Gehalte aan PCB's en organochloorpesticiden in mariene organismen van de Belgische kustwateren

Polychlorinated biphenyls (PCBs) and some oranochlorine pesticides were measured in flounder, cod, sole, shrimps and mussels by capillary gaschromatography. PCBs predomiated among the organochlorine residues and represented 75 to 90 % of the global content. The average PCB-concentration in the wet tissue ranged from 39.5 ppb in shrimps to 261.1 ppb in mussels. From the group "DDT and its metabolites"only the derivates p,p'-DDE and p,p'-DDD could be quantified.The different organochlorine pesticides were present in concentrations generally below 5ppb in wet tissue.From the point of view of public health the organochlorine residues in marine organisms seem to present no risk

Détermination de la teneur en hydrocarbures de l'eau de mer et des sédiments provenant du plateau continental belge par spectrophotométrie infrarouge

The determination of hvdrocarbons by infrared spectrophotometry is a smooth method to obtain quick information about the degree of pollution of sea-water and sediment immediately following an oil spill. A base-line study was carried out to measure the actual hydrocarbon levels in sea water and sediment of the Belgian Continental Shelf. The range of the total hvdrocarbon concentration in water was 0.08 to 0.46 ppm and in sediment 3.9 to 23.0 ppm. The non polar hydrocarbon level was in water as well as in sediment below the detection limit (0.05 ppm for water and 1 ppm for sediment). This does not exclude the occurrence of local oil spills but the selfcleaning capacity of the sea seems for the time being to be sufficient to eliminale hydrocarbon pollution

Het alkaanpatroon in biota van verschillende trofische niveaus

Uit: Landbouwtijdschrift - 37(1984)

Bepaling van het koolwaterstofgehalte in zeewater en sediment afkomstig van het Belgisch Kontinentaal Plat d.m.v. infrarood-spektrofotometrie

The determination of hvdrocarbons by infrared spectrophotometry is a smooth method to obtain quick information about the degree of pollution of sea-water and sediment immediately following an oil spill. A base-line study was carried out to measure the actual hydrocarbon levels in sea water and sediment of the Belgian Continental Shelf. The range of the total hvdrocarbon concentration in water was 0.08 to 0.46 ppm and in sediment 3.9 to 23.0 ppm. The non polar hydrocarbon level was in water as well as in sediment below the detection limit (0.05 ppm for water and 1 ppm for sediment). This does not exclude the occurrence of local oil spills but the selfcleaning capacity of the sea seems for the time being to be sufficient to eliminale hydrocarbon pollution

Molecular footprint of drug-selective pressure in a human immunodeficiency virus transmission chain

Known human immunodeficiency virus (HIV) transmission histories are invaluable models for investigating the evolutionary and transmission dynamics of the virus and to assess the accuracy of phylogenetic reconstructions. Here we have characterized an HIV-1 transmission chain consisting of nine infected patients, almost all of whom were treated with antiviral drugs at later stages of infection. Partial pol and env gp41 regions of the HIV genome were directly sequenced from plasma viral RNA for at least one sample from each patient. Phylogenetic analyses in pol using likelihood methods inferred an evolutionary history not fully compatible with the known transmission history. This could be attributed to parallel evolution of drug resistance mutations resulting in the incorrect clustering of multidrug-resistant virus. On the other hand, a fully compatible phylogenetic tree was reconstructed from the env sequences. We were able to identify and quantify the molecular footprint of drug-selective pressure in pol using maximum likelihood inference under different codon substitution models. An increased fixation rate of mutations in the HIV population of the multidrug-resistant patient was demonstrated using molecular clock modeling. We show that molecular evolutionary analyses, guided by a known transmission history, can reveal the presence of confounding factors like natural selection and caution should be taken when accurate descriptions of HIV evolution are required.status: publishe

The mobile epibenthic fauna of soft bottoms in the Dutch Delta (south-west Netherlands): spatial structure

During 1989 monthly beam trawl samples were collected at 48 stations in the Dutch Delta. The annual mean densities of the demersal fishes and mobile epibenthic invertebrates at these stations were calculated. These data were then subjected to multivariate statistical techniques for an analysis of the spatial structure of the communities found and to study the relationship between these communities and their environment. The present study confirms the results of HENDERSON (1989) that, given a fairly limited number of environmental variables, mainly salinity and exposure/substratum type, quite accurate predictions of the type of community expected at a certain site can be made. The explicit inclusion of epibenthic invertebrates, a dominant group in most assemblages, in studies mainly targeted at demersal fishes, is strongly recommended. In the Dutch Delta rich and varied communities exist in the Voordelta. A number of groups, such as salmonids, anadromous species and starfish, expected in the Westerschelde are absent or extremely rare probably as a consequence of pollution stress. The Oosterschelde is relatively poor in density terms but has a highly diverse epibenthic fauna dominated by fishes