The archipelago in northern Bohuslän is one of the most pristine coastal areas in Sweden. There are no large industries here, the water is the purest along the western coast of Sweden, and animal life is flourishing. Despite this, scientists recently discovered that the Sannäs Fjord, which is located within a Natura 2000 region, contains surprisingly high levels of heavy metals in the bottom sediment. This may be a result of the intensive use of leisure boats in the area.
Many Swedish and Norwegian boats visit the Sannäs Fjord every year, and these are taken up at the end of the season to have their hulls washed clean using high-pressure washing. This leads to toxic chemicals from the anti-fouling paints used on the boats being rinsed straight into the fjord. Older paint layers, which may be of older and more toxic paints than those used today, are also released during the process.
The vicinity to Norway makes the problem particularly serious: Norwegian legislation is less stringent than Swedish, and toxins that are forbidden for use in Swedish paints are spread in the Sannäs Fjord, and to other neighbouring coastal waters.
Researchers at the University of Gothenburg have worked together with the municipalities of Tanum and Stenungsund, Region Västra Götaland, the County Administrative Board of Västra Götaland, and local organisations and companies for some years in order to deal with the environmental problems in the Sannäs Fjord.
The result will be presented on 24 April in the form of what is the most modern and environmentally friendly boat washing facility in Sweden, possibly also in the world.
The facility is based on a specially designed system with a three-compartment tank in which paint particles with heavy metals sediment. The dissolved metals are subsequently precipitated in a small treatment plant, while other toxins are absorbed by a filter system with active charcoal. The purified water is discharged to the sea, and the waste products can be sent to an ordinary collection point.
“This is the best technology that is currently available, and its cost is reasonable”, says project manager Kjell Nordberg, researcher at the Department of Earth Sciences, University of Gothenburg.
One very important aim of the project is to ensure that the facility at Sannäs functions as a demonstration and training facility. The project provides a day of training, free of charge, for marina personnel, municipal employees and others who are involved in leisure boating and the marine environment. These are invited to Sannäs to learn how the facility works and why it is important for the environment.
The aim of the training is to aid municipalities, marinas and boat clubs to establish their own boat-washing facilities, which in this way will spread along the complete coast. The environmental impact of the new technology will be evaluated in scientific studies carried out by the University of Gothenburg.
The facility will be presented to the media and others interested on 24 April.