Abstract This study shows the results obtained of evaluation and comparison of chemical analysis and ecotoxicity for evaluated the quality of water contaminated with gasoline after Fenton process. The process Fenton was efficient to remove the aromatics organic compounds such as benzene, toluene and xylenes from water contaminated with gasoline. At 90 minutes of reaction time, the concentration measured of aromatics compounds by gas chromatography were less than limit of quantification (0.05mg L-1). This value is in accordance with the limits established by Brazilian legislation for the effluents discharge. On the other hand, analysis of total phenols and dissolved organic carbon demonstrated at 120 minutes that all dissolved organic compound and total phenols are not totally removed even though benzene, toluene and xylenes were almost completely removed. Phytotoxicity tests using Sinapis alba as biological response showed that water contaminated with gasoline are not toxic, however these results was probably influenced by volatilization of aromatics compounds during the assay. Differently, the ecotoxicity using Daphnia magna showed that water contaminated with aromatic compounds is toxic, but after 120 minutes of treatment the toxicity was reduced more than 50%. Then, Daphnia magna was the better bioindicator to evaluate the efficiency of Fenton process since these results were according with response of dissolved organic carbon and total phenol showing the toxicity of intermediates produced during the Fenton process.

RESUMO Reclaimed Asphalt Pavement (RAP) has a variety of organic and inorganic compounds that can interact with the environment and promote deleterious effects on human health. This study investigated the potential toxicity of RAP through metal determination, polycyclic aromatic hydrocarbon (PAH) analysis and acute toxicity tests with Daphnia magna. Leached and solubilized extracts of RAP samples and a freshly produced asphalt sample were compared. Regarding metals, Mn was above the Brazilian acceptance criteria in the solubilized extract. The samples showed concentrations of Cd, Cr, and Pb, which are on the list of substances that render waste hazardous. For PAH, two samples of leachate had BaP concentration above the maximum value allowed and the other samples had BaP values close to the established limit. In addition, the samples still presented concentrations of BaA, BbF, IcdP, and Chr. For the acute toxicity tests, two solubilized samples indicated acute toxicity to Daphnia magna. The results indicated that the method of preparing the leached and the solubilized extract influenced the values of metals and acute toxicity. Two samples of RAP could be classified as hazardous waste, pointing out that these materials have the potential to leach hazardous substances to the environment. Therefore, the disposal of this type of waste should be carefully evaluated, as its composition contains substances that may degrade the environment and cause toxicological effects on living organisms.

ABSTRACT Pavimentos asfálticos fresados (PAF) apresentam uma variedade de compostos orgânicos e inorgânicos que podem interagir com o meio ambiente e promover efeitos deletérios à saúde humana. Este estudo investigou o potencial de toxicidade dos PAF por meio da determinação de metais, hidrocarbonetos policíclicos aromáticos (HPA) e testes de toxicidade aguda com Daphnia magna. Foram comparados extratos lixiviados e solubilizados de amostras de PAF e de resíduo asfáltico fresco. As análises de Mn apresentaram concentrações acima do critério de aceitação normativo brasileiro para os extratos solubilizados. As amostras resultaram em concentrações de Cd, Cr e Pb, que estão na lista de substâncias que conferem periculosidade aos resíduos. Em relação aos HPA, duas amostras de lixiviado apresentaram concentração de BaP acima do valor máximo permitido e as demais amostras apresentaram valores de BaP próximos ao limite estabelecido. Ademais, foram identificadas nas amostras concentrações de BaA, BbF, IcdP e Chr. Para os ensaios de toxicidade aguda, duas amostras solubilizadas indicaram toxicidade aguda para Daphnia magna. Os resultados indicaram que o método de preparo dos lixiviados e do extrato solubilizado influenciaram os valores de metais e a toxicidade aguda. Duas amostras de PAF foram classificadas como resíduos perigosos, sinalizando que tais materiais apresentam potencial para lixiviar substâncias perigosas ao ambiente. Portanto, a disposição em solo desse tipo de resíduo deve ser criteriosa, uma vez que sua composição contém substâncias que podem impactar o meio ambiente e causar efeitos toxicológicos em organismos vivos.

Resumo A indústria de papel e celulose está entre as que mais consome água no mundo, gerando grandes volumes de efluentes. O processo Kraft produz efluentes com elevada DBO, DQO, sólidos suspensos, teor de lignina e uma mistura complexa de compostos potencialmente tóxicos, os quais necessitam de tratamento para posterior descarte no meio ambiente. Os processos oxidativos avançados, dentre eles o processo UV/H2O2, têm sido aplicado como alternativa de tratamento pois é capaz de degradar os mais diversos compostos até sua mineralização. No entanto, quando o processo oxidativo é incompleto, podem ser formados produtos intermediários com elevada toxicidade. Este estudo avaliou a toxicidade aguda em Daphnia magna de duas amostras de efluente Kraft (KE1 e KE2) tratadas por processo UV/H2O2. Os efeitos da variação de pH e da concentração do oxidante sobre a redução de COT, área espectral UV-vis e cor aparente foram utilizados para ajustar as condições experimentais com a amostra KE1 diluida. Ambas as amostras foram tratadas em pH 4.0 e com 70 mg L-1 de H2O2 por 40 min, alcançando remoções de até 69,4% na cor aparente, 73,7% de compostos fenólicos e 68,9% de compostos lignínicos. Quando a reação foi aplicada nas amostras não diluídas de efluentes, a toxicidade aguda para Daphnia magna diminuiu para KE1 após 780 min de tratamento, enquanto KE2 tornou-se três vezes mais tóxica. Os dados mostraram que embora o tratamento tenha sido eficiente, considerando os parâmetros físicos e químicos, é necessário acompanhar os processos oxidativos por ensaios ecotoxicológicos para garantir sua segurança, uma vez que cada efluente kraft pode apresentar diferentes níveis de mineralização de seus compostos orgânicos.

Abstract The pulp and paper industry is one of world’s largest water consumers, generating high volumes of effluents. The Kraft process produces effluents with high BOD, COD, suspended solids, lignin and a myriad of potentially toxic compounds, which require treatment before discharge into the aquatic environment. Advanced oxidation processes, such as UV/H2O2, have been applied as treatment alternatives because they can destroy many compounds before they mineralize. However, when the oxidation process is incomplete, occurs could be produced by products with high toxicity. This study evaluated the acute toxicity on Daphnia magna of two effluent samples of Kraft pulp mill (KE1 and KE2) treated by UV/H2O2 process. The effects of the pH variation and oxidant concentration on the removal of DOC, total UV-vis spectral area and apparent color were considered to adjust the experiments’ conditions with diluted effluent KE1. Both samples were treated at pH 4.0 and 70 mg L-1 of H2O2 for 40 min, achieving removals of up to 69.4% in apparent color, 73.7% of phenolic compounds and 68.9% of lignin compounds. When the reaction was applied in undiluted effluent samples, the acute toxicity for Daphnia magna decreased for KE1 after 780 min of treatment, whereas KE2 became four times more toxic. The data showed that although the treatment had been efficient considering physics and chemicals parameters, it is necessary follow the oxidative processes with ecotoxicological bioassays to guarantee their safety, since different effluents of the Kraft pulp mill could present different levels of organic compound mineralization.

In this work, the efficiency of some homogeneous advanced oxidation processes (UVC/H2O2, Fe2+/H2O2, UVC/Fe2+/H2O2, UVA/Fe2+/H2O2, solar/Fe2+/H2O2) was investigated toward the degradation of geosmin and 2-methylisoborneol (2-MIB). The effect of relevant experimental parameters (ie. pH, Fe2+ and H2O2 concentration) was first investigated by factorial design, using camphor as a model substrate. In the geosmin and 2-MIB degradation studies the Fenton processes assisted by solar and UVA radiation offered the most promising results, mainly on account of high degradation capacity (higher than 80% at a reaction time of 60 min), high operational simplicity and low cost.