Impact of Using Aldanfeeli Valley Water on the Pollution of Soils with Heavy Metals

Abstract

The current study included collecting samples of water and soil from three main agricultural sites on Aldanfeeli Valley in Mosul city (North Iraq), where soil samples included two from each location, one for agricultural soil watered with untreated Valley water, and the second sample was from the adjacent uncultivated soils. A fourth site was chosen for the purpose of comparison at the end of Aldanfeeli Valley where the cultivated soil was watered with water of the Tigris River before the confluence of the River Valley. In addition to estimating the concentrations of heavy metals (Zn, Cd, Pb, Cu, Fe) in both water and soils, the present study aimed to identify some chemical and physical properties of the soils, namely: electrical conductivity, pH, organic matter, calcium carbonate, cations and anions, soil texture, and specific gravity. Despite the fact that the waters of Aldanfeeli Valley are poor for agricultural purposes in terms of salinity and total concentrations of both chloride and half of sulphate ions, the results showed that all soils do not suffer from the problems of salinity and alkalinity. Regarding the concentrations of heavy elements (Zn, Pb, Cd, Cu, Fe), their averages in the cultivated soils (23.86, 5.98, 75.14, 7.53 and 140.18) p.p.m. respectively, were higher than their counterparts in non-cultivated ones (18.70, 5.47, 36.82, 6.17 and 114.63) p.p.m. respectively. All soil samples especially the cultivated ones indicated higher concentrations than those of the irrigation waters (6.47, 4.87, 8.87, 2.27 and 7.07 p.p.m. respectively. The iron recorded at all sites higher means when compared to the rest elements. These were (140.18 and 114.63) p.p.m. in both the cultivated and noncultivated soils respectively. In both the second and the third sites of the cultivated soils; lead concentration averages of (114.25 and 91.06) μg g-1 respectively, have exceeded its standard limit (50 μg g-1); whereas, cadmium concentration averages in these two sites were (8.23 and 6.88) μg g-1 respectively, have exceeded its critical limit (5 μg g-1).