Experts assess Lake Saimaa oil spill as no oiled animals are found

Experts are still assessing the extent and environmental impact of an oil spill in Haukivesi lake near Rantasalmi, Yle reports. No oil-covered animals have been found so far.

The spill occurred on August 18 when several hundred litres of engine oil leaked from a tank on a cargo vessel into the water. Some of the oil spread into Linnansaari National Park, and police are investigating the incident.

The Finnish state forestry agency Metsähallitus, the South Savo rescue department and the Central Savo lake rescue service are surveying the affected area and planning further response measures. The survey is being carried out with four boats around Karhosaari, where the spill occurred.

Oil has been observed along shores and in bays where wind is likely to have carried it. The oil is floating on the surface and moving with the wind, while the slick becomes thinner as it spreads. Booms have been used to prevent oil from escaping back into open water.

Petri Naumanen, an environmental expert at the Licensing and Supervisory Agency, said large oil spills caused by commercial vessels have been extremely rare in Finland’s inland waters. Previous spills have mainly involved small discharges of bilge water from vessels. The Haukivesi incident is also unusual because the substance is engine oil, whereas inland-water oil spills have more typically involved light fuel oil.

WWF Finland’s oil-response experts and trained volunteers are testing cleanup methods at the site. Teemu Niinimäki, a conservation expert with WWF, said oil is likely to be present in thin layers on rocks and among reeds. Absorbent products such as mats may be used.

The oil is particularly harmful to birds. Even a small amount can damage the structure of waterbirds’ feathers, allowing water to reach their skin and causing them to become cold. Oil can also affect fish gills and cause oxygen deficiency, while spawning grounds beneath the slick may be at risk.

Mussels and other animals that filter water may also take in oil, potentially causing symptoms of poisoning. The area is home to and used for nesting by endangered Saimaa ringed seals. Their vulnerability to the spill is considered lower than that of birds. The seal pups born this year have already developed a protective layer of fat.

Cleanup along the shores could take weeks, according to the South Savo rescue department. Authorities have warned people not to attempt oil cleanup independently because the oil is also harmful to humans. Oil sightings should be reported to the on-duty fire officer.

Compared with large oil accidents, the amount of oil in Rantasalmi is small, but experts are still working to determine the full effects on the environment and wildlife.