A new breed of hobbyists - the aquatic equivalent of metal detectionists - are called magnet fishers. On July 24, aficionados of this new pastime caught dangerous quarry along a section of the Nashua River running through Devens.
Their catch? Unexploded hand grenades, probably of Vietnam-era vintage. Their find brought the Devens Fire Department and the Massachusetts State Police Bomb Squad to secure the area and dispose of their catch.
Magnet fishing, a rapidly-growing hobby, involves tying a very strong magnet to a rope and repeatedly dragging it along the bottom of a body of water in search of submerged metallic "treasure". Such "treasure" may be things such as discarded bed springs, old bicycle frames and other detritus of industrial civilization.
It is often practiced as a team activity, with people on opposite banks of a river or pond repeatedly dragging a submerged, high-powered magnet back and forth along the bottom of the body of water.
But when a river flows through a former U.S. Army installation, this hobby can become dangerous. According to a spokesperson for MassDevelopment, magnet fishers at two locations on the Nashua River on two separate occasions this summer found three pieces of unexploded ordnance. A heavily corroded mortar shell and a hand grenade were found July 24, about a half-mile south of the Hospital Road Bridge. Yet another corroded hand grenade was found Aug. 12 just off the south side of the Hospital Road Bridge.
After MassDevelopment was notified of the findings, the U.S. Army, and U.S. Environmental Protection Massachusetts Department of Environmental Protection, and the abutting towns were also alerted.
After the second discovery, an emergency state regulation was drafted banning unauthorized attempts to excavate, disturb, dislodge, retrieve, take possession of, or dispose of “any man-made item or portion thereof from any lands or waters of Devens.” The regulation, 946 CMR 4.18, went into effect Aug. 20. Violators face a fine of $500 for first and subsequent offenses.
Banned activities include use of metal detectors or any device using magnets, electromagnets, SONAR, or ground-penetrating radar to identify “unseen or submerged metallic objects.” According to the regulation, these devices could trigger an explosive reaction in unexploded ordnance. Magnet fishing in Devens waters is expressly prohibited, as is the use of “dredging equipment, grappling hooks, or equipment used for dragging or trawling.”The ban does not apply to recreational fishing poles and tackle.
Beyond the lure of finding submerged treasure, magnet fishing is often promoted as an environmentally-positive hobby, claiming to remove large chunks of metal waste from waterways.