Metalloid Attenuation from Runoff Waters at an Historic Orogenic Gold Mine, New Zealand

Druzbicka, Joanna; Craw, D.

doi:10.1007/s10230-014-0316-2

Cited by 15 publications

(2 citation statements)

References 44 publications

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“…Natural atenua�on of metal(loid)s is frequently observed in the surrounding catchment to the facili�es (Markwiese et al 2014;Druzbicka and Craw, 2015;Dordievski et al 2018). At the Bor mine in Serbia, the Bor, Krivelj, and Bela Rivers receive metal-rich acidic wastewater from metallurgical facili�es and acid rock drainage from mine wastes (Figure 8).…”

Section: Chemical Adsorption and Precipitationmentioning

confidence: 99%

Natural attenuation in the vadose zone: Nature’s gift to mine closure

Bowell

2023

Proceedings of the International Conference on Mine Closure

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Natural geochemical attenuation in the vadose zone refers to the process by which chemical parameters are naturally degraded, transformed, or immobilized as they migrate through the unsaturated zone above the water table. The vadose zone that often underlies mine waste facilities is a chemical active environment that involves physical, biological, and chemical interactions. These processes can effectively reduce the concentrations and mobility of contaminants, leading to their eventual removal or degradation. Here are some key natural attenuation processes that can occur in the vadose zone: Biodegradation: Microorganisms present in the soil can metabolize certain chemicals such as ammonia, cyanide or nitrates, breaking them down into simpler and less toxic compounds.Sorption and adsorption are processes by which chemical parameters can be chemically or physically trapped or bound to soil particles through the mechanisms of sorption or adsorption. This can reduce their mobility and availability for further transport. These processes are a function of the pH and redox of the environment, minerals present in the soil and prevailing water chemistry.Volatilization can also occur within the vadose zone and is an important control on the removal of parameters such as cyanide and ammonia. In addition, other chemical reactions may occur involving oxidation-reduction reactions, hydrolysis, and photolysis that can lead to precipitation or incorporation of chemical parameters into non-soluble mineral forms. In addition, although not often spoken about dilution by lower concentration waters in the vadose zone, can reduce or mitigate groundwater impacts.The effectiveness of natural attenuation in the vadose zone depends on several factors, including the nature of the chemicals, the redox and pH potential of the environment, soil properties, groundwater flow rates, and site-specific conditions, such as the availability of oxygen, nutrients, and suitable microbial populations. Such processes can occur in a wide variety of environments.Natural attenuation is an important aspect in long-term management of chemical loading in the environment and whilst it has limitations, combined with other methods such processes are effective in mine closure and should be considered in the planning and assessment of long-term geochemistry in post closure facilities.

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Section: Chemical Adsorption and Precipitationmentioning

confidence: 99%

Natural attenuation in the vadose zone: Nature’s gift to mine closure

Bowell

2023

Proceedings of the International Conference on Mine Closure

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“…Antimony (Sb) is a toxic metalloid that is also primarily used in flame-retardants and alloys. , The emission of Sb-containing compounds has led to the elevated Sb levels in water and soil globally. − For example, elevated Sb concentration (29.4 mg/L) in groundwater was detected from the Xikuanghan mine, China, which is 1470, 4900, and 9800 times higher than the WHO, USEPA, and Australian drinking standards, respectively. , …”

Section: Introductionmentioning

confidence: 99%

Transformation of Antimonate at the Biochar–Solution Interface

Rahman

Sanderson

et al. 2021

ACS EST Water

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Antimony (Sb) is a potentially carcinogenic contaminant that is also of notable commercial and industrial demand. Antimony's toxicity is increased by the redox transformation of pentavalent antimony (Sb V ) to its trivalent form (Sb III ). This study reports the redox transformation of Sb at the biochar−water interface by using a range of analytical techniques. The X-ray diffraction analysis revealed the reduction of Sb V to Sb III and the formation of Sb 2 O 3 (senarmonite, which is a proven carcinogenic compound) when reacted with biochar. Under oxic conditions, the X-ray photoelectron spectroscopy (XPS) data confirmed the redox transformation of Sb V to Sb III on the surface of the biochars. The transformation of Sb V to Sb III in the aqueous phase could not be detected by high-performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC−ICP-MS). The maximum Sb V adsorption capacity by cow manure (CMBC) and horse manure (HMBC) biochar was 12.87 and 16.56 mg/g, respectively. The experimental Sb V sorption data were fitted with the second order rate kinetics and the Freundlich isotherm model, indicating that the sorption was a multilayer form on the heterogeneous surface of biochar through electrostatic attraction and surface complexation followed by precipitation and reduction. The results demonstrate the transformation of Sb V to potentially more toxic forms when reacted with biochar, questioning the suitability of biochar for environmental remediation applications.

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