Compilation of Summaries 
30 
System Nordsee 
Metals (p. 217 sqs.) 
Mercury, cadmium, lead, copper, and zinc have similar distribution patterns in surface 
water of the German Bight. Levels decrease markedly from the coast to the open sea. 
Highest concentrations generally occur in the inner German Bight and Elbe estuary, 
but also in the Weser and Ems estuaries have elevated levels been found. 
Cadmium, lead, and zinc levels in filtered water, and mercury in unfiltered water, had 
decreased until 1990, yet levels have been stagnant since then. In 2005, cadmium 
concentrations in filtered sea water from the outer German Bight were on the order of 
the background levels, while concentrations of copper, lead, and zinc were slightly 
higher. Near the coast (30 < S < 32), background levels of zinc and copper were clear 
ly exceeded, whereas lead and cadmium remained within background limits here, too. 
According to current knowledge, the metal levels found in sea water do not pose an 
immediate threat to the marine ecosystem. 
In some regions of the German Bight, enrichment of various elements in surface sed 
iment still exceeded background levels clearly although improved waste gas and waste 
water treatment methods and optimised production processes have led to a reduction 
of heavy metal input. Metals in riverine discharge are enriched preferably in nearshore 
sediments. Especially mercury, silver, zinc, cadmium, lead and copper levels show a 
spatial pattern with clearly elevated concentrations near the coast and decreasing gra 
dients toward the open sea. Levels of silver and mercury are particularly high along 
the North Frisian coast, pointing to the Elbe as pollution source. Unlike the other ele 
ments listed above, elevated concentrations of lead were also found in the outer Ger 
man Bight. Concentrations of mercury, zinc, and lead exceeded background levels in 
the entire monitoring area, those of cadmium and, to a lesser extent, copper especially 
close to the coast. 
Since the beginning of routine monitoring in the 1970s, most notably, concentrations 
of mercury, copper, cadmium, and nickel have decreased in the silt/clay fraction of 
surface sediments, especially inshore sediments. Decreasing zinc levels were found 
only here - specifically off the coast of Lower Saxony, whereas lead levels were found 
to fluctuate irregularly in the entire monitoring area. The former acid waste disposal 
site northwest of Helgoland has to be considered separately. Here, levels of iron in par 
ticular, and to a lesser extent zinc, lead, and arsenic continued to be above ambient 
levels. Although acid waste discharge was stopped as early as 1989, pollutant levels 
have not yet decreased. 
In contrast with the overall picture, rising levels of mercury, lead, and zinc have again 
been found in recent years in sediments influenced by the Elbe plume. Irrespective of 
these changes, which have been observed since 1999, sediments dredged from the 
Hamburg harbour and dumped at buoy E3 have led to a regional increase of pollutant 
levels in surface sediments, especially cadmium, copper, mercury, and zinc. 
Radioactive Substances (p. 231 sqs.) 
Monitoring in 2005 focused on the dose-relevant radionuclides 137 Cs, 90 Sr, and on the 
transuranics 238 Pu, ( 239+24 °)p Ui and 241 Am in the German Bight. Only minor spatial 
differences were found in the volume activity distributions of these radionuclides. Con 
centrations hardly exceeded those in North Atlantic surface water, which are due to 
global radioactive fallout from atmospheric nuclear weapons testing. Activity levels of 
137 Cs in western parts of the German Bight were slightly higher than in the coastal wa-