Toxicity of Metal–Ethylenediaminetetraacetic Acid Solution as a Function of Chemical Speciation: An Approach for Toxicity Assessment

• Published in: Archives of environmental contamination and toxicology 2012-11, Vol.63 (4), p.484-494
• Main Authors: Peraferrer, C., Martínez, M., Poch, J., Villaescusa, I.
• Format: Article
• Language: English
• Subjects: Acids; Aliivibrio fischeri - drug effects; Aliivibrio fischeri - metabolism; Animal, plant and microbial ecology; Applied ecology; Aspectes ambientals; Assessments; Bioassays; Bioavailability; Biological and medical sciences; Biological Assay - methods; Cadmium; Cadmium - chemistry; Cadmium - toxicity; Chemical engineering; Chemical speciation; Chloride; Copper - chemistry; Copper - toxicity; Correlation analysis; Earth and Environmental Science; Ecotoxicology; Ecotoxicology, biological effects of pollution; Edetic Acid - chemistry; Edetic Acid - toxicity; EDTA; Enginyeria química; Environment; Environmental aspects; Environmental Chemistry; Environmental Health; Environmental monitoring; Environmental Pollutants - chemistry; Environmental Pollutants - toxicity; Equilibrium; Fundamental and applied biological sciences. Psychology; General aspects; Heavy metals; Hydrogen-Ion Concentration; Indication; Ions; Lead; Lead - chemistry; Lead - toxicity; Linear Models; Mathematical models; Metalls pesants; Metals; Monitoring/Environmental Analysis; Nickel; Nickel - chemistry; Nickel - toxicity; Phenols; Pollution; Sodium chloride; Soil Science & Conservation; Solutions - chemistry; Speciation; Studies; Toxicants; Toxicity; Water pollution; Àrees temàtiques de la UPC
• ISSN: 0090-4341; 1432-0703
• DOI: 10.1007/s00244-012-9788-x

The influence of complexation by ethylenediaminetetraacetic acid (EDTA) on the toxicity of Cd(II), Cu(II), Cd(II), and Ni(II) was investigated. Result of the Microtox test, which is based on measuring the decrease of light emitted by Vibrio fischeri bacterium when exposed to a toxicant, was used as an indication of toxicity. The effect of pH and EDTA molar ratio that might potentially modify the percentage of chemical species in solution on toxicity was evaluated. In general, results indicate that toxicity decreases when increasing the pH value as well as the EDTA molar ratio. Chemical modeling was used to predict metal speciation and correlation analysis to relate chemical species with the obtained toxicity results. The species that most contribute to toxicity resulted to be MeCl + (Me = metal), which is formed as a consequence of the presence of the bioassay medium (2 % NaCl). A model that predicts metal-solution toxicity by using the chemical species, which most contribute to toxicity is proposed as a useful tool for toxicity assessment in waters containing metal ions and EDTA.