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dry weight (dw) in sediments. Considerable bioaccumulation was observed in fish liver 
with median concentrations of 0.36 |ag/kg wet weight (ww) corresponding to 1.6 pg/kg 
lipid weight (lw). The enrichment from water to sediment was calculated to a factor of 
about 350, from water to biota (fish liver) to about 14’000 (ww) and 62’000 (lw). This 
relatively low enrichment is in accordance with the moderate log Kow value of 3.6-4.5. 
Compared to the EQS value of 30 ng/L, which is proposed for the evaluation of inland 
and transitional waters by the WFD, the observed sea water concentrations for 
chlorpyrifos are quite low. It is remarkable that chlorpyrifos has been detected at all in 
the marine environment of the North and Baltic Seas considering the short half-live, the 
low volatility and low emissions from local sources. 
The low concentrations and the distribution patterns observed for North Sea and Baltic 
Sea water are best explained by a generally low background level with some minor local 
sources. Concentrations in the river Elbe - generally the most important input source of 
pollutants to the German Bight - are relatively low and consequently its impact on 
chlorpyrifos input. It is not surprising that TCPy was not found in sea water taken the 
low chlorpyrifos concentrations and the moderate environmental persistence of TCPy 
into account. 
Water concentrations of chlorpyrifos-ethyl were above those of the classical lipophilic 
pollutants such as HCB, DDT, PCBs or PAHs, but below those of HCHs. Sediment 
levels were below that of classical pollutants. In biota concentrations are in a range of 
HCHs and HCB, but lower than the more lipophilic DDT-group and PCBs. 
2.2.9 Endosulfan in the marine environment of the North and Baltic Seas 
This is the first time that quantifiable conencentration of endosulfan have been detected 
in the North Sea and Baltic Sea. Endosulfan II levels were generally lower than for 
endosulfan I and often not detectable in the marine samples of the North Sea and Baltic 
Sea. The isomer endosulfan I was found in many water samples and in some sediments 
and biota. However, concentrations were very low with a median of 25 pg/L for water 
and 20.5 ng/kg dw for sediments. In fish liver, median concentrations of 0.44 pg/kg ww