, 10%, 20%, 30% vol:vol). Columns were leached seven times over 65 days and leachate pH and concentration of toxic elements and base cations were measured at each leaching. Nutrient availability and soil physical and biological parameters were determined following the incubation period. We investigated the hypotheses that biochar incorporation into acidic mine materials will (1) reduce toxic element concentrations in leaching solution, (2) improve soil parameters (i.e. increase nutrient and water holding capacity and pH, and decrease compaction), and (3) increase microbial populations and activity. Biochar directly increased soil pH (from 3.33 to 3.63 and from 4.07 to 4.77 in the two materials) and organic matter content, and decreased bulk density and extractable salt content in both mine materials, and increased nitrate availability in one material. No changes in microbial population or activity were detected in either mine material upon biochar application. In leachate solution, biochar increased base cations from both materials and reduced the concentrations of Al, Cd, Cu, Pb, and Zn in leachate solution from one material. However, in the material with greater toxic element content, biochar did not reduce concentrations of any measured dissolved toxic elements in leachate and resulted in a potentially detrimental release of Cd and Zn into solution at concentrations above that of the pure mine material. The length of time of effectiveness and specific sorption by biochar is variable by element and the toxic element concentration and acidity of the initial mine material.

Applied Geochemistry↗
USGS2012

Distribution of arsenic, selenium, and other trace elements in high pyrite Appalachian coals: evidence for multiple episodes of pyrite formation

Pennsylvanian coals in the Appalachian Basin host pyrite that is locally enriched in potentially toxic trace elements such as As, Se, Hg, Pb, and Ni. A comparison of pyrite-rich coals from northwestern Alabama, eastern Kentucky, and West Virginia reveals differences in concentrations and mode of occurrence of trace elements in pyrite. Pyrite occurs as framboids, dendrites, or in massive crystalline form in cell lumens or crosscutting veins. Metal concentrations in pyrite vary over all scales, from microscopic to mine to regional, because trace elements are inhomogeneously distributed in the different morphological forms of pyrite, and in the multiple generations of sulfide mineral precipitates. Early diagenetic framboidal pyrite is usually depleted in As, Se, and Hg, and enriched in Pb and Ni, compared to other pyrite forms. In dendritic pyrite, maps of As distribution show a chemical gradient from As-rich centers to As-poor distal branches, whereas Se concentrations are highest at the distal edges of the branches. Massive crystalline pyrite that fills veins is composed of several generations of sulfide minerals. Pyrite in late-stage veins commonly exhibits As-rich growth zones, indicating a probable epigenetic hydrothermal origin. Selenium is concentrated at the distal edges of veins. A positive correlation of As and Se in pyrite veins from Kentucky coals, and of As and Hg in pyrite-filled veins from Alabama coals, suggests coprecipitation of these elements from the same fluid. In the Kentucky coal samples (n = 18), As and Se contents in pyrite-filled veins average 4200 ppm and 200 ppm, respectively. In Alabama coal samples, As in pyrite-filled veins averages 2700 ppm (n = 34), whereas As in pyrite-filled cellular structures averages 6470 ppm (n = 35). In these same Alabama samples, Se averages 80 ppm in pyrite-filled veins, but was below the detection limit in cell structures. In samples of West Virginia massive pyrite, As averages 1700 ppm, and Se averages 270 ppm (n = 24). The highest concentration of Hg (≤ 102 ppm) is in Alabama pyrite veins. Improved detailed descriptions of sulfide morphology, sulfide mineral paragenesis, and trace-element concentration and distribution allow more informed predictions of: (1) the relative rate of release of trace elements during weathering of pyrite in coals, and (2) the relative effectiveness of various coal-cleaning procedures of removing pyrite. For example, trace element-rich pyrite has been shown to be more soluble than stoichiometric pyrite, and fragile fine-grained pyrite forms such as dendrites and framboids are more susceptible to dissolution and disaggregation but less amenable to removal during coal cleaning.

Alabama;Kentucky;West Virginia↗
USGS2020

Trace and rare earth elements determination in milk whey from the Veneto region, Italy

Multi-element analyses determine the content of 17 trace elements (Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Cd, Cs, Ba, Pb, U) and 14 rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Y) in whey samples from cow and goat milk by inductively coupled plasma mass spectrometry and inductively coupled plasma-sector field mass spectrometry. A total of 261 milk whey samples were collected from four locations in the Veneto region of northeastern (NE) Italy. These samples contain a wide range concentration of 17 trace elements (0.06–1530 μg kg −1 ) and 14 rare earth elements (0.16–28.2 ng kg −1 ) in whey samples, but do not reach toxic concentrations. Elemental fingerprinting of trace and rare earth elements in cow and goat milk whey provide information on the dairy quality and, as they reflect the local environmental conditions, result in an excellent indicator of their geographical origin.

Veneto region↗
USGS2023

Rock-to-metal ratios of the rare earth elements

The relative quantities of ore mined and waste rock (i.e., overburden) removed to produce the rare earth elements—their rock-to-metal ratios—were calculated for 21 individual operations or regions covering nearly all mine production in 2018. The results indicate that the rock-to-metal ratios for the total rare earth elements ranged from a low of 1.6 × 10 1 to a high of 3.6 × 10 3 , with operations in Brazil and Russia having the lowest ratios and ion-adsorption clays operations in China and Myanmar having the highest. For comparison, the global average rock-to-metal ratio for the total rare earth elements (9.8 × 10 2 ) fell between that of cobalt (8.6 × 10 2 ) and tungsten (1.1 × 10 3 ). Driven by their relative abundance in the ore and unit prices that were used in the economic allocation of the environmental burdens, the global rock-to-metal ratio for individual rare earth elements was lowest for cerium (2.3 × 10 1 ) and lanthanum (7.7 × 10 1 ) and highest for dysprosium (1.7 × 10 4 ), terbium (3.7 × 10 4 ), and lutetium (6.4 × 10 4 ). Like the rock-to-metal ratios for the total rare earth elements, rock-to-metal ratios for individual rare earth elements varied by roughly two orders of magnitude among the various operations examined. An alternative perspective of only accounting for the overburden that is physically removed in ion-adsorption clays in-situ operations yielded global rock-to-metal ratios that were an order of magnitude lower or less for many of the rare earth elements.

Journal of Cleaner Production↗
USGS2018

Critical minerals: A review of elemental trends in comprehensive criticality studies

Mineral criticality is a subjective concept that has evolved throughout history. An abundance of literature on this topic has been published over the last decade, encompassing a variety of criteria and methodologies. To our knowledge, this work is the first large-scale effort to organize and analyze recent comprehensive criticality studies in order to determine if a consensus exists within the global community as to which elements are critical. Here, we set aside methodological differences and analyze the results of 32 comprehensive nonfuel mineral criticality studies that evaluate at least 10 elements. Of the 56 elements or elemental groups evaluated, the three most commonly identified as critical in these studies are the rare-earth elements (REE), the platinum-group metals (PGM), and indium. Most of the studies also identify tungsten, germanium, cobalt, niobium , tantalum, gallium, and antimonyas critical. These results are consistent with the 11 most recent studies, published post-2014, which also identify bismuth as critical. Furthermore, the same elements identified in the complete dataset, except antimony, were designated as critical when normalized by geographic region. Magnesium was also deemed critical. Elements may be identified consistently as critical for several reasons; similarities in methodologies, which embody evolving perceptions of risk, or changing national and institutional priorities. This work compiles a large number of recent criticality studies in an effort to define a consensus of currently critical materials, essentially defining the modern criticality paradigm, which is valuable when interpreting an individual perspective in more global context.

Resources Policy↗
USGS1997

Spatial and temporal heterogeneity in metallic elements in industrialized aquatic bird habitat

This study examined the potential for exposure of migratory aquatic birds to contaminants in highly industrialized habitats at Baltimore Harbor, Maryland. Seven nearshore, benthic sites were sampled every 3 or 6 months from June 1987 to December 1988. Twenty metallic elements were measured in composites (i.e. annelids, amphipods, and isopods were pooled), clams, and sediments. Elevated concentrations were widespread throughout the sites, depending on the element. Most concentrations in composites were lowest at sites innermost and outside the harbor. Higher concentrations in composites were not related to season. Most concentrations were higher in composites than in sediments or clams, but they varied by element for clams and sediments. The largest flock of wintering waterfowl frequented the site exhibiting the highest concentrations of most elements ( p < 0.0001). Average concentrations of known toxic elements were probably not harmful to aquatic birds or their prey, but the highest detected concentrations of eight elements warrant caution. At least eight other elements exceeded background concentrations, but toxicity to birds or their prey are unknown.

Maryland↗
USGS2012

Minor and trace element geochemistry of volcanic rocks dredged from the Galapagos spreading center: Role of crystal fractionation and mantle heterogeneity

A wide range of rock types (abyssal tholeiite, Fe-Ti-rich basalt, andesite, and rhyodacite) were dredged from near 95°W and 85°W on the Galapagos spreading center. Computer modeling of major element compositions has shown that these rocks could be derived from common parental magmas by successive degrees of fractional crystallization. However, the P 2 O 5 /K 2 O ratio averages 0.83 at 95°W and 1.66 at 85°W and implies distinct mantle source compositions for the two areas. These source regions also have different rare earth element (REE) abundance patterns, with [La/Sm] EF = 0.67 at 95°W and 0.46 at 85°W. The sequence of fractionated lavas differs for the two areas and indicates earlier fractionation of apatite and titanomagnetite in the lavas from 95°W. The mantle source regions for these two areas are interpreted to be depleted in incompatible (and volatile?) elements, although the source region beneath 95°W is less severely depleted in La and K. Incompatible trace element abundances in 26 samples are used to infer that the range of Fe-Ti-rich basalt from 85°W represents 19 to 35% residual liquid following crystal fractionation of a mineral assemblage of plagioclase, clinopyroxene, and lesser olivine. The most highly differentiated samples have also had less than 1% titanomagnetite removed. Most samples from 85°W can be related to a common parental magma that contained approximately 9 wt % FeO*, 1 wt % TiO 2 , and had an Mg number (Mg# = 100 Mg/(Mg + Fe 2+ )) of about 65. Although the samples from 95°W cannot all be derived from a common parental magma, the inferred parental magmas may have been derived by varying degrees of partial melting of a common source. The fractionation sequence consists of two parts: an initial iron enrichment trend followed by a silica enrichment trend. We interpret the trace element data to indicate that the most iron rich lavas represent about 32% residual liquid derived by crystal fractionation of plagioclase, clinopyroxene, and lesser olivine from a parental magma with an Mg number of about 66. The silica enrichment trend results from crystallization of titanomagnetite and some apatite. Fractionation of pigeonite, which is a minor phase in the major element models, cannot be distinguished from clinopyroxene fractionation by using trace elements.

Journal of Geophysical Research Solid Earth↗
USGS1982

Petrology and trace element geochemistry of the Honolulu volcanics, Oahu: Implications for the oceanic mantle below Hawaii

The Honolulu Volcanics comprises small volume, late-stage (post-erosional) vents along rifts cutting the older massive Koolau tholeütic shield on Oahu, Hawaii. Most of these lavas and tuff of the Honolulu Volcanics have geochemical features expected of near-primary magmas derived from a peridotite source containing Fo 87–89 olivine; e. g. 100 Mg/(Mg + Fe 2+ ) >65, >250 p. p. m. Ni, and presence of ultramafic mantle xenoliths at 18 of the 37 vents. Consequently, the geochemistry of the alkali olivine basalt, basanite, nephelinite and nepheline melilitite lavas and tuff of the Honolulu Volcanics have been used to deduce the composition of their mantle source and the conditions under which they were generated by partial melting in the mantle. Compositional trends in 30 samples establish that the magmas were derived by partial melting of a garnet (<10 per cent) Iherzolite source, which we infer to have been carbon-bearing, from analogy with experimental results. This source was isotopically homogeneous (Sr, Lanphere & Dalrymple, 1980; Pb, Sun, 1980; Nd, Roden et al ., 1981), and we infer that the source was compositionally uniform in all major-element oxides except TiO 2 , in compatible trace elements (Sc, V, Cr, Mn, Co and Ni), and in highly incompatible trace elements (P, Th, La, Ce). However, the source appears to have been heterogeneous in TiO 2 , Zr, Hf, Nb, and Ta, elements that were not strongly incompatible during partial melting. Some nepheline melilitite samples may be derived from a source with distinct Sc and heavy-rare-earth-elements (REE) abundances, or which had a phase or phases controlling the distribution of these elements. The relatively limited abundance range for several elements, such as Ti, Zr, Nb, is partly a consequence of the low degrees of melting inferred for the series (2 per cent for nepheline melilitite, 11 per cent for alkali olivine basalt), which failed to exhaust the source in minor residual phases. We infer that these residual phases probably included phlogopite, amphibole, and another Ti-rich phase (an oxide?), but not apatite.

Journal of Petrology↗
USGS2020

Direct trace element determination in oil and gas produced waters with inductively coupled plasma - Optical emission spectrometry (ICP-OES): Advantages of high salinity tolerance

Waters co-produced during petroleum extraction are the largest waste stream from oil and gas development. Reuse or disposal of these waters is difficult due to their high salinities and the sheer volumes generated. Produced waters may also contain valuable mineral commodities. While an understanding of produced water trace element composition is required for evaluating the associated resource and waste potential of these materials, measuring trace elements in brines is challenging due to the dilution requirements of typical methods. Alternatively, inductively coupled plasma-optical emission spectrometry (ICP-OES) has shown promise as being capable of direct measurements of trace elements within produced waters with minimal dilution. Here we evaluate direct ICP-OES trace element quantification in produced waters for 17 trace elements (As, Al, Ba, Be, Cd, Cr, Co, Cu, Hg, Mo, Ni, Pb, Rb, Sb, U, V, and Zn) within 15 produced waters from five U.S. continuous reservoirs. The ICP-OES results are compared against trace element levels determined using inductively coupled plasma-mass spectrometry from the same samples. Our results demonstrate the potential for direct analysis of high salinity waters using ICP-OES with minimal dilution and provide trace element concentrations in waters from several important U.S. petroleum-generating reservoirs where available data is sparse.

Montana, New York, North Dakota, Ohio, Pennsylvani↗
USGS2006

Element mobility during alteration of silicic ash to kaolinite - A study of tonstein

A laterally persistent kaolinitic mudstone parting (tonstein) occurring in a Wyoming coal bed of Eocene age was sampled to estimate the compositional contrast with a probable silicic ash precursor, and to determine the compositional influence of leached ash on immediately adjacent coal. With the exception of Al, and possibly Ti, the tonstein is highly to moderately leached of major elements, relative to a range of compositions estimated for silicic ash of the region. In agreement with the behaviour of geochemically similar major elements, alkali trace elements (Rb, Cs) are highly leached, transition-series metals moderately leached, and Ga is residual. Additional immobile trace elements are Zr and Hf but some other trace elements that are considered relatively immobile during low-temperature alteration (Th, Ta, Nb, REE, Y) were apparently leached by the low-Eh, low-pH, organic-rich pore fluids of the coal-forming swamp. The migrational range of many of the leached elements is highly limited by the intimate association of tonstein with enclosing organic matter. Mixtures of coal + minor tonstein that occur within 20 mm of contacts are consistently enriched in some elements relative to either tonstein or nearby coal (U, Cu), or relative to calculated mixtures of tonstein and coal in their measured proportions (Th, Y, REE, Pb, Ba, V, Ti). Direct observations by fission-track radiography and electron microprobe indicate a preference of U and Fe for the organic component of mixtures. Metal fixation is probably by adsorption on insoluble organic matter (humic acids), or by precipitation as minor sulphides in these low-sulphur coals.

Wyoming↗
USGS2007

Presence and distribution of trace elements in new jersey streambed sediments

ABSTRACT: The distribution of trace elements in New Jersey streambed sediments is described with respect to physiographic provinces and major drainage areas. Samples were collected during 1976–1993 at 295 sites distributed throughout New Jersey. Copper, chromium, lead, and zinc were detected with the greatest frequency and at the highest concentrations of the elements. Concentrations of most trace elements were significantly higher in streambed sediments from the New England (glaciated) and Piedmont physiographic provinces - the provinces with the lowest and highest percentages of urban land use, respectively - than in sediments from the other provinces. High trace-element concentrations in the New England (glaciated) province reflect previous mining of extensive magnetite deposits, whereas those in the Piedmont province most likely reflect urban land use. Significantly lower trace-element concentrations in streambed sediments from the Coastal Plain are attributable to the low pH of the streamwater, the lack of iron and manganese available to form coatings that scavenge trace elements, and the relatively low percentage of urban land use in the province. Trace-element concentrations were related to land use, population, or point sources in the drainage basin specific to the sampling location by using logistic regression. Results of this analysis indicate a relation between arsenic and agricultural land use; chromium and physiographic province; and copper, lead, and zinc and population density.

Journal of the American Water Resources Associatio↗
USGS2003

Atomic weights of the elements. Review 2000 (IUPAC Technical Report)

A consistent set of internationally accepted atomic weights has long been an essential aim of the scientific community because of the relevance of these values to science and technology, as well as to trade and commerce subject to ethical, legal, and international standards. The standard atomic weights of the elements are regularly evaluated, recommended, and published in updated tables by the Commission on Atomic Weights and Isotopic Abundances (CAWIA) of the International Union of Pure and Applied Chemistry (IUPAC). These values are invariably associated with carefully evaluated uncertainties. Atomic weights were originally determined by mass ratio measurements coupled with an understanding of chemical stoichiometry, but are now based almost exclusively on knowledge of the isotopic composition (derived from isotope-abundance ratio measurements) and the atomic masses of the isotopes of the elements. Atomic weights and atomic masses are now scaled to a numerical value of exactly 12 for the mass of the carbon isotope of mass number 12. Technological advances in mass spectrometry and nuclear-reaction energies have enabled atomic masses to be determined with a relative uncertainty of better than 1 ×10−7 . Isotope abundances for an increasing number of elements can be measured to better than 1 ×10−3 . The excellent precision of such measurements led to the discovery that many elements, in different specimens, display significant variations in their isotope-abundance ratios, caused by a variety of natural and industrial physicochemical processes. While such variations increasingly place a constraint on the uncertainties with which some standard atomic weights can be stated, they provide numerous opportunities for investigating a range of important phenomena in physical, chemical, cosmological, biological, and industrial processes. This review reflects the current and increasing interest of science in the measured differences between source-specific and even sample-specific atomic weights. These relative comparisons can often be made with a smaller uncertainty than is achieved in the best calibrated “absolute ” (=SI-traceable) atomic-weight determinations. Accurate determinations of the atomic weights of certain elements also influence the values of fundamental constants such as the Avogadro, Faraday, and universal gas constants. This review is in two parts: the first summarizes the development of the science of atomic-weight determinations during the 20th century; the second summarizes the changes and variations that have been recognized in the values and uncertainties of atomic weights, on an element-by-element basis, in the latter part of the 20th century.

Pure and Applied Chemistry↗