Organochlorine and heavy metals in newborns: Results from the Flemish Environment and Health Survey (FLEHS 2002–2006)

To collect regional information on internal levels of pollutants in humans in Flanders, 1196 mother–child pairs were systematically recruited in 2002–2003 via 25 maternities across Flanders. Cd, Pb, PCB congeners 118, 170, 138, 153 and 180, p,p′-DDE — a key metabolite of DDT- and hexachlorobenzene (HCB) were measured in cord blood or plasma. Cd was detected in 64% of the samples (geometric mean 0.21 µg/L cord blood). p,p′-DDE (110 ng/g plasma lipids) and Pb (14.7 µg/L blood), were measurable in nearly all samples. The individual PCB congeners could be detected in 40 to 81% of the newborns (138 + 153 + 180 = 64.4 ng/g plasma lipids). HCB (18.9 ng/g plasma lipids) and dioxin-like compounds measured by DR-CALUX® (23 pg CALUX-TEQ/g lipids) were above detection limit in more than 75% of the samples. Age and smoking habits of the mothers, did not influence the cord blood Pb and Cd levels. The organochlorines increased 4 to 9% per year of the mother's age (partial R² = 0.05 to 0.22). Mothers had 2.6% less PCBs in cord blood (partial R² = 0.02) for each unit increase in pre-pregnancy BMI. Season of delivery, breastfeeding previous children or consumption of local dairy products, were minor determinants. Up to 20% of the variability in organochlorine concentrations was explained by residence area. It was concluded that the place of birth in Flanders is an important determinant of the load of pollutants measured at the start of life. This underlines the validity of human biomonitoring on (relatively) small geographical scale.     

Sternentstehung und interstellare Materie

In recent years several hitherto unknown types of celestial objects related to star formation and early stellar evolution have been discovered by infrared and radio observations. New stars are born within large and massive interstellar molecular clouds. The onset of star formation in these clouds seems to be triggered by external forces.     

Control of bacterial speck of tomato by copper and ethylenebisdithiocarbamate fungicides: their efficacy and residues on leaves

Field studies were conducted to determine the synergism, persistence, and efficacy of a tank-mix spray of cupric hydroxide and mancozeb for control of bacterial speck of tomato. The increased efficacy of the cupric hydroxide-mancozeb mixture could not be attributed to the formation of a bacteriostatic compound in the tank mixture nor to a greater persistence of the mixture on the tomato foliage.     

Some pharmacokinetic aspects of PCDDs and PCDFs in mammals after administration of a fly ash extract from a municipal incinerator

Fly ash extracts were fed to male hamster (single dose), male rat (single dose and multiple dose), pregnant and lactating female rat (multiple dose). The retention of four isomers, 2,3,7,8-TCDD, 2,3,7,8-TCDF, 1,2,3,7,8-PnCDD and 2,3,4,7,8-PnCDF, was studied in the liver of the adults, foetuses and liver of the sucklings.

Liver retention was structure dependent and different for both species. Transportation of the isomers via the mother milk was 50–100 times more effective than via the placenta.

After a single intravenous dose of fly ash extract to male rats the elimination of these four isomers was studied in the liver, during a period of 10 days. Elimination rates for 2,3,7,8-TCDD, 1,2,3,7,8-PnCDD and 2,3,4,7,8-PnCDF were in the same range. Pharmacokinetic calculations were done on both tetra congeners, to obtain information about the validity of the published K_e values in the multiple dose experiments with male rats.

For 2,3,7,8-TCDF the K_e value was applicable, but for 2,3,7,8-TCDD the validity of the K_e could not be determined.     

Estimating the complexity of bird song by using capture-recapture approaches from community ecology

Repertoire size, the number of unique song or syllable types in the repertoire, is a widely used measure of song complexity in birds, but it is difficult to calculate this exactly in species with large repertoires. A new method of repertoire size estimation applies species richness estimation procedures from community ecology, but such capture-recapture approaches have not been much tested. Here, we establish standardized sampling schemes and estimation procedures using capture-recapture models for syllable repertoires from 18 bird species, and suggest how these may be used to tackle problems of repertoire estimation. Different models, with different assumptions regarding the heterogeneity of the use of syllable types, performed best for different species with different song organizations. For most species, models assuming heterogeneous probability of occurrence of syllables (so-called detection probability) were selected due to the presence of both rare and frequent syllables. Capture-recapture estimates of syllable repertoire size from our small sample did not differ significantly from previous estimates using larger samples of count data. However, the enumeration of syllables in 15 songs yielded significantly lower estimates than previous reports. Hence, heterogeneity in detection probability of syllables should be addressed when estimating repertoire size. This is neglected using simple enumeration procedures, but is taken into account when repertoire size is estimated by appropriate capture-recapture models adjusted for species-specific song organization characteristics. We suggest that such approaches, in combination with standardized sampling, should be applied in species with potentially large repertoire size. On the other hand, in species with small repertoire size and homogenous syllable usage, enumerations may be satisfactory. Although researchers often use repertoire size as a measure of song complexity, listeners to songs are unlikely to count entire repertoires and they may rely on other cues, such as syllable detection probability.Communicated by A. Cockburn