Toxicity biotests for dangerous chemicals (monolinuron and triclorphon) control to evaluate their toxic potential

The main objective of the present work was to evaluate acute and chronic toxicity of 2 chemicals from pesticides class (monolinuron and trichlorphon), included in the list of Prior dangerous substances, on aquatic organisms – fish (Cyprinus carpio sp. – which is a commune species in Romanian fresh waters and able to be tested in aquatic toxicity laboratory tests). the study was performed in 3 experimental steps conducting to the following results: the medium lethal concentration values (LC50) for the 2 chemicals established by performing acute toxicity tests in which evaluation criterion was the mortality of aquatic organisms, as a reply to noxious action of toxic; the values of the maximum allowable concentrations (experimental MATC) established through chronic toxicity tests monitoring evaluation criterion of influence of morphofunctional, physiological and biochemical state of contaminated aquatic organisms; and the toxic effects assessment on enzymatic antioxidant and hepatic systems (superoxide dismutase [SOD], glutathione peroxidase [GPx], catalase [CAT]), glutathione-s-transferase [Gst], glucoso-6-phoshate dehydrogenase [G6Pd], aspartate aminotransferase [Got] and alanin aminotransferase [GPt]). Because ecotoxicological bio tests represent a significant control parameter for determination of chemicals concentrations (possible existent in surface waters) with no toxic effect on aquatic organisms (fish), the obtained results can be used by chemicals manufactures/importers and authorities to evaluate the ecological risk and for elaboration of chemicals files in conformity with the European regulation – REACH.