ENVIRONMENTAL RISKS ASSESSMENT FOR SOILS AND PLANTS IRRIGATED FROM El-MARIOUTEYA AND EL-RAHAWY DRAIN

Abstract

The objective of this study was to evaluate the environmental risks of water, soils, and plants from the El-Mariouteya Canal and El-Rahawy drain. To achieve this aim, pH and electrical conductivity EC in water and soils, as well as sodium adsorption ratio (SAR) in water; some micro elements and heavy metals were estimated in water; soils and plants. In addition to calculation of contamination factor (CF), degree of contamination (Cd), modified degree of contamination (mCd); pollution load index (PLI) and bio-accumulation factor of elements in plants. The obtained results indicated that the values of pH and (SAR) in the water were different from season to another season. (EC) values were very high and unsuitable for irrigation in summer season; while they were suitable for irrigation in winter season according to FAO. Regard to soil pH values tend to be normal, slightly and moderately alkaline and (EC) was ranged between non-saline to highly saline soils. However, boron, cadmium, cobalt, chromium, nickel and lead were within the safe limits. The total content of cadmium exceeded the safe limits in both seasons, but other elements were within the safe limits. The lowest concentration of iron, boron, cobalt and chromium was found in Wheat yield. Manganese and nickel were found in the fruits of Eggplant, zinc and copper were found in Cabbage. While the highest concentrations of iron, manganese, copper, cobalt, chromium and nickel were found in Okra. Zinc was found in Spinach and boron was found in Watercress. BCF indicates that the most plants have more than 1 and showed high concentrations of heavy metals. The values of (CF) were low for both zinc, boron and lead for all sites and medium for copper and cobalt at all sites and low to medium with both iron, manganese, chromium and nickel indicating that this contamination is related to human activities. Modified contamination degree (mCd) is moderate to high in some sites. The (PLI) is generally high (> 1) in all sites; exception one site. The (PLI) was low (<1) in some sites in winter season.