Summary
The 24th Norwegian intercomparison study for analysis of fresh water, designated 15-24, was organized in November-December 2015 with 54 participants. It comprised analysis of three sample sets of four samples (A-D, E-H, I-L), and two sample sets of two samples (M-N and O-P), made by adding known amounts of stoichiometric material to water from the river Glomma and Damtjern in Aurskog-Høland municipality, which had been filtered through membrane filter with pore size 0,45 µm. The program included 32 different parameters: pH, conductivity, turbidity, colour, UV-absorption, sodium, potassium, calcium, magnesium, hardness, alkalinity, chloride, sulfate, fluoride, total organic carbon, chemical oxygen demand (CODMn), phosphate, total phosphorus, ammonium, nitrate, total nitrogen, aluminium, lead, iron, cadmium, copper, chromium, manganese, nickel, zinc, antimony and arsenic. The analysis was largely carried out according to Norwegian standards or equivalent methods (Table B1).