REMOVAL OF ARSENIC FROM LIQUID EFFLUENTS OF GOLD BENEFIT PLANTS AND WATER BODIES, FROM THE MINING ZONE OF PONCE ENRÍQUEZ, BY RIZOFILTRATION WITH BLUE GRASS (DACTYLIS GLOMERATA)

Abstract

The present study evaluated the removal of As from water samples from two rivers and two effluents from gold processing plants in the mining area of Camilo Ponce Enriquez, through the treatment of rizofiltration with blue grass (dactylis glomerata). This species was previously selected for its 96% As removal capacity in synthetic solutions. For the study, concentrations of As of 0,12 and 0,27 mg.L-1 were used, for samples of the Siete and Chico rivers, and 0,14 and 0,24 mg.L-1, for effluents of two gold processing plants, respectively. After the fourth day of treatment by rizofiltration, the concentration of As already had values below the maximum permissible limit established in the Ecuadorian environmental regulations (0,05 and 0,1 mg.L-1) that correspond to 80% removal. Likewise, it was determined that more than 70% of the As contained in the species accumulates in the root, this due to the retention of the metalloid in wall cell as well as the complexation of the phytochelatins in the cellular vacuole of the plant. From the results obtained at the laboratory scale, a pilot test is carried out in an artificial wetland with 5 L of effluent samples, achieving a 98% removal of As on the second day of treatment, the efficiency of the process was increased due to the interaction of the root of the blue grass with the wetland substrate.