Application of Amphitox Assay to Determine the Toxicity of Dichloroacetic and Trichloroacetic Acids.

HERKOVITS, J., MUÑOZ, L.M., ASOREY, C.M., AND LIPSCOMB, J.C.

TOXICOLOGICAL SCIENCES

OXFORD UNIV PRESS

Año: 2003 vol. 72 p. 156 - 156

1096-6080

Epidemiological studies point out that chlorinated drinking-water could be related to cardiovascular disease, cancer, adverse pregnancy outcomes, etc. AMPHITOX, an in vitro toxicity test conducted with amphibian (Bufo arenarum) embryos may be valuable as an alternative method for screening agents for developmental effects. The acute (96 hr) and short-term chronic (7 days) toxicity of trichloroacetic acid (TCA) and dichloroacetic acid (DCA) was evaluated. Triplicates of 10 embryos, at complete operculum stage (S25) were maintained in AMPHITOX Solution containing TCA and DCA in concentrations ranging from 25 to 10,000 mg/L. As DCA and TCA changed media pH markedly; normal embryo development was confirmed at this pH. TCA at 100mg/L reduced the pH to 4 and lethality was 50% at 24hr; DCA at 70mg/L also reduced the pH to 4 and lethality was 100%. Up to 8,000 mg/L of TCA at pH 4.6 did not exert lethality in the amphibian embryos until 96 hr of exposure; DCA at 60mg/L resulted in 30% lethality; the toxicity of neither compound increased markedly when exposure period was extended to 7 days. The results indicate i) the toxicity of both DCA and TCA may related to the decreasing of pH in the maintaining media and ii) DCA is more toxic than TCA at equivalent pH. This may be related to the metabolic pathways of these haloacetic acids. The results are consistent with the developmental and reproductive potencies of these two compounds and demonstrate the validity of the AMPHITOX assay in the evaluation of the adverse effects of these disinfectant byproducts.