D10: Impact of Contaminants - Hydromod

Integrated Water Resource Management for Important Deep European Lakes and their Catchment Areas
EUROLAKES
D10: Impact of Contaminants
FP5_Contract No.: EVK1-CT1999-00004
Version: 4.0
Date: 25/07/01
File: D10-vers.4.0.doc
Page 76 of 136
most toxic substances for aquatic organisms [BUWAL b]. In Switzerland no authorised
agricultural pesticide containing TBT but it is still used for wood treatment and has other
industrial applications [BECKER-VAN SLOOTEN AND TARRADELLAS, 1994]. On the
1 st of July 1988 a Swiss legalisation came into force banning the selling of antifouling
paints containing trialcyl- or triaryltins. Importers and sellers were allowed two years of
dispose of their stock. The selling of antifouling paint containing these compounds was
illegal after 1 st of July 1990. In France the use of TBT-containing antifoulings has been
forbidden since 1982 for vessels less than 25 m in length. [BECKER-VAN SLOOTEN
AND TARRADELLAS, 1994/1995]. Nowadays antifouling products contain besides
copper a triazine compound which is effective against algae [BUWAL b]. In the marina
of Lake Geneva only every fourth boat is painted annually and the boats left in the water
during winter [BECKER-VAN SLOOTEN AND TARRADELLAS, 1994]. [BECKER et
al 1992] showed high organotin levels in Lake Geneva in 1988 just as the ban came
into force. In this work it was shown that the TBT contamination of water, sediment and
bivalves was higher in Swiss marinas of Lake Geneva than in the French marinas. This
study of [BECKER et al 1992] was designed to compare the organotin concentrations in
marinas within two countries - Switzerland and France - having different legislation.
Water, sediment and mollusc samples were collected from three Swiss and two French
marinas (Figure 10-8). As a reference, a natural site was chosen away from sources of
organotin compounds, but presenting similar characteristics to a marina like a sheltered
and shallow site. The results of the assessment of butyl- and phenyltin compounds in
Lake Geneva are reported in Each value i a mean of 6 samples (3 stations each with
one surface and one bottom sample) except for the reference point (2 stations). The
range is indicated below in parantheses. TPT has not been detected. (nd = not detected,
CH = Switzerland, F = France)
Table 10-2, Table 10-3 and Table 10-4. the TBT concentrations ranged from not detected
to 1.08 µg/l in water and from 0.03 to 4.76 µg/g dry weight in sediment. The
Swiss marinas were up to 20 times more contaminated than the French ones. This difference
was more pronounced for the water than for the sediment. Partly it can be explained
by the fact that the use of antifouling paints is regulated in France since 1982.
Furthermore, the values might reflect the degree of flushing as Geneva and Lausanne
are the most enclosed marinas with the poorest water exchange. Generally the aqueous
concentrations of DBT and TBT measured in June were higher than in September.
This can result from the typical spring activities like hosing operations and launching of
the yachts .