Fast analysis of decabrominated diphenyl ether using low-pressure gas chromatography electron-capture negative ionization mass spectrometry

Peer reviewe

Evolution and spatial variability of heavy metals in mussels (<i>Mytilus edulis</i> L.) in the Scheldt estuary (1996-2002)

This paper presents data on the heavy metal contamination of the soft tissues of marine mussels along the Scheldt Estuary. The study considered both arms of the Scheldt estuary, i.e. the relatively polluted Western Scheldt (WS) and the now marine tidal bay of the Eastern Scheldt (ES). The two systems present an ideal opportunity to investigate, in a field situation, the role of physico-chemical and pollution gradients on metal accumulation in mussels. In the WS, depending on the metal, tissues concentrations decreased by 2 - 6 times from Hansweert (the landward limit for mussels) to Westkapelle on the North Sea coast. Similar decreases were also observed in the ES. With a few exceptions (i.e. Cd, Cu), there were no clear differences in tissue metal concentrations between WS and ES. The study also showed strong positive correlations between tissue metal concentrations and distance from the sea in both systems for most metals. Similar trends were observed for both WS and ES indicating that salinity and metal gradients are not entirely responsible for increasing metal tissue levels towards the inland. Additionally, the influence of the constructed storm surge barrier was evident as heavy metal levels in mussels at sites around the barrier were considered elevated. Furthermore, there were only modest decreases in metal concentrations in mussel tissues between 1996 to 2002, further indication that even in the cleaner ES, efforts to reduce the impact of environmental metal pollution take time to give results

Effect of hydrogen ions and inorganic complexing on the uptake of copper by the brine shrimp <i>Artemia franciscana</i>

The effect of hydrogen ions and inorganic complexing on copper uptake in the brine shrimp Artemia franciscana has been studied in chemically defined saltwater solutions. Uptake increases with decreasing hydrogen ion concentration and decreases with increasing carbonate complexation. A simple non-linear model that combines the effect of hydrogen ions on the transport of the metal across the solution-body interface and the effect of hydrogen ions and complexation on the speciation of the metal provided a close functional description of the observed variation in copper uptake by brine shrimp

Biochemodynamic features of metal ions bound by micro- and nano-plastics in aquatic media

A simple model, based on spherical geometry, is applied to the description of release kinetics of metal species from nano- and micro-plastic particles. Compiled literature data show that the effective diffusion coefficients, Deff, for metal species within plastic polymer bodies are many orders of magnitude lower than those applicable for metal ions in bulk aqueous media. Consequently, diffusion of metal ions in the aqueous medium is much faster than that within the body of the plastic particle. So long as the rate of dissociation of any inner-sphere metal complexes is greater than the rate of diffusion within the particle body, the latter process is the limiting step in the overall release kinetics of metal species that are sorbed within the body of the plastic particle. Metal ions that are sorbed at the very particle/medium interface and/or associated with surface-sorbed ligands do not need to traverse the particle body and thus in the diffusion-limiting case, their rate of release will correspond to the rate of diffusion in the aqueous medium. Irrespective of the intraparticulate metal speciation, for a given diffusion coefficient, the proportion of metal species released from plastic particles within a given time frame increases dramatically as the size of the particle decreases. The ensuing consequences for the chemodynamics and bioavailability of metal species associated with plastic micro- and nano-particles in aquatic systems are discussed and illustrated with practical examples

Differences in metal sequestration between zebra mussels from clean and polluted field locations

Organisms are able to detoxify accumulated metals by, e.g. binding them to metallothionein (MT) and/or sequestering them in metal-rich granules (MRG). The different factors involved in determining the capacity or efficiency with which metals are detoxified are not yet known.In this work we studied how the sub-cellular distribution pattern of cadmium, copper and zinc in whole tissue of zebra mussels from clean and polluted surface waters is influenced by the total accumulated metal concentration and by its physiological condition. Additionally we measured the metallothionein concentration in the mussel tissue. Metal concentration increased gradually in the metal-sensitive and detoxified sub-cellular fractions with increasing whole tissue concentrations. However, metal concentrations in the sensitive fractions did not increase to the same extent as metal concentrations in whole tissues. In more polluted mussels the contribution of MRG and MT became more important. Nevertheless, metal detoxification was not sufficient to prevent metal binding to heat-sensitive low molecular weight proteins (HDP fraction). Finally we found an indication that metal detoxification was influenced by the condition of the zebra mussels. MT content could be explained for up to 83% by variations in Zn concentration and physiological condition of the mussels