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​​​​​​​Key message

This core indicator evaluates the status of the marine environment based on concentrations of perfluorooctane sulphonate (PFOS) in Baltic Sea fish and in a few assessment unit using the secondary matrix seawater. Good status is achieved when the concentrations of PFOS are below the threshold values. The current evaluation considers the assessment period 2011-2016.


Key message figure 1. Status assessment results based on evaluation of the indicator 'perfluorooctane sulphonate (PFOS)'. One-Out-All-Out (OOAO) method (main figure), in biota (upper inset) and in seawater (lower inset). The assessment is carried out using scale 4 HELCOM assessment units (defined in the HELCOM Monitoring and Assessment Strategy Annex 4). Click here to access interactive maps at the HELCOM Map and Data Service: PFOS.


Concentrations of PFOS are below the threshold value in biota in almost all the monitored areas. However, the concentrations in seawater exceed the threshold value (EQS for water) where measured. This is the reason for the large red area in summary indicator map. Good status is achieved for all evaluated areas, except for L4-area FIN-006 (Merenkurkun sisäsaaristo), using the primary threshold in matrix biota for the assessment period 2011-2016. Data is available from Denmark, Finland, Poland and Sweden but there are still areas where data are absent, for example, Gulf of Riga and the Estonian coast of the Gulf of Finland. A lot of the monitoring stations are also only based on one or few years of monitoring data, therefore, extended monitoring would be required to enable a complete status evaluation throughout the Baltic Sea.

Time series of PFOS levels in biota show increasing concentrations since the 1970s and 1980s in the Baltic Proper and the Bothnian Sea. However, in the most recent ten-year period decreasing concentrations of PFOS are observed in the Baltic Sea.

The confidence of the indicator evaluation results is considered to be high for those areas for which data are available.

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

Relevance of the core indicator

PFOS is a persistent, bioaccumulative and toxic compound with possible effects on the immune, reproductive and developmental systems as well as lipid metabolism in organisms. It is considered a global environmental contaminant. PFOS has been produced since the 1950s, and has been used for production of fluoropolymers and used commercially to provide grease, oil and water resistance to materials such as textiles, carpets, paper and coatings in general. PFOS has also been used widely in firefighting foams.

The presence of PFOS in biological samples provides information on the contaminant load of the Baltic Sea and reflects the bioavailable part of the contaminant. (Top) predators and humans are exposed to the contaminant through consumption of the species assessed in this indicator. 

Policy Relevance of Indicator

 BSAP segment and objectivesMSFD Descriptor and criteria
Primary link

Hazardous substances

  • Concentrations of hazardous substances close to natural levels

D8 Concentrations of contaminants

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

Secondary link

Hazardous substances

  • Fish safe to eat

D9 Contaminants in fish and seafood

D9C1 The level of contaminants in edible tissues (muscle, liver, roe, flesh 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 exceed the threshold values

Other relevant legislation: The Water Framework Directive and EC regulation No 850/2004 (and its following amendments) and the Stockholm Convention on Persistent Organic Pollutants. ​ ​

Cite this indicator

HELCOM (2018) Perfluorooctane sulphonate (PFOS). HELCOM Core Indicator Report. Online. [Date Viewed], [Web link]. 

ISSN 2343-2543

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