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The development of a novel strategy for the microbial treatment of acrylonitrile effluents.

Effluent from the manufacture of acrylonitrile is difficult to biodegrade. It contains nine major organic components: acetic acid, acrylonitrile, acrylamide, acrylic acid, acrolein, cyanopyridine, fumaronitrile, succinonitrile, and maleimide. A range of bacteria have been isolated that can grow on, or convert all of the organic components of effluent from the manufacture of acrylonitrile. These bacteria can be used as the basis of a mixed culture system to treat the effluent. The bacteria were utilised in batch and continuous cultures to degrade a synthetic wastewater containing acrylonitrile, acrylamide, acrylic acid, cyanopyridine and succinonitrile. The mixed microbial population was adapted by varying the growth rate and switching from continuous to batch and back to continuous growth, to degrade these five compounds as well as acrolein, fumaronitrile and maleimide.

Acrolein↗

Environmental control in the uranium mine Lagoa Real, Brazil.

Uranium production in Brazil will be restarted in the year 2000, through exploration of the Jazida da Cachoeira, located in the uraniferous region of Lagoa Real, Bahia State, northeast Brazil. Because of the mining operations, an open cast mine of approximately 27 x 10(4) m2 will be produced and the material removed will constitute approximately 14 x 10(6) tons, occupying an estimated area of 50 x 10(4) m2. Currently, there is a new concept about project developing, where the impact assessment is addressed during the initial phases. Beside this, legislation requires an environmental impact assessment before starting mining activities. In this context purpose, it is the purpose of this work to evaluate the chemical composition of the future waste; thus, samples were collected from the rocks that surround the mineral deposits. Instrumental neutron activation analysis was used for the elemental quantification, the mean elemental concentrations were calculated, and the ratios were normalized using North American Shale Composite (NASC). In the raw material eight main mineral structures exist whose elementary composition were compared using the statistical techniques of analysis of variance, ranking ANOVA, and multivariate ANOVA.

Brazil↗

Application of nuclear analytical techniques using long-life sealed-tube neutron generators.

The new range of sealed-tube neutron generators developed by SODERN appears to be appropriate for the industrial environment. The main characteristics are the high emission stability during the very long lifetime of the tube, flexible pulsed mode capability, safety in operation with no radiation in "off" state, and the easy transportation of equipment. Some applications of the neutron generators, called GENIE, are considered: high-sensitivity measurement of transuranic elements in nuclear waste drums, bulk material analysis for process control, and determination of the airborne pollutants for environmental monitoring.

Air Pollutants, Radioactive↗

Nuclear analytical techniques in environmental studies.

Nuclear analytical techniques are particularly suitable for measuring trace components in a wide variety of environmental samples, and for that reason, the techniques have made a significant contribution to environmental research. Presently, at a time when biosphere contamination and threats of global change in the atmosphere are of widespread concern, there exist an impressive array of specialized instrumental methods available to life scientists engaged in environmental studies; however, the nuclear techniques will probably continue to play a useful role in the future, notwithstanding the decreasing availability of necessary facilities, such as research reactors and accelerators. Reasons for the particular suitability of radionanalytical techniques are reviewed and illustrated by examples of recent applications to solid wastes, biomonitoring, and urban aerosol source identification in this laboratory.

Environmental Pollution↗

Accumulation of biodegradable copolyesters of 3-hydroxy-butyrate and 3-hydroxyvalerate in Alcaligenes eutrophus.

Biodegradable copolyesters of 3-hydroxybutyrate-co-3-hydroxyvalerate (3HB-3HV) were produced by Alcaligenes eutrophus in a two-staged process, namely growth stage and nitrogen-deficient polyester-accumulation stage. When C5 was used as the sole carbon source, the copolyester contained 43 mol % of 3HV. A range of copolyesters with 0-43 mol % of 3HV could be produced by using a medium containing different concentration ratios of butyric acid C4 and C5. Tm of PHB homopolymer was 177.6 degrees C and that of copolyester with highest 3HV mol fraction of 43% was 99.0 degrees C. C5 concentration in the medium could be an effective means to control the polymeric composition and mechanical properties of the copolyesters accumulated in A. eutrophus.

3-Hydroxybutyric Acid↗