200 
In summer, very low concentrations in a range of <5 to 100 pg/L with a median of 15 
pg/L were observed in the German Bight and North Sea. The geographical distribution 
of the concentrations is shown in Figure 45 to Figure 47. In the German Bight, most 
concentrations were within a fairly narrow range from 10 to 30 pg/L. No clear and 
steady gradients were found during the surveys. A rather even distribution slightly 
above the LOQ was generally found in the southern part of the North Sea. One cause of 
this distribution is the absence of significant local inputs, e.g. by the river Elbe. 
Trifluralin levels in the river Elbe at Stade were only found to be slightly higher (30 to 
81 pg/L); this input to the German Bight has a major impact on the distribution in 
marine waters. Other sources must be considered to explain the “background level” of 
10 to 20 pg/L in the southern North Sea and the occasionally higher levels at the 
western border of the German Bight. This may either be due to atmospheric deposition 
or inputs from the rivers Rhine/Schelde or the UK. 
4 5 6 7 8 9 10 11 12 13 14 15 
Figure 45: Trifluralin concentrations [pg/L] in surface water (5 m) in the North Sea (July 2004) and 
Baltic Sea (June 2004) 
The results of the survey in July 2003, which covered the entire North Sea, were in line 
with findings in the German Bight. Concentrations in the southern North Sea were 
significantly higher than in the northern part, where hardly any trifluralin was found.