Compound dependence of the relationship log Kow and log BCFL

Linear relatinships between log bioconcentration factor (BCF) and log K^ow for a variety of compounds have been reported many times in the literature. Analysis of the thermodynamics of the two partition processes has, however, shown that they are not analogous and that linear relationships can be expected to have different slopes for structurally unrelated compounds. In this study a set of literature lipid normalized BCF (BCF_L) values of chlorbenzenes (CBs) for rainbow trout and polycyclic aromatic hydrocarbons (PAHs) forDaphnia was put together with literature K_ow values. The slopes of the regression lines for log BCF_L versus log K_ow for the two groups of compounds proved to differ significantly in a statistical test using analysis of variance (ANOVA). The difference, which is of significance for estimates of BCFs in environmental modelling of these types of compounds, is explained by the differences in chemical structure of the two groups of compounds.     

Sedimentation and sulfate reduction under a mussel culture

The sedimentation and dissimilatory sulfate reduction under a blue-mussel culture were quantified in order to gain information on the environmental impact of intense mussel farming. The sedimentation rate (3 g C·m^-2·d^-1) under a culture is nearly three times higher than at a nearby reference station. A build-up of sediment rich in organic material and sulfide takes place under the mussels. At 15°C the sulfate reduction rate was 30.5 mmol SO ₌ ⁴ ·m^-2·^-1 in the upper 10 cm of the mussel sediment. The increase in sedimentation under a mussel culture and the consequent effects should be considered when establishing mussel farms.     

Buoyancy of natural populations of marine phytoplankton

Buoyancy of natural populations of marine phytoplankton was studied in a fjord in western Norway during the diatom bloom and in autumn. The study was carried out under approximate in situ conditions by means of an apparatus described in the paper. During the spring bloom, positive buoyancy was observed only once. Sinking rates of individual fractions ranged from 0 to more than 9 m day^-1, and the mean sinking rates of the total chlorophyll content from 0 to at least 2. 2 m day^-1. The highest rates occurred in the post-bloom period, while sinking appeared negligible from the onset of the bloom up to its culmination. In autumn, the population was dominated by small, flagellated cells. Positive buoyancy, or upward migration, was then observed in two out of three experiments.     

Laboratory rearing of Sepiolinae (Mollusca: Cephalopoda)

Five species of Sepiola and Sepictta were reared in the laboratory from egg to adult size. Spawning was achieved in 3 species of Sepiola after 5 to 7 months. The growth rate of the species reared did not depend upon temperature, which ranged from 12.5° to 20°C. A fairly constant size increase (2.5 mm mantle length/month) was observed in Sepiola during the 5 months after hatching. In Sepietta, the same growth rate was observed until the fourth month after hatching, when it increased to the rate of 5 mm mantle length/month.Laboratoire associé au C.N.R.S.     

Green liquor dregs as an alternative neutralizing agent at a pulp mill

Green liquor dregs is the biggest waste fraction at sulphate pulp mills. It is commonly landfilled. Here we demonstrate that the utilization of green liquor dregs as a neutralizing agent for acidic wastewaters is a potential alternative and an environmentally friendly method in contrast to its landfill disposal. The liming effect value of 39.6% for green liquor dregs, expressed as Ca equivalent, is similar to the liming effect value of 38% of a commercial limestone product. In addition, the pH value of 10.7 indicates a strong liming effect.     

Wind tunnel attraction of grapevine moth females, Lobesia Botrana, to natural and artificial grape odour

Summary. Host plant volatiles which attract insect herbivores for egg-laying are of principal interest with respect to insect ecology and evolution. Direct applications concern population monitoring and control through behavioural manipulation. Identification of behaviourally active plant secondary metabolites is essential also for plant breeding for insect resistance. Grapevine moth females Lobesia botrana are attracted by upwind flight to green grape berries Vitis vinifera. The headspace of grape berries was collected on air filters. A solvent extract of these filters, released from a sprayer, attracted females in the wind tunnel. The results demonstrate that volatile cues mediate attraction of grapevine moth females to grape berries, and that headspace collections capture the essence of this odour signal. The air filter extracts were examined by gas chromatography coupled with electroantennographic detection, and the compounds eliciting a consistent antennal response in L. botrana females were identified by mass spectrometry. The headspace collection apparatus was calibrated for collection efficiency of the active compounds. Their recovery rate ranged from 35 % for methyl salicylate to 83 % for (E,E)-α-farnesene. A synthetic ten-component blend was then formulated. The blend consisted of compounds eliciting an antennal response, formulated in a blend ratio corrected for differences in collection efficiency. Subsequent wind tunnel tests showed that female attraction to this synthetic ten-component blend was not significantly different from attraction to grape berries, or to headspace collections of the same berries. At a release rate of 35 ng/h of the most abundant compound (E)-β-caryophyllene, 20 % of the test females approached the source of sprayed headspace collections and the ten-component synthetic blend, respectively. In comparison, 100 g of green berries, releasing the main compound (E)-β-caryophyllene at a rate of ca. 4.7 ng/h, attracted 10 % of the females by upwind flight followed by source contact.     

New potential mammalian lignan metabolites of environmental phytoestrogens

Seven new dibenzylbutyrolactone and six new dibenzylbutanediol lignans were prepared to assist in the identification of a number of potential mammalian metabolites of the endocrine disrupting plant lignans syringaresinol and medioresinol, present in food.