Sum mary 
18 
Nordseezustand 2003 
els since 1975. The lindane concentration was found to be about 18 % below the prior- 
year level. Since 1998, lindane levels have decreased by over 90 %. 
Out of the group of unpolar chlorinated hydrocarbons (CHC), the contaminant classes 
HCB, PCB, and DDT were investigated. All of the three groups had comparable spatial 
distribution patterns in German Bight water, with elevated levels near the coasts. Be 
cause of the high variability of measured values and the relatively short observation 
period, no temporal trend has been found either in water or in sediment. 
In the North Sea, a background load of aliphatic hydrocarbons (residues of petroleum 
hydrocarbons) was identified. Slightly elevated concentrations were found in the Ger 
man Bight and in the area of production platforms off the coast of Scotland. However, 
natural background levels of aliphatic hydrocarbons from biogenic sources are domi 
nant in large parts of the North Sea. 
Polycyclic aromatic hydrocarbons (PAH, e. g. naphthalene, anthracene, ben- 
zo[a]pyrene) are compounds forming in combustion processes; they are also present 
in petroleum products. Most of them are carcinogenic. In water, they showed typical 
concentration gradients from the coasts to the open sea, depending on their molecular 
size. Elevated levels of naphthalene were found not only in the sea area influenced by 
discharges from the Elbe river but also off the Themse estuary, the coast of Scotland, 
and the Norwegian coast. Based on the ratios of the individual PAHs in water, it was 
possible to identify and explain local hot spots. The highest PAH levels in sediment 
were found in the Elbe estuary and in the White Bank area, which is comparable to the 
CHC pattern. 
Of the 37 polar plant protection agents investigated (insecticides and herbicides), 21 
substances were found in the Elbe, and 20 in the German Bight. Usually, these com 
pounds show a marked annual cycle, which depends on the seasonal use of pesti 
cides in farming. The herbicides atrazine and simazine were still present at relatively 
high concentrations (1 -4ng/L) in the German Bight although their use has been 
banned in Germany for several years. Also relatively high levels (1 - 7.5 ng/L) of the 
herbicides diurone and isoproturone were found. TBT, a compound used in ship paints 
which has hormone-disrupting properties even at extremely low concentrations, still is 
of high ecological relevance. The concentrations of 1 - 2 ng/L observed in coastal wa 
ter have already reached the toxic threshold level. 
Metals 
The concentrations of some metals in coastal water, and locally in sediment, were still 
far above the natural background levels in some areas. Cadmium, copper, mercury, 
lead, and zinc in the dissolved phase showed a strong concentration gradient from the 
coast to the open sea, like most organic contaminants. The highest levels were mea 
sured in the area of the Elbe estuary and along the North Frisian coast. Near the coast, 
the background levels of all of the above elements were clearly exceeded; in the open 
North Sea, only the copper concentrations were elevated. Compared to the preceding 
years, however, the metal concentrations in water were not unusually high. 
The highest metal concentrations were observed in fine-grained surface sediments 
southeast of Helgoland and in the area of the White Bank, where fine-grained sedi 
ments prevail. Metal concentrations in the study area were found to be mostly stag 
nant or to have a downward trend. In 2003, following the 1999 - 2002 phase of mark