Geochemical Characteristics and Risk Assessment of PTEs in the Supergene Environment of the Former Zoige Uranium Mine

Carbonaceous–siliceous–argillaceous rock-type uranium deposits, a major uranium resource in China, pose significant environmental risks due to heavy metal contamination. Geochemical investigations in the former Zoige uranium mine revealed elevated As, Cd, Cr, Cu, Ni, U, and Zn concentrations in soil...

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Main Authors: Na Zhang, Zeming Shi, Chengjie Zou, Yinghai Zhu, Yun Hou
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Toxics
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Online Access:https://www.mdpi.com/2305-6304/13/7/561
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author Na Zhang
Zeming Shi
Chengjie Zou
Yinghai Zhu
Yun Hou
author_facet Na Zhang
Zeming Shi
Chengjie Zou
Yinghai Zhu
Yun Hou
author_sort Na Zhang
collection DOAJ
description Carbonaceous–siliceous–argillaceous rock-type uranium deposits, a major uranium resource in China, pose significant environmental risks due to heavy metal contamination. Geochemical investigations in the former Zoige uranium mine revealed elevated As, Cd, Cr, Cu, Ni, U, and Zn concentrations in soils and sediments, particularly at river confluences and downstream regions, attributed to leachate migration from ore bodies and tailings ponds. Surface samples exhibited high Cd bioavailability. The integrated BCR and mineral analysis reveals that Acid-soluble and reducible fractions of Ni, Cu, Zn, As, and Pb are governed by carbonate dissolution and Fe-Mn oxide dynamics via silicate weathering, while residual and oxidizable fractions show weak mineral-phase dependencies. Positive Matrix Factorization identified natural lithogenic, anthropogenic–natural composite, mining-related sources. Pollution assessments using geo-accumulation index and contamination factor demonstrated severe contamination disparities: soils showed extreme Cd pollution, moderate U, As, Zn contamination, and no Cr, Pb pollution (overall moderate risk); sediments exhibited extreme Cd pollution, moderate Ni, Zn, U levels, and negligible Cr, Pb impacts (overall extreme risk). USEPA health risk models indicated notable non-carcinogenic (higher in adults) and carcinogenic risks (higher in children) for both age groups. Ecological risk assessments categorized As, Cr, Cu, Ni, Pb, and Zn as low risk, contrasting with Cd (extremely high risk) and sediment-bound U (high risk). These findings underscore mining legacy as a critical environmental stressor and highlight the necessity for multi-source pollution mitigation strategies.
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spelling doaj-art-53a553586c1841b789a8151c2b5fd58b2025-08-20T03:07:57ZengMDPI AGToxics2305-63042025-06-0113756110.3390/toxics13070561Geochemical Characteristics and Risk Assessment of PTEs in the Supergene Environment of the Former Zoige Uranium MineNa Zhang0Zeming Shi1Chengjie Zou2Yinghai Zhu3Yun Hou4College of Earth Sciences, Chengdu University of Technology, Chengdu 610059, ChinaCollege of Earth Sciences, Chengdu University of Technology, Chengdu 610059, ChinaCollege of Earth Sciences, Chengdu University of Technology, Chengdu 610059, ChinaCollege of Earth Sciences, Chengdu University of Technology, Chengdu 610059, ChinaCollege of Earth Sciences, Chengdu University of Technology, Chengdu 610059, ChinaCarbonaceous–siliceous–argillaceous rock-type uranium deposits, a major uranium resource in China, pose significant environmental risks due to heavy metal contamination. Geochemical investigations in the former Zoige uranium mine revealed elevated As, Cd, Cr, Cu, Ni, U, and Zn concentrations in soils and sediments, particularly at river confluences and downstream regions, attributed to leachate migration from ore bodies and tailings ponds. Surface samples exhibited high Cd bioavailability. The integrated BCR and mineral analysis reveals that Acid-soluble and reducible fractions of Ni, Cu, Zn, As, and Pb are governed by carbonate dissolution and Fe-Mn oxide dynamics via silicate weathering, while residual and oxidizable fractions show weak mineral-phase dependencies. Positive Matrix Factorization identified natural lithogenic, anthropogenic–natural composite, mining-related sources. Pollution assessments using geo-accumulation index and contamination factor demonstrated severe contamination disparities: soils showed extreme Cd pollution, moderate U, As, Zn contamination, and no Cr, Pb pollution (overall moderate risk); sediments exhibited extreme Cd pollution, moderate Ni, Zn, U levels, and negligible Cr, Pb impacts (overall extreme risk). USEPA health risk models indicated notable non-carcinogenic (higher in adults) and carcinogenic risks (higher in children) for both age groups. Ecological risk assessments categorized As, Cr, Cu, Ni, Pb, and Zn as low risk, contrasting with Cd (extremely high risk) and sediment-bound U (high risk). These findings underscore mining legacy as a critical environmental stressor and highlight the necessity for multi-source pollution mitigation strategies.https://www.mdpi.com/2305-6304/13/7/561Zoige uranium minePTEssequential extractionsource apportionmentecological health risksediment
spellingShingle Na Zhang
Zeming Shi
Chengjie Zou
Yinghai Zhu
Yun Hou
Geochemical Characteristics and Risk Assessment of PTEs in the Supergene Environment of the Former Zoige Uranium Mine
Toxics
Zoige uranium mine
PTEs
sequential extraction
source apportionment
ecological health risk
sediment
title Geochemical Characteristics and Risk Assessment of PTEs in the Supergene Environment of the Former Zoige Uranium Mine
title_full Geochemical Characteristics and Risk Assessment of PTEs in the Supergene Environment of the Former Zoige Uranium Mine
title_fullStr Geochemical Characteristics and Risk Assessment of PTEs in the Supergene Environment of the Former Zoige Uranium Mine
title_full_unstemmed Geochemical Characteristics and Risk Assessment of PTEs in the Supergene Environment of the Former Zoige Uranium Mine
title_short Geochemical Characteristics and Risk Assessment of PTEs in the Supergene Environment of the Former Zoige Uranium Mine
title_sort geochemical characteristics and risk assessment of ptes in the supergene environment of the former zoige uranium mine
topic Zoige uranium mine
PTEs
sequential extraction
source apportionment
ecological health risk
sediment
url https://www.mdpi.com/2305-6304/13/7/561
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AT chengjiezou geochemicalcharacteristicsandriskassessmentofptesinthesupergeneenvironmentoftheformerzoigeuraniummine
AT yinghaizhu geochemicalcharacteristicsandriskassessmentofptesinthesupergeneenvironmentoftheformerzoigeuraniummine
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