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The contents and chemical speciation of vanadium(V) in different types of soil and soils with different particle were studied by the modified BCR method. The results indicated that the V content was in the order of as red soil > cinnamon soil > chernozem soil, and the content of V in red soil was as high as 264.9 mg/kg, which posesa potential risk to the environment and biosecurity. In cinnamon soil, V exhibitedan obvious gradation effect; that is, the content of V in fine particles was higher than in large particles. In addition, V(IV), with low toxicity, accounted for more than 87% of the total V in the three types of soil, and most V existed in the residual fraction. The pH was the main factor affecting the V valence state in the soil, and when the environmental conditions change due to various agricultural measures, such as applying fertiliser, long-term cultivation and intensive irrigation, V(IV) is easily oxidised to V(V) with high toxicity, and reduceable and oxidisable V is converted into an acid-soluble fraction, which leads to increased bioavailability and a potential threat to the environment. Therefore, it is necessary to strengthen environmental risk assessments and monitoring of heavy metals in cultivated soils, especially in areas with high background values. [ABSTRACT FROM AUTHOR]

The BCR sequential extraction procedure was compared with EDTA, HCl, and NaNO single extractions for evaluating vanadium bioavailability in alfalfa rhizosphere soil. The amounts of vanadium extracted by these methods were in the following order: BCR (bioavailable V) > EDTA ≈ HCl > NaNO. Both correlation analysis and stepwise regression were adopted to illustrate the extractable vanadium between different reagents. The correlation coefficients between extracted vanadium and the vanadium contents in alfalfa roots were R = 0.948, R = 0.902, R = 0.816, and R = 0.819. The stepwise multiple regression equation of the NaNO extraction was the most significant at a 95 % confidence interval. The influence of pH, total organic carbon, and cadmium content of soil to vanadium bioavailability were not definite. In summary, both the BCR sequential extraction and the single extraction methods were valid approaches for predicting vanadium bioavailability in alfalfa rhizosphere soil, especially the single extractions. [ABSTRACT FROM AUTHOR]

The Aha Lake is a seasonal anoxic water system in the southwest of Guiyang City, Guizhou Province, China. Seasonal variations in SO concentrations and their isotopic compositions in lake water as well as in the tributaries were investigated in this study. The results showed that sulfate concentrations in river water range from 0.94 to 6.52 mmol/L and their δS values range from t14.9‰ and 0.9‰, while lake water has sulfate concentrations ranging from 1.91 to 2.79 mmol/L, and δS values from −9.8‰ to −5.9‰. It is suggested that coal mining drainage is the major source of SO in the Aha Lake. Rainfall, sewage discharge, sulfide oxidation and gypsum dissolution have made only limited contributions. Different depth-dependent distributions of dissolved SO and δS were developed for both DB and LJK in summer and winter. Due to water overturn, δS values display homogenous vertical distributions in winter and spring. While in summer and autumn, significant positive shifts of δS were clearly observed in epilimnion and bottom strata as a result of water stratification. High δS values in epilimnion may result from the retention of rainwater during water stratification. Dissimilatory sulfate reduction by bacteria was thought to be responsible for the increase of δS value in hypolimnion. [ABSTRACT FROM AUTHOR]

Tri(1,3-dichloropropyl) phosphate (TDCPP) potentially damages the thyroid system in humans and animals. However, knowledge of its toxic effects and underlying mechanisms is limited. The present study was conducted to determine the thyroid hormone-disrupting effects of TDCPP and its major metabolite, bis(1,3-dichloro-2-propyl) phosphate (BDCPP) in rat pituitary cell lines (GH3). TDCPP and BDCPP, that mimic the thyroid hormone (TH), promoted GH3 cell proliferation and modulated the progression of the cell cycle at 20 and 200 μmol/L, respectively. Similar to T3, TDCPP and BDCPP also significantly upregulated c-fos and downregulated Tshβ gene expression. Although the binding affinity of these chemicals for thyroid receptor β (TRβ) was not measured, significant competition between these chemicals to bind to the membrane thyroid hormone receptor (integrin α v β 3) was found, suggesting that TDCPP and BDCPP were strongly bound to integrin α v β 3. Results from a molecular docking analysis provided further evidence of strong binding affinities of TDCPP and BDCPP for integrin α v β 3 , and the ligand binding site of Arg-Gly-Asp (RGD) was identified. Real-time PCR also supported the supposition that, after binding to integrin α v β 3 , TDCPP and BDCPP may induce the activation of the extracellular signal-regulated protein kinase (ERK1/2) signal transduction pathway. Taken together, our data suggest that TDCPP and BDCPP have the ability to mimic THs and that the underlying mechanism might be associated with their interactions with integrin α v β 3 and the activation of the ERK1/2 pathway, providing new insight into the mechanism of TDCPP- and BDCPP-induced cytotoxicity. Image 1 • TDCPP and BDCPP induced GH3 cell proliferation. • TDCPP and BDCPP showed strong binding with integrin α v β 3. • TDCPP and BDCPP induced thyroid disruption that is associated with integrin α v β 3 and ERK1/2 activation. [ABSTRACT FROM AUTHOR]