Arsenic Pollution in the Groundwater of Simav Plain, Turkey: Its Impact on Water Quality and Human Health

In this research, geological and hydrogeological studies were conducted to determine the source of high arsenic levels in the surficial aquifer of Simav Plain, Kutahya, Turkey. One of the two aquifer systems isolated in the study area was a deep confined aquifer composed of fractured metamorphic rocks that supply hot geothermal fluid. The other one was an unconfined alluvial aquifer, which developed within the graben area as a result of sediment deposition from the highlands. This aquifer serves as the primary water resource within the plain. A water quality sampling campaign conducted in 27 wells drilled in the surficial aquifer has yielded an average arsenic concentration of 99.1 µg/L with a maximum of 561.5 µg/L. Rock and sediment samples supported the fact that local metamorphic rocks contained significant amounts of sulfur minerals where arsenic-containing lenses are present inside. It was also determined that a Cu–Pb–Zn mine was operated in the past in the same formation. Arsenic-containing wastes of this mine were deposited near the Simav district center in an uncontrolled manner. This mined formation had arsenic levels reaching to levels as high as 660 mg/kg, which was found out to be the highest arsenic level in the area. Another potential arsenic source in the study area was the geothermal fluid that was used extensively in three geothermal fields with levels reaching to levels as high as 594 µg/L. Uncontrolled discharges of waste geothermal fluid and overexploitation of groundwater were also found to contribute to arsenic pollution in surface/subsurface waters of the plain. Thus, natural sources and anthropogenic influences of arsenic were found to create high concentrations in local water reserves of the area and influence human health. Consequently, death statistics from the 1995 to 2005 period collected from the area has revealed increased rates of gastrointestinal cancers above Turkish average.