Hazardous substances such as man-made chemicals and heavy metals enter the Baltic Sea via numerous sources, including waste water treatment plants, leaching from household materials or from waste deposits, and from atmospheric deposition from industrial plant emissions, amongst others.
Once in the Baltic Sea, these substances can cause various types of damage to the ecosystem. Some are highly visible in the form of oil-spills, others however can remain unnoticed or are only apparent when detrimental impacts on the ecosystem or biota are observed.
Many contaminants degrade slowly and their impacts can magnify as they accumulate within the aquatic food web. Compared to natural conditions, the contamination status is elevated in all parts of the Baltic Sea.
Read the latest HELCOM assessments and reports on hazardous substances: