Potential impacts of certain remediative amendments in enhancing phytoremediation in various contaminated soil ecosystems

Abstract

After building of Grand Ethiopian Renaissance Dam (GERD), significant drastic shortage in Nile water resources in Egypt is expected. This water shortage forced Egyptian farmers to use low quality water in irrigation resources impregnated with a variety of contaminants such as potential toxic elements PTEs transferred into the food chain. In a complete randomized plot design greenhouse experiment, three terrestrial soil ecosystems, collected from Abou-Rawash (Konbera), Sinai and Kafr El-Sheikh Governorates irrigated with varied types of low-quality waters for extended periods were trailed for the sake of valuation of new innovative phytoremediation practices using kinetic approach. Calculated Zinc equivalent ZE parameter, indices for soil safety for cultivation, the numerical values ranged between 340 and 630, while the critical level should not exceed 200. Integrated management practices were applied represented in using canola hyper accumulator plant, in association with Thiobacillus trioxidane, Thiobacillus ferroxidase and Glomus sp. [Arbuscular Mycorrhiza (AM)] after furnishing the soil ecosystem with the chemical stabilizer probentonite. Results indicated that canola was efficient especially in Ni uptake compared to Cu or Zn pollutants. In addition, the application of Thiobacillus bacteria and AM significantly enhanced the uptake of PTE's. The kinetic parameter of modified Freundlich equation (MFE) empirical model confirmed that a mixture of all remediation amendments was the best in minimizing Zn equivalent value to a safe level. The different mechanisms that might take place between the applied remediation amendments and PTE’s in the three contaminated soil ecosystems were discussed.