Investigation and risk assessment modeling of As and other heavy metals contamination around five abandoned metal mines in Korea

Abstract

Tailings, agricultural soils, vegetables and groundwater samples were collected from abandoned metal mines (Duckum, Dongil, Dongjung, Myoungbong and Songchun mines) in Korea. Total concentrations of arsenic (As) and heavy metals (Cd, Cu, Pb and Zn) were analyzed to investigate the contamination level. Several digestion methods (Toxicity characteristics leaching procedure (TCLP), synthetic precipitation leaching procedure (SPLP), 0.1 N/1 N HCl) and sequential extraction analysis for mine tailings were conducted to examine the potential leachability of As and heavy metals from the tailings. The order of urgent remediation for the studied mines based on the risk assessment and remedial goals was suggested. The Songchun mine tailings were most severely contaminated by As and heavy metals. Total concentrations of As and Pb in the tailings were 38,600-58,700 mg/kg (av. 47,400 mg/kg) and 11,800-16,800 mg/kg (av. 14,600 mg/kg), respectively. Agricultural soils having high As concentrations were found at the all mines. Average concentrations of Cd in the vegetables exceeded the normal value at all mines areas, while As only at the Dongjung, Myoungbong, and Songchun mine area. One groundwater sample each from the Dongil and Myoungbong mines, and 4 groundwater samples from the Songchun mine had values above 10 mug/L of As concentration. The TCLP method revealed that only Pb in the Songchun tailings, 6.49 mg/L, exceeded the regulatory level (5 mg/L). Employing the 1-N HCl digestion method, the concentration of As in the Songchun mine tailings, 4,250 mg/kg, was up to 3,000 times higher than its Korean countermeasure standard. Results from the sequential extraction of As in the tailings showed that the easily releasable fraction in the Myoungbong and Songchun mine tailings was more than 30% and the residual fraction was less than 40%. Based on results showing the exposure health risk employing the hazard quotient and cancer risk of As, Cd and Zn, the Dongil mine needs the most urgent remedial action. The concentration reduction factor (CRF) of As in both soil and groundwater follows the order: Songchun>Dongjung>Dongil>Myoungbong>Duckum mine.

Assessment of health risk associated with arsenic exposure from soil, groundwater, polished rice for setting target cleanup level nearby abandoned mines

“…Besides, a maximum As concentration of 53.54 mg kg -1 was observed in MB site, which exceeded the soil contamination concern guideline. Lee et al (2005) reported that the MB mine showed the maximum As concentration of 72.1 mg kg -1 in agricultural soil. On the contrary, the average concentration of As in KK mine was the lowest with 0.08 mg kg -1…”

“…Most of abandoned mines developed in the early 20th century have been left without environmental protection (Kim et al, 2005). The tailing is transferred to nearby agricultural lands, and hence contaminates the soil by weathering process and runoff.…”

“…The consumption of rice cultivated nearby mines may also pose a potential health risk for residents. The health risk posed as human As exposure depends on its concentration in exposed media, ingested amounts, and exposure duration (Lee et al, 2005). The developmental and physiological differences among population vary the degree of the human As exposure followed by digestion, absorption, and subsequently metabolism (Tsuji et al, 2004).…”

Screening risk assessment tools for assessing the environmental impact in an abandoned pyritic mine in Spain

“…Risk assessment methodology has been recognised as a powerful tool for the decision-making process in contaminated sites management, especially when contamination of soil or water is involved (Suter et al, 2000;US-EPA, 1998). The use of risk assessment techniques in mining activities has mainly focused on human health issues (Kim et al, 2005;Lee et al, 2006). Ecological risk tends to be considered a second priority however to propose remediation techniques or new occupation plans of these contaminated sites is very difficult if the potential risks to biological communities are not considered.…”

Speciation, Fate and Transport, and Ecological Risks of Cu, Pb, and Zn in Tailings from Huogeqi Copper Mine, Inner Mongolia, China

“…Inlet water pH = 7 Inlet water pH = 8 The release of metals and their environmental fate and transport are a topic of great concern [13][14][15][16]. The relationship between metals in tailings and the surrounding environment and properties of tailings/soil/water have also been widely explored [17,18].…”