32 
0.2 to 0.6 |ug/kg ww in 2000. HCB had a median of 0.84 |ag/kg ww and the sum of 
DDTs of 3.7 |ag/kg ww. 
In summary, chlorpyrifos, endosulfan and trifluralin have very similar concentrations 
in the different marine matrices. The slightly higher median levels of endosulfan 
compared to chlorpyrifos and trifluralin may have statistical and analytical causes, since 
the limit of detection and the limit of quantification (LOD/LOQ) of endosulfan were 
higher in this study than those of the other compounds and values < LOD/LOQ were not 
taken into account. The observed low concentrations of the compounds studied are in 
accordance with their limited persistence in the environment compared to classical 
POPs and their relatively low consumption volume in northern Europe (chlorpyrifos, 
endosulfan, dicofol, PCP). With the exception of PCP and possibly trifluralin, major 
local input sources have not been detected. The enrichment factors for sediments and 
biota samples are similar for all compounds and reflect a comparable intermediate 
polarity of these pesticides. They are lower than for most classical POPs, since the 
investigated compounds are less lipophilic and stable. 
2.2.13 Recommendations for future monitoring activities 
Based on the observed environmental concentrations in the North Sea and Baltic Sea, 
available data on the use of these substances, and their physical, chemical and biological 
behaviour in the marine environment, the following recommendations are made: 
Polychlorinated paraffins should be monitored at least with a screening method, which 
quantifies the total amount of short and medium-chained compounds in fish and 
sediment. Such techniques require relatively inexpensive equipment and only one 
separation by gas chromatography. However, the determination of complete formula 
and congener group pattern for at least selected samples should be part of any 
specifically designed monitoring project. 
Chlordanes occur in concentrations in the very low ng/g range in fish and sediments 
from the North and Baltic Sea and are therefore not recommended for routine 
monitoring. Concentrations are about one order of magnitude lower than in the