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Cd and Pb in farmland topsoil are controlled by many factors. To identify the source of potential toxic metals in the farmland topsoil around Mianyuan River, the chemical analysis and multivariate statistical analysis are performed in this study. The results indicate the following: (1) The concentration of Cd and Pb in soil exceed the background value of Chinese soil elements. (2) Cd is significantly enriched in the whole region and Pb is locally enriched, both of them are more or less influenced by human activities. (3) The contents of Cd and Pb increase significantly following the flow direction of river. (4)
Junji Zhang; Zeming Shi; Shijun Ni; Xinyu Wang; Chao Liao; Fei Wei. Source Identification of Cd and Pb in Typical Farmland Topsoil in the Southwest of China: A Case Study. Sustainability 2021, 13, 3729 .
AMA StyleJunji Zhang, Zeming Shi, Shijun Ni, Xinyu Wang, Chao Liao, Fei Wei. Source Identification of Cd and Pb in Typical Farmland Topsoil in the Southwest of China: A Case Study. Sustainability. 2021; 13 (7):3729.
Chicago/Turabian StyleJunji Zhang; Zeming Shi; Shijun Ni; Xinyu Wang; Chao Liao; Fei Wei. 2021. "Source Identification of Cd and Pb in Typical Farmland Topsoil in the Southwest of China: A Case Study." Sustainability 13, no. 7: 3729.
A complete and accurate set of thermodynamic data for aqueous uranium species is necessary in order to determine the toxicity of uranium in water, to predict its fate in the environment and to design possible remediation strategies for polluted environments. Comparisons of the completeness and accuracy of the thermodynamic databases for aqueous uranyl complexes involving common inorganic anions (OH−, SO42−, PO43−, CO32−, SO42−, Cl−,F−, I−, Br−) and some organic ligands have been made between a number of publicly-available thermodynamic databases (MINTEQ, LLNL, WATEQ4F, ThermoChimie, NEA-TDB, and PSI/Nagra). The results indicates that: (1) stability constants for most aqueous inorganic uranium species in the ThermoChimie, NEA-TDB, and PSI/Nagra databases are broadly similar, but ThermoChimie includes a greater number of organic uranium species; (2) ThermoChimie and two other modern developing databases (NEA-TDB, and PSI/Nagra) are recommended for calculating uranium speciation in natural/polluted waters except for those containing high concentrations of inorganic phosphate; (3) the stability constant for U(OH)4 from the LLNL database is much greater than the values found in the other databases (by four orders of magnitude) and needs to be replaced; (4) the MINTEQ, LLNL, and WATEQ4F databases need updating for many important uranium species including Ca2UO2(CO3)3, UO2(H2AsO4)2 and all the organic uranium species, and (5) the MINTEQ database does not include U(IV)‑bromine, U(IV)‑iodine or U(IV)-nitrate complexes, while the other databases do not include U(IV)-phosphate complexes. A case study of the water chemistry in a phosphate mining region of China, including river water from close to a fertilizer plant, indicates that the calculated uranium speciation varies greatly between the different databases. In particular, the existence and stability of the UO2(HPO4)22− species needs confirmation and quantification including supporting spectroscopic measurements. Although the stability of the stronger bioavailable uranyl-phosphate complexes remains uncertain, the available thermodynamic data suggests that the proportion and toxicity of most uranyl-phosphate complexes will be negligible when the pH exceeds 8.5 and the inorganic phosphate concentration (as PO43−) is <2 mg/L.
Xinyu Wang; Zeming Shi; David G. Kinniburgh; Laishi Zhao; Shijun Ni; Ruilin Wang; Yun Hou; Ke Cheng; Bocheng Zhu. Effect of thermodynamic database selection on the estimated aqueous uranium speciation. Journal of Geochemical Exploration 2019, 204, 33 -42.
AMA StyleXinyu Wang, Zeming Shi, David G. Kinniburgh, Laishi Zhao, Shijun Ni, Ruilin Wang, Yun Hou, Ke Cheng, Bocheng Zhu. Effect of thermodynamic database selection on the estimated aqueous uranium speciation. Journal of Geochemical Exploration. 2019; 204 ():33-42.
Chicago/Turabian StyleXinyu Wang; Zeming Shi; David G. Kinniburgh; Laishi Zhao; Shijun Ni; Ruilin Wang; Yun Hou; Ke Cheng; Bocheng Zhu. 2019. "Effect of thermodynamic database selection on the estimated aqueous uranium speciation." Journal of Geochemical Exploration 204, no. : 33-42.
Metal contamination in sediment of the Mianyuan River (one of the major upper reaches of the Yangtze River) in Longmenshan Region (China) was investigated in 2012. Means of metal concentrations in sediment (<74μm) were Cr: 59.93 ± 19.8% mg/kg; As: 7.21 ± 50.2% mg/kg; Se: 0.45 ± 66.3% mg/kg; Pb: 19.89 ± 29.3% mg/kg; Zn: 78.98 ± 31.9% mg/kg; Cd: 0.69 ± 28.3% mg/kg; Ba: 0.71 ± 34.0% g/kg; Mn: 0.55 ± 62.2% g/kg. This study suggested: (1) concentrations of Cd, As, Cr, and Pb in Mianyuan River sediment were lower than those of the middle and lower reaches of the Yangtze River; (2) the increase of metals during the period from 2006 to 2009 was probably related to the destruction of tailings piles by the Wen Chun earthquake in 2008; (3) organic materials decided the distribution of Cd, Se, As, Ba, and Mn in the upstream sediment, while the iron and manganese minerals controlled the distribution of Ba, Cr, and Zn in the downstream sediment; (4) sources of Cd, Se, and As were geogenic, while sources of Cr, Zn, Ba, and Mn were anthropogenic; (5) the source of Pb in the upstream sediment was probably automobile exhaust, but that of Pb in the downstream sediment was geogenic.
Zeming Shi; Xinyu Wang; Shijun Ni. Metal Contamination in Sediment of One of the Upper Reaches of the Yangtze River: Mianyuan River in Longmenshan Region, Southwest of China. Soil and Sediment Contamination: An International Journal 2014, 24, 368 -385.
AMA StyleZeming Shi, Xinyu Wang, Shijun Ni. Metal Contamination in Sediment of One of the Upper Reaches of the Yangtze River: Mianyuan River in Longmenshan Region, Southwest of China. Soil and Sediment Contamination: An International Journal. 2014; 24 (4):368-385.
Chicago/Turabian StyleZeming Shi; Xinyu Wang; Shijun Ni. 2014. "Metal Contamination in Sediment of One of the Upper Reaches of the Yangtze River: Mianyuan River in Longmenshan Region, Southwest of China." Soil and Sediment Contamination: An International Journal 24, no. 4: 368-385.