No chemical contamination related to fracking activity in Pennsylvania has been detected in the river that's used as a source for the city of Binghamton's drinking water.

Mayor Matthew Ryan says test results conducted on samples from the Susquehanna River revealed no pollution problems that could be linked to gas drilling outside New York state.

The mayor said although no dangerous levels of chemicals were detected, he's not convinced that some pollution from Pennsylvania drilling activities doesn't occur. He said chemicals that enter the river could be diluted to the extent where they aren't present at hazardous levels at the intake point used by the Binghamton water treatment facility.

Speaking on WNBF Radio's Binghamton Now program, Ryan said additional tests will be performed in the future to assure the safety of the city's drinking water supply.

The mayor said the tests will be done "periodically," perhaps on a monthly basis.

Ryan said the procedure isn't very expensive, although he did not indicate what each round of tests would cost the city.

Ryan has been an outspoken opponent of high-volume hydraulic fracturing in the Marcellus Shale.