Level and Potential Risk Assessment of Soil Contamination by Trace Metal from Mining Activities

ABSTRACT

The trace metals in soil samples collected from a waste dump near eight kinds of mining sites included kaolin, gold, iron, clay, bauxite, bazan, construction stone, and antimony, located in Tay Nguyen region, Central highlands of Vietnam were investigated. The concentration of Cu, Pb, and Zn in soil were higher group compared to others heavy metal at almost mining areas in Tay Nguyen, Viet Nam. The highest concentration of Cu, Zn, Pb, Mo, B, As, Hg, and Cd was 120.46 mg/kg (Dak Drong antimony), 71.70 mg/kg (Tam Bo), 21.70 (Felspat Ea Kar), 17.33 (Trai Mat), 15.61 (Felspat Ea Kar), 8.87 (Trai Mat), 6.96 (Tan Rai), and 2.91 (Nhan Co), respectively. The content of trace metals was varying in different kinds of mining sites. Cd, Zn were mainly accumulated at waste dump from mining sites of clay, bauxite, and bazan; Pb was recorded at mining sites of clay, bazan, and construction stone while As and other trace metals were enriched at kaolin, gold, clay, and bazan. The calculated results of enrichment factor (EF) and pollution load index (PLI) indicate that almost the EF > 2 and PLI > 1 and the high contamination of trace metals for mining sites in Tay Nguyen due to human activities. The first spatial variations of trace elements in the central highlands region in Vietnam were demonstrated. The main causes of soil pollution were due to human activities, from the waste dump, waste tailings and dust from mining activities and the landfill leachate after closing mining extraction. The mixture of untreated waste soils and rocks in the backfill soil layer was also the cause of soil pollution. In bauxite mining areas, the red mud combined with many chemicals was also the main causes of soil pollution. The calculated EFs and PLI also indicated that human activities from extraction of mineral caused the main soil pollution.

KEYWORDS:

• Enrichment factor
• mining sites
• pollution load index
• spatial distribution
• trace elements

Additional information

Funding

This work was supported by Tay Nguyen Program 2016-2020 (No. TN17/T04) of Vietnam Academy of Science and Technology.