Leibniz-Institut für Ostseeforschung, Warnemünde
(IOW) (Baltic Sea Research Institute, Warnemünde)
Bundesamtes für Seeschifffahrt und Hydrographie, Hamburg, Rostock
(Federal Maritime and Hydrographic Agency of Germany, Hamburg, Rostock)
(Summary of the Baltic Sea Monitoring 2006, Organic contaminants)
In January 2006 water samples from the Baltic Sea were collected to evaluate
long term trends of organic compounds. Along eight transects samples were collected for
PCBs (polychlorinated biphenyls),
PAHs (polycyclic aromatic hydrocarbons) and
using a pump/filtration system. Hereby an in-situ pump system separated dissolved and
For HCHs (hexachlorocyclohexane) samples were collected at
selected stations from the clean water line in 5 meters depth at stations in the following areas:
Western Baltic, Transect 2: Arkona Sea/Bornholm Sea, Transect 1: Eastern Gotland Sea.
For alpha-HCH the concentrations ranged
between 237 pg/L and 350 pg/L,
between 312 pg/L and 441 pg/L
and for beta-HCH
between 346 pg/L and 482 pg/L.
The spatial distribution of alpha-HCH
showed slightly lower concentrations west of Bornholm (237-280 pg/L)
than in the Gotland Sea (317 - 329 pg/L), whereas higher concentrations
were observed at Station 109 in the Arkona Sea (350 pg/L). For
gamma-HCH increasing concentrations from the
Mecklenburg Bight (317 pg/L) to the Gotland Sea
(441 pg/L) were observed. To estimate long-term trends of the
pollution with HCHs, the sampling grid has been changed, the new data
set contains results over ten years period.
Between 2000 and 2006 the concentration of all 3 HCH congeners
decreased by about a factor of 2 in the entire study area.
The vertical distribution of HCHs was measured at
3 stations with a clearly stratified water column (213, 259, 271). In the Bornholm Sea (station 213) the
HCH concentrations of all HCH
congeners in the deep water were clearly lower than the concentrations in surface water. At Station 259
(SE Gotland Basin) the difference between surface and deep water concentrations of
beta-HCH and gamma-HCH
was insignificant, whereas the concentration of alpha-HCH in the deep
water was clearly higher than in the surface water. In the Gotland Sea at Station 271 the concentrations of
beta-HCH in the
deep water were slightly higher than the concentrations measured in the surface water.
A new dataset of five years with the dissolved concentrations of
p,p'-DDT is used
to estimate long-term trends in the study area.
Since 2003 the exposure of p,p'-DDE
has ranged on a level of 4 - 5 pg/L,
shows a slightly decreasing trend. In 2006 the dissolved concentrations for
ranged between 1.7 pg/L and
between 2.7 pg/L and 4.7 pg/L,
for p,p'-DDD between
2,2 pg/L and 5.1 pg/L.
The spatial distribution of DDT and
metabolites was characterized by decreasing concentrations from the western Baltic Sea to the Gotland Sea,
the highest concentration were observed in the Mecklenburg Bight.
In 2006 the exposure of the surface water with dissolved
indicated by a slightly decreasing trend
(0.2 - 3 pg/L). The dissolved concentrations
are better suited for judging the spatial distribution of contamination and for determination of
temporal trends. Most of the study area showed homogenous dissolved concentrations, whereas the levels
in the western Baltic Sea were slightly higher than in the Gotland Sea. The comparison with the data from
1988 (Schulz-Bull, 1995) indicated for all PCB congeners a
reduction of 50 percent.
The pollution of the surface water with dissolved
PAHs was observed between 2002-2006,
there is no significant trend in the study area. After lower concentrations in the previous
year, notably in the Arkona Sea/Bornholm Sea, the PAH
concentrations (0.01 - 2.6 ng/L) were found on the level
of 2003/2004. For the study area of the Arkona Sea/Bornholm Sea the values show a greater variability. For
PAHs with medium and low vapour pressure a approximately
constant or a slight decrease was observed in the eastern Gotland Sea.
In November 2006 five sediment samples were collected for
PAH analysis from the
area of eastern Baltic Sea and the Arkona Sea. The
concentrations ranged between 8 and 4091 pg/g.
The PAH concentrations in the study
area ranged between 1 and 462 ng/g
with a similar distribution to that of the PCBs. There was a strong
correlation between the PCB/PAH
concentrations and the Corg content.
Aim of the monitoring research part was to analyse one sediment core in the area of the Arkona Sea and
five surface sediment samples for sediment monitoring of polybrominated diphenylethers
especially the development of a GC-MS
method to measure PBDE 209.
The detektion limit is 100 pg/g sediment.
Contrary to expectations PBDE 209 was not detected in the