Estudio de biorremediación de metales pesados en suelos contaminados por la caída de ceniza volcánica en un cultivo de ciclo corto de la fundación San Juan Bautista del cantón Mocha, provincia de Tungurahua

Abstract

The main objective of this research project was to study the bioremediation process of heavy metals in contaminated soils by the fall of volcanic ash through short-cycle crops at the Foundation San Juan Bautista of Mocha canton, province of Tungurahua. For this purpose, onions were planted as plant material amended with “compost”. The physical parameters and chemicals from the soil and cultivated plants during the crop cycle. The pH, electrical conductivity, organic matter, texture, anions (C, N, K, P, and Na) and metals heavy, as well as germination index and polyphenols and the commercial parameters of the onion, were analyzed. The initial soil results were: pH(7.13), C.E(0.19 dS/m), D.R(1.248), D.A(1.186) and loamy sand texture. For soil S1 the results were: pH(7.47-7.21), C.E(0.17-0.42 dS/m), M.O(3.88- 5.73%), C(3.75- 5.75%), N(0.68-0.69%), K(2448.02-3013.20 mg/kg), P(1019.61-1031.66 mg/kg), Cd(0.11-0.15 mg/kg) and Hg(0.05-0.05 mg/kg), in S.N and S.C respectively. The results obtained in S2: pH(7.09-7.03), C.E(0.19-0.23 dS/m), M.O(5.55-5.25%), C(4.42-1.66%), N(0.72-1.26%), K(3233.11-2806.72 mg/kg), P(994.35-1062.06 mg/kg), Cd(0.16- 0.09 mg/kg) and Hg(0.04-0.05 mg/kg) in S.N and S.C. For commercial parameters, it was concluded that the onions with compost had better commercial quality. Finally, B.C.F was evaluated for Cd (0.519-3.013) for S.N and S.C plants, and also for Hg (1.371-0.591). In T.F for Cd (0.858-0.678 stem) (0.290-1.013 leaves), in Hg (0.251-1.744 stem) (0.343-1,668 leaves) for S.N and S.C. plants. It is concluded that the concentration of the metals Hg and Cd does not exceed the permissible limits by the aforementioned regulations, however, if they can enter the food chain through plant matter, assuming a risk to the food safety. It is recommended to periodically check the levels of pollutants in soil, especially in areas close to volcanic exposure.