Efeitos do Fenol e 4-Clorofenol sobre o desenvolvimento embriolarval de EchinometraLucunter (Linnaeus, 1758):avaliação dessas substâncias como referência

by Lins do, Cíntia Levita

Innumerable chemical substances that compose the manufactured products and arefound in the industrial effluents of industrial complex are currently disposed in theenvironment. The aquatic toxicity tests are used to evaluate the effect of thesechemical agents on the organisms, thus complementing the ecological survey basedon chemicals analysis which are normally used for this purpose. To be validated theecotoxicological tests need to be carried out following specific protocols and using areference substance, that is a chemical of known effect on the organisms, to certifythe trustworthiness of the results. The aim of this work was to evaluate the use oforganic substances Phenol and 4-Clorophenol, as an alternative for reference inecotoxicological tests with embryos of the sea-urchin Echinometra lucunter. For this,fifteen chronic tests of short duration had been carried out for the two investigatedsubstance, besides Dodecil Sodium Sulphate (SDS), that was used as positivecontrol. The CE50-36h values ranged from 125,88 to 143,84 mg/L for Phenol and from26.31 to 16,90 mg/L for 4-Clorophenol. The alternative level of effect was determinedbased on the critical DMS values. The equivalent level to estimated concentration ofcronic effects was CE10. From such concentration it would be possible to observesignificant deleterious effect in the population of the test organism. The average valueof CE10-36h found for Phenol was of 36,63 mg/L and for 4-Clorophenol was of 4,58mg/L. The variation coefficients of the results indicated that the values found forPhenol in the level of 50% effect have greater analytical precision (4,04%), while thatin the level of alternative effect, 4-Clorophenol presented greater precision among theused substances (27,98%). The control chart to the results gotten with the DSS teststhat had been carried out in parallel to other substances, certified the health of theused organisms and the attainment of trustworthy results in the led experiments.Embryos of E. lucunter presented more sensitivity to 4-Clorophenol than to Phenol,therefore under the same concentrations, the value of CE50-36h obtained for Phenolwas higher than the one for 4-Clorophenol. Allied the peculiar characteristics to eachsubstance, 4-Clorophenol was presented as more indicated for the use as referencein ecotoxicological tests with embryos of E. lucunter.