(Providence, RI) -- The Rhode Island Department of Environmental Management is advising the public to avoid contact with water from the Seekonk River. The DEM says an estimated 215-thousand gallons of sewage entered the Blackstone River due to an apparent blockage. The department says Narragansett Bay Commission crews were able to disinfect a portion of the discharge with chlorine and stop the overflow on Monday. The advisory is in effect until sundown on Thursday.