SCIENTIFIC PUBLICATIONS USING ELEMENTAL SCIENTIFIC PRODUCTS

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Spatial assessment of major and trace element concentrations from Lower Athabasca Region Trout-perch (Percopsis omiscomaycus) otoliths

Year: 2019
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Authors: Sinnatamby, RN;Loewen, TN;Luo, Y;Pearson, DG;Bicalho, B;Grant-Weaver, I;Cuss, CW;Poesch, M;Shotyk, W;
Journal: Sci. Total Environ.

The Lower Athabasca Region (LAR) is home to the largest bitumen deposit in Alberta, and has seen industrial development related to the extraction and processing of bituminous sands since the late 1960s. Along with industrial and economic growth related to oil sands development, environmental concerns have increased in recent decades, including those about potential effects on fish. We measured major and trace element concentrations in Trout-perch otoliths from the Athabasca and Clearwater Rivers in the LAR, to illustrate spatial variations and identify possible industrial impacts. Both laser ablation ICP-MS and solution-based ICP-MS methods were employed. Of the trace elements enriched in bitumen (V, Ni, Mo and Re), only Ni and Re were above the limits of detection using at least one of the methods. The only significant differences in element concentrations between upstream and downstream locations were found for Li, Cu, and Pb which were more abundant upstream of industry. For comparison and additional perspective, otoliths from the same fish species, but taken from the Batchawana River in northern Ontario, were also examined. The fish from Alberta yielded greater concentrations of Ba, Bi, Li, Mg, Na, Re, Sc, Th and Y, but the Ontario fish had more Cr, Rb and Tl, likely because of differences in geology.

Impact of natural re-oxygenation on the sediment dynamics of manganese, iron and phosphorus in a euxinic Baltic Sea basin

Year: 2019
Products: SC-DX SeaFAST S2
Authors: Hermans, M;Lenstra, W;van Helmond, N;Behrends, T;Egger, M;Séguret, M;Gustafsson, E;Gustafsson, B;Slomp, C;
Journal: Geochimica et Cosmochimica Acta

The Baltic Sea is characterized by the largest area of hypoxic (oxygen (O2) < 2 mg L−1) bottom waters in the world’s ocean induced by human activities. Natural ventilation of these O2-depleted waters largely depends on episodic Major Baltic Inflows from the adjacent North Sea. In 2014 and 2015, two such inflows led to a strong rise in O2 and decline in phosphate (HPO42−) in waters below 125 m depth in the Eastern Gotland Basin. This provided the opportunity to assess the impact of such re-oxygenation events on the cycles of manganese (Mn), iron (Fe) and phosphorus (P) in the sediment for the first time. We demonstrate that the re-oxygenation induced the activity of sulphur (S)-oxidising bacteria, known as Beggiatoaceae in the surface sediment where a thin oxic and suboxic layer developed. At the two deepest sites, strong enrichments of total Mn and to a lesser extent Fe oxides and P were observed in this surface layer. A combination of sequential sediment extractions and synchrotron-based X-ray spectroscopy revealed evidence for the abundant presence of P-bearing rhodochrosite and Mn(II) phosphates. In contrast to what is typically assumed, the formation of Fe oxides in the surface sediment was limited. We attribute this lack of Fe oxide formation to the high flux of reductants, such as sulphide, from deeper sediments which allows Fe(II) in the form of FeS to be preserved and restricts the penetration of O2 into the sediment. We estimate that enhanced P sequestration in surface sediments accounts for only ∼5% of water column HPO42− removal in the Eastern Gotland Basin linked to the recent inflows. The remaining HPO42− was transported to adjacent areas in the Baltic Sea. Our results highlight that the benthic O2 demand arising from the accumulation of organic-rich sediments over several decades, the legacy of hypoxia, has major implications for the biogeochemical response of euxinic basins to re-oxygenation. In particular, P sequestration in the sediment in association with Fe oxides is limited. This implies that artificial ventilation projects that aim at removing water column HPO42− and thereby improving water quality in the Baltic Sea will likely not have the desired effect.

Terrestrial sources as the primary delivery mechanism of mercury to the oceans across the Toarcian Oceanic Anoxic Event (Early Jurassic)

Year: 2019
Products: Apex-Q desolvation unit
Authors: Them, T;Jagoe, C;Caruthers, A;Gill, B;Grasby, S;Gröcke, D;Yin, R;Owens, J;
Journal: Earth and Planetary Science Letters

This study evaluates the utility of sedimentary mercury (Hg) contents as a proxy for fingerprinting ancient massive volcanism, which is often associated with biogeochemical perturbations. Herein we present new Hg geochemical data from anoxic marine basins across the Toarcian Oceanic Anoxic Event (T-OAE; ∼183 Ma) as a test of the complex Hg cycle. The T-OAE was likely initiated by the main eruptive phase of the Karoo–Ferrar large igneous province, which caused a subsequent cascade of environmental perturbations and resulting mass extinction. At present the leading interpretation of sedimentary Hg anomalies has been volcanogenic outgassing as the primary source. Our study and compilation results suggest, however, that Hg/TOC anomalies were restricted to shallow-water, and/or proximal environments, while deep-water, more distal depositional settings document no significant Hg-related anomalies. Furthermore, asynchronous stratigraphic deviations in Hg enrichments favor terrestrially sourced materials and local redox variability, rather than direct volcanogenic emissions, as a primary control mechanism. Additionally, Hg isotope signatures from our only study site documenting an Hg anomaly are also consistent with a terrestrial Hg origin during the T-OAE. Therefore, our results suggest that Hg anomalies in the geological record need to be re-evaluated as a “smoking gun” proxy that only infers volcanogenic inputs.

Size exclusion chromatography – Inductively coupled plasma – Mass spectrometry for determining metal-low molecular weight compound complexes in natural wines

Year: 2019
Products: SeaFast SC2 DX autosampler
Authors: Latorre, M;Herbello-Hermelo, P;Peña-Farfal, C;Neira, Y;Bermejo-Barrera, P;Moreda-Piñeiro, A;
Journal: Talanta

Size exclusion chromatography (SEC) hyphenated to inductively coupled plasma – mass spectrometry (ICP-MS), as a specific detector for metals, has been used for monitoring and determining metal-low molecular weight organic compound (LMWC) complexes in natural wines. SEC with UV detection (wavelength of 205 nm) was used for monitoring organic compounds eluted from the chromatographic column. SEC-UV has revealed the presence of low molecular weight compounds (commonly three fractions of molecular weights ranging from 230 to 1579 Da).’ Further experiments using ICP-MS as a detector showed that elements such as B, Cu, Li, Mn, Ni, Ti, and Zn are bound to compounds of molecular weights within the 338–1579 Da range. Total metal concentrations, as well as metal concentrations in SEC fractions were also assessed in several monovarietal red (five varieties) and monovarietal white (three varieties) wines.

Enzymatic hydrolysis as a sample pre-treatment for titanium dioxide nanoparticles assessment in surimi (crab sticks) by single particle ICP-MS

Year: 2019
Products: SeaFast SC2 DX autosampler
Authors: Taboada-López, M;Herbello-Hermelo, P;Domínguez-González, R;Bermejo-Barrera, P;Moreda-Piñeiro, A;
Journal: Talanta

A reliable sample pre-treatment based on enzymatic hydrolysis has been fully optimized and validated for TiO2 NPs isolation and determination/characterization in surimi (crab sticks). Efficient extractions have been found when using a pancreatin/lipase mixture at pH 7.4 and 37 °C for 12 h under continuous stirring. The proposed sample pre-treatment procedure has been found not to change TiO2 NPs size distribution, therefore guaranteeing TiO2 NPs integrity. TiO2 NPs determination (TiO2 NPs concentration) and TiO2 NPs characterization (size distribution) were assessed by single-particle inductively coupled plasma mass spectrometry (sp-ICP-MS) working with dwell times in the microsecond range (high frequency of data acquisition). Method validation was performed for TiO2 NPs concentrations and TiO2 NPs sizes. Good repeatability (25% and 8% for TiO2 NPs concentration and TiO2 NPs most frequent size), and sensitivity (limit of detection of 5.28 × 105 NPs g−1for TiO2 NPs concentrations, and 31.3–37.1 nm for TiO2 NPs size) were obtained. Accuracy, calculated through analytical recovery was adequate. Recoveries for TiO2 NPs standards of 50 and 100 nm were 108 ± 5 and 105 ± 4%, respectively. The proposed methodology was applied to several surimi samples for assessing TiO2 NPs concentrations and size distribution. Some surimi samples were found to contain TiO2 NPs (concentrations from 1.40 × 107 to 1.19 × 109 NPs g−1). TiO2 NPs size distributions were very different among the samples, and some of them showed wide size ranges (the most frequent size varied from 53.8 to 62.1 nm; whereas, the mean size values were within the 73.4–217.5 nm range).

Metabolism and disposition of arsenic species from oral dosing with sodium arsenite in neonatal CD-1 mice. IV. Toxicokinetics following gavage administration and lactational transfer

Year: 2019
Products: PC3
Authors: Twaddle, NC;Vanlandingham, M;Beland, FA;Fisher, JW;Doerge, DR;
Journal: Food Chem. Toxicol.

Arsenic is a ubiquitous contaminant, with typical human dietary intake below 1 μg/kg bw/d and extreme drinking water exposures up to ∼50 μg/kg bw/d. The formation and binding of trivalent metabolites are central to arsenic toxicity and strong human evidence suggests special concern for early life exposures in the etiology of adult diseases, especially cancer. This study measured the metabolism and disposition of arsenite in neonatal mice to understand the role of maturation in metabolic activation and detoxification of arsenic. Many age-related differences were observed after gavage administration of arsenite, with consistent evidence in blood and tissues for higher exposures to trivalent arsenic species in neonatal mice related to the immaturity of metabolic and/or excretory functions. The evidence for greater tissue binding of arsenic species in young mice is consistent with enhanced susceptibility to toxicity based on metabolic and toxicokinetic differences alone. Lactational transfer from arsenite-dosed dams to suckling mice was minimal, based on no dosing-related changes in the levels of arsenic species in pup blood or milk collected from the dams. Animal models evaluating whole-life exposure to inorganic arsenic must use direct dosing in early neonatal life to predict accurately potential toxicity from early life exposures in children.

A common parentage-low abundance trace element data of gem diamonds reveals similar fluids to fibrous diamonds

Year: 2019
Products: APEX-Q high-efficiency sample introduction system
Authors: Krebs, M;Pearson, D;Stachel, T;Laiginhas, F;Woodland, S;Chinn, I;Kong, J;
Journal: Lithos

Quantitative trace element data from high-purity gem diamonds from the Victor Mine, Ontario, Canada as well as near-gem diamonds from peridotite and eclogite xenoliths from the Finsch and Newlands mines, South Africa, acquired using an off-line laser ablation method show that we see the same spectrum of fluids in both high-purity gem and near-gem diamonds that was previously documented in fibrous diamonds. “Planed” and “ribbed” trace element patterns characterize not only the high-density fluid (HDF) inclusions in fibrous diamonds but also in gem diamonds. Two diamonds from two Finsch harzburgite xenoliths show trace element patterns similar to those of saline fluids, documenting the involvement of saline fluids in the precipitation of gem diamonds, further strengthening the link between the parental fluids of both gem and fibrous diamonds. Differences in trace element characteristics are evident between Victor diamonds containing silicate inclusions compared with Victor diamonds containing sulphide inclusions. The sulphide-bearing diamonds show lower levels of inter-element fractionation and more widely varying siderophile element concentrations - indicating that the silicate and sulphide-bearing diamonds likely formed by gradations of the same processes, via melt-rock reaction or from a subtly different fluid source. The shallow negative LREEN-HREEN slopes displayed by the Victor diamonds establish a signature indicative of original derivation of the diamond forming agent during major melting (~10% melt). Consequently, this signature must have been passed on to HDFs separating from such silicate melts.

High-resolution Sr-isotopic evolution of Black Sea water during the Holocene: Implications for reconnection with the global ocean

Year: 2019
Products: ESI SC-2 autosampler
Authors: Ankindinova, O;Hiscott, R;Aksu, A;Grimes, V;
Journal: Marine Geology

The 10 m-thick Holocene succession at core site M02-45 (41°41.17′N, 28°19.08′E, −69 m water depth) has key advantages for investigation of the Sr-isotopic evolution of the Holocene Black Sea. Earlier studies have focussed on thinner successions and coquinas. At the M02-45 site (augmented by nearby core M05-03P), 87Sr/86Sr determinations on mollusc shells extracted at mostly 10–20 cm depth increments provide a temporal resolution mostly <200 years in sediment older than ~5500 cal yr BP, and ~20–25 years for the early Holocene reconnection between the Black Sea (formerly the Neoeuxine Lake) and the global ocean. Isotopic measurements are in stratigraphic order, so temporal trends are unambiguous. Measurements were made using a Neptune multi-collector inductively coupled plasma mass spectrometer (MC-ICPMS) and have 1σ uncertainties of ~ ±0.000015. There are four stages of 87Sr/86Sr increase and salination associated with the reconnection. From 12,145–9580 cal yr BP (stage A), before first Mediterranean inflow, the Sr-isotopic ratio varied from 0.708847–0.708881. Modelling suggests that the Sr concentration in the Neoeuxine Lake might have been several times higher than modern river values because of evaporative concentration. For ~100 years immediately before reconnection (9580–9490 cal yr BP, stage B), 87Sr/86Sr values dropped to their lowest levels: 0.708841–0.708843. Abruptly (in geological terms), 87Sr/86Sr then began to climb starting 9465–9490 cal yr BP and reached a quasi-steady-state ‘plateau’ with ratios ~0.708965 by ~9380 cal yr BP (stage C). The sharp 87Sr/86Sr increase marks the first significant intrusion of saline water into a previously isolated Neoeuxine Lake. The quasi-steady-state condition lasted 350–400 years. Subsequently, starting ~8985 cal yr BP and proceeding to the present day, there was a step-wise rise of 87Sr/86Sr to modern levels (stage D), during which a salinity threshold was passed that allowed widespread replacement of brackish-water faunas by Mediterranean species. Modelling suggests that the lake/sea level likely did not, and could not, rise from −120 m to −30 m between 9490 and 9380 cal yr BP unless (a) the Sr concentration in the pre-reconnection Neoeuxine Lake was 3–4 times higher than today, or (b) the water column was strongly stratified during first entry of saline water. The second alternative is very unlikely because of seasonal vertical mixing (downwelling/upwelling) in what was then a rather homogeneous temperate lake. Catastrophic flooding of a lowstand lake would require an average discharge through the Strait of Bosphorus of ~9500 m3 s−1, whereas saline entry of Mediterranean water as an underflow into an already high lake could reproduce the first stage of 87Sr/86Sr increase with an average discharge as low as ~2200 m3 s−1. Because the M02-45 site is ~50 m above the late Pleistocene lowstand shoreline and contains sub-wavebase sediments with 87Sr/86Sr values that record the first entry of saline water into the Neoeuxine Lake, the surface of the lake must have been significantly higher than −70 m at the time of the reconnection. Two prominent ‘plateaux’ which punctuate the long-term 87Sr/86Sr increase are attributed to decadal to centennial periods of increased discharge from European rivers, creating a positive hydrological balance and effectively blocking or seriously impeding saline-water advance up the Strait of Bosphorus toward the Black Sea.

Single particle mineralogy of microparticles from Himalayan ice-cores using SEM/EDX and ATR-FTIR imaging techniques for identification of volcanic ash signatures

Year: 2019
Products: Apex HF
Authors: Malek, M;Eom, H;Hwang, H;Hur, S;Hong, S;Hou, S;Ro, C;
Journal: Chemical Geology

In this study, insoluble microparticles from four discrete layers of ice-cores drilled out from the East Rongbuk glacier of the Himalayas were characterized on a single particle basis by scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM/EDX) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) imaging. The combined application of the two single particle analytical techniques for the analysis of the same individual particles provided complementary information, i.e., their elemental compositions and morphology by SEM/EDX and their molecular species, functional groups, and crystallinity by ATR-FTIR imaging, which is crucial for the definite identification of the mineral species including their polymorphs. The results showed that the integrated signatures of volcanic ash (VA), involving their mineralogical characteristics for silica polymorphs, vitreous nature of silica and silicate particles, chemical heterogeneity within the micrometer sized particles, and unique morphology, can be used to clearly differentiate micrometer sized VA from the mineral dust of a soil origin on a single-particle basis. The different mineralogical characteristics among the volcanic samples would be due to their association with different volcanic eruptions.

Matrix separation of Sr and Pb for isotopic ratio analysis of Ca-rich samples via an automated simultaneous separation procedure

Year: 2019
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Authors: Zimmermann, T;Retzmann, A;Schober, M;Pröfrock, D;Prohaska, T;Irrgeher, J;
Journal: Spectrochimica Acta Part B: Atomic Spectroscopy

This paper presents a systematic investigation of the effects of Ca on the matrix separation of Sr and Pb and subsequent isotope-amount ratio measurements using a variety of synthetic solutions and reference materials with varying Ca content during the application of an automated analyte/matrix separation approach. The separation method based on the DGA Resin was optimized by using increased column bed volumes, comparing two different column sizes (1-mL and 3-mL-bed volume). Certified reference materials (synthetic calcium carbonate – MACS-3, basalt – BCR-2, saggital otolith – FEBS-1, bone meal – NIST SRM 1486, bone ash – NIST SRM 1400, and skim milk powder – BCR-063R) with varying Ca content, Ca/Sr and Ca/Pb mass fraction ratios were separated using the optimized method and analyzed for the Sr and Pb isotopic composition by multi collector inductively coupled plasma mass spectrometry (MC ICP-MS). The developed separation method based on the 3-mL-bed volume column provides quantitative recoveries (84% to 105% for Sr, 77% to 96% for Pb), while maintaining a quantitative separation of Sr and Pb. Procedural blank levels were < 0.04 ng g−1 for Sr and < 0.05 ng g−1 for Pb, respectively. The method allows for the automated extraction of Sr in Ca-rich matrices with Ca/Sr mass fraction ratios of up to 4051 corresponding to an absolute Ca load of 965 μg ± 86 μg (BCR-063R, milk powder). Furthermore, the method allows for the simultaneous extraction of Pb from these matrices showing Ca/Pb mass fraction ratios of up to 42,095 corresponding to an absolute Ca load of 761 μg ± 122 μg on column (NIST SRM 1400, bone tissue), respectively. This results in at least 5-times higher tolerable Ca loads compared to previous methods. Measured δ(87Sr/86Sr)NIST SRM 987 values of FEBS-1 (−1.58 ‰ ± 0.23 ‰ (U, k = 2)), MACS-3 (−4.11 ‰ ± 0.29 ‰ (U, k = 2)) and NIST SRM 1400 (3.87 ‰ ± 0.23 ‰ (U, k = 2)) were in accordance with published results. Measured δ(208Pb/206Pb)NIST SRM 981 (−29.87 ‰ ± 0.07 ‰ (U, k = 2)), δ(207Pb/206Pb)NIST SRM 981 (−66.95 ‰ ± 0.17 ‰ (U, k = 2)) and δ(208Pb/204Pb)NIST SRM 981 (51.55 ‰ ± 0.26 ‰ (U, k = 2)) values of NIST SRM 1400 were also in accordance with published results. Furthermore, we propose a n(87Sr)/n(86Sr) isotope-amount ratio of 0.70884 ± 0.00017 (U, k = 2) corresponding to a δ(87Sr/86Sr)NIST SRM 987 value of −2.11 ‰ ± 0.24 ‰ (U, k = 2) for the BCR-063R reference material. Additionally, we propose a n(208Pb)/n(206Pb) isotope-amount ratio of 2.0793 ± 0.0001 (U, k = 2) corresponding to a δ(208Pb/206Pb)NIST SRM 981 of −40.97 ‰ ± 0.05 ‰ (U, k = 2), a n(207Pb)/n(206Pb) isotope-amount ratio of 0.84995 ± 0.00008 (U, k = 2) corresponding to a δ(207Pb/206Pb)NIST SRM 981 of −70.72 ‰ ± 0.09 ‰ (U, k = 2) and a n(208Pb)/n(204Pb) isotope-amount ratio of 38.221 ± 0.008 (U, k = 2) corresponding to a δ(208Pb/204Pb)NIST SRM 981 of 40.82 ‰ ± 0.23 ‰ (U, k = 2) for the reference material MACS-3.

LA-ICP-MS/MS improves limits of detection in elemental bioimaging of gadolinium deposition originating from MRI contrast agents in skin and brain tissues

Year: 2019
Products: MicroMist concentric nebuliser
Authors: Clases, D;Fingerhut, S;Jeibmann, A;Sperling, M;Doble, P;Karst, U;
Journal: J Trace Elem Med Biol

A novel analytical method to detect the retention of gadolinium from contrast agents for magnetic resonance imaging (MRI) in tissue samples of patients is presented. It is based on laser ablation - inductively coupled plasma - triple quadrupole - mass spectrometry (LA-ICP-MS/MS). Both Gd and P were monitored with a mass shift of +16, corresponding to mono-oxygenated species, as well as Zn, Ca, and Fe on-mass. This method resulted in a significantly reduced background and improved limits of detection not only for phosphorus, but also for gadolinium. These improvements were essential to perform elemental bioimaging with improved resolution of 5 μm x 5 μm, allowing the detection of small Gd deposits in fibrotic skin and brain tumour tissue with diameters of approximately 50 μm. Detailed analyses of these regions revealed that most Gd was accompanied with P and Ca, indicating co-precipitation.

Detrital zircon ages and heavy mineral composition along the Gulf of Tonkin - Implication for sand provenance in the Yinggehai-Song Hong and Qiongdongnan basins

Year: 2019
Products: NWR213 frequency-quintupled solid state Nd:YAG laser system
Authors: Fyhn, M;Thomsen, T;Keulen, N;Knudsen, C;Rizzi, M;Bojesen-Koefoed, J;Olivarius, M;Tri, T;Phach, P;Minh, N;Abatzis, I;Nielsen, L;
Journal: Marine and Petroleum Geology

Neogene reservoir sand in the Yinggehai-Song Hong (YGH-SHB) and Qiongdongnan basins (QDNB) was derived from the Red River, Hainan Island and the Vietnamese Truong Son Belt. We investigate the sand dispersal pathways through comparisons of detrital zircon geochronology and heavy mineral analyses of modern Vietnamese river sand, Holocene to Recent near-coastal sand from Hainan Island and Vietnam and offshore Neogene sand, and we evaluate the methodologies. Eleven distinct zircon age clusters characterize the Gulf of Tonkin provenances. Red River sand contains the most complex age pattern with ∼35Ma, ∼88Ma, ∼155Ma, ∼250Ma, ∼440Ma peaks and broader pre-Cambrian clusters. The ∼88Ma peak uniquely occurs in Red River sand. Northern Truong Son Belt sand contains ∼35Ma, ∼250Ma, ∼440Ma peaks and pre-Cambrian clusters comparable to the Red River. The lack of Cretaceous zircons and a high proportion of ∼250Ma relative to ∼440Ma zircons distinguishes the northern Truong Son Belt from the Red River. The southern Truong Son Belt is characterized by low proportions of ∼250Ma relative to ∼440Ma zircons and the absence of Cretaceous and Cenozoic zircons. Hainan Island sand is identified by the presence of ∼100 Ma zircons and the absence of Cenozoic and ∼88 Ma zircons. The zircon age patterns suggest simple, although dynamic, sand dispersal pathways with mixed sand sources over much of the basins likely resulting from sediment reworking and down-stream river merging induced by Neogene sea-level fluctuations. Sand in the western YGH-SHB was mainly sourced from the Truong Son Belt, the Red River sourced the northern and central YGH-SHB and QDNB, and Hainan sand was primarily deposited along the island margin.

Association between catatonia and levels of hair and serum trace elements and minerals in autism spectrum disorder

Year: 2019
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Authors: Tinkov, AA;Skalnaya, MG;Simashkova, NV;Klyushnik, TP;Skalnaya, AA;Bjørklund, G;Notova, SV;Kiyaeva, EV;Skalny, AV;
Journal: Biomed. Pharmacother.

The objective of the study was to investigate the association between catatonia in autism spectrum disorder (ASD) and the levels of hair and serum trace elements and minerals in children with ASD. The levels of hair and serum trace elements and minerals of boys suffering from ASD with (n = 30) and without (n = 30) catatonia, as well as 30 age- and sex-matched neurotypical controls were assessed using ICP-MS. Hair calcium (Ca) and selenium (Se) levels were lower in ASD patients as compared to the controls. Hair mercury (Hg) levels in ASD patients were more than 3-fold and 2-fold higher as compared to the controls and children with catatonia in ASD. Hair iodine (I) and manganese (Mn) were the lowest and the highest in ASD + Catatonia, respectively. Serum aluminium (Al) and cadmium (Cd) levels in healthy controls were significantly higher in comparison to the patients of both groups. Serum chromium (Cr), copper (Cu) levels were significantly increased in patients with ASD and catatonia, whereas vanadium (V) levels were elevated in patients both with and without catatonia. Multiple regression analysis demonstrated that hair Hg and serum Al and Cd levels were negatively associated with catatonia in ASD in crude and adjusted models. Although the etiology of catatonia in ASD is unclear, the obtained data demonstrate that catatonic symptoms in ASD may be at least partially mediated by altered trace element levels. Further studies are required to elucidate the role of trace elements in the potential signaling mechanisms of catatonia.

Speciation of zinc in fish feed by size exclusion chromatography coupled to inductively coupled plasma mass spectrometry - using fractional factorial design for method optimisation and mild extraction conditions

Year: 2019
Products: FAST SC-4Q DX
Authors: Silva, MS;Sele, V;Sloth, JJ;Araujo, P;Amlund, H;
Journal: J. Chromatogr. B Analyt. Technol. Biomed. Life Sci.

Zinc (Zn) is an element essential to all living organisms and it has an important role as a cofactor of several enzymes. In fish, Zn deficiency has been associated with impaired growth, cataracts, skeletal abnormalities and reduced activity of various Zn metalloenzymes. Fish meal and fish oil traditionally used in salmon feed preparation are being replaced by plant-based ingredients. Zinc additives are supplemented to salmon feed to ensure adequate Zn levels, promoting good health and welfare in Atlantic salmon (Salmo salar). The main objective of the present study was to evaluate Zn species found in an Atlantic salmon feed. This work describes a Zn extraction method that was optimized using a fractional factorial design (FFD), whereby the effect of six factors could be studied by performing only eight experiments. The effects of the type of extraction solution and its molar concentration, pH, presence of sodium dodecyl sulphate, temperature and extraction time on Zn extraction were investigated. Mild extraction conditions were chosen in order to keep the Zn species intact. Total Zn (soluble fractions and non-soluble fractions) was determined by inductively coupled plasma mass spectrometry (ICP-MS). The highest Zn recovery was obtained using 100 mM Tris-HCl, pH 8.5 at a temperature of 4 °C for 24 h where the total Zn in soluble fraction and non-soluble fraction was 9.9 ± 0.2% and 98 ± 6%, respectively. Zinc speciation analysis (on the soluble fractions) was further conducted by size exclusion inductively coupled plasma mass spectroscopy (SEC-ICP-MS). The SEC-ICP-MS method provided qualitative and semi-quantitative information regarding Zn species present in the soluble fractions of the feed. Four Zn-containing peaks were found, each with different molecular weights: Peak 1 (high molecular weight - ≥600 kDa), peak 2 and peak 3 (medium molecular weight - 32 to 17 kDa) were the least abundant (1-6%), while peak 4 (low molecular weight - 17 to 1.36 kDa) was the most abundant (84-95%).

An evaluation of Rb-Sr isotope dilution analyses with a 86Sr-enriched tracer and Multiple Collection-ICP-MS

Year: 2019
Products: Apex IR
Authors: Beranoaguirre, A;Pin, C;Sanchez-Lorda, M;García de Madinabeitia, S;Gil Ibarguchi, J;
Journal: International Journal of Mass Spectrometry

A straightforward method is described allowing to determine on a routine basis Rb and Sr concentrations and 87Rb/86Sr isotope by using the isotope dilution method with isotopic tracers enriched in 87Rb and in 86Sr, respectively, and MC-ICP-MS for mass spectrometric measurements. The 87Sr/86Sr isotope ratios are measured separately on unspiked sample aliquots, thereby alleviating the need for correcting the contribution that would arise in case of total spiking with an 84Sr enriched tracer. The sample preparation involves sample dissolution with hydrofluoric acid, and the separation of Rb and Sr from matrix elements and from each other by combining extraction chromatography and cation exchange in nitric acid medium. The concentration and 87Rb/86Sr data measured on replicate dissolutions of several international geostandards display the very good reproducibility typical of the isotope dilution method, even at low analyte concentration. The within-run precisions of 87Sr/86Sr isotope ratios (2 S.E. from 1 10−5 to 3 10-5) are not as good as those typically achieved by TIMS, but the data show a good reproducibility (0.002% RSD) and are accurate, based on their fair agreement with recommended values. However, these figures are significantly worse at low Sr concentration, indicating that 87Sr/86Sr ratios should preferably be measured by TIMS when Sr-poor samples are processed.

Mesoscale variability related to iron speciation in a coastal Ross Sea area (Antarctica) during summer 2014

Year: 2019
Products: PFA-ST microne- bulizer
Authors: Rivaro, P;Ardini, F;Grotti, M;Aulicino, G;Cotroneo, Y;Fusco, G;Mangoni, O;Bolinesi, F;Saggiomo, M;Celussi, M;
Journal: Chemistry and Ecology

Dissolved iron (Fe) distribution and speciation was determined in water samples (0–200 m) collected in a coastal area near Terra Nova Bay during the austral summer of 2014. Nutrients, dissolved oxygen, chlorophyll-a, phytoplankton composition and prokaryotic biomass distribution were investigated in combination with measurements of the physical properties of the water columns and its dynamics. The dFe value was above the limiting growth concentration, ranging from 0.52 to 4.51 nM, and it showed a spatial variability with a horizontal length scale of about 10 km, according to the variability of the water column physical properties and to iron sources. The organic ligands (L) maintained the concentrations of dFe at levels much higher than the inorganic solubility of Fe, keeping it available for phytoplankton and the log K’FeL values found (from 22.1 to 23.6) highlighted the presence of complexes of differing stabilities.

Hg isotope ratio measurements of methylmercury in fish tissues using HPLC with off line cold vapour generation MC-ICPMS

Year: 2018
Products: APEX-Q desolvating inlet system
Authors: Entwisle, J;Malinovsky, D;Dunn, P;Goenaga-Infante, H;
Journal: J. Anal. At. Spectrom.

Species-specific Hg isotope ratio data has increasingly become an important tool in understanding biogeochemistry of mercury. Among the plethora of analytical techniques capable of separating Hg species to date only gas chromatography has been used to study natural variations in their isotopic composition. Here, we report new methodology for precise and accurate Hg isotope ratio measurements of methylmercury in fish tissues at environmentally relevant levels using high performance liquid chromatography (HPLC) and cold vapour generation multi-collector inductively coupled plasma mass spectrometry (CVG MC-ICPMS). The chromatographic baseline separation of Hg species such as methylmercury (CH3Hg) and inorganic Hg (iHg) was achieved in isocratic mode using reverse phase HPLC with a mobile phase containing L-cysteine as a complexing agent and without the need for species derivatisation. The signal-to-noise ratio of Hg detection by MC-ICP-MS was improved using a cold vapour generation interface with SnCl2 as reducing agent. Challenges driven by the non-reactivity of CH3Hg with SnCl2 and, interferences caused by the presence of L-cysteine in the mobile phase were efficiently overcome through complete oxidation of isolated Hg species prior to cold vapour generation and species-specific Hg isotope ratio measurements. Combined standard uncertainties of δ199/198Hg, δ200/198Hg, δ201/198Hg and δ202/198Hg values determined from replicated measurements of CH3Hg in fish tissue reference materials BCR 463 and NIST SRM 1947 ranged from 0.10‰ to 0.22‰. The obtained δ-values for the Hg isotope ratios are in very good agreement with indicative values of NIST SRM 1947 and those previously reported for BCR 463 material. The developed technique offers a complimentary measurement method to gas chromatography MC-ICPMS in producing isotopically certified species-specific reference materials for Hg. Furthermore, evidence for Hg isotope fractionation induced by dissociation of CH3Hg and interactions with sulphur compounds in solution is provided here as well.

Mechanism of Yellowing: Carbonyl Formation during Hygrothermal Aging in a Common Amine Epoxy

Year: 2018
Products: sample introduction system PrepFAST
Authors: Krauklis, A;Echtermeyer, A;
Journal: Polymers

Epoxies are often exposed to water due to rain and humid air environments. Epoxy yellows during its service time under these conditions, even when protected from UV radiation. The material’s color is not regained upon redrying, indicating irreversible aging mechanisms. Understanding what causes a discoloration is of importance for applications where the visual aspect of the material is significant. In this work, irreversible aging mechanisms and the cause of yellowing were identified. Experiments were performed using a combination of FT-NIR, ATR-FT-IR, EDX, HR-ICP-MS, pH measurements, optical microscopy, SEM, and DMTA. Such extensive material characterization and structured logic of investigation, provided the necessary evidence to investigate the long-term changes. No chain scission (hydrolysis or oxidation-induced) was present in the studied common DGEBA/HDDGE/IPDA/POPA epoxy, whilst it was found that thermo-oxidation and leaching occurred. Thermo-oxidation involved evolution of carbonyl groups in the polymeric carbon–carbon backbone, via nucleophilic radical attack and minor crosslinking of the HDDGE segments. Four probable reactive sites were identified, and respective reactions were proposed. Compounds involved in leaching were identified to be epichlorohydrin and inorganic impurities but were found to be unrelated to yellowing. Carbonyl formation in the epoxy backbone due to thermo-oxidation was the cause for the yellowing of the material.

Influence of weathering and hydrothermal alteration on the REE and δ56Fe composition of iron formation, Cauê Formation, Iron Quadrangle, Brazil

Year: 2018
Products: Fe separation
Authors: Sampaio, G;Pufahl, P;Raye, U;Kyser, K;Abreu, A;Alkmim, A;Nalini, H;
Journal: Chemical Geology

Continental margin (Superior-type) iron formation of the Cauê Formation, Iron Quadrangle, Brazil, is composed of a laminated, magnetite-rich chemical meta-mudstone that was altered during hydrothermal circulation of basinal fluids, greenschist to amphibolite facies metamorphism, and subsequent supergene enrichment of Fe. The absence of traction current deposits and storm-generated structures suggests that deposition occurred on the distal shelf, possibly as deep as the continental slope. Paragenesis-based lithogeochemical analyses of two drill cores with contrasting alteration styles highlight the importance of hydrothermal, metamorphic, and supergene processes on the rare-earth element plus yttrium (REE + Y) and δ56Fe compositions of iron formation. The first drill core penetrates to a depth of 540 m in the Ouro Fino Syncline (OFS) where lithofacies have experienced intense hydrothermal and supergene alteration. The second core is from the Gandarela Syncline (GS) and contains 450 m of metamorphosed iron formation that has undergone later supergene enrichment of Fe.

Determination of accurate and precise chromium isotope ratios in seawater samples by MC-ICP-MS illustrated by analysis of SAFe Station in the North Pacific Ocean

Year: 2018
Products: heated Spiro desolvating membrane
Authors: Moos, S;Boyle, E;
Journal: Chemical Geology

Although the cycling of chromium (Cr) in the ocean may have direct implications on the Cr isotope system's application as a paleo-redox proxy, little seawater Cr isotope data has been published. This may be partly due to the analytical challenges associated with the preconcentration and the purification of the nano-molar trace metal Cr from the seawater matrix. Here, we present a reliable method for the determination of accurate and precise 53Cr/52Cr isotope ratios of total chromium (=Cr(III) + Cr(VI)) in seawater, which could be modified to be redox species-specific. Seawater acidification induces the slow conversion of Cr(VI) to Cr(III). Total Cr of the sample and an equilibrated 50Cr-54Cr double spike is preconcentrated as Cr(III) using Mg(OH)2 coprecipitation. Cr captured by the Mg(OH)2 pellet is oxidized to Cr(VI) using (NH4)2S2O8 under carefully controlled pH, temperature and time settings, in order to avoid H2O2 generation and to control sulfur speciation. Taking advantage of the differing charges of Cr(III) and Cr(VI), three AG 1-X8 columns separate Cr from the salt matrix and isobaric interferences V, Ti, and Fe (column 1), sulfur polyatomic interferences (column 2), and Fe traces (column 3). Analysis is conducted on a MC-ICP-MS IsoProbe featuring a hexapole collision cell in low resolution mode. When pure solutions of SRM 979 are processed via this low blank method (~0.017 nmol of Cr), δ53Cr w.r.t. SRM 979 = +0.02 ± 0.06‰ (±2 SD) is obtained (n = 10). Using this technique, the first full water column profile of Cr isotope ratios at a station in the Pacific Ocean (SAFe station, 30°N 140°W) was generated and demonstrates high oceanographic consistency.

High-precision zirconium stable isotope measurements of geological reference materials as measured by double-spike MC-ICPMS

Year: 2018
Products: Elemental Scientific Instruments (ESI) PFA-50 (~50 μl min −1 ) self-aspirating nebuliser
Authors: Inglis, E;Creech, J;Deng, Z;Moynier, F;
Journal: Chemical Geology

Zirconium plays a major role in geochemistry as it is the major cation of zircons - the oldest preserved minerals on Earth. While Zr isotopic anomalies in meteorites have been widely studied, mass dependant Zr stable isotope fractionation during geological processing has been untouched. Here, we report Zr stable isotopic data for terrestrial igneous rocks and present a novel method for the determination of Zr stable isotope ratios within natural geological materials using ion exchange, double-spike, multiple-collector inductively coupled mass spectrometry (MC-ICPMS). Zirconium is isolated from the rock matrix via a chromatographic separation protocol using a first pass column with AG1-X8 anion exchange resin, and a second pass column containing Eichrom® DGA resin. A 91Zr–96Zr double-spike was created from enriched single 91Zr and 96Zr isotope spikes. Samples were combined with the Zr double-spike at a 43:57 spike:sample [Zr] ratio, prior to dissolution and column chemistry. After column chemistry the purified sample solutions were analysed on a Thermo Scientific Neptune Plus MC-ICPMS and the data was reduced using IsoSpike, with the final Zr isotope data being reported as the per mil deviation of the 94Zr/90Zr from the IPGP-Zr standard (δ94/90ZrIPGP-Zr). The δ94/90ZrIPGP-Zr of six igneous standard reference materials: two basalts (BHVO-2 and JB-2), one andesite (AGV-2), two granites (GA and GS-N) and a serpentinite (UB-N) as well as one individual zircon grain (Plešovice zircon), are presented using this method. Sample measurements are presented with an analytical uncertainty of ±~0.05‰ (2sd) for δ94/90ZrIPGP-Zr and these rocks exhibit isotopic variations of ~0.15‰ for δ94/90ZrIPGP-Zr. These results demonstrate that natural variations of Zr isotopes occur within terrestrial igneous rocks, and are resolvable with this method. Finally the variation of δ94/90ZrIPGP-Zr values observed within the magmatic rock reference materials is correlated (R2 = 0.78; n = 5) with SiO2, suggesting that Zr isotopes could serve as a sensitive tracer of magmatic processes.

Hypoxia in the Holocene Baltic Sea: Comparing modern versus past intervals using sedimentary trace metals

Year: 2018
Products: SC-4 DX
Authors: van Helmond, N;Jilbert, T;Slomp, C;
Journal: Chemical Geology

Anthropogenic nutrient input has caused a rapid expansion of bottom water hypoxia in the Baltic Sea over the past century. Two earlier intervals of widespread hypoxia, coinciding with the Holocene Thermal Maximum (HTMHI; 8–4 ka before present; BP) and the Medieval Climate Anomaly (MCAHI; ~1200–750 years BP), have been identified from Baltic Sea sediments. Here we present sediment records from two sites in the Baltic Sea, and compare the trace metal (As, Ba, Cd, Cu, Mo, Ni, Pb, Re, Sb, Tl, U, V, Zn) enrichments during all three hypoxic intervals. Distinct differences are observed between the intervals and the various elements, highlighting the much stronger perturbation of trace metal cycles during the modern hypoxic interval. Both Mo and U show a strong correlation with Corg and very high absolute concentrations, indicative of frequently euxinic bottom waters during hypoxic intervals. During the modern hypoxic interval (ModernHI) comparatively less Mo is sequestered relative to Corg than in earlier intervals. This suggests partial drawdown of the water column Mo inventory in the modern water column due to persistent euxinia and only partial replenishment of Mo through North Sea inflows. Molybdenum contents in modern sediments are likely also affected by the recent slowdown in input of Mo in association with deposition of Fe and Mn oxides. Strong enrichments of U in recent sediments confirm that the ModernHI is more intense than past intervals. These results suggest that U is a more reliable indicator for the intensity of bottom water deoxygenation in the Baltic Sea than Mo. Sedimentary Re enrichment commences under mildly reducing conditions, but this element is not further enriched under more reducing conditions. Enrichments of V are relatively minor for the MCAHI and ModernHI, possibly due to strong reservoir effects on V in the water column, indicating that V is unreliable as an indicator for the intensity of bottom water hypoxia in this setting. Furthermore, Ba profiles are strongly influenced by post-depositional remobilization throughout the Holocene. The strong relationship between Corg and Ni, Tl and particularly Cu suggests that these trace metals can be used to reconstruct the Corg flux into the sediments. Profiles of As, Sb and Cd and especially Pb and Zn are strongly influenced by anthropogenic pollution.

Quantifying Changes to the Electrolyte and Negative Electrode in Aged NMC532/Graphite Lithium-Ion Cells

Year: 2018
Products: SC FAST Valve
Authors: Thompson, L;Stone, W;Eldesoky, A;Smith, N;McFarlane, C;Kim, J;Johnson, M;Petibon, R;Dahn, J;
Journal: J. Electrochem. Soc.

A set of LiNi0.5Mn0.3Co0.2O2/graphite lithium-ion cells underwent 750 charge-discharge cycles during about 8 months at 55°C to upper cutoff potentials of 4.0, 4.1, 4.2, 4.3, and 4.4 V. The electrolyte in these cells was extracted using a centrifuge method and studied using gas chromatography/mass spectrometry to determine the changes to the solvents and by inductively coupled plasma-mass spectrometry to determine the changes to the salt content in the electrolyte. The negative electrodes from the cells were harvested and studied by micro-X-ray fluorescence to quantify the amount of transition metals which migrated from the positive electrode to the negative electrode during the testing. Emphasis is given to a detailed description of the quantitative methods used in the hope that others will adopt them in similar studies of different types of aged lithium-ion cells. The cells studied here initially had 1.1 molal LiPF6 ethylene carbonate (EC): ethyl methyl carbonate (EMC) (3:7 by weight) electrolyte. The aged cells showed increasing amounts of dimethyl carbonate and diethyl carbonate created by transesterification as the upper cutoff potential increased. Only extremely small amounts of Mn, less than 0.1% of the total Mn in the positive electrode, were found on the negative electrode after this aggressive testing.

An ICP-MS platform for metal content assessment of cell culture media and evaluation of spikes in metal concentration on the quality of an IgG3:κ monoclonal antibody during production

Year: 2018
Products: PrepFast
Authors: Mohammad, A;Agarabi, C;Rogstad, S;DiCioccio, E;Brorson, K;Ashraf, M;Faustino, PJ;Madhavarao, CN;
Journal: J Pharm Biomed Anal

Metal ions can be enzyme cofactors and can directly influence the kinetics of biochemical reactions that also influence the biological production and quality attributes of therapeutic proteins, such as glycan formation and distribution. However, the concentrations of metals in commercially available chemically defined media can range from 1 to 25,000 ppb. Because such concentration changes can impact cell growth, manufacturing yield and product quality the alteration/fluctuation in media composition should be well controlled to maintain product quality. Here, we describe a platform of analytical methods to determine the composition of several metals in different sample matrices using an advanced automated Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). These methods, validated to ICH Q2R1 regulatory validation parameters, were successfully applied to- (a) screen cell culture media; (b) determine changes in the metal concentration during cell growth in spinner flasks, and, (c) determine effect on the glycosylation pattern and homogeneity of an IgG3:κ produced from a murine-hybridoma cell line in bench-top parallel bioreactors due to a spike in copper and iron concentration. Our results show that maintenance of metal content in the cell culture media is critical for product consistency of the IgG3:κ produced. Published by Elsevier B.V.

In vitro human bioavailability of major, trace and ultra-trace elements in Chilean ‘natural’ wines from Itata Valley

Year: 2018
Products: SeaFast SC2 DX autosampler
Authors: Latorre, M;Peña-Farfal, C;Neira, Y;Herbello-Hermelo, P;Domínguez-González, R;Bermejo-Barrera, P;Moreda-Piñeiro, A;
Journal: Food Funct.

In vitro human bioavailability of elements in ‘natural’ wines from Chile's Itata Valley has been assessed using an in vitro dialyzability approach. The red wines (fifteen samples) were of the Cinsault, Cabernet sauvignon, Carmènére, Malbec, and Pinot noir varieties. All white wines (three samples) were of the Muscat of Alexandria variety. Inductively coupled plasma-mass spectrometry was used for determination. Elements such as Ag, As, Be, Cd, Cr, Hg, Mo, Ni, Pb, Sb, Se, Sn, Ti, Tl, and V were not found to be bioavailable (concentrations lower than the limit of detection in the dialysates). Elements such as Al, Co, and Fe showed low bioavailability ratios (lower than 20%), whereas B, K, Li, Mg, and Mn were found to be of moderate bioavailability (bioavailability ratios within the 20–79% range for most wine samples). Ca, Cu, and Sr bioavailability was moderate (higher than 20%) in some wines, but most of the samples showed Ca, Cu, and Sr bioavailabilty ratios lower than 20%. No differences were found regarding bioavailability ratios among red and white wines, or among the grape varieties.

Study of the uptake and bioaccumulation of palladium nanoparticles by Sinapis alba using single particle ICP-MS

Year: 2018
Products: ICP;ICP-MS;Nebulizer;
Authors: Kińska, K;Jiménez-Lamana, J;Kowalska, J;Krasnodębska-Ostręga, B;Szpunar, J;
Journal: Science of The Total Environment

In recent years, increased palladium content has been found in the environment, due to its wide use in various fields, especially as catalytic converters. Palladium can be emitted as a range of soluble and insoluble compounds and in the form of palladium nanoparticles (PdNPs). The level of toxicity is equally dependent on concentration and form of palladium and hence, it is important to determine not only the total content of this element, but also its forms of occurrence. This study for the first time investigates the uptake degree and distribution of PdNPs by model plant Sinapis alba, in comparison with a platinum salt (Pd(NO3)2). An enzymatic digestion method which allows the extraction of PdNPs from the different plant tissues without altering their properties was applied. After extraction, samples were analysed by single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) to provide information about the presences of palladium in nanoparticulated or dissolved form, the nanoparticle size and the nanoparticle number concentration. Significant amounts of PdNPs were found even in aboveground organs, but no significant changes in plant morphology were observed. Size distributions of PdNPs found in all tissues presented lower diameters than size distribution of the PdNPs stock suspension, suggesting that bigger nanoparticles are not taken up by the plant. The average size found is in good agreement between the different organs. Moreover, dissolved palladium was found in all samples, with the biggest contribution, in relative terms, observed in leaves followed by stems and roots.

Quantitative dried blood spot analysis for metallodrugs by laser ablation-inductively coupled plasma-mass spectrometry

Year: 2018
Products: SC4-SL
Authors: Kröger, S;Sperling, M;Karst, U;
Journal: Journal of Trace Elements in Medicine and Biology

A quantitative dried blood spot (DBS) method based on direct sampling by means of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is presented. Gadolinium-based contrast agents were used as model metallodrugs with a significant relevance for pharmaceutical applications. Challenges regarding the ablation of the complex blood-filter matrix were characterized and successfully addressed by a thorough adaption of the laser ablation conditions. Especially the laser fluence was optimized with respect to the particle size distribution of the generated aerosol as monitored by an optical particle counter. Thus, generation of micrometer-sized particles could be minimized in favor of smaller particles increasing the transport efficiency of the DBS ablation aerosol to the plasma and the recorded signal stability. Inhomogeneous blood drying on the porous filter paper could be compensated by the addition of an internal standard prior to blood spotting. To preserve the advantages of DBS sampling, such as small blood volumes and minimal invasiveness, the combined use of DBS and a capillary blood sampling system is demonstrated. By placing the internal standard into the capillary prior to blood sampling, a simple workflow usable for clinical application was implemented. The applicability of the developed method, achieving limits of detection and quantification in the low µg∙L-1 range and covering a linear range of over four orders of magnitude, was demonstrated for blood samples containing different concentrations of the gadolinium contrast agents gadopentetate and gadoterate.

Particulate Trace Metal Composition and Sources in the Kuroshio Adjacent to the East China Sea: The Importance of Aerosol Deposition

Year: 2018
Products: SC-Fast autosampler
Authors: Liao, W;Ho, T;
Journal: J. Geophys. Res. Oceans

The Kuroshio, flowing through the eastern end of the East China Sea, transports terrestrial material to the Northwestern Pacific Ocean. Along the Kuroshio path, we collected size‐fractionated suspended particles in the upper 200 m to investigate the composition and sources of particulate trace metals. Demonstrated by Al‐ and P‐normalized elemental ratios, we found that anthropogenic aerosol deposition was the major source of most particulate trace metals in the Kuroshio region although the impact of bottom resuspension and riverine input may be significant at some specific regions. As seen in our previous studies in the South China Sea and the Western Philippine Sea, this study concluded that anthropogenic aerosol deposition is the dominant particulate trace metal source in the surface water of the Northwestern Pacific Ocean and its marginal seas. Compared to particulate trace metal composition obtained in other open oceans, we found that the distribution patterns of particulate trace metal composition in the surface waters are closely associated with aerosol deposition fluxes. In regions with low deposition, the particulate trace metal concentrations were extremely low and metal to P ratios were all comparable to their intracellular quota previously proposed. In regions with high deposition, metal to P ratios were highly elevated in comparison to their intracellular quota and metal to Al ratios were deviated from lithogenic ratios to various extents. The globally consistent distribution patterns validate trace metal stoichiometry concept in plankton intracellularly and the primary role of aerosol deposition on deciding particulate trace metal composition in oceanic surface water globally.

Sustained Upwelling of Subsurface Iron Supplies Seasonally Persistent Phytoplankton Blooms Around the Southern Kerguelen Plateau, Southern Ocean

Year: 2018
Products: SeaFAST S2 pico
Authors: Schallenberg, C;Bestley, S;Klocker, A;Trull, T;Davies, D;Gault-Ringold, M;Eriksen, R;Roden, N;Sander, S;Sumner, M;Townsend, A;van der Merwe, P;Westwood, K;Wuttig, K;Bowie, A;
Journal: J. Geophys. Res. Oceans

Although the supply of iron generally limits phytoplankton productivity in the Southern Ocean, substantial seasonal blooms are observed over and downstream of the Kerguelen plateau in the Indian sector of the Southern Ocean. Surprisingly, of the oceanic blooms, those associated with the deeper southern plateau last much longer (~3 months) than the northern bloom (~1‐month downstream of northern plateau). In this study, iron supply mechanisms around the southern plateau were investigated, obtaining profiles of dissolved iron (<0.2 μm, dFe) to 2,000‐m deep at 25 stations during austral summer 2016. The dFe concentrations in surface waters (≤100‐m depth) ranged from below the detection limit (DL, median of 0.026 nmol/kg) to 0.34 nmol/kg near the Antarctic shelf, with almost half the data points below detection. These low and—with few exceptions—largely spatially invariant concentrations, presumably driven by seasonal drawdown of this essential micronutrient by phytoplankton, could not explain observed patterns in chlorophyll a. In contrast, dFe concentrations (0.05–1.27 nmol/kg) in subsurface waters (100–800 m) showed strong spatial variations that can explain bloom patterns around the southern Kerguelen plateau when considered in the context of frontal locations and associated frontal processes, including upwelling, that may increase the upward supply of dFe in the region. This sustained vertical dFe supply distinguishes the southern blooms from the bloom downstream of the northern Kerguelen plateau and explains their persistence through the season.

Mercury Inputs to Chinese Marginal Seas: Impact of Industrialization and Development of China

Year: 2018
Products: Apex-Q desolvation unit
Authors: Yin, R;Guo, Z;Hu, L;Liu, W;Hurley, J;Lepak, R;Lin, T;Feng, X;Li, X;
Journal: J. Geophys. Res. Oceans

In the past decades, China has experienced substantial economic growth and industrialization. However, the effects of vast development of China on Hg input to the nearby oceans are still unclear. In this study, the influx and isotopic compositions of Hg in four 210Pb‐dated sediment cores were examined to investigate changes in Hg deposition to the marginal seas off China over a century. Nearshore cores had higher Hg influxes than offshore cores. Increases of Hg influxes started since the 1950s, which coincides with China's economic development. Dramatic historical changes in Hg isotopic composition were observed in the cores (δ202Hg: −2.01‰ to −0.69‰; Δ199Hg: −0.16‰ to 0.31‰; n = 106). δ202Hg increased from the deep to the surface layers of the cores. The offshore cores mainly showed positive Δ199Hg values, but the pre‐1950 samples had more positive Δ199Hg values than the younger samples. The nearshore cores mainly showed negative Δ199Hg values in the pre‐1950s samples, but the younger samples showed Δ199Hg values close to zero. A triple‐mixing isotope model, used to quantify the contribution of potential Hg inputs (e.g., direct discharge of industrial Hg, soil Hg, and precipitation‐derived Hg), showed clear evidence of enhanced industrial Hg inputs to the ocean margin, but slightly decreased watershed soil Hg inputs in the last few decades. The variations of watershed‐derived Hg were likely caused by the construction of impoundments in major rivers of China. This study demonstrates that mercury inputs to Chinese marginal seas have been largely altered due to the industrialization and economic development of China.


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