Heavy metal pollution in some soil and water resources of Bursa Province, Turkey

Abstract

Bursa, the fourth most densely populated province in Turkey, is important to the national economy for agricultural and industrial production. During the past two decades, substantial migration into the region has increased drastically the risk of soil degradation. Urbanization and industrial development in the province have mainly occurred on soil types with land capability Class I and 2 and produce large amounts of nonbiodegradable urban and industrial waste, much of which is disposed of in the Nilufer River, the Ayvali Canal, and on agricultural land. Regulation of effluent quality disposed of to surface waters has been limited, so it was decided to conduct a preliminary survey of selected potentially toxic element (PTE) concentrations in agricultural soils and the PTEs in irrigation waters in the area to deter-mine what potential pollution and health risk may exist. The pH and concentrations of calcium (Ca), magnesium (Mg), and heavy metals were determined in water samples from along the Nilufer River, above and below the industrialized area, and one of its tributaries, the Ayvali Canal. The results indicated considerable pollution from industry and city sewage in the surface waters, which are used directly by local farmers for irrigation of adjacent fields. Total heavy metal contents of the Fluvisols and Vertisols showed that these agricultural soils were polluted with iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), cadmium (Cd), cobalt (Co), chromium (Cr), nickel (Ni), and lead (Pb). The DTPA-extractable Cd, Cu, Fe, Mn, and Zn concentrations in irrigated Fluvisols and Vertisols indicated that the practice caused the accumulation of the Cd and Cu in the upper parts of the soil profiles. In the longer term, irrigation of the soils with the polluted waters may damage soil, crop, and human health.