Interim report of the HELCOM CORESET project

214
5.6. Organochlorine compounds
General information
Author: Michael Haarich
Acknowledged persons:
Anders Bignert, Elin Boalt, Anna Brzozowska, Galina Garnaga,
Jenny Hedman, Ulrike Kamman, Thomas Lang, Martin M.
Larsen, Kari Lehtonen, Jaakko Mannio, Rita Poikane, Rolf Schneider,
Doris Schiedek, Jakob Strand, Joanna Szlinder-Richert,
Tamara Zalewska
General properties
Hexachlorobenzene (HCB) , Hexachlorohexane isomers (HCHs) and 1,1,1-trichloro-2,2-di(chlorophenyl)
ethane (DDT) and its metabolites DDD (1-chloro-4-[2,2-dichloro-1-(chlorophenyl)ethyl]benzene) and DDE
(1,1-bis-(chlorophenyl)-2,2-dichloroethene) are toxic organic pollutants, which have been used mainly
as insecticides (HCHs, DDTs) or fungicides (HCB) in the Baltic region partly up to the mid-1990s. HCHs
and DDTs have been applied as technical mixtures, the DDTs dominated by the para-phenyl-chlorinated
isomers, the HCHs by alpha and gamma-HCH in the past, later in Western Europe only more or less pure
gamma-HCH was used. They are less volatile and water soluble, in the marine environment they are mainly
attached to particles of suspended matter (SPM) and sediments and accumulate in the lipids of organisms.
Due to their properties these substances are belonging to the so-called PBT-compounds (persistent, bioaccumulating
and toxic).
Main impacts on the environment and human health
Due to their persistence HCB, HCHs and DDTs are still remaining in the marine environment even decades
after the use having been banned or phased out. They are taken up by organisms, bio-accumulated and
bio-magnifi ed in the food chain up to the top-predators, the marine mammals, seabirds and humans. The
prevailing toxic effects described for these substances are negative impacts on behavior, growth, enzyme
and hormone status and reproduction, histo-pathological fi ndings, carcinogenic, increased mortality, acute
intoxication and decrease of populations. The best example for the latter was the threat to the sea eagle at
the Baltic Sea. The ecotoxicological classifi cation for fi sh is ranging from high to very high toxic (only HCB
is ranked as moderate), and for molluscs, crustaceans and plankton differing and depending on substance
and isomer from slight (DDE in zooplankton) to very high toxic for DDD in crustaceans or DDT in phytoplankton.
The HELCOM thematic assessment showed that the concentrations of DDE exceeded in many sites the
thresholds (HELCOM 2010), whereas HCHs and HCB were generally below the thresholds.
Status of a compound on international priority lists and other policy relevance
In Table 5.2 the most important conventions, directives and related monitoring programmes are listed,
which are including HCB, HCHs and DDTs as indicator, parameter or hazardous substance of concern.