JOURNAL GEOLOGICAL SOCIETY OF INDIA Vol.86, August 2015, pp.215-222 0016-7622/2015-86-2-215/$ 1.00 © GEOL. SOC. INDIA Contamination Assessment of Heavy Metals Associated with an Alteration Area: Demirören Gumushane, NE Turkey ALAADDIN VURAL Gumushane University, Engineering and Natural Sciences, Department of Geological Engineering, Baglarbasi Gumushane, Turkey Email: vural@gumushane.edu.tr Abstract: Soil samples collected from Demirören Alteration area, Gümüshane NE Turkey were analyzed for heavy metals by using Inductively Coupled Plasma-Atomic Emission Spectrometry and Inductively Coupled Plasma-Mass Spectrometry and the contamination level of heavy metals was assessed on the basis of Geoaccumulation Index, Enrichment Factor, Pollution Index and Integrated Pollution Index. The results indicated that, in comparison with background value of upper crust, soil samples in Demirören alteration area have elevated levels of metal concentrations as a whole. High Geoaccumulation Indexes and Enrichment Factors for molybdenum, lead, selenium, bismuth, cadmium and copper in alteration area indicated that there is a considerable amount of especially molybdenum, lead and copper pollution, which mainly originate from alteration in the area. Keywords: Geochemistry, Heavy Metal Contamination, Geoaccumulation Index, Enrichment Factor, Turkey. INTRODUCTION The Demirören alteration area is located at the Black Sea Tectonic Unit in northeast Turkey. This belt hosts a lot of ore deposits, including, intensely altered Demirören area. While alteration areas are important targets for mineral exploration, these areas are a risk for environmental pollution (El Kheir et al. 2008; Nganje et al. 2011; Vural, 2013a). Mining activities result in serious environmental impacts. In addition to local dispersion in soil profiles, they also cause extensive contamination of soils and plants, and increase in concentrations of toxic metals (Down and Stocks, 1977). Many studies on mining areas during the last decade have focused on concentration, distribution and source identification of trace metal elements (e.g. Gemici andTarcan, 2007; Prasad and Sangita, 2008; Yaylali-Abanuz and Tüysüz, 2009; Nikolaidis et al. 2010). But there is almost no study on the impact of alteration areas on environment. The study on alteration areas is important for determining the origin, distribution and level of heavy metals (HMs) in aquatic and terrestrial environments. Increased inputs of metals in the terrestrial and aquatic environments have led to large-scale pollution of the environment. Same as anthropogenic mobilization of trace metals into the biosphere (Baslar et al. 2009; Kinalioglu et al. 2010), mobilization of trace metals in the alteration areas is also an important process in the global geochemical cycling of these elements. These elements in the environment clearly pose a significant risk to the quality of soils, plants, natural waters, and human health (Andriano, 2001; Soylak et al. 2001; Üstün, 2009; Osma et al. 2012; Alam and Umar, 2013; Vural, 2013b; Purushotham et al. 2013). Consequently, the effects on aquatic and terrestrial ecosystems, especially human health are evident in urban environments, particularly in developing countries where urbanization, industrialization and rapid population growth are taking place on an unprecedented scale (Lu et al. 2009). Many elements such as Co, Cu, Zn, Fe, Mn and Sr provide the essential elements for normal growth of living organisms and also plants, however, high concentrations of these elements might become toxic. Other metals which are not included in the group of essential elements, such as As, Pb, or Cr may be tolerated by the ecosystem in low concentration, but become harmful in higher concentrations (Moon et al. 2000; Mapanda et al. 2005). For example, Se is both an essential and potentially toxic element for animals and human. Se deficiency in soil and food has close relationships with some diseases and cancers (Xue et al. 1993). However, high Se in environment can also cause toxic problems to biota (Rodriguez et al. 2005; Yonghua et al. 2008). In order to determine the degree and extent of heavy metal contamination in the Demirören alteration area, samples from the area has been collected and analyzed especially