“The danger period is over,” said Provincial Sanitary Inspector Tomasz Augustyniak.
He added that checks would continue to be carried out in the Bay of Gdańsk.
Thousands of tonnes of untreated sewage were dumped into the Motława River and the bay after pumps broke down as a result of flooding at a sewage pumping station in the northern Polish city of Gdańsk in mid-May, according to reports.
Local sanitary inspectors said at the time that preliminary checks in the Bay of Gdańsk had indicated that acceptable pollution levels may have been exceeded.
Sewage was discharged directly to the Motława River as an emergency measure designed to prevent Gdańsk from being flooded by a blocked-up sewer system, the PAP news agency reported.