Words Heavy Metals
Mostrando 1-9 de 9 artigos, teses e dissertações.
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1. Resposta de crotalaria juncea a exposição ao niguel
The contamination of the environment with heavy metals has become a world-wide problem. Heavy metals can have direct effects on human health and decreases agricultural yields. In the presence of Nickel (Ni), plant growth and the net photosynthetic rate have been shown to be significantly reduced, even at low concentrations. Moreover, Ni can also inhibit the
Publicado em: 2005
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2. "Estudo da influência do coeficiente de partição de metais no solo de Figueira, Paraná, no cálculo de risco à saúde humana, utilizando o modelo C-Soil" / STUDY OF THE INFLUENCE OF THE METAL PARTITION COEFFICIENT ON THE HUMAN HEALTH RISK EVALUATION, APPLIED TO FIGUEIRA (PR) SOIL REGION, USING C-SOIL MODEL
Studies of partition coefficient show that Kp values of metals can vary orders of magnitude according to the soil physical-chemistry characteristics. Therefore, the Kp is a sensible parameter in human health risk assessment model. In general, a default value is adopted by environmental agencies and often it is not represent suitably the soil studied and can
Publicado em: 2005
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3. Comparative study of cadmium, lead, and mercury concentrations in six watersheds located in the State of São Paulo (Southeast, Brazil) / "Estudo comparativo das concentrações de cádmio, chumbo e mercúrio em seis bacias hidrográficas do Estado de São Paulo".
Concentrações de cádmio (Cd), chumbo (Pb) e mercúrio (Hg) foram determinadas em amostras de água (teores dissolvidos e particulados), sedimento de fundo, peixes e bivalves, coletados em seis bacias hidrográficas do Estado de São Paulo: Alto Paranapanema, Peixe, Aguapeí, São José dos Dourados, Mogi-Guaçu e Piracicaba, as quais apresentam diferentes
Publicado em: 2003
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4. Heavy metals alter the electrokinetic properties of bacteria, yeasts, and clay minerals.
The electrokinetic patterns of four bacterial species (Bacillus subtilis, Bacillus megaterium, Pseudomonas aeruginosa, and Agrobacterium radiobacter), two yeasts (Saccharomyces cerevisiae and Candida albicans), and two clay minerals (montmorillonite and kaolinite) in the presence of the chloride salts of the heavy metals, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, and
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5. Survey of metal tolerance in moderately halophilic eubacteria.
The tolerance patterns, expressed as MICs, for 250 moderately halophilic eubacteria to 10 heavy metals were surveyed by using an agar dilution method. The moderate halophiles tested included 12 culture collection strains and fresh isolates representative of Deleya halophila (37 strains), Acinetobacter sp. (24 strains), Flavobacterium sp. (28 strains), and 14
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6. Physicochemical interaction of Escherichia coli cell envelopes and Bacillus subtilis cell walls with two clays and ability of the composite to immobilize heavy metals from solution.
Isolated Escherichia coli K-12 cell envelopes or Bacillus subtilis 168 cell walls were reacted with smectite or kaolinite clay in distilled deionized water (pH 6.0); unbound envelopes or walls were separated by sucrose density gradient centrifugation, and the extent of adsorption was calculated. At saturation, both clays adsorbed approximately 1.0 mg (dry we
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7. Quantitative assessment of the effects of metals on microbial degradation of organic chemicals.
Biodegradation inhibition of a benchmark chemical, 2,4-dichloro-phenoxyacetic acid methyl ester (2,4-DME), was used to quantify the inhibitory effects of heavy metals on aerobic microbial degradation rates of organic chemicals. This procedure used lake sediments and aufwuchs (floating mats) collected in the field or from laboratory microcosms. Effects of CuC
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8. Gene escape model: transfer of heavy metal resistance genes from Escherichia coli to Alcaligenes eutrophus on agar plates and in soil samples.
Conjugal transfer from Escherichia coli to Alcaligenes eutrophus of the A. eutrophus genes coding for plasmid-borne resistance to cadmium, cobalt, and zinc (czc genes) was investigated on agar plates and in soil samples. This czc fragment is not expressed in the donor strain, E. coli, but it is expressed in the recipient strain, A. eutrophus. Hence, expressi
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9. Tributyltin-resistant bacteria from estuarine and freshwater sediments.
Resistance to tributyltin (TBT) was examined in populations from TBT-polluted sediments and nonpolluted sediments from an estuary and from fresh water as well as in pure cultures isolated from those sediments. The 50% effective concentrations (EC50s) for populations were higher at a TBT-polluted freshwater site than at a site without TBT, suggesting that TBT