[en] Speciation studies are described for Cd and Pb in a broad range of polluted soils. Cadmium was present mainly in cationic forms whereas cationic species of Pb predominated in the acid soils and neutral species were most important in the alkaline soil. Cadmium was present in higher concentrations than Pb in soil solutions, although, in most cases, the total Pb contents of the soils were usually higher than those for Cd. Adsorption of Cd at low concentrations (<10μg ml/sup -1/), could be described by the Freundlich equation but at the lower end of this concentration range a linear equation proved most suitable for describing adsorption. Kd values were determined from this linear equation and found to be affected by pH, organic matter and hydrous oxide content. Greenhouse pot trials showed that CaCl/sub 2/-extractable CD correlated closely with Cd in the edible portions of carrots and cabbages

[en] Monosodium methanearsonic acid (MSMA) was chosen as the model compound for a study of the degradation of organic arsenicals in soil. Comparison of evolved ¹⁴CO₂ from four sterile and nonsterile soils 60 days after treatment with MSMA-¹⁴C showed that from 1.7 to 10.0% of the MSMA-¹⁴C was degraded in nonsterile soil, as compared with 0.7% in steam-sterilized controls. Four soil microorganisms isolated in pure culture degraded from 3 to 20% of the MSMA-¹⁴C to ¹⁴CO₂ when grown in liquid culture containing 10 ppm of MSMA and 1 gram per liter of yeast extract. Thin-layer chromatography (TLC) on silica gel G-coated plates effected the separation of MSMA, arsenate, and arsenite. Only arsenate and MSMA were detected after TLC of extracts from the soil and microbial growth experiments. These data indicate that soil microorganisms are at least partly responsible for MSMA degradation in soil. 10 references, 3 figures, 3 tables

No abstract available

[en] Wastewater is passed sequentially through an anaerobic treating zone and an oxic treating zone, followed by separation from the treated liquor of a dense sludge containing activated biomass, at least part of which is recycled to provide the activated biomass employed in treating the influent wastewater. Of the part of the sludge so recycled a minor portion is introduced into the anaerobic treating zone for admixture with the wastewater influent and the remaining major portion is introduced into the oxic treating zone, into which oxic zone oxygen-containing gas is admitted to effect oxygenation of the contents of that zone

[en] Heat causes an extremely wide spectrum of cellular alterations; their relative importance is however yet undefined. The authors have explored the effects of heat on cellular regulation at the cytoplasmic level. One level of regulations, historically of interest investigation of thermal responses, is bioenergy status. The common intermediates of energy exchange are the adenylates (ATP, ADP, AMP). Heating inhibits energy production and perturbs energy-dependant processes such as Rb/sup +/ uptake, maintenance of H/sup +/ gradients and membrane potential. However the significance of such changes is not clear; energy depletion is not tightly coupled to cell killing, as it is for instance in the starved cell. A second, more finely tuned area of regulation is mediated through the ''second messengers'' cyclic AMP and Ca/sup 2+/. The intracellular concentrations of these 2 substances are closely controlled; major alternations in their concentrations are associated with a number of explosive cellular events. Lin et al (1978) found large heat-induced alterations in cyclic AMP level. Recent studies indicate major and complex changes in Ca/sup 2+/ after heating. Clearly the above processes are not the only ones altered by hyperthermia. However metabolic regulations at the cytoplasmic level seems a fruitful area for study due to the rapid responses involved and their tendency to amplification by intracellular cascade reactions

[en] The authors used 12-O-tetradecanoyl-phorbol-13-acetate (TPA) to directly stimulate protein kinase C (PKC) in order to examine the role of PKC in transduction of biological signals that increase metabolism of arachidonic acid. Release of radioactive arachidonic acid and prostaglandins from TPA-stimulated MDCK cells is inhibited by either of two PKC inhibitors: 1-(5-isoquinolinesulfonyl)piperazine and 1-octadecyl-2-methoxy-glycero-3-phosphocholine (ALP). ALP is unable to inhibit cyclooxygenase when added into an in vitro assay for this enzyme. Furthermore, TPA induces de novo synthesis of cyclooxygenase in MDCK cells but ALP fails to prevent this effect of TPA. Thus, cyclooxygenase activity appears to be independent of PKC and TPA can still induce de novo synthesis of cyclooxygenase even in the presence of the PKC inhibitor ALP. Also, ALP has no effect on the release of arachidonic acid which occurs upon addition of the calcium ionophore A23187 to MDCK cells suggesting that there are multiple mechanisms to mobilize arachidonic acid. Their data indicate that activation of PKC by TPA leads to increased release of arachidonic acid through regulation of phospholipase(s) by PKC

[en] The broad-spectrum mercurial-resistance plasmid pDU1358 was analyzed by cloning the resistance determinants and preparing a physical and genetic map of a 45-kilobase (kb) region of the plasmid that contains two separate mercurial-resistance operons that mapped about 20 kb apart. One encoded narrow-spectrum mercurial resistance to Hg²⁺ and a few organomercurials; the other specified broad-spectrum resistance to phenylmercury and additional organomercurials. Each determinant governed mercurial transport functions. Southern DNA x DNA hybridization experiments using gene-specific probes from the plasmid R100 mer operon indicated close homology with the R100 deteminant. The 2153 base pairs of the promoter-distal part of the broad-spectrum Hg²⁺-resistance operon of pDU1358 were sequenced. This region included the 3'-terminal part of the merA gene, merD, unidentified reading frame URF1, and a part of URF2 homologous to previously sequenced determinants of plasmid R100. Between the merA and merD genes, an open reading frame encoding a 212 amino acid polypeptide was identified as the merB gene that determines the enzyme organomercurial lyase that cleaves the C-Hg bond of phenylmercury

[en] Spectral responses for DNA damages caused by far-uv, near-uv, and visible light radiations have been studied. The near congruence of the spectra for far-uv damages and the spectrum of DNA is good evidence that the mechanism is the same for the induction of breaks, crosslinks, and pyrimidine dimers. For near-uv, the different spectra imply that at least several nonDNA sensitizer molecules act as primary chromophores, but that DNA damage eventually results. With the understanding that near-uv and visible radiations produce a variety of chemically potent reactive oxygen species within the cell, we recognize the possibility for many types of DNA damage. If we assume that SSBs and DNA-to-protein crosslinks are random single events along the genome, it is possible to compute the number of events per cell genome per lethal event caused by the different energies used. In the near-uv and visible region, many more breaks and crosslinks are formed per lethal event than by far-uv. About 20 times more SSBs per lethal event are caused by 365-nm radiation than by x-rays, strong evidence that these breaks are effectively repaired. It is therefore likely that SSBs are not a serious event with regard to cellular lethality. The role of crosslinks and their repair in lethal events is less clear. The lack of any correlation at all between the action spectra for SSBs, or crosslinks, and lethality and mutagenesis in the same cells is evidence that another lesion or lesions are involved in these events. The multitude of chemical events that can be caused in cellular metabolites by the reactive species generated by these long wavelengths of radiation means that death is attributable to the total spectrum of changed chemicals delivered by a lethal dose, only some of which are DNA changes leading to SSBs and crosslinks. 43 refs., 3 figs., 2 tabs

[en] The Federal Health Office was the central research institution of Germany working on the sector of public health and commissioned to recognise health hazards, assess them and fight them with the legal instruments at its disposal and also give scientific advice. By setting up an information service on environmental medicine the Office attempts to provide a forum of discussion for this cross-sectional, interdisciplinary area of medicine. The omnibus presented here is distributed free of charge by the health offices in the country and addressed to all interested parties. The 1992 and 1993 contributions give an overview of the wide spectrum of problems of environmental medicine and also explains the viewpoints and opinions of the Federal Health Office. An index is provided. (orig.)

[en] Some needle parameters (water content, fiber, sugar, starch, nitrogen, tannins) important for the nutritional quality for the larvae of the small spruce sawfly Pristiphora abietina (Christ) were determined to explain the partial mass outbreak of this insect in the Hausruck (Upper Austria). The stands chosen for investigation - comparable in microclimate and coincidence, but with different infestation rates - were exposed to variable air contaminants. The trees seriously attacked by the insect even though exposed to higher nitrogen impact - showed significantly lower nitrogen levels, lower water content, sugar and starch levels, but increased fiber and tannin concentrations. Shoot length also was significantly reduced. We suppose that the excessive air pollution in the area investigated is responsible for these changes in needle chemistry, enhanced by the counteractions of the heavily attacked trees against the insect pest. (orig.)