IMPACT OF IRRIGATION WITH SEWAGE WATER ON , CALCARIOUS SOIL: 1- SOIL PROPERTIES AND HEAVY METALS CONTENT IN SOILS AND PLANTS.

Soil and plant samples were collected from experimental fields at 89 kg
Cairo -Alex. desert road ,irrigated with raw sewage water for different periods
(3,10,and 30 years)to assess the impact of sewage water On soil properties,
distribution of Cu, Zn, Cd, Ni and Pb content in soil profiles and the concentration of
the metal in DTPA-extract of the surface soil layer (0-20 cm). Also, the heavy metals
concentration in some pastures as well as in leaves, fruits, and oil olives were
determined in both plants irrigated with sewage water (30 years)and those irrigated
with' ground water .irrigation with sewage water increased the levels of heavy metals
and O.M. In soils, and decreased the soil pH value as compared with ground water.
The relative enrichment for total metals concentration in sewage water irrigated soil
(0-20cm)were proportional to the amount of sewage water applied, where Zn had the
highest enrichment factor (average EF=16.53), while cu had the lowest value
(average EF =1.38).the soil appeared to be very poor in DTPA-extractable metals,
which were 0.27 ,0.67 .0.06 ,0.27 and 0.80mg kg-1 for Cu, Zn, Cd, Ni and Pb,
respectively. However, these levels had increased with sewage water irrigation. There
were significant correlations between DTPA-extractable metals and total metal
contents in soil .thirty years period of irrigation with raw sewage water were not
sufficient to cause phytotoxic 'Ievels of various heavy metals for the plants grown on
highly calcareous soil cadmium leaching, in highly calcareous soil is Higher than the
other heavy metals (Cu, Zn, Ni and Pb).