Don’t eat locally caught freshwater fish

The Merrimack River, as seen on Aug. 15, 2023. (Peter Currier/Lowell Sun)

LOWELL — The Massachusetts Department of Public Health has warned freshwater anglers and fish consumers against eating most of what is caught in local rivers and ponds.

In a recent advisory, the DPH gave contamination with hazardous chemical compounds and a naturally occurring metal as the reason for avoiding or minimizing consumption of locally caught freshwater fish.

PFAS, or per- and polyfluoroalkyl substances also known as forever chemicals, and mercury are the primary substances of concern in the region’s waterways. The most recent advisory from the DPH is based on sampling and testing of rivers and lakes across the state. The advisory is specific to where fish are caught.

Dracut Health Director Dave Ouellette summarizes the general recommendation as having “no more than one meal a month of freshwater fish” and, in some cases, no more than every two months. The DPH also has advised against eating largemouth bass entirely.

Vulnerable individuals — children under the age of 12 and any individual who is pregnant, lactating or may become pregnant — should avoid freshwater fish entirely.

The DPH excludes trout from the advisory because it stocks the state water bodies twice a year.

Topping the list of waterways with contaminated fish are the Concord, Merrimack and Nashua rivers as well as the Lowell canals. Many local lakes and ponds are also on the list.

The Concord River advisory affects Concord, Carlisle, Bedford, Billerica and Lowell.

The Merrimack River advisory affects Tyngsboro, Chelmsford, Lowell, Dracut, Tewksbury, Methuen, Andover and Lawrence.

On the Nashua River, the advisory affects Clinton, Lancaster, Harvard, Shirley, Devens, Ayer, Groton, Pepperell and Dunstable.

Lakes and ponds are also included in the advisory. Among them, but not limited to them, are: Nabnasset Pond, Westford; Ames Pond, Tewksbury; Heart Pond, Chelmsford and Westford; Massapoag Pond, Dunstable, Groton and Tyngsboro; Mirror Lake, Devens and Harvard; Flint Pond, Tyngsboro; Forge Pond, Littleton and Westford; Long Pond and Lake Mascuppic in Dracut and Tyngsboro; Hickory Hills Lake, Lunenburg; and Falls Brook Reservoir, Leominster.

To read the complete list of water sources contaminated with PFAS or mercury, go to mass.gov/lists/fish-consumption-advisories.

The DPH leaves testing for E. coli to cities and towns.