Arsenic in Sediments, Soil and Plants in a Remediated Area of the Iron Quadrangle, Brazil, and its Accumulation and Biotransformation in Eleocharis geniculata.

Since arsenic (As) exposure is largely due to geochemical contamination, this study focused on the remediated area of Santana do Morro, a district of Santa Bárbara, Minas Gerais, Brazil, which was previously contaminated with As due to gold mining. Total As concentrations in sediment, soil and plants were determined, next to As species, anionic arsenic compounds As(III), As(V), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), in plants samples. Total As concentrations in soil and sediments were slightly elevated (16-18 µg g-1) and most of the plants contained low levels of As (< 1 µg g-1). The exception was a native plant Eleocharis geniculata (L.) which contained elevated levels of As (4 µg g-1). The exposure of this plant to As under controlled conditions (hydroponics) indicated its possible tolerance to elevated As levels and suggesting its potential use in phytomonitoring of As-contaminated sites. This plant is able to metabolize arsenate to arsenite and contained MMA and DMA, both in its natural habitat and under controlled conditions.

Management of effluents and waste from pharmaceutical industry in Minas Gerais, Brazil

Today the management of solid waste and wastewater is a major concern for humanity. In the last decade, traces of pharmaceuticals have been reported in the water cycle and have raised concerns among regulators, water suppliers and the public regarding the potential risks to human health. This study evaluated solid waste management in the state of Minas Gerais and concluded that the main fate of hazardous waste has been incineration, while the non-hazardous waste has been recycled or sent to landfills. However, complaints to the Environmental Agency - FEAM have indicated that a significant number of companies just send their hazardous wastes to landfills or even to garbage dumps, thus highlighting the urgent need for adequate waste management in Minas Gerais. Most of the pharmaceutical companies in Minas Gerais use conventional wastewater treatment. Mass spectrometry with electrospray ionization (ESI-MS) showed that the treatment routes adopted by the two 2 selected pharmaceutical industries were not effective enough since residues and degradation products of antibiotics were detected. The physicochemical analysis of the effluents showed variability in their characteristics, which may influence their treatability. The degradation assay with Fenton's reagent stood out as a promising route in achieving a higher removal capacity compared to the conventional treatment. This study contributes to enhancing our knowledge of the management of wastewater as well as of solid waste from the pharmaceutical industry in Minas Gerais and points out the need for further research.

Atualmente, a gestão de resíduos sólidos e águas residuais é uma grande preocupação para a humanidade. Na ultima década, a detecção de traços de medicamentos no ciclo da água tem sido reportada e tem gerado preocupação entre os agentes reguladores, fornecedores de água e público devido os riscos potenciais para a saúde humana. As empresas farmacêuticas, em Minas Gerais, aplicam tratamentos convencionais para as águas residuais e não há praticamente avaliação sobre a eficiência de remoção de resíduos de antibióticos. Este estudo avaliou a gestão de resíduos sólidos e concluiu que o destino principal foi, para o caso de resíduos perigosos, a incineração e, para os não perigosos, a reciclagem e o aterro sanitário. No entanto, denúncias apresentadas à Agência Ambiental - FEAM indicam que número significativo de empresas envia seus resíduos perigosos para aterros sanitários e até mesmo para lixões, ressaltando, assim, a necessidade urgente de adequada gestão dos resíduos gerados. A espectrometria de massas com ionização electrospray (ESI-MS) mostrou que a rota de tratamento convencional adotada por duas empresas do setor selecionadas não foi suficientemente eficaz, uma vez que resíduos e fragmentos de antibióticos foram detectados. Os resultados da caracterização físico-química de efluentes evidenciaram suas características variáveis, que podem influenciar a sua tratabilidade. O ensaio de degradação com o reagente Fenton destaca-se como caminho promissor para alcançar maior remoção. Este estudo contribuiu para elevar o nível de conhecimento no gerenciamento de águas residuais e resíduos sólidos da indústria farmacêutica no estado de Minas Gerais e evidenciou a necessidade de estudos mais detalhados.

Removal of As(III) and As(V) from water using a natural Fe and Mn enriched sample.

The arsenic removal capacity of a natural oxide sample consisting basically of Mn-minerals (birnessite, cryptomelane, todorokite), and Fe-oxides (goethite, hematite), collected in the Iron Quadrangle mineral province in Minas Gerais, Brazil, has been investigated. As-spiked tap water and an As-rich mining effluent with As-concentrations from 100 microg L(-1) to 100 mg L(-1) were used for the experiments. Sorbent fractions of different particle sizes (<38 microm to 0.5 mm), including spherical material (diameter 2 mm), have been used. Batch and column experiments (pH values of 3.0, 5.5, and 8.5 for batch, and about pH 7.0 for column) demonstrated the high adsorption capacity of the material, with the sorption of As(III) being higher than that of As(V). At pH 3.0, the maximum uptake for As(V) and for As(III)-treated materials were 8.5 and 14.7 mg g(-1), respectively. The Mn-minerals promoted the oxidation of As(III) to As(V), for both sorbed and dissolved As-species. Column experiments with the cFeMn-c sample for an initial As-concentration of 100 microg L(-1) demonstrated a very efficient elimination of As(III), since the drinking water limit of 10 microg L(-1) was exceeded only after 7400 BV total throughput. The As-release from the loaded samples was below the limit established by the toxicity characteristic leaching procedure, thus making the spent material suitable for discharge in landfill deposits.