Impact of Arsenic on Environmental Geochemistry of South East of Kurdistan, Iran Artimes Ghassemi Dehnavi, Ramin Sarikhani* and D. Nagaraju** Department of Mining, Safashahr Branch, Islamic Azad University, Safashahr , Iran *Department of Geology, University of Lorestan, Khoramabad, Iran **Department of Studies in Geology, University of Mysore, Manasagangothri, Mysore- 570 006, India ABSTRACT Contamination of the environment by arsenic is one of the major environmental problems. Arsenic is usually present in small amounts in all rocks, soil, dust, water, air and biological tissues. However, the knowledge of its source, pathways and hydrogeochemistry are still matters of research and study. The aim of present study is the arsenic occurrence in sediments and groundwater in the south eastern Kurdistan, Iran that has caused serious health problems in rural population in the area, especially children, who are running the risk of hazardous effects of arsenic compounds in environment. The goal of this paper is to present objective and systematic data on this problem in south eastern of Kurdistan, Iran. Chemical analyses of groundwater and sediment samples indicate high levels in near alteration rocks. INTRODUCTION The occurrence of high concentrations of arsenic (As), one of the most hazardous chemical elements in drinking waters, has been recognized over the past two or three decades as of great public health concern in several parts of the world, including Argentina, Bangladesh, India, Pakistan, Mexico, Mongolia, Germany, Thailand, China, Chile, the USA, Canada, Hungary, Romania, Vietnam, Nepal, Myanmar and Iran (Anwar et al. 2003). However, the most widespread arsenic enrichment of groundwater occurs in a large region covering portions of West Bengal in India and Bangladesh. Even low levels arsenic exposure can cause a variety of cancerous (skin, lung, bladder) and non-cancerous (diabetes mellitus, vascular hypertension, dermal lesions) diseases (Lottermoser et al. 1999). Arsenic is ubiquitous in the earth’s crust, although generally constituting less than 1% of most rocks, coals and soils (Casiot et al. 2007). Higher arsenic concentrations are associated with alluvial/lacustrine deposits in semi arid regions, volcanic deposits, alteration rocks and geothermal systems. The major arsenic containing minerals are arsenopyrites (FeAsS), realgar (As 4 S 4 ), orpiment and arsenic trisulfide (As 2 S 3 ). Arsenic combined with oxygen, chlorine or sulphur is referred to as inorganic arsenic, whereas arsenic combined with carbon-based molecules is referred to as organic arsenic. In general, arsenic in groundwater is released from minerals and organic matters. Naturally occurring arsenic in groundwater aquifers is a result of various factors, including physico-chemical properties, regional climate and geological conditions. The causes of natural leaching-out of arsenic to groundwater are considered to be oxidation or reduction. The oxidation theory suggests that causing oxidization of minerals, including pyrite, reaches out arsenic to groundwater. Also sediments are usually an efficient means of accumulation and transport downstream of inorganic contaminants. Arsenic and heavy metals originate from altered rocks, volcanic rocks and mine wastes (tailings) either as particulate matter or acid mine drainage (Tamaki et al. 1992). Arsenic associated with geothermal waters also has been reported in several parts of the world and Iran. In most of these cases, the origin of arsenic was attributed to natural sources associated with the regional geological and hydrological background such as the reducing character of the water, its long residence time, the low water flow and a potential impact on the aquifers of the hydrothermal activity manifested in an adjacent area (Chormann 1985, Woo et al. 2001)). The arsenic in Kurdistan, Iran may originate in a natural enrichment process by geothermal activities and alteration in the study area. The primary source and release mechanism of arsenic from alteration rocks and sediments into groundwater is still not well understood. The objective of this paper is to carry out arsenic analysis of drinking waters and sediment samples from wells and springs in domestic and rural areas of southeastern Kurdistan and to check if its levels comply with International Standards for sediments and drinking water (Rose et al. 1979). MATERIALS AND METHODS The Study Area 2011 pp. 473-480 Vol. 10 ISSN: 0972-6268 No. 3 Nature Environment and Pollution Technology An International Quarterly Scientific Journal Received: 4/12/2010 Accepted: 31/12/2010 Key Words: Hazardous materials Environmental problems Arsenic, Alteration rocks Nat. Env. & Poll. Tech. Website: www.neptjournal.com Original Research Paper