Geochemical Behaviors of Heavy Metal(loid)s in Soil Ferromanganese Nodules in Typical Karst Areas in Southwest China
The ferromanganese nodules (FMNs) developing in soils of karst regions are naturally characterized by high heavy metal(loid)s contents due to several geological factors. Soil FMNs can considerably influence the geochemical behaviors of soil heavy metal(loid)s. However, the mechanisms of the FMN effe...
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MDPI AG
2023-06-01
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| Series: | Agronomy |
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| Online Access: | https://www.mdpi.com/2073-4395/13/6/1602 |
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| author | Wenbing Ji Zhixiang Luo Jianyu Huang Xu Liu Haiyun He Yang Gong Meng Chen Yubo Wen Rongrong Ying |
| author_facet | Wenbing Ji Zhixiang Luo Jianyu Huang Xu Liu Haiyun He Yang Gong Meng Chen Yubo Wen Rongrong Ying |
| author_sort | Wenbing Ji |
| collection | DOAJ |
| description | The ferromanganese nodules (FMNs) developing in soils of karst regions are naturally characterized by high heavy metal(loid)s contents due to several geological factors. Soil FMNs can considerably influence the geochemical behaviors of soil heavy metal(loid)s. However, the mechanisms of the FMN effects in soils of karst areas soils remain unclear, resulting in less understanding of the development process of karst soils. Therefore, the present study aims to investigate 21 individual FMNs collected in soils derived from carbonate rocks in Guangxi province, China, to reveal the mechanisms of heavy metal(loid)s enrichment in FMNs. The studied soil FMNs were mainly composed of Fe<sub>2</sub>O<sub>3</sub>, SiO<sub>2</sub>, Al<sub>2</sub>O<sub>3</sub>, MnO<sub>2</sub>, and TiO<sub>2</sub>, with proportions of 25.95, 20.8, 19.07, 3.98, and 1.23%, respectively. Compared to the background soils of Guangxi, the soil FMNs exhibited great enrichment in heavy metal(loid)s. The enrichment factors followed the order of Cd (243.33), Cr (49.67), Cu (5.46), Ni (8.37), Pb (23.68), Zn (15.4), and As (20.11). The heavy metal(loid)s contents in the soil FMNs of the karst areas were much higher than those observed in non-karst areas worldwide. According to the principal component analysis (PCA) results, the first three principal components contributed to about 88.81% of the total variance of the FMN compositions. PC1 (50.90%) suggested the presence of quartz, feldspar, and clay minerals-related elements in the soil FMNs, whereas PC2 (27.10%) and PC3 (10.81%) indicated the presence of Mn(oxyhydr)oxides and Fe(oxyhydr)oxides-related elements in the soil FMNs, respectively. The obtained selective extraction results demonstrated that up to 93% of the total contents of heavy metal(loid)s, namely, Cd, Pb, Cu, Ni, and Zn, were bound to Mn(oxyhydr)oxides. In contrast, oxyanionic species (As and Cr) were predominantly sequestered in Fe(oxyhydr)oxides. |
| first_indexed | 2024-03-11T02:51:48Z |
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| spelling | doaj.art-7594b70dab7942eaa60facc30b13bb772023-11-18T08:55:28ZengMDPI AGAgronomy2073-43952023-06-01136160210.3390/agronomy13061602Geochemical Behaviors of Heavy Metal(loid)s in Soil Ferromanganese Nodules in Typical Karst Areas in Southwest ChinaWenbing Ji0Zhixiang Luo1Jianyu Huang2Xu Liu3Haiyun He4Yang Gong5Meng Chen6Yubo Wen7Rongrong Ying8Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, ChinaGuangxi Product Quality Inspection Institute, Nanning 530007, ChinaHechi Environmental Emergency and Solid Waste Technology Center, Hechi 547000, ChinaChinese Research Academy of Environmental Sciences, Beijing 100012, ChinaEco-Environmental Sciences Research & Design Institute of Zhejiang Province, Hangzhou 310007, ChinaNanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, ChinaNanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, ChinaSchool of Geographical Science, Nantong University, Nantong 226000, ChinaNanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, ChinaThe ferromanganese nodules (FMNs) developing in soils of karst regions are naturally characterized by high heavy metal(loid)s contents due to several geological factors. Soil FMNs can considerably influence the geochemical behaviors of soil heavy metal(loid)s. However, the mechanisms of the FMN effects in soils of karst areas soils remain unclear, resulting in less understanding of the development process of karst soils. Therefore, the present study aims to investigate 21 individual FMNs collected in soils derived from carbonate rocks in Guangxi province, China, to reveal the mechanisms of heavy metal(loid)s enrichment in FMNs. The studied soil FMNs were mainly composed of Fe<sub>2</sub>O<sub>3</sub>, SiO<sub>2</sub>, Al<sub>2</sub>O<sub>3</sub>, MnO<sub>2</sub>, and TiO<sub>2</sub>, with proportions of 25.95, 20.8, 19.07, 3.98, and 1.23%, respectively. Compared to the background soils of Guangxi, the soil FMNs exhibited great enrichment in heavy metal(loid)s. The enrichment factors followed the order of Cd (243.33), Cr (49.67), Cu (5.46), Ni (8.37), Pb (23.68), Zn (15.4), and As (20.11). The heavy metal(loid)s contents in the soil FMNs of the karst areas were much higher than those observed in non-karst areas worldwide. According to the principal component analysis (PCA) results, the first three principal components contributed to about 88.81% of the total variance of the FMN compositions. PC1 (50.90%) suggested the presence of quartz, feldspar, and clay minerals-related elements in the soil FMNs, whereas PC2 (27.10%) and PC3 (10.81%) indicated the presence of Mn(oxyhydr)oxides and Fe(oxyhydr)oxides-related elements in the soil FMNs, respectively. The obtained selective extraction results demonstrated that up to 93% of the total contents of heavy metal(loid)s, namely, Cd, Pb, Cu, Ni, and Zn, were bound to Mn(oxyhydr)oxides. In contrast, oxyanionic species (As and Cr) were predominantly sequestered in Fe(oxyhydr)oxides.https://www.mdpi.com/2073-4395/13/6/1602ferromanganese nodulesheavy metal(loid)skarst areasenrichment factorsobtained selective extraction |
| spellingShingle | Wenbing Ji Zhixiang Luo Jianyu Huang Xu Liu Haiyun He Yang Gong Meng Chen Yubo Wen Rongrong Ying Geochemical Behaviors of Heavy Metal(loid)s in Soil Ferromanganese Nodules in Typical Karst Areas in Southwest China Agronomy ferromanganese nodules heavy metal(loid)s karst areas enrichment factors obtained selective extraction |
| title | Geochemical Behaviors of Heavy Metal(loid)s in Soil Ferromanganese Nodules in Typical Karst Areas in Southwest China |
| title_full | Geochemical Behaviors of Heavy Metal(loid)s in Soil Ferromanganese Nodules in Typical Karst Areas in Southwest China |
| title_fullStr | Geochemical Behaviors of Heavy Metal(loid)s in Soil Ferromanganese Nodules in Typical Karst Areas in Southwest China |
| title_full_unstemmed | Geochemical Behaviors of Heavy Metal(loid)s in Soil Ferromanganese Nodules in Typical Karst Areas in Southwest China |
| title_short | Geochemical Behaviors of Heavy Metal(loid)s in Soil Ferromanganese Nodules in Typical Karst Areas in Southwest China |
| title_sort | geochemical behaviors of heavy metal loid s in soil ferromanganese nodules in typical karst areas in southwest china |
| topic | ferromanganese nodules heavy metal(loid)s karst areas enrichment factors obtained selective extraction |
| url | https://www.mdpi.com/2073-4395/13/6/1602 |
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