ABSTRACT
Background: Ethanol has been shown to inhibit spontaneous cell-mediated cytotoxicity and antibody-dependent cell-mediated cytotoxicity in vitro in a dose-dependent manner. A mixture of ethanol in biofuel may show interaction with respect to spontaneous and cell-mediated cytotoxicity. Methods: The cytotoxicity on Human Red Blood Cells (RBCs) and White Blood Cells (WBCs) was studied in vitro model of 4 types of biofuels (gasohol) (octane 91, octane 95, E 20, and E 80) in serial dilutions. The lysis and abnormal morphology of cells were analyzed by colorimetric and microscopic methods. Results: Quantitative hemolysis of RBCs was increased with rising ethanol concentration as well as abnormal morphology of RBCs like spherocyte. Moreover, ethanol might effect to lysis and morphology of WBCs. Conclusion: It is suggested that the gasohol-induced cytotoxicity may be related to concentration of ethanol in gasohol. However, it is possible to future study on mechanism of action leading to cell lysis and kinetic of morphological change in RBCs and WBCs.
ABSTRACT
Nesse estudo, foram avaliados os resultados de um experimento de derramamento controlado de gasolina brasileira em água subterrânea durante 6,5 anos de monitoramento. A exaustão do etanol, aos 32 meses de monitoramento, e a significativa redução de mais de 90 por cento da massa máxima dos compostos BTEX dissolvidos no meio, aos 79 meses, associadas ao uso dos receptores de elétrons e acúmulo de seus subprodutos metabólicos, demonstraram a eficácia da atenuação natural monitorada para contaminações de águas subterrâneas sem riscos imediatos a receptores críticos. Constatou-se ainda que a biodegradação do etanol permitiu a formação de uma biobarreira natural que, após a sua completa degradação, acelerou a taxa de biodegradação dos BTEX e impediu o avanço da pluma destes contaminantes.
In this study, results of 6.5 years of a controlled release experiment with Brazilian gasoline in groundwater were evaluated. Ethanol exhaustion after 32 months and the significant dissolved BTEX mass reduction of more than 90 percent after 79 months, associated with the electron acceptors use and their metabolic byproducts accumulation, demonstrated the efficiency of monitored natural attenuation for groundwater contamination without immediate risk to receptors. Moreover, ethanol degradation provided a natural biobarrier formation that increased BTEX biodegradation rate and prevented the BTEX plume expansion.