Maria Eugenia Gimenez Boscov

Biodegradation of di(2-ethylhexyl)phthalate in a typical tropical soil

The aim of this research was to evaluate the possibility of biodegradation of di(2-ethylhexyl)phthalate (DEHP), widely used as an industrial plasticizer and considered an endocrine-disrupting chemical included in the U.S. Environmental Protection Agency priority list, in a Brazilian tropical soil, which has not been previously reported in the literature, despite the geographic importance of tropical soils. Preliminary laboratory testing comprised respirometric, air and water permeability, and pilot scale infiltration tests. Standard respirometric tests were found inadequate for studying biodegradation in tropical contaminated soils, due to the effect of the addition of significant amounts of calcium carbonate, necessary to adjust soil pH. Pilot scale infiltration tests performed for 5 months indicated that DEHP was retained in the superficial layer of the soil, barely migrating downwards, whereas air and water permeability tests discarded in situ bioremediation. However, ex situ bioremediation was possible, using a slurry-phase reactor with acclimated microorganisms, in pilot scale tests conducted to remediate a total mass of 150 kg of contaminated soil with 100 mg DEHP/kg. The removal of DEHP in the slurry-phase reactor achieved the percentage of 99% in 49 days, with biodegradation following a first-order kinetic model with a biodegradation coefficient of 0.127 day(-1).

Estimativa da geração de resíduos de equipamentos elétricos e eletrônicos de origem domiciliar: proposição de método e aplicação ao município de São Paulo, São Paulo, Brasil

Conhecer a geracao de residuos de equipamentos eletricos e eletronicos (REEE) e fundamental para sua gestao. O fluxo domiciliar de EEE e complexo, pois tem seu descarte associado a fatores tecnologicos, economicos e comportamentais. O artigo apresenta metodo para estimativas de REEE de origem domiciliar: estoque de equipamentos em uso, armazenados e descartados, e do potencial de geracao de residuos. O metodo aplicado ao municipio de Sao Paulo, Sao Paulo, resultou em 71,9 milhoes de EEE, dos quais 8,8 milhoes (12,2%) fora de uso. O valor medio de EEE correspondeu a 18,2 EEE por domicilio; media per capita de 5,3 EEE por habitante. A media de descarte per capita estimada resultou em 4,8 kg.hab-¹.ano-¹. O potencial de geracao de residuos a partir dos EEE fora de uso variou entre 2,9 a 6,0 kg.hab-¹.ano-¹. O metodo proposto proporcionou qualidade as estimativas, resultando em importantes indicadores para a gestao.