​​​​​​​​KEY MESSA​​GE

The concentrations of benzo(a)pyrene, representing the concentration of polyaromatic hydrocarbons (PAH), achieve the threshold value in the open sea assessment units of the Norther Baltic Proper, the Arkona Basin and the Sound (Key message figure 1). The concentrations are below the threshold value in all evaluated coastal assessment units, namely in the Gdansk Basin, The Sound and The Great Belt. There are many areas for which data were not available for the evaluated assessment period of 2011-2015 and for which there is currently no evaluation (Key message figure 1).

As there is no commonly agreed threshold value for measuring metabolites available, this report only considers concentrations of PAH.​


Key message figure 1.png 

Key message figure 1: Status assessment results based evaluation of the indicator ‘PAH and metabolites’. The assessment is carried out using Scale 4 HELCOM assessment units (defined in the HELCOM Monitoring and Assessment Strategy Annex 4). Click to enlarge.


The confidence of the indicator evaluation is high, however the spatial coverage of available data is currently not sufficient to evaluate the whole Baltic Sea area.

The indicator is applicable in the waters of all countries bordering the Baltic Sea.​


Relevance of the core i​​​ndicator​​

Polycyclic aromatic hydrocarbons (PAHs) are of concern due to their persistence and potential to accumulate in aquatic organisms, particularly invertebrates such as bivalves and crustaceans. In most vertebrates, PAHs are fairly rapidly metabolized however PAHs and the toxic intermediates that are formed during metabolic degradation can cause harmful effects in fish. PAHs associate with particles in the water accumulate in sediments, and are persistent especially in anaerobic sediments.

Some PAHs are formed naturally, but the majority of PAHs in the marine environment stem from human activity. Sources of PAH include the release of crude oil products into the sea (oil-spills), as well as all types of incomplete combustion of fossil fuels and waste incineration.​


Policy relevance of the core indicator

BSAP segment and objective​​s

MSFD descriptor and criteria

Primary link

Concentrations of hazardous substances close to natural levels

D8 Concentration of contaminants

- D8C1 Within coastal and territorial and beyond territorial waters, the concentrations of contaminants do not exceed the threshold values

Secondary link

Fish safe to eat

D9 Contaminants in seafood

- D9C1 The level of contaminants in edible tissues (muscle, liver, roe or other soft parts, as appropriate) of seafood (including fish, crustaceans, molluscs, echinoderms, seaweed and other marine plants) caught or harvested in the wild (excluding fin-fish from mariculture) does not the exceed threshold values.

Other relevant legislation: EU Water ​Framework Directive ​ ​


Cite this indi​​cator

HELCOM (2017). PAH and metabolites. HELCOM core indicator report. Online. [Date Viewed], [Web link].

ISSN 2343-2543


Download ​​full indicator report

HOLAS II component - Core indicator report – web-based version July 2017 (pdf)