Report from the Sub-comittee on the environment and health

Analyses of surface water
in Funen County 1997
Analyses of water <strong>from</strong> a
watercourse in Kolding
Municipality in 1998
watercourse. Particle-borne transport occurs during heavy run-off of
rainwater or melt water and soil erosion.
Up to and including 1996, 32 different pesticides were detected in Danish
watercourses, corresponding to approx. 30% of <strong>the</strong> pesticides tested for
(see table 4.9). Several different pesticides can be found simultaneously in
<strong>the</strong> individual watercourses. Pesticides are found in watercourses in all
seasons, but most frequently in <strong>the</strong> spraying season and during increased
run-off after rain. The frequency of pesticide finds and <strong>the</strong> concentration of
pesticides are generally highest in agricultural catchment areas with clayey
soil. Some of <strong>the</strong> pesticides are found in only a few per cent of <strong>the</strong> samples,
while o<strong>the</strong>rs are found in up to 64% of <strong>the</strong>m.
The detection frequency is highest in <strong>the</strong> spraying periods and in
connection with precipitation with increased run-off in watercourses. The
highest value in <strong>the</strong> analyses up to and including 1996 was 10
microgramme per litre (bentazon). 12 of <strong>the</strong> pesticides were found in
concentrations above 1 microgramme per litre and 31 substances were
found in concentrations above 0.1 microgramme per litre. Glyphosate was
tested for in 6 samples and found in all of <strong>the</strong>m in concentrations <strong>from</strong> 0.02
to 0.21 microgramme per litre (Funen County 1997, Kronvang 1998;
Spliid, Mogensen 1995).
Since 1996 <strong>the</strong>re have as yet been only a few reports <strong>from</strong> counties and
municipalities. Funen County Council has published <strong>the</strong> results of analyses
of 6 watercourses, 4 springs and 11 drains in agricultural areas (Funen
County 1999). Samples were tested for 94 active ingredients and 5
metabolites. Of <strong>the</strong>se, 33 different substances were found in concentrations
up to 10 microgrammes per litre (<strong>the</strong> herbicide bentazon). Of <strong>the</strong>se, 26 are
authorised for use today. It should be noted that one of <strong>the</strong> substances
found, metazachlor has never been authorised in Denmark. Most of <strong>the</strong>
substances were found in concentrations above 0.1 microgramme per litre.
Up to 18 different pesticides were found in individual watercourses within
<strong>the</strong> same day. The substances found most frequently in 33 samples <strong>from</strong>
watercourses in concentration of or over 0.1 microgramme per litre were
<strong>the</strong> metabolite AMPA <strong>from</strong> glyphosate (79%), <strong>the</strong> metabolite BAM <strong>from</strong>
<strong>the</strong> banned herbicide dichlobenil (48%), isoproturon (36%), glyphosate
(31%), <strong>the</strong> banned herbicide hexazinone (30%), and diuron (24%). The
substances and concentrations found largely correspond to earlier finds.
The study indicates that many of <strong>the</strong> pesticides occurring in <strong>the</strong>
watercourses are transported to <strong>the</strong>m via drains, particularly in <strong>the</strong> spraying
season. It has also been established that <strong>the</strong>re is some transport of
pesticides via urban wastewater. Drift does not seem to be of any great
significance to <strong>the</strong> occurrence of pesticides in <strong>the</strong> watercourses tested. On
<strong>the</strong> basis of observations over a 10-year period, Funen County Council
estimates that more than 200 km of watercourse, corresponding to around
20% of <strong>the</strong> watercourses tested, have been exposed to acute damage, since
large numbers of crustaceans and aquatic insects have been killed.
In May-June 1998, Kolding Municipal Council tested 14 water samples
<strong>from</strong> Dalby Møllebæk (a mill brook), situated in an agricultural catchment
area consisting mainly of moraine clay (Kolding Municipality 1998). The
analysis covered 33 pesticides or metabolites, of which 21 were found in
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