Sewage irrigation may provide an alternative resource due to scarcity of fresh water in Egypt, thus such a practice should be evaluated. A number of 36 pairs of soil samples were collected; each pair consisted of one sample irrigated with fresh water and another irrigated with sewage water from two different sites in Al-Qalyubia Governorate, Egypt. Sewage water-irrigated soils showed higher pH, EC, N, P, K, Fe Mn, Zn, Cd, Pb and Ni than fresh water-irrigated soils. Positive changes in soil properties occurred with sewage irrigation. Bulk density decreased field capacity, organic carbon and nutrients increased by sewage water irrigation. There was build-up in Cd, Pb, Ni and Zn. Single pollution index (SPI) and pollution load index (PLI) indicated none pollution in fresh water irrigated soils as both parameters did not exceed 1.0. Sewage irrigated soils were moderately polluted. The contamination factor (CF) revealed a considered contamination with Pb and high for Cd, Ni and Zn. The contamination degree was very high. Food crops cultivation in such soils should be practiced under precautions with a change in the cropping pattern. |
