Sammendrag
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. The interlaboratory comparison exercises cover the most common analytical variables included in the Norwegian Environment Agency’s control programme for industrial effluents; pH, suspended matter (dry substance and its residue on ignition), chemical oxygen demand, biochemical oxygen demand, total organic carbon, total phosphorus, total nitrogen, aluminium, lead, iron, cadmium, copper, chromium, manganese, nickel and zinc. All samples are synthetic and stable. Each set of samples includes four samples, grouped in two concentration levels.