Concentrations and distribution patterns of rare earth elements (REEs) in the intertidal flat of Tianjin were studied using P 507 resin and ICP-MS analytical technology. The results show that average concentrations of REEs in the filtered ( dissolved REEs), unfiltered and interstitial water are 0.461 mug (.) L-1, 4.98 mug (.) L-1 and 0. 845 mug (.) L-1, respectively. Their distribution patterns are similar to those in inland natural rivers, but quite different from those in oceans. The average concentrations of REEs in sediments and suspended matters are 161.2 mg (.) L-1 and 168.1 mg (.) L-1, respectively, which are much lower than those in sediments of natural rivers but higher than those in sediments of the continental shelf of East China Sea. It is suggested that REEs in sediments and suspended matters of intertidal flat can have mainly originated from terrestrial soils and thus their transportation and transformation processes are similar with those in rivers, and different from those in continental shelves. Pollutants discharged into the Bohai Bay do (.) not cause significant effect on REEs in the intertidal flat of Tianjin yet.

Intertidal ecology

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A New Dgt Technique Comprising a Hybrid Sensor for the Selective and Simultaneous High Resolution 2-D Imaging of Asiii, Criii and Sbiii and Dissolved Oxygen

SSRN Electronic Journal (2022)

Mingyi Ren Zhilin Zhong Shiming Ding Jingfu Wang Zhihui Dai

A new diffusive gradients in thin films technique (HR-MPTS DGT) with mercapto-functionalized attapulgite in a binding gel was developed for simultaneous two-dimensional (2-D) chemical imaging of As III , Cr III and Sb III selectively at the submillimeter scale, combined with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis. The HR-MPTS DGT exhibited selective accumulation of As III , Sb III and Cr III (> 97%), yet negligible accumulation of As V , Sb V and Cr VI (< 2%). Accumulation of As III , Cr III and Sb III on the binding gel had a linear relationship (R 2 > 0.99) with the corresponding standardized laser ablation signals, proving the feasibility of LA-ICP-MS analysis. Analysis for As III , Cr III and Sb III was provided with favorable analytical precision (relative standard deviation < 10%). With the purpose of evaluating the dynamics of As III , Cr III , Sb III and O 2 in the rooting zone, a hybrid sensor, which comprises the HR-MPTS gel overlying an O 2 planar optode , was deployed in rhizosphere sediments. Results showed that the consumption of both As III and Sb III due to the oxidation extended ~4.48 mm into the sediments, which was consistent with the extension length of the oxidized sediment layers around the roots created by O 2 leakage.

Low resolution

10.2139/ssrn.4027281

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Effects of organic ligands on fractionation of rare earth elements (REEs) in hydroponic plants: An application to the determination of binding capacities by humic acid for modeling (Retracted article. See vol. 80, pg. 1408, 2010)

Shiming Ding Tao Liang ChaoSheng Zhang JunCai Yan Zili Zhang

Previous studies have revealed the fractionation processes of rare earth elements (REEs) in hydroponic plants, with a heavy REE (HREE, the elements from Gd to Lu) enrichment in leaves. In this study, effects on the HREE enrichment in soybean leaves with additions of carboxylic acids (acetate, malate, citrate, NTA, EDTA and DTPA) and two soil humic acids (HAs) were investigated. REE speciation in carboxylic acid and HA solutions was simulated using Visual MINTEQ and Model V, respectively. The results showed that the effects caused by carboxylic acids were strongly dependent on the differences between their binding strengths for light REEs (LREEs, the elements from La to Eu) and those for HREEs. A good correlation existed between these effects and the changes of free REE ions in solutions. This relationship was also observed for the HA treatments, provided that the intrinsic equilibrium constants of REEs for cation-proton exchange with HA (i.e., pK(MHA)) in Model V were estimated using a free-energy relationship with the stability constants for REE complexation with lactic acid. It is suggested that this set of pK(MHA) values is more suitable for use in Model V for the simulation of REE complexation with HA. (c) 2006 Elsevier Ltd. All rights reserved.

Genetic algorithm

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Preface: selected papers from SESEH 2012 Sino-European Symposium on Environment and Health

Environmental Geochemistry and Health (2013)

Chaosheng Zhang Olle Selinus Andrew Hursthouse Xinghui Xia Shiming Ding

10.1007/s10653-013-9552-9

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