This core indicator evaluates the status of the marine environment based on concentrations of the heavy metals in the Baltic Sea, namely lead (Pb), cadmium (Cd) and mercury (Hg) measured in water, biota (fish and mussels) and sediments. Good status is achieved when the concentrations of heavy metals are below the threshold values.
The indicator presents a status evaluation using all available data until 2015 to evaluate the assessment period 2011 - 2015.
Concentrations of cadmium (Cd) in seawater, mussel and sediment did not achieve good status in most of the monitoring areas, that is in the Eastern Gotland Basin, the Bornholm Basin, the Arkona Basin and in coastal waters of the Gdańsk Basin, the Kattegat, Great Belt and The Sound. Good status was found in the Kiel Bay and Bay of Mecklenburg (Key message figure 1).
Key message figure 1: Status assessment results based on evaluation of the cadmium concentrations in seawater, mussel and sediment. The assessment is carried out using Scale 4 HELCOM assessment units (defined in the HELCOM Monitoring and Assessment Strategy Annex 4). Click to enlarge.
of lead (Pb) in seawater, fish, mussel and sediment indicated good status in
the Bothnian Sea, Northern Baltic Proper, Eastern Gotland Basin and in coastal
areas of the Gulf of Finland, The Quark and the Kattegat. Areas where the
status exceeded the threshold value were Western Gotland Basin, Bornholm Basin, Arkona
Basin, Kiel Bay and the Bay of Mecklenburg, as well as in some of the coastal
areas in Gulf of Finland and Gdańsk Basin (Key message figure 2).
Key message figure 2: Status assessment results based on evaluation of the lead concentrations in seawater, mussel and sediment. The assessment is carried out using Scale 4 HELCOM assessment units (defined in the HELCOM Monitoring and Assessment Strategy Annex 4). Click to enlarge.
(Hg) concentration threshold value in fish muscle exceeded the threshold level
in almost all monitored sub-basins indicating not good status, that is the
Bothnian Sea, Northern Baltic Proper, Western- and Eastern Gotland Basins,
Bornholm Basin, Arkona Basin, the Kiel Bay and the Kattegat. Only some coastal
areas of the Kattegat achieved good status (Key message figure 3).
Key message figure 3: Status assessment results based on evaluation of the mercury concentrations in fish muscle. 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. The data on metal concentrations in fish and bivalves 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.
The heavy metals cadmium (Cd), lead (Pb) and mercury (Hg) are toxic to marine organisms 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 cause different biological effects on the individual organism, which transform into changes at population, then species level, and finally affect the biodiversity and ecosystem functioning. Heavy metal contents in fish, specifically destined for human consumption, directly affect human health.
BSAP segment and objectives
MSFD descriptors and criteria
Concentrations of hazardous substances close to natural levels
D8 Concentrations of contaminants
D8C1 Within coastal, territorial and aras beyond territorial waters the concentration of contaminants do not exceed the threshold values
Fish safe to eat
D9 Contaminants in fish and seafood
D9C1 The level of contaminants in edible tisues 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 substanes).
HELCOM (2017) Metals (lead, cadmium and mercury). HELCOM Core Indicator Report. Online. [Date Viewed], [Web link].
II component - core indicator report – web-based version July 2017 (pdf)