Certain marine species have naturally high concentrations of arsenic (e.g. cod, shrimp and bivalves) and mercury (e.g. halibut) whereas other species contain naturally high dioxin levels (e.g. salmon). The toxicity of these compounds is dependent on their chemical form. The arsenic content in food items is usually measured as total arsenic, whereas the inorganic arsenic content is seldom given. In terms of food safety it is inorganic arsenic, organic mercury, and 17 congeners of dioxins and 12 dioxin-like PCBs which are of interest since these are toxic chemical form, and hence potentially hazardous to human health. There are currently no maximum limits for either arsenic or dioxins in food in either Norway or the EU The maximum limit for mercury in most fish species is 0.5 mg/kg in both Norway and the EU, with a higher limit (1 mg/kg) for certain species, such as tuna and halibut. Current maximum limits for contaminants in fish feed are based on total concentrations as opposed to the hazardous chemical forms (e.g. inorganic arsenic and organic mercury). This is primarily due to the difficulties and costs of the relevant analytical methods, hence there is a need for establishing rapid, less costly methodology for analysing the chem ical forms potenially toxic to humans.