US EPA

2202239 

Technical Report 

Polychlorinated biphenyls and compounds of the DDT group in sediments of the central North Sea and the Norwegian depression 

Eder, G 

1976 

PESTAB/76/1877 

2 

2 

101-106; 1976 

PESTAB. The vertical distributions of chlorinated hydrocarbons within the upper 20 cm of North Sea sediments were studied at sites not directly affected by river outfalls or dumping. Analysis was by gas-liquid chromatography with helium-glow electron capture detection. The average PCB concentrations varied from 14.0 to 28.0 ppb (mug/kg dry sediment) in the upper 10 cm and from 10.5 to 40.5 ppb in samples taken from below 10 cm. The average DDE, DDD, and DDT concentrations in the upper 10 cm were 0.12-0.27, 0.074-0.45, and 0.30-0.44 ppb, respectively, while the average levels in the deeper samples were 0.064-0.29, 0.02-0.26, and 0.15-0.36 ppb, respectively. Most of the DDD and DDT values were not statistically significant, and in most cases, the residue levels showed a significant decrease with increasing core depth. Two of the sampling sites seem sufficiently remote from any presumptive sources of direct pollution to regard the residue concentrations at these sites as background values, but more extended investigations are required.