Potential Ecological Risk Assessment of Heavy Metals in the Fe–Mn Nodules in the Karst Area of Guangxi, Southwest China

• Published in: Bulletin of environmental contamination and toxicology Vol. 106; no. 1; pp. 51 - 56
• Main Authors: Ji, Wenbing, Yang, Zhongfang, Yu, Tao, Yang, Qiong, Wen, Yubo, Wu, Tiansheng
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.01.2021; Springer Nature B.V
• Subjects: Acidification; Aquatic Pollution; Cadmium; Calcium chloride; Carbonate rocks; carbonates; China; Chromium; Copper; Earth and Environmental Science; Earth science; Ecological effects; Ecological risk assessment; Ecotoxicology; edaphic factors; Environment; environmental assessment; Environmental Chemistry; Environmental Health; Environmental Monitoring; Experiments; Heavy metals; Iron; Karst; karsts; Leachates; Leaching; Lead; Manganese; Metal concentrations; Metals; Metals, Heavy - analysis; Nickel; Nodules; pH effects; Pollution; Risk Assessment; Soil; Soil conditions; Soil contamination; Soil environment; Soil Pollutants - analysis; Soil Science & Conservation; Soils; Toxicology; Waste Water Technology; Water Management; Water Pollution Control; China; Ecological risk; Fe–Mn nodules; Karst area; CaCl; extraction; Heavy metals; pH-static leaching experiments; CaCl2 extraction
• ISSN: 0007-4861; 1432-0800; 1432-0800
• DOI: 10.1007/s00128-020-02837-6

We investigated the concentration of heavy metals in the Fe–Mn nodules in soils derived from the carbonate rocks of typical karst areas in Guangxi, Southwest China. Compared with the soil background values in Guangxi, heavy metals are substantially enriched in the following order: Cd (268.13) > Pb (39.46) > Cr (11.80) > Zn (8.43) > Ni (6.16) > Cu (3.65). CaCl 2 extraction results indicate that heavy metals in the nodules are substantially stable, while the proportions of the metals released to the surrounding environment are extremely low (≤ 0.003%). Moreover, pH-static leaching experiments indicate that heavy metals can hardly be dissolved into the surrounding soil environment under natural conditions (pH 6–8). However, once the soil environment is acidified, heavy metals incorporated in the nodules will gradually release into the surrounding environment, thereby causing potential ecological risks.