Concentration and patterns of PAHs along the salinity gradient of the Scheldt estuary

At MUMM a method was recently developed to determine Polycyclic Aromatic Hydrocarbons (PAHs) in surface waters, even with high particulate matter concentrations, as is the case for the Scheldt Estuary. The method is based on a solid phase extraction with Bakerbond Speedisk C18 cartridges (Baker Inc, Phillipsburg, NJ). After testing this method during a one-year international OSPAR pilot study, the same method was applied for water samples collected for the ENDIS-RISKS program during 2003. Total water concentrations varied between 10 ng/L and 1200 ng/L. Concentrations are tight linked to sources. Fluoranthene was found in the highest concentrations near Antwerp, while in Doel acenaphtylene seemed to be the most dominant compound. The patterns were generally dominated by the lower molecule weight PAHs. There is a clear gradient from Antwerp to the mouth of the estuary near Flushing. Concentrations and PAH patterns were further compared to previous results

Endocrine disruptors in the Scheldt estuary (2)

The Scheldt Estuary is known as one of the more polluted estuaries in Europe (OSPAR, 2000). All major compartments of the estuary, i.e. water, suspended matter, sediments and biota, may be contaminated with chemicals such as polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and organotin compounds. In the framework of the ENDIS-RISKS project, the different compartments of the estuary were sampled during the last 2 years and the concentration levels of 22 different polycyclic aromatic hydrocarbons (PAHs), 18 polybrominated diphenylethers (PBDEs), 5 OCPs, 16 PCBs and 6 organotin compounds were determined. For the biota, mysids were selected as indicator organism for this particular ecosystem. In this group of organisms, the highest contaminant levels were found for TBT with concentrations of up to 2500µg/kg on a dry weight basis (or approx. 100µg/kg on a wet weight basis). With an ecotoxicological assessment criterium (EAC) - as established by OSPAR - of 2.4µg/kg on wet weight basis, the EAC is exceeded by a factor of 50 at some sampling stations. For the same species, the body concentrations of SPCB7 varyied from 200 to 1400µg/kg (dry weight), again exceeding the OSPAR-EAC by a factor of more than 100. OCPs and PAHs are found in quantities varying from 5 to 100µg/kg (dry weight) which is below the EAC, except for lindane (EAC 0.29µg/kg on wet weight basis)

Endocrine disruptors in the Scheldt estuary: distribution exposure and effects

The Scheldt Estuary is known as one of the more polluted estuaries in Europe (OSPAR, 2000). The major compartments of the estuary, i.e. water, suspended solids, sediments and biota, are all affected by common POPs (persistent organic pollutants). In the framework of the ENDIS-RISKS project these compartments were frequently sampled during the last four years and analysed for these POPs indicated as possible endocrine disruptors. As such, the concentration levels of 22 different polycyclic aromatic hydrocarbons (PAHs), 18 polybrominated diphenylethers (PBDEs), 5 organochlorine pesticides (OCPs), 16 polychlorinated biphenyls (PCBs) and 6 organotin compounds e.g. TBT were determined by the MUMM laboratory. Their distribution (speciation within different compartments), concentration and geographic distribution are assessed. For the biota compartment, mysids were selected as an indicator organism for this particular ecosystem. In these invertebrates, the highest levels ever found for TBT were noted, with concentrations of up to 2500µg.kg-1 on a dry weight basis (or approx. 100µg.kg-1 on a wet weight basis). In the same species, SPCB7 levels varying from 200 to 1400 µg.kg-1 on dry weight were noted. OCPs and PAHs concentrations varied from 5 to 100µg.kg-1dw. The geographic distribution - along the salinity gradient of the Scheldt Estuary - of the body burdens of these compounds in mysids are discussed. Finally, the observations were compared to internationally accepted ‘Ecotoxicological Assessment Criteria’ used to assess the potential adverse effects on the ecosystem

The use of integrative passive samplers as a source of contaminant mixtures in ecotoxicological laboratory experiments

The INRAM project aims to introduce a new application of passive sampling devices in ecological toxicity testing. Conventional (laboratory) ecotoxicity studies are mostly performed by exposing test organisms to various (high) concentrations of a single test compound. This clearly does not reflect in situ conditions: i.e. exposure to mixtures of low levels of various micro-pollutants. In order to expose organisms to environmentally realistic contaminant mixtures, this study explored a novel use of integrative passive samplers. Firstly, the dynamics of the contaminant release from the samplers was studied in the presence of organic material, i.e. algal cells. This study showed that the samplers released the compounds into the test medium as expected. Constant concentrations were achieved in the test medium, but the target concentrations (based on the amount of compound spiked on the samplers) were not reached. Additional experiments will be carried out in order to improve the dynamics of contaminant release. Secondly, samplers were used to collect micro-pollutants from three Belgian coastal harbours and were used ‘inversely’ as a contaminant mixture source in laboratory toxicity assays with Crassostrea gigas larvae. Significant differences in normal development of the oyster larvae were observed between the three harbours. Within each harbour a pollution gradient was apparent. These results show that the targeted application of passive samplers is feasible. As these passive samplers also allow to determine the aqueous concentrations of otherwise (nearly) undetectable trace compounds, they could be a powerful new tool in environmental toxicology

ENDIS-RISKS: endocrine disruption in the Scheldt estuary - a field study

ENDIS-RISKS, a multidisciplinary research project with five institutes, evaluates the distribution, exposure and effects of endocrine disruptors in the Scheldt Estuary. This estuary is known to be one of the most polluted estuaries in the world. Untreated domestic wastewater and effluents of the industrial areas of Ghent and Antwerp are to a large extent responsible for this pollution. During an intensive field study of four years, eight sampling campaigns were executed on seven sampling points along the Scheldt Estuary. A detailed analysis of the distribution of endocrine disrupting substances in the Scheldt Estuary was executed. Water, sediment, suspended solids and biota were analysed for seven groups of chemicals: estrogens, pesticides, organotins, polyaromatic components, polyaromatic hydrocarbons and phenols. Special attention was given to the estuarine mysid shrimp Neomysis integer. Its ecotoxicology and population characteristics were studied in detail. A selection of results of this field study is put forward. Water samples, tested in vitro for their potential to bind with estrogen, revealed more estrogenic activity in the more upstream stations. Concentrations of chlorotriazine herbicides in water samples, were higher in the upstream reaches compared to the downstream sites. Analyses of TBT in mysid shrimps revealed high concentrations (>2mg.kg-1 dry weight) which suggests a high bioaccumulation capacity. Population characteristics results of N. integer show that it has a broader distribution range, with a shift more upstream, in comparison with historical data (Mees et al., 1995). On the other hand, length distribution of developmental stages of N. integer along the estuary indicates some environmental stress, caused by the estuarine gradient or by pollutants. Some hypotheses will be put forward to explain these patterns

Detection of virus-specific intrathecally synthesised immunoglobulin G with a fully automated enzyme immunoassay system

<p>Abstract</p> <p>Background</p> <p>The determination of virus-specific immunoglobulin G (IgG) antibodies in cerebrospinal fluid (CSF) is useful for the diagnosis of virus associated diseases of the central nervous system (CNS) and for the detection of a polyspecific intrathecal immune response in patients with multiple sclerosis. Quantification of virus-specific IgG in the CSF is frequently performed by calculation of a virus-specific antibody index (AI). Determination of the AI is a demanding and labour-intensive technique and therefore automation is desirable. We evaluated the precision and the diagnostic value of a fully automated enzyme immunoassay for the detection of virus-specific IgG in serum and CSF using the analyser BEP2000 (Dade Behring).</p> <p>Methods</p> <p>The AI for measles, rubella, varicella-zoster, and herpes simplex virus IgG was determined from pairs of serum and CSF samples of patients with viral CNS infections, multiple sclerosis and of control patients. CSF and serum samples were tested simultaneously with reference to a standard curve. Starting dilutions were 1:6 and 1:36 for CSF and 1:1386 and 1:8316 for serum samples.</p> <p>Results</p> <p>The interassay coefficient of variation was below 10% for all parameters tested. There was good agreement between AIs obtained with the BEP2000 and AIs derived from the semi-automated reference method.</p> <p>Conclusion</p> <p>Determination of virus-specific IgG in serum-CSF-pairs for calculation of AI has been successfully automated on the BEP2000. Current limitations of the assay layout imposed by the analyser software should be solved in future versions to offer more convenience in comparison to manual or semi-automated methods.</p

Giant Galápagos tortoises; molecular genetic analyses identify a trans-island hybrid in a repatriation program of an endangered taxon

BACKGROUND: Giant Galápagos tortoises on the island of Española have been the focus of an intensive captive breeding-repatriation programme for over 35 years that saved the taxon from extinction. However, analysis of 118 samples from released individuals indicated that the bias sex ratio and large variance in reproductive success among the 15 breeders has severely reduced the effective population size (N(e)). RESULTS: We report here that an analysis of an additional 473 captive-bred tortoises released back to the island reveals an individual (E1465) that exhibits nuclear microsatellite alleles not found in any of the 15 breeders. Statistical analyses incorporating genotypes of 304 field-sampled individuals from all populations on the major islands indicate that E1465 is most probably a hybrid between an Española female tortoise and a male from the island of Pinzón, likely present on Española due to human transport. CONCLUSION: Removal of E1465 as well as its father and possible (half-)siblings is warranted to prevent further contamination within this taxon of particular conservation significance. Despite this detected single contamination, it is highly noteworthy to emphasize the success of this repatriation program conducted over nearly 40 years and involving release of over 2000 captive-bred tortoises that now reproduce in situ. The incorporation of molecular genetic analysis of the program is providing guidance that will aid in monitoring the genetic integrity of this ambitious effort to restore a unique linage of a spectacular animal