Waste water shows traces of radioactive substances

Sludge at sewage treatment plants has been found to contain radioactive substances originating in hospitals, nuclear weapon tests, the Chernobyl accident, the Finnish nuclear power plants and natural sources. Radioactive substances also enter sewers together with excretions after patients have left the hospital. Hospitals used to let the excretions of patients receiving the iodine 131 treatment into the sewer system only after the activity of the excretions had decreased. Today, excretions can be led into the sewer directly. Calculations have shown that hospital staff receive higher radiation doses when the waste is collected than sewage treatment plant staff receive when the radioactive iodine is led directly into the sewer