Dietary exposure to dioxin-like compounds in three age groups: results from the Flemish environment and health study

Lipophilic contaminants are present in the environment and bioaccumulate in the food chain. Therefore, their intake via animal fat of various sources was assessed for three age groups of the Flemish population, participating in a large biomonitoring program of the Flemish government. In total, 1636 adolescents (14-15 years), 1186 mothers (18-44 years), and 1586 adults (50-65 years) participated in the study and completed a semi quantitative food frequency questionnaire. Individual consumption data were combined, via a so-called simple distribution approach, with recent data on polychlorinated dibenzo-p-dioxins/furans and dioxin-like polychlorinated biphenyls, measured via the chemical-activated luciferase gene expression (CALUX) bio-assay in food items available on the Flemish market. The median (95th percentile) estimated intakes of dioxin-like contaminants were 2.24 (4.61), 2.09 (4.26), and 1.74 (3.53) pg CALUX-TEQ kg(-1) bw d(-1) for, respectively adolescents, mothers and adults. These data are in the same range as those found in other European studies. The CALUX-TEQ results of respectively 59.8%, 53.7% and 36.2% of the adolescent, mother and adult population exceed the tolerable weekly intake (TWI) of 14 pg WHO-TEQ kg(-1) bw w(-1), as derived by the Scientific Committee on Food [Scientific Committee on Food, 2001. Opinion of the Scientific Committee on Food on the Risk Assessment of Dioxins and Dioxin-like PCBs in Food, CS/CNTM/DIOXIN/20 final Brussels, Belgium]. The main contributors of dioxin-like substances are fish and seafood (25-43% of the total intake), added fats (22-25% of the total intake) and dairy products (17-20% of the total intake).     

Behaviour and redox sensitivity of antimicrobial residues during bank filtration

The behaviour of residues of antibiotic drugs during bank filtration was studied at a field site in Berlin, Germany, where bank-filtered water is used for the production of drinking water. The neighbouring surface water used for bank filtration is under the influence of treated municipal wastewater. Seven out of 19 investigated antimicrobial residues were found in the surface water with median concentrations between 7 and 151ngL(-1). Out of the seven analytes detected in the surface water only three (anhydroerythromycin, clindamycin and sulfamethoxazole) were found with median concentrations above their limits of quantitation in bank filtrate with a travel time of one month or less. With the exception of sulfamethoxazole, none of the 19 analytes were present in bank filtrate with a residence time larger than one month or in the water-supply well itself. Sulfamethoxazole found with a median concentration of 151ngL(-1) in the surface water was the most persistent of all antimicrobial residues. Nevertheless, it was also removed by more than 98% and only found with a median concentration of 2ngL(-1) in the water-supply well. The degradation of clindamycin and sulfamethoxazole appear to be redox-dependent. Clindamycin was eliminated more efficiently under oxic infiltration conditions while sulfamethoxazole was eliminated more rapidly under anoxic infiltration conditions. A slight preference for an improved degradation under oxic (clarithromycin and roxithromycin) or anoxic (anhydroerythromycin) conditions was also observed for the macrolide antibiotics. Nevertheless, all macrolides were readily removable by bank filtration both under oxic and anoxic conditions.     

Relationships between meiofaunal population densities and physico-chemical properties of unpolluted sandy beaches

Water and sediment samples from ten unpolluted sandy beaches have been analysed for various chemical parameters and meiofauna. The results have indicated that, within the range of grain sizes found, (196–337 m), short term fluctuations in the natural levels of the various chemical constituents do not significantly influence the densities of meiofauna populations. These are, however, governed largely by the median grain size of the sediments. The relationships between median grain size and the population densities of nematodes and harpacticoid copepods have been established. The optimum grain size for the populations studied was 284 m, and as the sediment size deviated from this, the population density decreased. Thus knowledge of the median grain size of sediments should indicate the approximate meiofaunal density which can be expected in the absence of any other external influence. Deviations from this can then be attributed to perturbation.     

Comparison of two carbon analysis methods for monitoring diesel particulate levels in mines

Two carbon analysis methods are currently being applied to the occupational monitoring of diesel particulate matter. Both methods are based on thermal techniques for the determination of organic and elemental carbon. In Germany, method ZH 1/120.44 has been published. This method, or a variation of it, is being used for compliance measurements in several European countries, and a Comité Européen de Normalization Working Group was formed recently to address the establishment of a European measurement standard. In the USA, a 'thermal-optical' method has been published as Method 5040 by the National Institute for Occupational Safety and Health. As with ZH 1/120.44, organic and elemental carbon are determined through temperature and atmosphere control, but different instrumentation and analysis conditions are used. Although the two methods are similar in principle, they gave statistically different results in a previous interlaboratory comparison. Because different instruments and operating conditions are used, between-method differences can be expected in some cases. Reasonable agreement is expected when the sample contains no other (i.e., non-diesel) sources of carbonaceous particulate and the organic fraction is essentially removed below about 500 degrees C. Airborne particulate samples from some mines may meet these criteria. Comparison data on samples from mines are important because the methods are being applied in this workplace for occupational monitoring and epidemiological studies. In this paper, results of a recent comparison on samples collected in a Canadian mine are reported. As seen in a previous comparison, there was good agreement between the total carbon results found by the two methods, with ZH 1/120.44 giving about 6% less carbon than Method 5040. Differences in the organic and elemental carbon results were again seen, but they were much smaller than those obtained in the previous comparison. The relatively small differences in the split between organic and elemental carbon are attributed to the different thermal programs used.     

Ratio and population density of psammolittoral meiofauna as a perturbation indicator of sandy beaches in South Africa

Since 1975, pollution surveys have been carried out along the South African south and west coasts as part of a monitoring program of unpolluted areas and known and anticipated impact areas. To evaluate these data a reference or baseline level was needed. In unpolluted beaches a close relationship between meiofauna and sediment grain size was found and granulometric analysis was found to be important. This relationship was used to evaluated perturbation effects. It was found that contamination by chemical effluent depressed numbers of the nematodes and harpacticoids drastically. Mechanical perturbation increased the number of harpacticoid copepods but did not affect nematode densities. Oil in beaches decreased the number of harpacticoids, while normal nematode densities were found. Organic enrichment increased the number of nematodes, harpacticoid numbers remained normal while the perturbation effect due to sewage increased the number of both taxa.Explanations for these effects are given, together with related chemical analyses. The application of these results to other sandy beaches elsewhere is discussed briefly.     

Der einfluß des lichtes auf Körperfärbung und dämmerungsverhalten des korallenfisches Chaetodon melanotus

The influence of light on colour patterns and behaviour of the coral-reef fish Chaetodon melanotus were investigated under aquarium and field conditions. Colour pattern and fin position are correlated with agonistic behaviour: they were used as criterion for analysing the behavioural patterns during morning and evening transition.Readiness for attack is correlated with a darkening of the analfin. A specimen with yellow anal fin and spread dorsal fin is more likely to flee. The colour patterns vary during day, twilight, and night time. The speed of colour change was measured experimentally; it appears to be hormonally regulated. During twilight, 5 different colour patterns are related with certain anal-fin colour-patterns and dorsal-fin positions. Swimming activity decreases with reduction in irradiance, while the readiness to flee increases. In groups, specimens become more territorial with diminishing day light. Territorial aggression can be light-dependent; no territorial aggression was observed at illuminations less than 50 lux. Behaviour and concomitant coloration-changes during the evening and morning transition periods are interpreted as adaptational protections against predators. The remarkable white eyespots in the twilight body-coloration could represent a warning signal, and could also have a somatolytic effect. The increased readiness to flee during dusk and dawn may be a behavioural mechanism for reducing predator pressure.