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Key Message

This core indicator evaluates the status of the marine environment based on concentrations of the heavy metals in the Baltic Sea. Lead (Pb), cadmium (Cd) and mercury (Hg) are measured in water, biota (fish and mussels) and sediments. Good status is achieved when the concentrations of heavy metals are below the specific threshold values.

The indicator presents a status evaluation using all available data in the HELCOM region during the assessment period 2011 - 2016.

 

Key message figure 1.png

Key message figure 1. Status assessment results based on evaluation of the mercury concentrations in fish and mussels. 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: Mercury.

 

Mercury (Hg) concentrations in fish muscle (used for the assessment) exceeded the threshold level in almost all monitored open sea sub-basins, indicating not good status in the Bothnian Bay, The Quark, Bothnian Sea, Gulf of Finland, Northern Baltic Proper, Western- and Eastern Gotland Basins, Gdańsk Basin, Bornholm Basin, Bay of Mecklenburg, Kiel Bay and Kattegat (Key message figure 1). Good status was not achieved in the majority of coastal areas assessed, including: Finnish, Swedish, Estonian, Polish, German and Danish assessment units.  Good status was only achieved in the Arkona Basin open sea assessment unit and few coastal Danish and Swedish coastal areas.

 

Data on concentrations of cadmium (Cd) in seawater, biota (mussels) and sediment was used for the status assessment, and taking into account all matrices by applying the One-Out-All-Out (OOAO) method, good status was achieved in the Bothnian Sea, Åland Sea, Kattegat, Great Belt and Kiel Bay as well as in some of the Danish and German coastal areas (Key message figure 2). Good status was not achieved in the Bothnian Bay, Northern Baltic Proper, Western Gotland Basin, Eastern Gotland Basin, Bornholm Basin, Arkona Basin, Gdańsk Basin, Bay of Macklenburg and in some coastal areas: German, Danish and Polish.

 

Key message figure 2.png

Key message figure 2. Status assessment results based on evaluation of the cadmium concentrations. One-Out-All-Out (OOAO) method (large upper figure), in seawater (lower left), in biota (lower middle) and in sediment (lower right). 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: Cadmium.

 

Concentrations of lead (Pb) in seawater, biota (fish and mussel) and sediment were monitored, and when summarised using the OOAO approach good status was only achieved in the Bothnian Bay, Åland Sea, Kattegat and Great Belt open sea assessment units as well as in some Finnish, Swedish, Danish and German coastal areas  (Key message figure 3). Areas where good status was not met were the Quark, Northern Baltic Proper, Gulf of Finland, Western Gotland Basin, Eastern Gotland Basin, Gdańsk Basin, Bornholm Basin, Arkona Basin, Kiel Bay and the Bay of Mecklenburg, as well as of the coastal areas: Finnish, Swedish, Estonian, Polish, German and Danish.

 

Key message figure 3.png

Key message figure 3. Status assessment results based on the evaluation of lead concentrations. One-Out-All-Out (OOAO) method (large upper figure), in seawater (lower left), in biota (lower middle) and in sediment (lower right). 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: Lead.

 

The confidence of the indicator evaluation is high. The data on metal concentrations is spatially adequate and time series are available for several stations.

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

 

Relevance of the core indicator

The heavy metals cadmium (Cd), lead (Pb) and mercury (Hg) are toxic to marine organisms when encountered at high concentrations.

Metals are bioaccumulated by marine organisms causing harmful effects. The severity of effect mainly depends on the concentration in the tissues. Additionally, both Cd and Hg are also known to biomagnify, i.e. the concentration levels increase upwards through the food chain. When heavy metals bioaccumulate in tissues they can cause different biological effects on the individual organism, which transform into changes at population, then species level, and finally affect biodiversity and ecosystem functioning. Heavy metal accumulation in fish, specifically destined for human consumption, directly affect human health.

 

Policy relevance of the core indicator


BSAP segment and objectivesMSFD Descriptor and criteria
Primary link

Hazardous substances

  • Concentration of hazardous substances close to natural levels.
  • Healthy wildlife.

D8 Concentrations of contaminants

D8C1 Within coastal, territorial and areas 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 of seafood caught or harvested in the wild does not exceed maximum levels which are the threshold values.

Other relevant legislation: The Water Framework Directive (Cd, Pb and Hg are listed as priority substances).

 

Cite this indicator

HELCOM (2018) Metals (lead, cadmium and mercury). HELCOM Core Indicator Report. Online. [Date Viewed], [Web link].

ISSN: 2343-2543

 

Download full indicator report

Metals HELCOM core indicator 2018 (pdf)