An international cooperation between Czech Republic and Poland has been started. During the fieldwork the radon in water activities in the total of 156 water maifestations were measured.
Three sources were found with the activities of more than 1500 Bq/l Rn-222. The most remarkable are Haida and St.
Vojtěch springs in Horní Malá Úpa. Some most important springs were catched up in tubes for public medicinal use.