The report addresses radioactive discharges to sewers originating from hospitals, mainly in the form of the excretion of patients treated with radioisotopes for diagnostic or therapeutic purposes. Assessments of doses to the public, including sewage workers, arising from such discharges are performed. Doses are compared against the exemption level of 10 μSv/a and the dose constraint of 100 μSv/a.
As a basis for the dose assessments, information on the use of radionuclides in Swedish hospitals during the period 1999-2004 is presented and estimates of discharges to the sewage systems are derived. Current sewage treatment practices in Sweden are summarised focusing particularly on the fate of sewage sludge, both in the sewage plant and outside.