posted on 2013-10-01, 00:00authored byEvy Van Ael, Adrian Covaci, Krishna Das, Gilles Lepoint, Ronny Blust, Lieven Bervoets
Concentrations of
several persistent organic pollutants (POPs:
PCBs, PBDEs, OCPs) in aquatic species from the Scheldt estuary were
related with factors (body size, lipids, trophic position) possibly
influencing their bioaccumulation. Stable nitrogen isotope ratios
(δ15N) were used as a measure for trophic position.
A decreasing trend in POP levels toward the sea was observed. For
POP concentrations in sediments, this trend could be attributed to
a dilution effect from mixing with seawater. However, concentrations
in biota more downstream were higher than expected after taking into
account the dilution effect, possibly due to differences in bioavailability.
Tissue concentrations were correlated with the lipid content in biota,
but not with body size. Biomagnification was only significant for
some PCB congeners and p,p′-DDE
at the most marine sampling location (Terneuzen, L1) and for p,p′-DDD and BDE 100 at the second
sampling location (Bath, L2). A significant decreasing relationship
was found for γ-HCH concentrations with increasing δ15N at Terneuzen. For Antwerpen (L3), no significant relationships
were detected. TMFs ranged from 0.64 for γ-HCH up to 1.60 for
PCB 194. These results suggest that biomagnification was more important
in the marine part of the estuary, although the presence of multiple
carbon sources at the freshwater side might have led to an underestimation
of the influence of trophic position.