IMPROVEMENT OF SOLID WASTES FROM PROCESSED RADIOACTIVE MATERIALS TO STUDY THEIR EFFECTS ON AGRICULTURE AND ENVIRONMENT IN SOUTH WESTERN SINAI

Abstract

The acid processing of radioactive sedimentary rock material led to the production of huge amounts of milling solid radioactive wastes. These wastes represent environmental pollution of some heavy metals and radioactive elements in the areas surrounding the mining and milling area in Wadi Allouga and Wadi Nasab and their surroundings located the in south western Sinai, Egypt. The aim of this study was to decrease the grade of environmental pollution and permit the safe storage of milling solid wastes or to use them in agriculture in the study area. Moreover, studying heavy and radioactive elements effects on soil, herb weeds and water wells contamination in study area and surroundings. Additional, studying the ability of sunflower (Helianthus Annuus) to remediate some heavy and radioactive elements to decrease their effects on germination and growth characteristics of plant. The geochemical characteristic of the original ore material was chemically consisted of around 50% SiO2, 10.6% Al2O3, 10.2 Fe2O3, 13% (CaO + MgO) and around 10% loss on ignition. This figure indicated high carbonate and total iron contents. The mineralogic constituents of milling solid wastes were consisted of Quartz, Kaolinite, Jarosite and Gypsum. The milling solid wastes contained 60.2% SiO2, 6.8% Al2O3, 9.4% Fe2O3, 4.7% (CaO + MgO) and 14.8% loss on ignition. The picture of some trace elements was as follows; Cu was 2900 mg Kg-1 in original ore material and 359 mg Kg-1 in milling solid wastes. In the same order, Zn was 1865 and 92 mg Kg-1, Th was 14 and 26 mg Kg-1, U was 346 and 184 mg Kg-1, The value of the main specific activity of radionuclides as 238U, 232Th, 226Ra and 40K in original ore material, milling solid wastes and mixed soil samples were 4527.63, 2385.72 and 6.23 Bq kg-1; 58.39, 56.44 and 5.93 Bq kg-1; 5608.31, 5864.33 and 9.35 Bq kg-1 and 377.32, 385.51 and 1.10 Bq kg-1, respectively. The optimum conditions of leaching efficiency of heavy metals and radioactive elements from milling solid wastes by agitation leaching were application of 40 g L-1 from sulfuric acid, with particles size; < 2.8 mm, solid/ liquid ratio 1/ 2 at room temperature 25oC and agitation time 4 hrs. The leaching efficiency of U, Cu and Zn elements were 88.0, 58.1 and 37.3%, respectively. Application of 40 g L-1 from sulfuric acid, with flow rate of 1.2 ml min-1 particles size < 5.0 mm by column method achieved leaching efficiency of U, Cu and Zn elements as 69.91, 60.42 and 27.5%. While leaching efficiency of U, Cu and Zn elements were 52.8, 79.3 and 36.7% by application of 10 g L-1 from citric acid concentration, respectively, by column leaching method.