MERRIMACK RIVER – If you like to boat, swim or just walk along this river, the $35,000 that the Fluidion sensor pollution testing device costs, plus the $4,000 to $6,000 a year to maintain it, may be the one of the best investments for the river.
On July 2, just in time for the 4th of July holiday, the Merrimack River Watershed Council activated for the first time the new high-tech pollution sensor on the Newburyport Harbormaster dock. The sensor, which belongs to the city of Methuen, allows the water to be tested quickly and accurately for pollution caused by consolidated sewage overflows (CSOs).
On August 8, at 8:04 p.m. the sensor floating in the Newburyport Harbor showed safe levels of E.coli. But with the recent rains, the testers were expecting the levels of E.coli to rise. “We will run the sensor at least once more before the weekend,” the council reported on Facebook.
But those tests proved to be inconclusive, so the council and city health department advised people to limit water activities for themselves and their dogs.
“The results vary significantly,” said John Macone, the council’s vice president. “Generally after CSOs we see a day or two when the sensor detects levels of bacteria that are high enough to exceed the state’s standards for swimming.”
The sensor has reported “not safe” results on some days even when no CSOs have occurred, Macone wrote in an email. “We are not sure yet why we are getting these results. We have theorized that it is caused by illicit wastewater discharges from boats in Newburyport harbor, but that has yet to be proven.”
The council has been asked to install additional bacteria monitors near sites where people swim, such as the river sandbar off Amesbury and at Salisbury Beach and Plum Island beach.
Currently, the council has only one sensor, and it is on loan. But it is looking into whether more can be obtained.
