Hazardous substances in coastal waters

Published by the Norwegian Environment Agency Lag rapport Les på norsk

Reductions in emissions of hazardous subtances have resulted in improvements in the state of the environment in several places. However, hazardous substances are still a serious problem in some fjords and harbours along the Norwegian coast.

Situation improved in polluted fjords

More than 20 years of monitoring hazardous substances along the Norwegian coast has provided a good overview of the content of contaminants in fish, shellfish and seabed sediments.

In the open sea pollution levels are generally low, but along the Norwegian coast there are a number of problem areas with high levels of hazardous substances in seabed sediments. This particularly applies to harbours and fjords affected by emissions from industry.

Clean up measures have improved the state of the environment in some areas, for example in Sørfjorden on the west coast. However, new studies have revealed an increasing number of problem areas.


The content of environmentally hazardous substances in mussels is a good indicator of the state of the environment in a fjord. Surveys of mussels in polluted fjords show an improvement from 1993 to 2002.

In 2002 the basis for producing the aggregated index above was changed. New stations and parameters were introduced to improve the index. The data for 2002-2010 are therefore not directly comparable with data for earlier years. To illustrate this, the 2002 data is shown with both the new and the old index.

Chemicals accumulate in the food chain

A number of the hazardous substances found in coastal areas are very persistent, which means that they break down very slowly in the environment. Some, such as PCBs and dioxins, can cause damage even in small concentrations.

Hazardous substances accumulate in the food chain and top-level predators such as polar bear and seals may be exposed to very high levels of pollution. The levels of mercury and cadmium registered in some sea-birds and mammals are high enough to be injurious to health if they are eaten by people or animals. High levels of hazardous substances have been registered at a number of locations along the Norwegian coast. The Norwegian Food Safety Authority therefore advises against the consumption of seafood from these fjords.

Hazardous substances can lead to deformities in marine organisms or reduce their reproductive capacity, and thus alter the distribution of species. One example is tributyltin (TBT) which has had adverse effects on dogwhelks (Nucella lapillus). Both along the Norwegian coast and in other countries scientists have found female dogwhelks that have developed male sexual organs. This phenomenon is called imposex and results in sterility.

Earlier pollution is still creating problems

Pollutants are transported to marine areas from a number of different sources. High levels of hazardous substances in some fjords and harbours are mainly the result of earlier industrial discharges. The use of chemical pesticides in the agricultural sector can also play a part.

Emissions from landbased industry have been reduced, but seepage from old landfills and leakage from contaminated soil and sediments still poses a serious problem. In some fjords there are still problems caused by earlier use of pesticides, such as DDT.

Long-range pollution, carried to Norway by wind or ocean currents, is another important source of hazardous substances. Hazardous substances are also transported to coastal waters via rivers.

International cooperation

The Norwegian Environment Agency has organised surveys of polluted locations along the Norwegian coast. The Environmental Departments at the County Governor's offices are responsible for working out county action plans for contaminated sediments. The Norwegian Environment Agency and the County Governors have a common responsibility to follow up the plans, and to make sure that the most polluted areas along the coast are cleaned up.

In addition, the clean up of contaminated sites, the reduction of hazardous substances in products and reductions in discharges from industry and agriculture are important measures in reducing discharges of hazardous chemicals to coastal waters.

International cooperation

Norway is working towards legally binding commitments in environmental cooperation in the North-East Atlantic through the OSPAR Convention. The goal is to stop emissions of hazardous substances within one generation (2020).