Index of contamination/pollution factor, geo-accumulation and ecological risk in ex-gold mining soil contaminated with mercury

Abstract

Mercury is a hazardous contaminant, and it is necessary to clean up Hg contamination on an ongoing basis. However, Hg contamination and ecological risks have not become a particular concern in the community. As a first step, this study evaluated the environmental risk assessment of Hg contamination/pollution in ex-gold mining soil. The results showed that the average total Hg in ex-gold mining soil was 4.11 and 4.25 mg kg<sup>-1</sup> for depths 0-20 and 20-40 cm, respectively, greater than the threshold limit set nationally (0.3 mg kg<sup>-1</sup>) and internationally (0.05-1 mg kg<sup>-1</sup>). The index of contamination/pollution factor and geo-accumulation of Hg were 13.70 and 1.39 at a depth of 0-20 cm, and 14.16 and 1.47 at a depth of 20-40 cm. The prospective ecological risk index and risk quotient were 5.48E2 and 1.03E2 at a depth of 0-20 cm, and 5.66E2 and 1.06E2 at a depth of 20-40 cm. The contamination/ pollution factor and ecological risk index indicate high Hg contamination and pollution in the soil. Therefore, appropriate technology is needed for the remediation process of ex-gold mining soil that considers all elements to a user-friendly level, such as amelioration technology with heavy metal inactivation techniques.

The Ability of Sub-Bituminous Coal Activated with NaOH in Removal of Mercury: Equilibrium and Isotherm Study

“…The adsorption isotherm models used linear models (Eqs. ( 5), (6), and ( 7)) [18]. Henry non-linear model: (5) Freundlich non-linear model: (6) Langmuir non-linear model: (7) where:…”

“…Based on US EPA regulations, it explains that the Hg threshold limit allowed to enter treated wastewater is 10 g/l and drinking water is 2 g/l [5]. Meanwhile, the threshold limit for Hg contamination in soil is only allowed to be 1 mg/kg [6]. Therefore, a suitable technology is needed to reduce the impact of Hg pollution in the environment through the adsorption process with the application of amelioration technology.…”

Equilibrium study for mercury removal using sub-bituminous coal and its application on ex-gold mining soil contaminated with mercury

“…Hg in treated wastewater (10 g L -1 ) and drinking water (2 g L -1 ) according to US EPA regulations (Suess et al, 2020). Meanwhile, the soil content should be less than 1 mg kg -1 (Maulana et al, 2023). Therefore, a suitable technology is needed to reduce the impact of Hg pollution in the environment through the adsorption process with the application of amelioration technology.…”