Metal status of soils and plants irrigated with water from lake İznik, Turkey

Abstract

Lake Iznik, located in the southeast part of the Marmara region in Turkey, is considered the largest lake in the region. Soil pollution from irrigation with lake water has become an important concern for arable lands surrounding the lake. Therefore, a study was conducted to investigate trace element contamination of soils and plants irrigated with water from the lake, which has been polluted with industrial and municipal wastes. Eleven different crops grown in 30 different horticultural fields, consistently irrigated with lake water, were studied. To determine pollutant concentrations, soils, plants, and water were sampled and analyzed for both total and extractable iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), cobalt (Co), nickel (Ni), chromium (Cr), lead (Pb), and cadmium (Cd). Iron, Cu, and Ni in destructively sampled soils were found to be excessive in soils. The results were subjected to statistical analysis using simple correlations and t-test. There were no statistically significant relationships among the total and extractable metals in soils and extractable plant metals. Because of lack of standard concentrations indicating excessive concentration of extractable elements, statuses of extractable elements in the soils were not evaluated. Cobalt, Pb, Cr, and Cu concentrations were greater than the normal range in leaves. The accumulation of metals differed greatly among the various plant species, but irrigation with lake water did not increase metals in soils. The appearance of metals in soils might be due to agricultural activities and parent material. Continuous monitoring and future studies of the area are recommended to ascertain long-term impacts of pollution on plants.