PCBs in cod (<i>Gadus morhua</i>), flounder (<i>Platichthys flesus</i>), blue mussel (<i>Mytilus edulis</i>) and brown shrimp (<i>Crangon crangon</i>) from the Belgian Continental Shelf: relation to biological parameters and trend analysis

PCB levels in cod, flounder, mussel and shrimp, covering a ten-year period, were assessed for temporal trends and their relation to biological parameters. A significant relation was found between the PCB levels on a wet weight basis and the total lipid content. Normalising on the total lipid content reduced the differences in PCB levels between the organisms and between different tissues within the organisms. A general downward trend was observed for the PCB levels on the Belgian continental shelf

PCBs in cod (<i>Gadus morhua</i>), flounder (<i>Platichthys flesus</i>), blue mussel (<i>Mytilus edulis</i>) and brown shrimp (<i>Crangon crangon</i>) from the Belgian Continental Shelf: relation to biological parameters and trend analysis

PCB levels in cod, flounder, mussel and shrimp, covering a ten-year period, were assessed for temporal trends and their relation to biological parameters. A significant relation was found between the PCB levels on a wet weight basis and the total lipid content. Normalising on the total lipid content reduced the differences in PCB levels between the organisms and between different tissues within the organisms. A general downward trend was observed for the PCB levels on the Belgian continental shelf

A databank able to be used for identifying and authenticating commercial flatfish (Pleuronectiformes) products at the species level using isoelectric focusing of native muscle proteins

A computerized databank of IEF protein patterns for use in identifying flatfish species (in total 17 species, including 15 commercial ones) is presented. The databank includes all species regulated by the Belgian Law (22 May 1996) on the use of official names for fishes and seafood products. It was found that interspecimen similarity of the IEF patterns, as processed by digitization, was always larger than interspecies similarity, which allows for unequivocal authentication of unknown samples, as long as the authentic pattern is available in the databank. The databank was used to authenticate 17 commercial fish fillets

Development and validation of the <i>in vivo</i> alkaline comet assay for detecting genomic damage in marine flatfish

Biomonitoring is an important subject within environmental sciences. Biomonitoring tests are required to be quick, relatively inexpensive, accurate, and reproducible. No genetic test currently fulfils all of these requirements. The chromosome aberration and sister chromatid exchange tests are very time consuming, the DNA adduct technique is rather expensive, and the micronucleus test has not inconclusively proven its use as a reliable monitoring tool. This work is focused on the validation of the comet assay as a candidate for monitoring marine ecosystems. For the comet assay, this work deals with the effectiveness of tissue dissociation, storage of cells in lysing buffer and in liquid nitrogen, different electrophoretic conditions, neutralisation and fixation of slides, interindividual variation between samples, and responsiveness of four tissue types to ethyl methanesulphonate (EMS). The main conclusions are: (i) dissociation of solid tissues in a phosphate buffer supplemented with 200 mM N-t-butyl-alpha-phenylnitrone provides cells with an acceptable background DNA damage; (ii) freezing of cells or tissues in liquid nitrogen generally leads to an increase in DNA breakage, especially for liver, gill and kidney tissue; (iii) storage of slides in the lysing solution for up to one week gives minor changes in comet tails; (iv) differences in protocols for neutralisation and fixation may influence the results; (v) high intra- and interindividual variations in comets (length and DNA content) may obscure the interpretation of comet results; (vi) blood, gill, liver and kidney all showed a statistically significant increase of DNA damage after exposure to 50 mg EMS/l; (vii) electrophoresis at low voltage for longer periods is to be preferred to high voltage and short electrophoresis times. The simplicity and sensitivity of the comet assay make it an adequate test system for biomonitoring of chronic low level exposure. However, protocols and experimental conditions have to be chosen carefully