Summary
As part of the control with industrial effluents, the Norwegian Environment Agency and the Secretary of County Governor for the Environment have instructed a series of industrial companies to periodically report the composition of their effluents. The companies have to fulfil certain analytical quality requirements. This may be achieved by partici¬pat¬ing in interlaboratory comparison exercises (SLP). In accordance with an agreement between NIVA and the Norwegian Environment Agency, NIVA organises two exercises yearly. The samples distributed represent industrial effluent water.