RESUMO Lagos artificiais formados em áreas de mineração a céu aberto são unidades complexas e se constituem em passivos ambientais emergentes advindos da indústria da mineração. Embora estejam aumentando em número em várias partes do globo, são um problema ambiental recente e ainda pouco estudado, especialmente no tocante à qualidade e à toxicidade de suas águas, que podem apresentar riscos ambientais preocupantes, dado seu potencial de contaminação. O presente trabalho descreve os resultados da análise sazonal de aspectos químicos, ecotoxicológicos e genotoxicológicos das águas de três cavas de mineração de ouro desativadas localizadas em Mara Rosa, Goiás, Brasil. Amostras de água foram coletadas em perfil em duas estações climáticas distintas - inverno e verão - e foram analisadas quimicamente para determinação de metais e ânions. Também foram desenvolvidos testes ecotoxicológicos e ensaios cometa com peixes da espécie Danio rerio. Os resultados indicaram que as concentrações das espécies químicas analisadas se mostraram predominantemente crescentes no sentido da superfície ao fundo e mais elevadas durante a estação seca. As águas do Lago Azul demonstram estar quimicamente comprometidas, pois são ácidas e ricas em analitos potencialmente tóxicos, como alumínio, cádmio, chumbo, cobre, manganês, níquel e zinco. Não foram identificadas alterações ecotoxicológicas significativas para nenhuma das amostras analisadas, todavia, em termos genotoxicológicos, o Lago Azul apresentou danos ao DNA a partir da concentração de 25% na estação seca e de 50% na estação chuvosa.

ABSTRACT Artificial lakes formed in open pit mining areas are complex units and constitute emerging environmental liabilities arising from the mining industry. Although they are increasing in number in several parts of the world, they still form a recent and little studied environmental problem, especially regarding the quality and toxicity of its waters, which may represent worrying environmental risks. This study describes the results of the seasonal analysis of chemical, ecotoxicological and genotoxicological aspects of the waters of three disused gold mining pit lakes located in Mara Rosa, Goiás, Brazil. Samples were collected in profile in two different climatic seasons, winter and summer, and were chemically analyzed to determine their load of metals and anions. Ecotoxicological Tests and Comet Assays were also developed with fish of the Danio rerio species. The results indicated that the concentrations of the chemical species analyzed were predominantly increased in the surface-bottom direction and higher during the dry season. Lago Azul waters have been shown to be chemically more compromised as they are acidic and rich in potentially toxic analytes such as aluminum, cadmium, lead, copper, manganese, nickel, and zinc. No significant ecotoxicological alterations were identified for any of the analyzed samples, although, in genotoxicological terms, Lago Azul presented DNA damage from concentrations of 25% in the dry season and 50% in the wet season.

Considering the high interest and commercial value of pigments from microalgae, this study aimed to stablish the best lutein and β-carotene extraction method for Desmodesmus sp., a microalgae with high biomass production. The evaluation was done considering the best solvent or solvent mixture, number of extractions, pre-treatment of dry biomass with acetone, saponification in methanol and ethanol and stability evaluation of the obtained extract. Among achieved results, the best solvent extractor was a hexane:ethanol mixture in a 1:1 (v/v) proportion. In order to obtain maximum yield, the pattern stablished includes six extractions performed for 40 minutes. Stability tests presented that xanthophylls and carotenes pigments were more stable in methanol and that xanthophylls and carotenes pigments were less negatively affected than chlorophylls in the methanolic extract. Chromatographic identification and quantification of pigments from Desmodesmus sp. microalgae revealed that its major constituents are trans-zeaxanthin, chlorophyll b, β-carotene and trans-lutein.

In this work, the fatty acid quantity and composition of six freshwater microalgae and soybean grains was determined by direct transesterification and gas chromatography analysis. The results showed that all the freshwater microalgae species presented a higher quantity of fatty acid than soybean grain. Choricystis sp. (A) provides 115% more fatty acids per gram of biomass than soybean grain. With regard to the fatty acid composition, Choricystis sp. (A) showed an adequate proportion of saturated and unsaturated fatty acids, with lower quantity of polyunsaturated fatty acids and, akin to some marine microalgae, constitutes an alternative raw material for biodiesel production.

Anthocyanins extracted from picao, quaresmeira, petunia, flamboyant, purple ipe, lobeira, pata de vaca, jaboticaba, purple cabbage and jambul were evaluated as natural acid-base indicators. Anthocyanins in extracts were identified using HPLC/MS. Clear, rapid change in color at final-point titration was observed for extracts but only picao showed strong change in pH. Indirect determination of carbonate in limestone using a natural indicator was performed and results compared with phenolphthalein indicator and potentiometer titration. Optimal results were obtained with picao but other extracts showed good accuracy and precision.

O objetivo deste estudo foi avaliar a capacidade de polimerização de três unidades fotopolimerizadoras por meio da análise da influência das fontes de luz, regimes de cura (QTH, L1, L2 e L3) e diferentes permeantes (água e etanol) na sorção, solubilidade e quantidade de monômeros residuais de um adesivo dentário. Espécimes de AdperTM Single Bond 2 foram feitos utilizando uma matriz circular de aço inoxidável (8 mm x 1 mm). Três fontes de luz, uma a base de luz halógena (QTH) e duas a base de diodos emissores de luz (LED), em três diferentes regimes de cura (L1 = 12J; L2 = 24J; L3 = 24J) foram usados para fotoativar os espécimes. Os espécimes foram armazenados em dois tipos de permeantes (água deionizada ou etanol a 75%), por dois diferentes períodos de armazenamento (G1 =7 dias; G2 = 30 dias). Os espécimes foram submetidos a testes de sorção e solubilidade de acordo com a ISO 4049:2000. Após o período de armazenamento, os monômeros residuais foram identificados e quantificados por cromatografia líquida de alta eficiência (HPLC). Para sorção, L1 apresentou os maiores valores significantes e QTH os menores. Para solubilidade, nos grupos do etanol, L1 apresentou os maiores valores e QTH os menores e os achados foram estatisticamente diferentes dos outros regimes de cura. L1 extraiu significantemente mais monômeros do que os outros regimes e QTH teve os menores resultados. As fontes de luz, os regimes de polimerização e os diferentes permeantes influenciaram na sorção, solubilidade e quantidade de monômeros residuais extraídos do adesivo em estudo.

The aim of this study was to assess polymerization ability of three light-curing units by evaluating the influence of the light source, curing regimen and permeant (water or ethanol) on sorption, solubility and amount of residual monomers of a dental adhesive. Specimens of Adper Single Bond 2 were fabricated using a stainless steel circular matrix (8 mm x 1 mm). One quartz-tungsten-halogen (QTH) lamp and two light-emitting diode (LED) device at three different curing regimes (L1 = 12 J; L2 = 24 J; L3 = 24 J) were used to cure the specimens. Specimens were stored in two types of permeants - deionized water or 75% ethanol - for two storage times (G1 =7 days; G2 = 30 days). The specimens underwent water sorption and solubility tests, according to ISO 4049:2000 standard. After storage, residual monomers were identified and quantified by high performance liquid chromatography (HPLC). For sorption, L1 showed the highest values and QTH, the lowest. For solubility, in ethanol-stored groups, L1 had also the highest values, and QTH, the lowest, and findings were significantly different from the other curing regimens. L1 leached significantly more monomers than the others, and QTH had the lowest results. In conclusion, the type of light source, the curing regimen and the permeant affected sorption, solubility and amount of residual monomers of the adhesive under study.

The objective of this study was to assess a new monitoring technique of particulate and trace metals in the atmosphere via the use of a passive sampler of air pollutants in the city of Goiânia. The average particulate weight and average concentrations of metals Fe, Cr, Zn, Pb, Cu, Mn, and Cd were 0.1104 g and 257.5; 23.4; 17.8; 6.7; 1.9; 0.8; 0.2 μg/m²/day, respectively. Higher Pb and Cr concentrations were obtained in areas with intense traffic. This study revealed that it is possible to monitor trace metals with passive sampling, developed at a low cost and operational facility.

This study investigates the use of wild animal hair of C. brachyurus, C. thous and L. pardalis as biomonitors of trace metal at Parque Nacional das Emas, Brazil. Results reveal a strong correlation between Cd and Pb as well as Cu and Zn, which suggests a single source of emission. Most metals showed a lower or equal concentration than those obtained in previous studies. The research shows that monitoring may be performed only with Zn, Pb, Cd, and Cr because of statistical similarity and of a non-natural occurrence of large amounts of the material under analysis.

A isotretinoína, quimicamente conhecida como ácido-13-cis-retinóico, faz parte do amplo grupo de compostos relacionados à vitamina A. É empregada particularmente no tratamento da acne cística e nodular e como inibidor da proliferação de células neoplásicas, por exercer efeito regulador sobre a diferenciação celular. Os efeitos adversos envolvendo o uso de isotretinoína estão relacionados à pele e membranas mucosas, sistemas nervoso, músculo esquelético, linfático, gastrintestinal, cardiorespiratório e geniturinário. A isotretinoína é um composto termo e fotossensível e, por assim se apresentar, desperta o interesse pelo estudo de sua estabilidade, empregando-se para isso várias metodologias analíticas como a CLAE, CG, análise térmica, espectroscopia de massa, microcalorimetria, difratometria de raios-X e muitas outras que devem ser selecionadas de acordo com o interesse do pesquisador.

Isotretinoin, or 13-cis-retinoic acid, is one of the vitamin A related compounds. Isotretinoin is used for the treatment of severe cystic acne and also shows inhibitory activity over the proliferation of neoplasic cells, due to its efficiency in regulating cell diferentiation. Side effects are related to skin and mucous membranes, central nervous system, muscles, lymphatic, gastrintestinal, pulmonary and genitourinary systems. Isotretinoin is a highly thermal and photolabile compound. Stability studies require several analytical methods such as HPLC, GC, thermal analysis, mass spectrometry, microcalorimetry and X-Ray difratometry.

Óleos e gorduras vegetais são muito ultilizados pela indústria alimentícia e farmacêutica, tem exigido de pesquisadores e técnicos métodos analíticos capazes de avaliar as condições de processamento e estocagem. A estabilidade térmica de óleos vegetais é um fator determinante na sua qualidade. Neste trabalho avaliou-se a estabilidade térmica de óleos e gorduras vegetais extraídos de semente de plantas do cerrado ( araticum, babaçu, buriti, guariroba e murici) usando os resultados de TG, DTG e DTA, numa faixa de temperatura entre 30 e 650ºC, em atmosfera de nitrogênio, com razão de aquecimento de 10ºC min-1. As técnicas termoanalíticas utilizadas mostraram-se eficientes e rápidas na determinação da estabilidade térmica dos óleos e gorduras estudados.

Vegetal oils and fats are very useful in the food and chemist industry, they have demanded from researchers and technicians analytical methods able to estimate the conditions for their processing and storage. The thermal stability of vegetal oils is a main determinant in recognizing their value. The goal of this study is to evaluate the thermal stability of vegetable oils and fats extracted from the seeds of plants from Brazilian cerrado (araticum, babassu, Brazilian wine-palm, guariroba, murici). The thermal stability was evaluated by TG/DTG and DTA techniques, in a temperature range from 30º to 650º, under nitrogen atmosphere, and at a heating rate 10º C min-1. The TG/DTG and DTA used were efficient and fast in the determination of oils and fasts studied.