The behaviour of aluminium, manganese, iron, cobalt, and lead in the subarctic Pacific Ocean: boundary scavenging and temporal changes

Aluminium (Al), manganese (Mn), iron (Fe), cobalt (Co), and lead (Pb) are trace metals that exhibit significant scavenging tendencies in the oceans. This study presents the full-depth distributions of the dissolved (d) and labile particulate (lp) fractions of these five elements in the subarctic Pacific Ocean, obtained during the GEOTRACES Japan KH-17-3 cruise. Along the 145° W meridional transect, the d and lp species of Al, Mn, Fe, and Co reflected fluvial supply from Alaska and benthic input from the continental shelf. We estimated that the boundary-scavenging zone has a width of approximately 250 km off Alaska. Along the 47° N zonal transect (GEOTRACES GP02 Line), we found input of trace metals from the Okhotsk and Bering Seas in the west, contrasting to the limited input of trace metals due to boundary scavenging in the east. The hydrothermal activity of the Juan de Fuca Ridge influenced the distribution of deep-water trace metals at the easternmost station, CL-21. Temporal change in the vertical profiles of dPb in the middle of the subarctic gyre highlighted a decline in anthropogenic Pb emissions from 2005 to 2017. Temporal change of the vertical profiles of Al, Mn, and Fe at 47° N, 160° E from 2011 to 2017 indicates the influence of the Great East Japan Earthquake. In particular, lp trace metals were brought by tsunami and ocean circulation in 2011, and decreased over time through scavenging

Distributions of aluminum, manganese, cobalt, and lead in the western South Pacific: Interplay between the South and North Pacific

Aluminum (Al), manganese (Mn), cobalt (Co), and lead (Pb) are strongly scavenged from seawater. We reported that each element is uniquely related to ocean circulation in the North Pacific (Zheng et al., 2019). Herein, we present the full-depth distributions of these elements in the western South Pacific, which include meridional sections along 170°W (GEOTRACES GP19). We determined dissolved (d) and total dissolvable (td) concentrations using filtered and unfiltered seawater without UV treatment, and we calculated labile particulate (lp) concentrations as the difference between td and d concentrations. This and the previous studies present the basin scale distributions, which enable us to investigate first order processes that drive the biogeochemistry of Al, Mn, Co, and Pb in the Pacific Ocean. The meridional section of dAl along 170°W (GP19)-160°W (GPc06) from 64°S to 54°N indicates that elevated concentrations (maximum 6.1 nmol/kg) occur between 40°S and 10°S from surface to bottom. However, the maxima of lpAl occur at high latitudes. The lpAl/tdAl ratio has a minimum of 0.26 ± 0.12 (ave ± sd, n = 116) in the zone from 30°S to 0°S. Based on these results, we propose a hypothesis that weathering on land has a significant effect on the distribution of Al in the ocean. Intensive weathering on tropical and subtropical islands and Australia forms kaolinite-dominated soils and laterite. This process provides dAl and kaolinite to the ocean. The supply of kaolinite results in kaolinite-dominated sediments that become a major bottom source for dAl. In contrast, strong sources of Mn and Co are continental shelves around the northern boundary. Dissolved Mn and dCo are released from sediments by manganese reduction and carried by intermediate water circulation. In particular, dCo spreads in the North Pacific Intermediate Water (NPIW), Equatorial Pacific Intermediate Water (EqPIW), and Antarctic Intermediate Water (AAIW); 23–59 pmol/kg at a potential density anomaly (σθ) of 27.0. This is partly owing to the uptake of dCo by phytoplankton and remineralization from settling particles. The dPb concentrations are 10 ± 6 pmol/kg (n = 397) in the South Pacific and 30 ± 20 pmol/kg (n = 566) in the North Pacific. The distribution of dPb is characterized by a maximum in the Subtropical Mode Water (SMW) and Central Mode Water (CMW) with σθ∼26 in the North Pacific. These results indicate that Pb is predominantly supplied by anthropogenic aerosols from Asia and Russia to the Pacific Ocean. Because Pb is not actively taken up by phytoplankton, Pb enters mode waters during winter convection and is transported with mode waters

Solid-phase extraction of palladium, platinum, and gold from water samples: comparison between a chelating resin and a chelating fiber with ethylenediamine groups

Dissolved palladium (Pd), platinum (Pt), and gold (Au) form inert chloride complexes at low concentrations of pmol/kg in environmental water, thus rendering difficulty in the development of a precise analytical method for these metals. Herein, we report the preconcentration of Pd, Pt, and Au with a chelating fiber Vonnel-en and a chelating resin TYP-en with ethylenediamine (en) groups. Batch adsorption experiments reveal the adsorption capacity of Vonnel-en for Pd(II), Pt(IV), and Au(III) in 0.10 M HCl as 0.53, 0.22, and 0.27 mmol/g, respectively. The adsorption capacity of TYP-en for Pd(II), Pt(IV), and Au(III) in 0.10 M HCl is 0.31, 0.17, and 0.52 mmol/g, respectively. In column extraction experiments using small-volume samples containing Pd(II), Pt(II), Pt(IV), Au(I), or Au(III) at concentrations of μmol/kg, TYP-en is able to quantitatively recover Pd, Pt, and Au from 0.01 to 0.2 M HCl irrespective of their oxidation states. In contrast, Vonnel-en is unable to quantitatively recover Au(I). In column extraction experiments using large-volume samples containing Pd(II), Pt(IV), and Au(III) at concentrations of pmol/kg, the recovery of Pd(II), Pt(IV), and Au(III) by TYP-en from 0.07 M HCl is 100–105%. However, the recovery of Pd(II), Pt(IV), and Au(III) by Vonnel-en from 0.03 to 0.3 M HCl is 102–110, 7–15, and 20–52%, respectively. Thus, the chelating resin TYP-en has a high potential for the multielemental determination of Pd, Pt, and Au in environmental water

Determination of chromium, copper and lead in river water by graphite-furnace atomic absorption spectrometry after coprecipitation with terbium hydroxide

金沢大学教育学部理科教

Selective coprecipitation of chromium(Ⅲ)in water with scandium hydroxide prior to graphite furnace atomic absorption spectrometric determination

金沢大学教育学部理科教

特異な立体効果を有する配位子による新規分離機能の創製

金沢大学理工研究域本研究は、従来の有機配位子とは異なる立体的因子によって金属イオンサイズを認識する新規な有機配位子を創製し、その分離機能を溶液反応と結晶構造および化学計算の解析によって明らかにすることを目的とした。(1) ポリビラゾリルボレイトの金属イオン選択性ポリビラゾリルボレイトは四面体型のホウ素原子にピラゾール環が2〜4個結合した負1価の窒素配位子であり、2座または3座配位子として働く。この配位子は、ホウ素原子またはピラゾール環上の置換基を様々に変えることができ、種々の立体的因子、電子的因子を通して鎖生成反応に影響をおよぼし、その分離機能を制御しうる。本年度は3座配位子であるトリスおよびテトラキスピラゾリルボレイト、ならびにトリスおよびテトラキス(3-メチルピラゾリル)ボレイトの遷移系列金属に対する選択性を溶媒抽出法により検討した。これらの配位子がきわめて安定な鎖体を生成し、またIrving-Williams系列に従わない特異な金属イオン選択性を示すことを見出した。この原因を解明するために、Mn、Fe、Co、Ni、Cu、Zn、Cd鎖体の構造解析を行った。現在成果の一部を論文にまとめつつある。また、ピラゾリルボレイト-β-ジケトン-希土類金属の三元鎖体の構造解析、ピラゾール環の3位にトリフルオロメチル基をもつ配位子などの合成に着手した。(2) ポリピラゾリルメタンの金属イオン選択性ポリピラゾリルボレイトと等電的構造をもち、無電荷の配位子であるポリピラゾリルメタンを合成した。紫外-可視分光光度法によりこれらの配位子の酸解離定数、2族金属イオンとの鎖体の安定度定数を決定した。現在、遷移系列元素との鎖生成を検討中である。今後はこれらの研究を継続するとともに、(1)ピラゾリルボレイトおよびピラゾリルメタン鎖体の物性の研究、(2)新しい有機配位子の設計、合成への展開を行う。硫黄を配位原子とする三方三座配位子の研究を計画している。研究課題/領域番号:09740551, 研究期間(年度):1997 – 1998出典：「特異な立体効果を有する配位子による新規分離機能の創製」研究成果報告書　課題番号09740551（KAKEN：科学研究費助成事業データベース（国立情報学研究所））（https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-09740551/)を加工して作

配位子の立体構造によるイオンサイズ認識能と錯体物性の制御

京都大学 / 金沢大学理工研究域物質化学系本研究は、従来の有機配位子とは異なる立体的因子によって金属イオンサイズを認識する新奇な有機配位子を創製し、その分離機能を溶液反応と結晶構造および化学計算の解析によって明らかにすることを目的とした。(1)ポリピラゾリルボレイトの金属イオン選択性ポリピラゾリルボレイトは四面体型のホウ素原子にピラゾール環が2〜4個結合した負1価の窒素配位子であり、2座または3座配位子として働く。この配位子は、ホウ素元子またはピラゾール環上の置換基を様々に変えることができ、種々の立体的因子、電子的因子を通して錯生成反応に影響をおよぼし、その分離機能を制御しういる。我々は、ピラゾール環の3位に置換基を有するビスピラゾリルボレイトがIrving-Williams系列に従わない特異な金属イオン選択性を示すことを見出した。コバルトおよびニッケル錯体のX-線構造解析などにもとづき、配位子間立体反発が特異な選択性の原因であることを明らかにした。3座配位子であるトリス、テトラキスピラゾリルボレイトもまた特異な金属イオン選択性を示した。この原因を解明するために、ニッケル、カドミウム錯体の構造解析を行った。現在そのほかの金属の錯体の構造について検討中である。(2)ポリピラゾリルボレイト錯体の物性ポリピラゾリルボレイトの配位子内および配位子間立体反発が、錯体の酸化還元におよぼす影響について、予備的な検討を行った。(3)新しい有機配位子の設計、合成、評価種々の置換基を有するポリピラゾリルボレイトの合成を行った。ポリピラゾリルボレイトと類似の構造をもち、無電荷の配位子であるポリピラゾリルメタンの合成に着手した。研究課題/領域番号:08740575, 研究期間(年度):1996出典：研究課題「配位子の立体構造によるイオンサイズ認識能と錯体物性の制御」課題番号08740575（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-08740575/）を加工して作

Sectional Distribution Patterns of Cd, Ni, Zn, and Cu in the North Pacific Ocean: Relationships to Nutrients and Importance of Scavenging

The North Pacific Ocean is located at the end of the thermohaline circulation of deep water. This study reports on basin-scale full-depth sectional distributions of total dissolvable (td), dissolved (d), and labile particulate (lp) Cd, Ni, Zn, and Cu along three transects: the GEOTRACES transects GP18 (165°E) and GP02 (47°N), and along 160°W. We find that scavenging is an important factor that significantly affects the distributions of dZn, dNi, and dCu, of which the magnitude of influence increases in the order of Cd 800 m deep, which is in the range of the phytoplankton Cd/P ratio. This is indicative of the dominant effect of water circulation and biological processes on dCd distribution. The dissolved metals (dMs) to PO₄ ratios of other examined metals were either partially or completely outside the range of typical biomass ratios. They generally increased with depth in waters >800 m deep; the magnitude of increase was the highest for Cu and moderate for Ni and Zn. Below 800 m, an increase in the apparent oxygen utilization from 150 to 300 μmol/kg was concurrent with a decrease in the dMs/PO4 ratios: 4 ± 3% for Cd, 21 ± 4% for Zn, 21 ± 3% for Ni, and 69 ± 7% for Cu

Distribution and stoichiometry of Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb in the East China Sea

The dissolved (d) and total dissolvable (td) trace metals were determined in seawater samples collected from the East China Sea (ECS). Labile particulate (lp) species was calculated as td minus d, and the sectional and vertical distributions of d and lp trace metals were evaluated. The surface concentrations of dAl, dCo, dNi, dCu, and dPb were higher in the continental shelf region than in the Kuroshio region. lpAl and lpFe were the dominant species below a depth of 400 m, and a strong positive correlation was observed between them in the Kuroshio region. The enrichment factor (EF) against crustal abundance was calculated for the purpose of estimating the origin of dMs in the ECS. The EF(dFe) was close to unity. These results suggest that both lpFe and dFe are dominated by crustal sources. The other elements had high EF, indicating significant contributions from other sources. EF(dPb) was close to the enrichment factor in aerosol, suggesting atmospheric input from anthropogenic sources. The dM/P ratios were calculated to investigate the validity of the extended Redfield ratio in the ECS. The Mn/P, Co/P, Cu/P, Zn/P, and Cd/P ratios in shallow water (< 200 m) were within the same order of magnitude as those in phytoplankton. In contrast, the Al/P and Fe/P ratios were, respectively, 27 and 213 times higher in phytoplankton compared to those in shallow water. These results suggest that dFe is a potential limiting factor for biological production, although it is not exhausted in surface water

Distribution of stable isotopes of Mo and W from a river to the ocean: signatures of anthropogenic pollution

Molybdenum and tungsten are redox-sensitive elements, and their stable isotope ratios have attracted attention as paleoceanographic proxies. However, our knowledge of the distribution of stable Mo and W isotopes in the modern hydrosphere remains limited. In this study, we provided the concentrations and isotope ratios of dissolved Mo and W in the oceans (the North Pacific and Indian Oceans), marginal seas (the East China Sea and Sea of Japan), and a river-estuary system in Japan (from the Uji-Yodo rivers to Osaka Bay). In the North Pacific and Indian Oceans, the W concentration was 48.2 ± 6.2 pmol/kg (ave ± 2sd, n = 109), δ186/184W was 0.52 ± 0.06 ‰, the Mo concentration was 105.1 ± 8.0 nmol/kg, and δ98/95Mo was 2.40 ± 0.06 ‰. The results indicate that W has the constant concentration and isotopic composition in the modern ocean as well as Mo. In the East China Sea and the Sea of Japan, the W concentration and δ186/184W in the upper water (&lt; 1000 m depth) were different from those in the ocean (W = 56 ± 18 pmol/kg, δ186/184W = 0.45 ± 0.06 ‰, n = 24). However, the concentrations in deeper water were congruent with those in the oceans (W = 49.9 ± 7.6 pmol/kg, δ186/184W = 0.50 ± 0.02 ‰, n = 7). The Mo concentration was 105.4 ± 3.1 nmol/kg and δ98/95Mo was 2.36 ± 0.03 ‰ (n = 31) throughout the water column, congruent with those in the ocean. In the Uji River-Yodo River-Osaka Bay system, the W concentration reached 1074 pmol/kg and δ186/184W reached 0.20 ‰. We propose that the enrichment of W with a low δ186/184W in the river-estuary system and marginal seas is caused by anthropogenic pollution. Anthropogenic Mo pollution was not detected in marginal seas. However, the Mo concentration and δ98/95Mo showed high anomalies above the mixing line of river water and seawater in the lower Yodo River and Osaka Bay, implying possible anthropogenic pollution of Mo in the metropolitan area