Institute for Sanitary Engineering, Water Quality and Solid Waste ...

Hydrochemistry CH
Projects
Flame retardants in organisms of Lake Constance
(FLABO)
The Lake Constance is an important habitat for fish and
therefore a large food resource - the fishing quota for
2008 was around 725 tones. Organic micro-pollutants,
especially persistent lipophilic compounds enter Lake
Constance and accumulate in the sediments, as well
as in fish and shellfish.
Typical representatives of these contaminants are polychlorinated
biphenyls (PCBs) which were banned because
of their toxic properties already over 20 years
ago, but can still be detected in various environmental
samples. Polybrominated diphenyl ethers (PBDEs)
have been used since the 1970s as flame retardants
in textiles and electrical housings and also showed rising
environmental levels over the last few decades.
Since the industry signed a voluntary negotiated agreement
on production and application concentrations
seem to have stagnated. The study of dated sediment
cores from Lake Constance in 2004/2005 (Interreg III)
showed an increase of PBDE-concentrations in younger
sedimentary layers. Within the current project, the
PBDEs compared to the group of PCBs were determinated
in fish (bream - Abramis brama), zebra mussels
(Dreissena polymorpha) and sediments of Lake
Constance. The bream is a species of fish living close
to the sediment partly feeding on zebra mussels. In
addition obtaining information on the present load, the
aim was to have a closer look on substance accumulation
along the food chain.
The contaminants could be detected in all investigated
environmental samples. The concentrations of PCBs in
the sediments were at similar levels as in 2004/2005
and are thereby lower than quality objectives of the
WFD (20 micrograms / kg dry matter). On examination
of the upper layers lower concentration levels than
in the older deeper layers could be determinated. The
PCB concentrations in the mussels were at small levels
similar to those in the sediment. The congener pattern
(concentration distribution of the various individual
compounds) showed similarities with the technical
mixture „Chlophen-A60“. The pattern of the PBDEs
also shows similarities with the technical penta-bromo
diphenyl ether mixture. While the PCB pattern between
the investigated environmental samples looked
similar, the PBDE profile of the various samples were
significantly different. This gives us an indication of
specific uptake or degradation of certain PBDE congeners.
The maximum PCB-concentrations found in the fillets
of bream are far below the threshold limit for fresh
water fish (Schadstoff-Höchstmengen Verordnung).
Compared to PCB concentrations the PBDE concentrations
are lower by an order of magnitude. Threshold
limits do not exist for the group of PBDEs.
Fig:
Trip with the research ship of the Institute of Lake Research, Langenargen (LUBW) for sediment and mussel
sampling.
123