Open access publications in the SLU publication database

Abstract

Chlorinated fatty acids (CFAs), major constituents of extractable, organically bound
chlorine in biota, are found in almost all fish studied in this respect. The concentration of
CFAs in fish varies considerably from some micrograms per gram of lipids in fish from
remote areas up to more than two thousand micrograms per gram of lipids in fish from the
vicinity of chlorine bleached kraft mills.

CFAs were liberated from fish lipids as the corresponding methyl esters and subjected
to enrichment. The methylated CFAs were studied by gas chromatography with electrolytic conductivity detection and/or mass spectrometry.

A considerable diversity of CFAs were found in fish, e.g. more than twenty were
indicated in pike from Latvian lakes. However, only part of the CFAs could be identified.
Pattern of CFAs differ considerably between fish from different areas. Thus, the patterns of CFAs in previously studied eel caught in Idefjord differ from the CFA patterns of pike
from Latvian lakes and also from that of perch from Latvian rivers. The main CFAs in
pike are likely chlorohydroxy fatty acids and in perch chlorinated, possibly sulphur containing
carboxylic acids. In the study of pike, CFAs were released from all lipid
classes considered: steryl esters, triacylglycerols, and phospholipids.

Because an enrichment is usually needed to make CFAs in lipids detectable, their
quantification may be difficult. A method to facilitate quantitative studies was developed,
where the enrichment factor is calculated using cholesterol.

Dichlorostearic acid was taken up by rats via food and were distributed within different
organs with the highest concentration in heart lipids and the lowest in muscle lipids.
Dichlorostearic acid was metabolised in rats yielding dichloropalmitic and
dichloromyristic acids. Some shorter-chain metabolites, possibly including dichlorotridecanoic
acid were found in the liver lipids. CFAs in the lipid extracts of rat tissues
were studied also by liquid chromatography with electrospray ionisation mass
spectrometry.

In a test for mutagenicity, the Ames test, dichlorostearic acid did not show any adverse
effects. In contrast, dichlorostearic acid caused inhibition of mutagenicity of some
indirectly-acting mutagens, possibly by the inactivation of Cytochrome P450 enzymes.
Certain effects on the ability of rat enzymes to activate indirectly acting mutagens by the
same acid was found also in in vivo studies. A possible explanation to this observation
might be an interaction of dichlorostearic acid with membrane bound enzymes or changes
in the membrane lipid composition resulting from the exposure to dichlorostearic acid.