Toxicity decline of effluents containing Cr(VI) by means of heterogeneous photocatalysis. Toxicity assessment by employing the AMPHITOX test

J. HOJMAN; .M. MEICHTRY; M.I. LITTER; C.S. PÉREZ COLL

ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2015 vol. 122 p. 545 - 550

0147-6513

Toxicity of a Cr(VI) solution before and after treatment by TiO2 heterogeneous photocatalysis (HP) wasperformed with AMPHITOX bioassay. Changes in toxicity on Rhinella arenarum larvae for 10-d weremonitored after exposure to an untreated Cr(VI) solution and to the same solution after HP treatment.The HP treatment of a 41.60 mg L 1 Cr(VI) solution reduced to 37.5% the concentration of the metal ion. A10-fold reduction in toxicity at acute exposure (72 h) and 150-fold reduction in toxicity after 240 h wasfound. Further, the LOEC value increased from 0.001% for the untreated solution to 0.153% after HPtreatment. Moreover, the safe concentration in untreated solution corresponded to 0.0001% sample, andit was 0.01% after the treatment, i.e., 100 times higher. A saving of water of about 100,000 L per L ofeffluent would be possible through dilution to allow safer concentrations for discharge; the saving wouldreach the highest value (1,000,000 L per L) at 240 h. Sub-lethal effects were completely absent in larvaeexposed to the treated solution. The AMPHITOX test allowed to detect chronic effects at low Cr concentrations, i.e. at environmentally relevant levels.