Mussels infested with diarrhetic shellfish toxins were collected for toxin analyses at Arendal on the south coast and at Sogndal in Sognefiord of Norway. The Arendal mussels contained okadaic acid as the principal toxin, while the Sogndal mussels contained dinophysistoxin-1 as the major toxin and yessotoxin as the minor toxin. These results provide the first evidence for mul-tiple toxin profiles in mussels from European country. Chromatographic and spectrometric methods for determining microquantities of the toxins were established.
