MWRA's Boston Harbor Update

FLOUNDER, MUSSEL AND LOBSTER MONITORING

Fish and shellfish at test locations in Boston Harbor and Massachusetts Bay are showing lower concentrations of contaminants, overall. Pesticide levels are decreasing at all sites, and are consistently meeting the limits in MWRA's discharge permit. Even though these pesticides are banned, they break down very slowly and persist in the environment.

WINTER FLOUNDER

Massachusetts Bay: Contaminant levels in edible flounder fillet from the treatment plant discharge site are well below levels of concern.

WINTER FLOUNDER IN MASS. BAY MWRA Caution Level			2018 Results
Chlordane	484	ppb lipid	27
DDT	1552	ppb lipid	107
Dieldrin	127	ppb lipid	0
PCB	1000	ppb wet	36
Mercury	500	ppb wet	57
Liver Disease (CHV)	44.9	percent	6

Boston Harbor: Flounder liver disease levels are now at less than half of what they were before the Boston Harbor Project.

More about flounder

BLUE MUSSEL

Mussels feed by filtering particles out of the water, and can concentrate (bioaccumulate) toxic materials from the water in their tissues.

Massachusetts Bay: Contaminants in mussel tissues have decreased at the Mass. Bay discharge site.

BLUE MUSSEL IN MASS. BAY MWRA Caution Level			2018 Results
Chlordane	205	ppb lipid	33
DDT	483	ppb lipid	71
Dieldrin	50	ppb lipid	0
PCB	1000	ppb wet	1.3
Mercury	500	ppb wet	10
(ppb=parts per billion;lipid=lipid normalized; wet=wet weight; CHV=Centrotubular hydropic vacuolation.)

Boston Harbor: Data from mussels placed in two locations show that levels of PCBs or polychlorinated biphenyls and pesticides have decreased and are well within safety guidelines.

LOBSTER

MWRA checks lobsters for signs of disease, and tests the tail and claw meat for mercury, PCBs, DDT, and other pesticides.

Massachusetts Bay: Concentrations of banned pesticides such as chlordane have declined due to improved treatment at Deer Island Treatment Plant.

LOBSTER IN MASS. BAY MWRA Caution Level			2018 Results
Chlordane	150	ppb lipid	2.6
DDT	683	ppb lipid	28.5
Dieldrin	322	ppb lipid	0
PCB	1000	ppb wet	9
Mercury	500	ppb wet	170
(ppb=parts per billion;lipid=lipid normalized; wet=wet weight; CHV=Centrotubular hydropic vacuolation.)

Boston Harbor: Contaminants levels in lobster meat are well below the FDA limit for human consumption, but there are advisories against eating the hepatopancreas, or tomalley.

Lobster tomalley, considered a delicacy, is a soft, green substance found in the body cavity of the lobster that functions as the liver and pancreas. Therefore, the tomalley is the natural filter for contaminants.

Updated September 7, 2021