Toxicological evaluation of organic residues

Abstract

It is pointed out the importance of short term assays for the characterization of organic residues, specially some methods for toxicological, mutagenic, genotoxic and cytotoxic evaluation (Vibrio fischeri, Salmonella typhimurium and Allium cepa), used in the characterization of environmental complex mixtures lixiviates. These methods take part together with other bioassays in the evaluation by toxicological identification (VIT), which allows the evaluation of other ecotoxicological effects: a) bioluminescence inhibition of Vibrio fischeri; b) germination and root length of Lepidum sativum; c) root length of Allium cepa and Tradescantia sp.; d) inhibition of the mobility of Daphnia magna; and e) abnormalities in the development of Oryzias latipes, or medaka fish. All these assays take part in the EU battery of bioassays, applied to discriminate and select between those environmental matrixes which must be subject to more complex and specific chemical characterizations.

We make a review of the methods for toxicological evaluation, used for the characterization of chemical compounds or complex mixtures, as well as the use of its results for the human and environmental risk assessment. This evaluation consists, in short, of the identification of dangers, evaluation of dose-response ratio, evaluation of exposure and risk characterization, resulting in the analysis, use and communication of this risk. It is emphasized the high predictive value for carcinogenicity of some of these bioassays.

It is shown the utility of short term assays for the evaluation of substances, products and complex mixtures, which would contribute to improve the toxicological knowledge of a greater number substances. This is a vital need in the EU, due to the lack of complete toxicological information of about the 70% of the 106.000 existing and used substances.

It is emphasized the great value that mutagenicity assays represent inside the toxicological tests in the basic level, which are used in the evaluation of new and existing substances. It also helps to improve the knowledge about substances with incomplete toxicological data. Another aspect to consider about these methods is that they represent an alternative to animal experimentation, carrying out one of the basic requirements that the EU establishes in the new policy about substances, which is known as REACH, the acronym of record, evaluation and authorization of chemical substances. This policy is a basic part of the European strategy on environment and health (SCALE).