• Economic and Environmental Geology
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• v.56 no.4
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• pp.409-419
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• 2023

Acid mine drainage(AMD) treatment is classified as both passive and active treatment. During the treatment, about 5,000 tons of neutralization sludge is generated as a by-product per year in Korea. This study was conducted to evaluate the characteristics of sludge generated from physico·chemical treatment processes as an active treatment from 5 different sources (D, H, S, T, Y) and the possibility of the sludges being recycled. The sludges have a pH range of 5.86 ~ pH 7.89, and a water content range of 51% ~ 82%. Most of particle sizes were less than 25 ㎛. In analysis of inorganic elements, the concentration of Al, Fe, and Mn were between 1,189 mg/kg ~ 129,344 mg/kg, 106,132 mg/kg ~ 338,011 mg/kg, and 3,472 mg/kg ~ 11,743 mg/kg, respectively. The concentration of As and Zn in sludge-T, Cd in sludge-D, Ni in sludge-H, Zn in sludge-S, and Cd in sludge-Y exceeded the soil contamination standards of Korea. The results from 2 separate kinds of leaching test, the Korea Standard Leaching Test(KSLT) and Toxicity Characteristic Leaching Procedure(TCLP), showed that all the sludges met the Korea groundwater standards. From the XRD and SEM-EDS analysis, the peaks of calcite and quartz were found in the sludges. The sludge also had a high proportion of Fe and O, and the majority of the composition was amorphous iron hydroxide.

• Korean Journal of Environmental Agriculture
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• v.24 no.3
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• pp.222-231
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• 2005

Most of the tailings have been left without any management in abandoned metalliferous mines and have become the main source of heavy metal contamination of agricultural soils and crops in the these areas. To compare of environmental assessment of heavy metals in tailings derived from various 25-metalliferous mines in Korea, 3 different analysis methods such as water soluble, 0.1 M-HCl extractable, and total acid digestion method (aqua regia) were used. The chemical composition of water soluble in mine tailing were in the order ${SO_4}^{2-}>Ca^{2+}>Mn^{2+},\;Na^+,\;Al^{3+}>Mg^{2+},\;Fe^{3+}>Cl^-$. Specially, pH, EC, ${SO_4}^{2-},\;and\;Ca^{2+}$ concentrations in tailing varied considerably among the different mines. The average total concentrations of Cd, Cu, Pb, Zn, and As in tailing were 31.8, 708, 4,961, 2,275 and 3,235 mg/kg, respectively. Specially, the contents of Cd, Zn and As were higher than those of countermeasure values for soil contamination (Cd : 4, Zn : 700 and As : 15 mg/kg in soil) by Soil Environmental Conservation Act in Korea. The rates of water soluble heavy metals to total contents in tailings were in the order Cd > Zn > Cu > Pb > As. The rates of 0.1M-HCl extractable Cd, Cu, Pb, Zn, and As (1M-HCl) to total content were 17.4, 10.2, 6.5, 6.8 and 11.4% respectively. The enrichment factor of heavy metals in tailings were in the order As > Pb > Cd > Cu > Zn. The pollution index in tailing Au-Ag mine tailing were higher than those of other mine tailing. As a results of enrichment factor and pollution index for heavy metal contaminations in mine tailing of metalliferous mines, the main contaminants are mine waste materials including tailings.

• Economic and Environmental Geology
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• v.37 no.1
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• pp.121-131
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• 2004

Removal efficiencies of soil washing and soil improvement processes to remediate farmland soils and stream deposits around Goro abandoned mine were investigated with batch and column experiments. For As-contaminated farm-land soils around Goro mine, batch tests to quantify As extraction rate from contaminated soils and lime treated contaminated soils were performed. The contaminated soil mixed with lime decreased As extraction rate less than one fourth, suggesting that the soil improvement method mixed with lime dramatically decrease As extraction rate. A storage dam will be constructed in the lower part of the main stream connected to Goro abandoned mine and the amount of As extracted from the bottom soils of reservoir could be the main source to contaminate water of reservoir. The decrease of As extraction amount from the bottom in reservoir, caused by the application of the soil improvement method was investigated from the physically simulated column experiment and results showed that As extraction rate decreased to one forty when 1％ lime mixed soil improvement was applied to contaminated soils. For contaminated stream deposits connected Goro mine, the removal efficiency of the soil washing method was investigated with batch experiments. Hydrochloric acid, citric acid, acetic acid and distilled water were used as soil washing solution and 0.01, 0.05, 0.1, 0.5, 1.0 N of washing solution were applied to extract As. When washing with 0.05 N of hydrochloric acid or citric acid, more than 99.9% of As was removed from stream deposits, suggesting that As contaminated stream deposits around Goro mine be successfully remediated with the soil washing process. Total volumes of contaminated soils and deposits needed for remediation were calculated based on three different reme-diation target concentrations and the operation cost of soil washing for calculated soil volumes was estimated. Results from this research could be directly used to make a comprehensive countermeasure to remediate contaminated area around Goro mine and also many contaminated areas similar to this research area.

• Journal of Food Hygiene and Safety
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• v.37 no.3
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• pp.166-172
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• 2022

This study evaluated the migrant and residue tests of lead (Pb), cadmium (Cd), nickel (Ni), arsenic (As), and antimony (Sb) in 70 tumbler samples. The migration levels of hazardous metals in all the samples were within the migration limits outlined in the Korean standards and specifications for utensils, containers, and packages. Moreover, in all the tumbler samples, only Ni was detected in 0.5% citric acid solution of a food stimulant. The maximum level of Ni 0.0144 mg/L was 14.4% of the migrant specification (not more than 0.1 mg/L), which was relatively safe. The 0.5% citric acid solution was eluted at 4℃, 70℃, and 100℃ for 30 min, and only Ni was detected while testing for migration levels according to the temperature variations; all temperature conditions conformed to the standards. The level of Ni migration increased significantly with increasing migration temperature. Regarding the residue level outside the paint-coated tumbler samples, the Pb level was found to range from N.D. to 20638.1323 mg/kg. The risk of Ni was further estimated to be at a safe level of 0.00 to 0.01% compared to the %TDI as a result.

• Journal of the Korean earth science society
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• v.23 no.5
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• pp.406-415
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• 2002

Heavy metal concentrations (Cu(II), Zn(II), Pb(II) and Cd(II)) at field and upland soils were investigated with two extraction methods, 0.1mole L$^{-1}$ HCI extraction and HNO$_3$-HCIO$_4$ digestion, in order to estimate soil pollution and to understand their distribution and accumulation characteristics. Through an application of 0.1mole L$^{-1}$ HCI extraction method, the surface horizons of field soils were found to have higher concentrations of heavy metals (except Pb(II)) than those of upland soil. It was also seen that Cu(II), Zn(II) and Cd(II) were enriched in surface horizon of field soils, whereas upland soils did not show much difference across depth. When the method of HNO$_3$-HCIO$_4$ digestion was used, upland soils showed higher concentrations than those of other soils, and the distribution of heavy metals did not show much difference between horizons of all soils. From these results, it was recognized that, although total natural contents of heavy metals were the largest in upland soil, surface horizons of field soils became gradually polluted with heavy metals. Especially, Cd(II) is considered as a potential metallic pollutant in field soils because of its weak adsorption strength. Concentrations of heavy metals also seemed to be influenced by their adsorption characteristics. When we computed 0.1HCl$_{ext}$HNCL$_{dig}$ ratios to estimate the adsorption strengths of soil heavy metals, their adsorption strengths decreased on the order of Cu(II) > Zn(II)> Pb(II) > Cd(II). The distribution characteristics of heavy metals in field soil, especially Cd(II),are required more detail study because of its importance of land use and complicated mobilization characteristic.

• Analytical Science and Technology
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• v.25 no.6
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• pp.416-420
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• 2012

The increasing use of recycling products results in the need for assessing the risk to human health. In this study heavy metals's contents of playground flooring were compared with rubber powder which is row material. And it is reviewed characteristics of heavy metals's exposure from absorption of skin, checking amount of dermal uptake for each heavy metal. Despite its high content, Zn had a very low migration rate with 0.1 $mg/cm^2$. This indicates that Zn is not easily released by surface contact. However, the contents of Fe and Al in flooring were 12 times higher than that of Zn and Fe, and Al showed migration rate 5 times higher than that of Zn. This implies that Fe and Al were derived from pigment in flooring. The measurement of dermal exposure to heavy metals at 6 playgrounds found higher level of exposure in Ba than in other heavy metals. It is assumed that despite high content of Zn, Ba had a higher exposure rate because five times as much Ba as Zn was darmal absorptionactor ($AF_{darmal}$).

• Journal of Korean Society of Environmental Engineers
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• v.39 no.5
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• pp.265-276
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• 2017

Heavy metals leaching from closed mines have been causing severe environmental problems in nearby soil ecosystems. Mine reclamation in Korea has been recently implemented based on the heavy metal immobilization (a.k.a., stabilization). Since the immobilization temporarily fixes the heavy metals to the soil matrix, the potential risk of heavy metal leaching still exists. Therefore the appropriate monitoring and the related policies are required to safeguard the soils, where all the cultivations occur. The current monitoring methods are based on either heavy metal concentration or simple toxicity test. Those methods, however, are fragmented and hence it is difficult to evaluate the site in an integrated manner. In this study, as the integrated approach, ecological functional state evaluation with a multivariate statistical tool was employed targeting physiochemical soil properties, heavy metal concentrations, microbial enzymatic activity, and arsenic respiratory reductase gene quantity. Total 60 soil samples obtained from three mines (Pungjeong, Jeomdong, Seosung) were analyzed. As a result, the stabilized layer soil and lower layer soil have shown the similar pattern in Pungjeong mine. In contrast, Jeomdong and Seosung mine have shown the similarity between the stabilized layer soil and the cover layer soil, indicating the possible contamination of the cover layer soil.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.3
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• pp.236-242
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• 1996

This study was conducted to investigate the changes of heavy metals in percolated water of paddy soil in which rice was cultivated in conditions of 0%, 5%. 30% addition of bituminous and anthracite fly ash respectively. In cultivated plot, the contents of Fe in percolated water increased gradually during the cultivation. But there was no sharp difference of Fe contents in fly ash treated plots. The contents of Mn in percolated water increased gradually during the cultivation and was high in the cultivated plot. But difference in the contents of Mn among plots not clear. The contents of Zn in percolated water was highest during 20-25 days in the cultivation, thereafter decreased gradually. The fly ash did not cause to increase the contents of Zn in percolated water. The contents of Cu in percolated water decreased through the cultivation. Fly ash treatment did not cause to increase the contents of Cu in percolated water. The contents of Pb in percolated water decreased gradually over the cultivation. Fly ash treatment did not largely influence to Pb percolation. In mid-July. Pb did not almost appeared in percolated water. The contents of Cd was highest about 15 days of the transplant, thereafter decreased gradually. After 40 day of the cultivation, leach of Cd stopped. When fly ashes were applied in paddy soil, the contents of heavy metals in percolated water was not so much compared with control plot. It seems that originally low contents of heavy metals in fly ash and decrease in solubility of heavy metals in a relatively high soil pH make it possible to use fly ash as a soil conditioner.

• Journal of the Korean Wood Science and Technology
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• v.33 no.6 s.134
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• pp.95-100
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• 2005

The using amount of preservative-treated wood equipments has been increased. Specially, chromate copper arsenate (CCA) has been widely used to exterior wood. We are faced to the disposal problem after service period of CCA treated wood due to its toxic heavy metals. For the disposal of end-used treated wood, land-filling and incinerating methods are mainly applied. The essential problem of incinerating is an arsenic release into atmosphere. Low pyrolysis is suggested as the methods of protecting arsenic release during incineration. The heavy metals were recovered after combustion of the treated wood at the low temperature which arsenic can not released. The recovery amounts of effectiveness compounds was determined in various solvents (citric acid, nitric acid, sulfuric acid, acetic acid, phosphoric acid) and different temperature (300, 400, $500^{\circ}C$). The higher temperature was applied, the more copper was recovered. The chromium was difficult to be recovered on the carbonized CCA treated wood at 0.5% acid concentration. The recovery mass of arsenic decreased on the higher combustion treated wood. The recovery of chromium was difficult due to the chemical change of the chromium arsenate during pyrolysis.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.1
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• pp.67-73
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• 2014

In this study, the residual heavy metals in the mine tailings, primarily treated by soil washing, were stabilized using phosphate salts. The concentrations of residual contaminants in the washed mine tailings were As (1,861 mg/kg), Cd (20 mg/kg), Cu (56 mg/kg), Pb (2,149 mg/kg), and Zn (633 mg/kg). They were stabilized with $CaHPO_4$, $Ca(H_2PO_4)_2{\cdot}H_2O$, and hydroxyapatite at 0.1 wt%, 1 wt%, and 10 wt% for 1, 3, 5, 7, and 14 days. It was found that 1 wt% $Ca(H_2PO_4)_2{\cdot}H_2O$ was optimum in our experiments, but the stabilization duration did not affect the efficiency. After stabilization with 1 wt% $Ca(H_2PO_4)_2{\cdot}H_2O$ for 1 day, the concentrations of arsenic and heavy metals, As (0.328 mg/L), Cd (0.250 mg/L), Cu (0.143 mg/L), Pb (0.359 mg/L), and Zn (2.622 mg/L), in TCLP leachate were below the RCRA-TCLP limits, which meant the contaminants in the treated mine tailings were stably immobilized.