Modeling oxyanion adsorption on ferralic soil, part 2: chromate, selenate, molybdate, and arsenate adsorption.

High levels of oxyanions are found in the soil environment, often as a result of human activity. At high concentrations, oxyanions can be harmful to both humans and wildlife. Information about the interactions between oxyanions and natural samples is essential for understanding the bioavailability, toxicity, and transport of these compounds in the environment. In the present study, the authors investigated the reactivity of different oxyanions (AsO4 , MoO4 , SeO4 , and CrO4 ) at different pH values in 2 horizons of a ferralic soil. By combining available microscopic data on iron oxides with the macroscopic data obtained, the authors were able to use the charge distribution model to accurately describe the adsorption of these 4 oxyanions and thus to determine the surface speciation. The charge distribution model was previously calibrated and evaluated using phosphate adsorption/desorption data. The adsorption behavior on ferralic soil is controlled mainly by the natural iron oxides present, and it is qualitatively analogous to that exhibited by synthetic iron oxides. The highest adsorption was found for arsenate ions, whereas the lowest was found for selenate, with chromate and molybdate ions showing an intermediate behavior.

Punica granatum L. protects mice against hexavalent chromium-induced genotoxicity

This study investigated the chemoprotective effects of Punica granatum L. (Punicaceae) fruits alcoholic extract (PGE) on mice exposed to hexavalent chromium [Cr(VI)]. Animals were pretreated with PGE (25, 50 or 75 mg/kg/day) for 10 days and subsequently exposed to a sub-lethal dose of Cr(VI) (30 mg/kg). The frequency of micronucleated polychromatic erythrocytes in the bone marrow was investigated and the Cr(VI) levels were measured in the kidneys, liver and plasm. For the survival analysis, mice were previously treated with PGE for 10 days and exposed to a single lethal dose of Cr(VI) (50 mg/kg). Exposure to a sub-lethal dose of Cr(VI) induced a significant increase in the frequency of micronucleated cells. However, the prophylactic treatment with PGE led to a reduction of 44.5% (25 mg/kg), 86.3% (50 mg/kg) and 64.2% (75 mg/kg) in the incidence of micronuclei. In addition, the 50 mg/kg dose of PGE produced a higher chemoprotective effect, since the survival rate was 90%, when compared to that of the non-treated group. In these animals, reduced amounts of chromium were detected in the biological materials, in comparison with the other groups. Taken together, the results demonstrated that PGE exerts a protective effect against Cr(VI)-induced genotoxicity.

Este estudo investigou os efeitos quimioprotetores do extrato alcoólico dos frutos da Punica granatum L. (Punicaceae) (EPG) em camundongos expostos ao cromo hexavalente [Cr(VI)]. Os animais foram pré-tratados com o EPG (25, 50 ou 75 mg/kg/dia) durante 10 dias e subsequentemente expostos a uma dose subletal de Cr(VI) (30 mg/kg). A frequência de eritrócitos policromáticos micronucleados na medula óssea foi investigada e os níveis de Cr(VI) foram quantificados nos rins, fígado e plasma. Para a análise de sobrevida, os camundongos foram previamente tratados com EPG durante 10 dias e expostos a única dose letal de Cr(VI) (50 mg/kg). A exposição à dose subletal de Cr(VI) induziu aumento significativo na frequência de células micronucleadas. Entretanto, o tratamento profilático com EPG levou à redução de 44,5% (25 mg/kg), 86,3% (50 mg/kg) e 64,2% (75 mg/kg) na incidência de micronúcleo. Além disso, a dose de 50 mg/kg de EPG produziu maior efeito quimioprotetor, uma vez que a taxa de sobrevivência foi de 90%, quando comparada àquela do grupo não tratado. Nesses animais, quantidades reduzidas de cromo foram detectadas nos materiais biológicos, em comparação com os outros grupos. Em conjunto, os resultados demonstram que o EPG exerce efeito protetor contra a genotoxicidade induzida pelo Cr(VI).