115
5.4.3.4 PCA formula group and congener profiles
Table 36 gives a survey over the relative formula and congener group compositions of
the North and Baltic Sea sediments with total PCA concentrations > 50 ng/g dw. They
were determined with CH4/CH2CI2-NICI, which is able to determine compounds with 3-10
Cl atoms. Moreover, these results were partly checked by ECNI-MS on a new instrument
(Varían 1200L), which had a strongly improved sensitivity. The formula and
congener group composition could be confirmed within the measuring uncertainty of
the methodology (see chapter 5.3.3.3) but without the Ch-CU-compounds. In addition,
the relative formula and congener group fractions were also determined for river
sediments and suspended particulate matter. The results are summarised in Table 37.
The findings can be summarised as follows:
• PCAs with C13 and C14 chain and 4 to 6 Cl atoms were the main components in
the marine sediments with exception of CioHuClg for station 718 and C12H20CI6 for
710(2001).
• C17 chains were not detected in any sediment.
• sPCAs in marine sediments consisted to 50-87 % of C12- and Ci3-compounds
and mPCAs between 56-81 % of Ci4-constituents. The content of Ci6 chains
length was maximum 12 % in mPCAs.
Differences were found between marine and river sediments as well as suspended
particulate matter (SPM).
• The chlorine content of sPCAs was lower in marine sediments (51-59 %) than in
river sediments/SPM (58-63 %). Main compounds were Cn and C12 chains with 7-8
Cl. However, the chlorine content of mPCAs and their composition was comparable.
• The fraction of Cn compounds was somewhat lower in marine sediments (19-34
%) than in river sediments/SPM (24-43 %). Also sediments from Czech rivers
contained a higher amount of Cn congeners (Steinarova et al, 2005). Moreover, a
Cn amount around 40 % was reported for SPM from German rivers and creeks
(Maulshagen et al, 2003).
