The official said the source of the radiation, a rod made of strontium, which is a highly radioactive metal, had been taken to Promtechnopolis, a specialized firm that deals with nuclear materials.
Measurements made soon after the source of radiation was taken away from the port showed that the level of background radiation had returned to the normal limits.
Port staff had detected a major radiation source (300 micro-roentgen per hour) in a pile of scrap metal loaded on a truck.
Promtechnopolis experts told RIA Novosti the rod was probably a part of special density measuring device.
The region's deputy transport prosecutor, Andrei Samarkin, told RIA that the strontium rod had probably been found and sold to a scrap yard by as yet unidentified individuals. He said officers from the Federal Security Service would check a list of sites from where the rod could have been stolen.
He added that a criminal case had been opened into the incident.
