The Impact of Molybdenum Mining on Cd Pollution along Wenyu Stream in Qinling Mountains, Northwest China

Mining has brought many environmental problems to the surrounding soil, water, and air, with toxic elements contaminating surface water, threatening ecological balance and human health. This study selected the Wenyu watershed downstream from a large molybdenum mine in the Qinling Mountains as the st...

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Main Authors: Huaqing Chen, Aning Zhao, Youning Xu, Jianghua Zhang, Min Yang
Format: Article
Language:English
Published: MDPI AG 2023-07-01
Series:Water
Subjects:
Online Access:https://www.mdpi.com/2073-4441/15/15/2779
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author Huaqing Chen
Aning Zhao
Youning Xu
Jianghua Zhang
Min Yang
author_facet Huaqing Chen
Aning Zhao
Youning Xu
Jianghua Zhang
Min Yang
author_sort Huaqing Chen
collection DOAJ
description Mining has brought many environmental problems to the surrounding soil, water, and air, with toxic elements contaminating surface water, threatening ecological balance and human health. This study selected the Wenyu watershed downstream from a large molybdenum mine in the Qinling Mountains as the study area, aiming to explore the impact of molybdenum mining on surface water quality. The content characteristics of Cd, Pb, Cu, Cr and Hg in surface water, sediment, and rock samples were analyzed by field sampling and chemical testing. The results showed only obvious Cd pollution. The pollution status and ecological risk level of surface water and sediment samples in the Wenyu Stream watershed were evaluated using the single pollution index method, geo-accumulation index method, and Hakanson potential ecological risk assessment method. Finally, the sources of Cd pollution and the impact of mining on Cd distribution in the Wenyu Stream were comprehensively discussed. The research results showed that Cd content in the Wenyu Stream was significantly affected by mining activity and the coefficient of variation of Cd content reached 99.44%. Among 22 surface water samples, 21 samples met the Class II water standard, indicating a clean overall water quality of the Wenyu Stream, and only one sample exceeded the Class II water standard with a mild pollution level. All 15 sediment samples were polluted to varying degrees and the most severely polluted sample had reached a moderate to strong pollution level. Most of the samples were at a moderate pollution level. The potential ecological hazard indexes of Cd content were at medium to very strong risk level, indicating that the overall sediment in the main ditch of the Wenyu Stream was under a strong ecological risk level. The main sources of Cd pollution, including acid mine drainage, regional geological background, sediment release, and atmospheric dry and wet deposition, were discussed.
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spelling doaj.art-0ac5c5ac5a9f4300aa17eb9f667a054a2023-11-18T23:47:37ZengMDPI AGWater2073-44412023-07-011515277910.3390/w15152779The Impact of Molybdenum Mining on Cd Pollution along Wenyu Stream in Qinling Mountains, Northwest ChinaHuaqing Chen0Aning Zhao1Youning Xu2Jianghua Zhang3Min Yang4Xi’an Geological Survey Center of China Geological Survey, Xi’an 710054, ChinaXi’an Geological Survey Center of China Geological Survey, Xi’an 710054, ChinaXi’an Geological Survey Center of China Geological Survey, Xi’an 710054, ChinaField Observation Base for Environmental Geology of Typical Mines in Shaanxi Province, Ministry of Natural Resources, Xi’an 710054, ChinaSchool of Resources Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, ChinaMining has brought many environmental problems to the surrounding soil, water, and air, with toxic elements contaminating surface water, threatening ecological balance and human health. This study selected the Wenyu watershed downstream from a large molybdenum mine in the Qinling Mountains as the study area, aiming to explore the impact of molybdenum mining on surface water quality. The content characteristics of Cd, Pb, Cu, Cr and Hg in surface water, sediment, and rock samples were analyzed by field sampling and chemical testing. The results showed only obvious Cd pollution. The pollution status and ecological risk level of surface water and sediment samples in the Wenyu Stream watershed were evaluated using the single pollution index method, geo-accumulation index method, and Hakanson potential ecological risk assessment method. Finally, the sources of Cd pollution and the impact of mining on Cd distribution in the Wenyu Stream were comprehensively discussed. The research results showed that Cd content in the Wenyu Stream was significantly affected by mining activity and the coefficient of variation of Cd content reached 99.44%. Among 22 surface water samples, 21 samples met the Class II water standard, indicating a clean overall water quality of the Wenyu Stream, and only one sample exceeded the Class II water standard with a mild pollution level. All 15 sediment samples were polluted to varying degrees and the most severely polluted sample had reached a moderate to strong pollution level. Most of the samples were at a moderate pollution level. The potential ecological hazard indexes of Cd content were at medium to very strong risk level, indicating that the overall sediment in the main ditch of the Wenyu Stream was under a strong ecological risk level. The main sources of Cd pollution, including acid mine drainage, regional geological background, sediment release, and atmospheric dry and wet deposition, were discussed.https://www.mdpi.com/2073-4441/15/15/2779molybdenum miningcadmium pollutionsurface watersediment
spellingShingle Huaqing Chen
Aning Zhao
Youning Xu
Jianghua Zhang
Min Yang
The Impact of Molybdenum Mining on Cd Pollution along Wenyu Stream in Qinling Mountains, Northwest China
Water
molybdenum mining
cadmium pollution
surface water
sediment
title The Impact of Molybdenum Mining on Cd Pollution along Wenyu Stream in Qinling Mountains, Northwest China
title_full The Impact of Molybdenum Mining on Cd Pollution along Wenyu Stream in Qinling Mountains, Northwest China
title_fullStr The Impact of Molybdenum Mining on Cd Pollution along Wenyu Stream in Qinling Mountains, Northwest China
title_full_unstemmed The Impact of Molybdenum Mining on Cd Pollution along Wenyu Stream in Qinling Mountains, Northwest China
title_short The Impact of Molybdenum Mining on Cd Pollution along Wenyu Stream in Qinling Mountains, Northwest China
title_sort impact of molybdenum mining on cd pollution along wenyu stream in qinling mountains northwest china
topic molybdenum mining
cadmium pollution
surface water
sediment
url https://www.mdpi.com/2073-4441/15/15/2779
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