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2 Executive summary 
The aim of the project „Identification of Organic Pollutants in the North and Baltic 
Seas” was to identify and quantify toxic organic substances in the marine environment 
of the North Sea and Baltic Sea for which environmental data are either insufficient or 
not available. The selection of compounds is based on the lists of substances identified 
for priority action by the OSPAR and HELCOM Conventions and the European 
Commissions Water Framework Directive. 
2.1 Part Polychlorinated paraffins and chlordanes 
2.1.1 Characterisation of polychlorinated paraffins (PCAs) 
Polychlorinated n-alkanes (PCAs) are complex technical mixtures containing thousands 
of different isomers, congeners, diastereomers and enantiomers. The chlorine content of 
the products varies between 30 and 70 %. PCAs are divided into short chain PCAs 
(Cio-i3, sPCAs), medium chain PCAs (Ci4_n, mPCAs) and long chain PCAs (C>n, 
lPCAs) depending on the length of the carbon chain. PCAs are persistent, 
bioaccumulate and have physical properties, which allow dispersion in the environment 
by long-range transport. Therefore, they fulfil the properties of a persistent organic 
pollutant. PCAs are applied as additives in metal working fluids, as plasticizers and/or 
flame retardants in polymers and as surface coating agents. 
Since their first large scale usage in 1932 as extreme pressure additives, the world wide 
production of PCAs has increased to estimated 300kt/year in 1993 and is probably at 
the same level today (estimate of production capacity up to 160'000 t annually in the EU 
in 2002). However, the application has changed from sPCAs to mPCAs due to the 
unfavourable toxic properties of sPCAs. sPCAs have low acute toxicity, but are 
carcinogenic and show high chronic toxicity to aquatic biota, whereas mPCAs and 
lPCAs do not. Due to their widespread and mainly unrestricted use and due to the 
properties mentioned above, PCAs are present in aquatic and terrestrial food webs of 
rural and remote areas at levels comparable to polychlorinated biphenyls (PCBs). For 
example, levels in fish and marine mammals were reported to be between 100 -