Interim report of the HELCOM CORESET project

For US EPA it is the list of 16 priority compounds quoted under 1.1.
Relevance of the indicator for describing the developments in the environment
Low-molecular-weight PAH compounds, containing two or three rings, are acutely toxic to a broad spectrum
of marine organisms. Examples of low-molecular-weight PAHs that tend to be toxic are anthracene,
fl uorene, naphthalene and phenanthrene. The high-molecular-weight PAH compounds, containing four,
fi ve, and six rings, are less toxic but have greater carcinogenic potential, e.g. benzo(a)pyrene, dibenz(a,h)
anthracene, benzo(b)fl uoranthene (Kennish 1997). While PAHs can be weakly carcinogenic or noncarcinogenic,
they can modify the carcinogenic activity of other PAHs in complex mixtures (Marston et al.
2001). Therefore, synergistic effects of PAHs can be larger than the total levels of PAHs would indicate.
Higher concentrations of PAHs are also harmful to reproduction of fi sh and can damage cellular membrane
structures (Knutzen 1995). When PAHs are exposed to sunlight, the mechanism known as phototoxicity is
involved, producing reactive and toxic photomodifi cation products (HELCOM 2010).
Anthropogenic PAH sources in the marine environment include the release of crude oil products (petrogenic
source) and all types of incomplete combustion of fossil fuels—coal, oil and gas or wood and waste
incineration (pyrolytic sources) (Neff 2004). Some PAHs are formed naturally, but the majority of PAHs in
the marine environment come from anthropogenic activity. Each source generates a characteristic PAH
pattern, enabling distinction of the sources in a sample; concentration relationships of individual PAH compounds
can be used to reveal the sources of the PAH compounds (Baumard et al. 1998, Sicre et al. 1987,
Yunker et al. 2002). Molecular indices calculated from both sediment and biota showed that pyrolytic
sources predominate in the Baltic Sea PAH contamination. However, in the Gulf of Finland and some areas
in the western Baltic Sea (Sound, Belt Sea and Kattegat), molecular indices indicated a signifi cant contribution
of petrogenic PAHs. This may indicate that atmospheric deposition combined with shipping activities is
the main source of PAHs in these areas. The dominance of pyrolytic sources could be surprising in view of
the heavy maritime traffi c and illegal oil discharges. On the other hand, no reliable information is available
on the airborne deposition of PAHs onto Baltic Sea surface waters (Pikkarainen 2004).
Status of restrictions, bans or use
The maximum levels of benzo(a(pyrene and also a sum of benzo(a)pyrene, benz(a)anthracene, benzo(b)
fl uoranthene and chrysene are regulated in food stuff according to the Commission Regulation (EC) No
835/2011. There are no other regulations for the production or use of PAHs.
95