Investigation of the effect of binding material and Thiobacillus thiooxidans on the heavy metals mobilization in the mine tailings

The total concentrations of arsenic (As), boron (B), cadmium (Cd), copper (Cu), manganese (Mn), lead (Pb), thallium (Tl) and zinc (Zn) in the mine tailings of an abandoned Pb-Zn mining site and an open boron mining site are investigated in this study. In addition, heavy metals’ distributions in chemical binding forms and their mobilities with the presence of binding materials and acidic bacteria are examined. The amounts of sulfur and carbonate in the waste and binding materials are also determined according to the static method, in order to define the acid neutralization potential of the wastes. For mobilization studies, mine tailings are mixed with with leonardite and domestic solid waste compost in different ratios (10/0, 9.5 / 0.5, 9/1; 8/2). Independent from the binding materials, the mobilization effect of sulfur oxidizing Thiobacillus thiooxidans bacteria has been tested and evaluated. Experiments are conducted using a standard leach test EPA 1310B Extraction Procedure, and correlations between the parameters studied were statistically evaluated using the findings of SPSS 24. Although there is no statistically significant reduction in metals’ mobilization with the use of leonardite and waste compost, it has been concluded that different binding agents may have different impacts due to the metal type. As a result, it is understood that metals mobility increases in the presence of Thiobacillus thiooxidans in the environment, and that the heavy metal mobility is directly proportional to the exchangeable and acid soluble fraction, followed by the reducible fraction and the amount of metals bound to the organic fractions.

Maden sahasý atýklarýnda baðlayýcý materyal ve Thiobacillus thiooxidans varlýðýnýn aðýr metal mobilizasyonuna etkisinin araþtýrýlmasý

Çalýþmada, terk edilmiþ bir Pb-Zn madeni ve iþletilmekte olan bor madeni atýklarýndaki arsenik (As), bor (B), kadmiyum (Cd), bakýr (Cu), mangan (Mn), kurþun (Pb), talyum (Tl) ve çinko (Zn) elementlerinin toplam konsantrasyonlarý, kimyasal baðlanma formlarýndaki daðýlýmlarý ile bu elementlerin baðlayýcý materyal ve asidik bakteri olan Thiobacillus thiooxidans varlýðýnda mobilizasyonlarý incelenmiþtir. Ayrýca atýk ve baðlayýcý materyallerdeki sülfür ve karbonat miktarlarý da belirlenerek, statik testlere göre atýklarýn asit nötralize etme potansiyeli hesaplanmýþtýr. Mobilizasyon çalýþmalarý için iki farklý bölgeden temin edilen atýk ile baðlayýcý materyal olarak seçilen leonardit ve evsel katý atýk kompostu farklý oranlarda karýþtýrýlmak suretiyle (10/0, 9.5/0.5, 9/1, 8/2) deneyler yürütülmüþtür. Ayrýca, sülfür oksitleyen bir bakteri olan Thiobacillus thiooxidans’ýn ortama ilave edilmesiyle mobilizasyona olan etkisi çalýþýlmýþtýr. Standart bir liç testi olan EPA 1310B Ekstraksiyon Prosedürü kullanýlarak mobilize olan aðýr metaller tespit edilmiþ, bulgular SPSS 24 programý ile istatistiksel olarak deðerlendirilerek çalýþýlan parametreler arasýndaki korelasyonlar ortaya çýkarýlmýþtýr. Leonardit ve kompostun maden atýklarýna karýþtýrýlmasýyla, aðýr metal mobilitesinde istatistiksel olarak anlamlý bir azalma görülmemiþtir. Ancak farklý baðlayýcý materyaller, aðýr metal türüne göre farklý etkiler göstermiþtir. Sonuç olarak, ortamda Thiobacillus thiooxidans olmasý durumunda aðýr metal mobilitesinin arttýðý ve bunun öncelikli olarak deðiþken ve asitle çözülebilir fraksiyonda ve sonrasýnda indirgenebilir fraksiyon ile organik fraksiyonlarýna baðlý metal miktarý ile doðru orantýlý olduðu anlaþýlmýþtýr.