Live mussels are being used in an oil industry project to see whether chemicals discharged from Norway's offshore installations are harmful to marine life.
These shellfish have been chosen because they live in one place and ingest all marine pollutants without excreting them.
Measuring the concentration of pollutants in their shells allows researchers to determine how much derives from chemicals in produced water, which is discharged to the sea after treatment.
Statoil has taken a lead in establishing this project in cooperation with Norsk Hydro and the Norwegian Oil Industry Association (OLF).
Four parts of the continental shelf will be investigated, with the area around Ekofisk as the first. Mussels were placed at various sites up to 15 kilometres from the field during June.
"Preliminary results indicate that the only ecosystem impact is occurring in the immediate vicinity of the platforms," reports adviser Ståle Johnsen in the environment technology unit at Statoil's research centre in Trondheim.
He explains that the mussels are being used to check the accuracy of mathematical calculations in the environmental impact assessments carried out by the oil companies.
These studies claim that living organisms only suffer from pollution in the immediate vicinity of offshore installations.
In addition to measuring the concentration of hazardous substances in mussels, the project is also carrying out studies of marine plankton. No increase in pollution in these life forms has so far been found on the Ekofisk field.
Funded by Phillips Petroleum and BP Amoco as well as Statoil, the mussel project forms part of a national programme headed by the Norwegian Pollution Control Authority (SFT) to monitor marine pollution.