세창 폐금속광산 수계에서 미량원소의 지구화학적 거동특성 규명 = Characteristics of Geochemical Behaviors of Trace Metals in Drainage from Abandoned Sechang Mine

다국어 초록 (Multilingual Abstract)

The geochemical evolution of mine drainage and leachate from waste rock dumps and stream water in Pb-As-rich abandoned Sechang mine area was investigated to elucidate mechanisms of trace metals. Total and sequential extractions were applied to estimate the distribution of trace metals in constituent phases of the waste rocks and to assess the mobility of trace metals according to physicochemical conditions. These discharged waters varied largely in chemical composition both spatially and temporally, and included cases with significant]y low pH (in the range 2.1-3.3), and extremely sulphate (up to 661 mg/l and metal contents (e.g. up to 169 mg/l for Zn, 27 mg/l for As, 3.97 mg/l for Pb, 2.99 mg/l for Cu, and 1.88 mg/l for Cd). Arsenic and heavy metal concentrations at the down-stream of Sechang mine have been decreased nearly to the background level in downstream sites (sites 8 and 16) without any artificial treatments. The oxidation of Fe-sulfides and the subsequent hydrolysis, of Fe(II), with precipitation of poorly crystallized minerals, constituted an efficient mechanism of natural attenuation which reduces considerably the transference of trace metals (i.e. Fe and As) to rivers. The dilution of drainage by mixing with pristine waters provoked an additional decrease of trace metal concentrations and a progressive pH increase. On the other hand, the most soluble cations (i.e. Zn) remained significantly as dissolved solutes until the pH was raised to approximately neutral values. With respect to ecotoxicity, it is likely that the Zn pollution is of particular concern in Sechang mine area. This was confirmed by the sequential extraction experiment, where Zn in wet waste-rock samples occurred predominantly in the exchangeable fraction (65-89% of total), while Pb was the highest in the reducible and carbonate fractions, and Cd, Cu and As in the residual fraction. Pb concentration in the readily available exchangeable fraction (34-48% of total) was dominated for dried waste rock samples. Considering the proportion of metals bound to the exchangeable and carbonate fractions, the comparative mobility of metals probably decreased in the order of Zn>Pb>Cd>As=Cu.

참고문헌 (Reference)

1 "폐광산 지역 폐광석 및 광미에서 비소의 고정 메커니즘과 용출특성." 38 : 499-512, 2005

2 "서보광산 폐광석내 2차 광물에 의한 중금속 고정화" 36 : 177-189, 2003

3 "광상시추조사보고 3호." 대한광업진흥공사 1977

4 "Trace metal adsorption onto an acid mine drainageFe(III) oxyhydroxysulphate." 32 : 1361-1368, 1998

5 "The solid-phase controls on themobility of heavy metals at the Copper Cliff tailings area" 33 : 247-271, 1998

6 "The formation-dissolution-precipitationcycle of melanterite at the abandoned pyrite mine ofGenna Luas in Sardinia , Italy" 64 : 995-1006, 2000

7 "Surface complexationmodeling in aqueous geochemistry. In reviews in mineralogy. Mineralogical Society of America" 23 : 177-260, 1990

8 "Sulfide oxidation and the natural attenuation of arsenicand trace metals in the waste rocks of the abandonedSeobo tungsten mine" 20 : 1687-1703, 2005

9 "Sequential extraction procedure for the speciation ofparticulate trace metal. Anal. Chem." 51 : 844-850, 1979

10 "Processescontrolling metal ion attenuation in acid minedrainage stream. Geochim. Cosmochim." -47, 1983

11 "Mineralogyand trace element association in an acid minedrainage iron oxide precipitate comparison of selectiveextraction." 13 : 165-176, 1998

12 "Mineralogy of ochre deposits formedby sulfide oxidation. In 1994. Short Course Handbook on EnvironmentalGeochemistry of Sulfide Mine-Wastes MineralogicalAssociation of Canada" 103-132, 1994

13 "Mineralogy and geochemistry of alluvium contaminatedby metal minig in the Rio Tionto area,southwest Spain." 14 : 1015-1030, 1999

14 "Mineralogical study of base metal tailings with various sulfide contents oxidized in laboratory columns and field lysimeters" 33 : 209-217, 1998

15 "Mine wastesat the polymetallic deposit of Fenice Capanne" 41 : 417-429, 2001

16 "Metal sorption on mineral surfaces: an overview with examples relating to mineral deposits." 6A : 161-182, 1999

17 "Iron and aluminumhydroxysulfates from acid sulfate waters." 40 : 351-403, 2000

18 "Geochemistry of iron ochres and mine waters from Levant Mine" 10 : 237-250, 1995

19 "Effects of instream pH modificationon transport of sulfide-oxidation products. In 1994. The EnvironmentalGeochemistry of Sulfide Oxidation" 550 : 2248211 243-, 1994

20 "Bacterial immobilization and oxidation of arsenic in acid mine drainage" 37 : 2929-2936, 2003

21 "Arsenicand zinc biogeochemistry in pyrite mine waste from the Aznalcó enbironmental disaster" 122 : 195-203, 2004

22 "Arsenic in iron cements developed within tailingsof a former metalliferous mine-Enguialè" 18 : 395-408, 2003

23 "Accumulationof arsenic from acidic mine waters by ferruginousbacterial accretions (stromatolites)" 11 : 541-549, 1996

24 "A process model of natural attenuation in drainage from ahistoric mining district." 15 : 655-666, 2000

25 "A natural attenuation of arsenic indrainage from an abandoned arsenic mine dump." 18 : 1267-1278, 2003

26 "A mineralogical andgeochemical study of element mobility in sulfide minetailings of Fe oxide Cu-Au deposits from the Punta delCobre belt" 189 : 135-163, 2002