24 
Compilation of Summaries 
In contrast, the concentrations of the hexachlorocyclohexane isomers alpha- 
and gamma-HCH declined exponentially over the time span from 1989 to 2007. 
The amounts of alpha-HCH in the German Bight decreased by half every 
4 years, while the amounts of gamma-HCH, depending on the sampling loca 
tion, declined by 5 %-35 % roughly until 1998, and showed reductions of 50 
% every two years to now. Today, the concentrations of both alpha- and 
gamma-HCH are lower than 0.1 ng/L. Already by the turn of the millennium, the 
long-term downward trend of alpha-HCH had changed to a more lateral trend 
in the waters off the North Frisian coast, which are influenced by the discharge 
of the river Elbe. A similar trend could be observed for gamma-HCH since 2007 
and during the recent assessment period from 2008 to 2011. Thus, no decreas 
ing trends were to be found for the HCH isomers in the Elbe plume. Beyond 
coastal waters, slightly minor downward trends were occasionally observed for 
gamma-HCH. 
As in previous observation periods, the concentrations of polar pesticides dis 
played strong seasonal variations in the years 2008 to 2011. These variations 
are caused by different periods of application for various herbicides over the 
course of a year. Although regular monitoring for these compounds is only in 
place since the year 2000, for some polar pesticides a downward trend was 
ascertained within recent period of investigations. This pertained not only to 
controlled herbicides like Atrazin, which is banned since the mid-1990s, but 
also to substances which are still on the market. Declining trends in the coastal 
zone were also observed for perfluorinated surfactants which have been re 
stricted since 2002. In contrast, hardly any downward trends were identified in 
the open sea. 
Sediment: Although lipophilic substances are strongly enriched by sediments 
and are consequently present in concentrations approximately 100 times 
higher than in the water phase, it is hardly possible to correlate the amounts of 
these substances to potential sources in the German Bight. Instead, spatial 
distributions are mainly determined by sediment characteristics (grain size dis 
tribution, TOC contents). The concentrations of all investigated compounds in 
sediment samples showed considerable small-scale spatial and temporal vari 
ations. As a result of these variabilities, which could not be sufficiently reduced 
by organic carbon normalisation of the data, it was not possible to identify any 
robust, temporal trend. 
Metals (Page 232 et seq.) 
Water: Metal concentrations (Cd, Cu, Hg, Ni, Pb and Zn) above levels, which 
could have a negative impact on the living nature, were not detected in the 
waters of the German Exclusive Economic Zone (EEZ) from 2008-2011. This 
assessment is based on the evaluation of the dissolved element concentration 
of cadmium, lead, mercury and nickel present on the basis of the EU Water 
Framework Directive AA-EQS. The copper and zinc concentrations were evalu 
ated on the basis of the Water Quality Standard (WQA) of the United States 
Environmental Protection Agency (EPA) as no corresponding Water Framework 
Directive quality standard is available. The metal contents (dissolved) of the 
elements cadmium, mercury, nickel, lead and zinc reached background levels 
in the open sea (salinity > 34). The “effect limit” was not reached in any way, 
either in direct proximity to the coast or in water masses with > 28 salinity.