Connecticut River Coordinator's Office
Northeast Region
Trash on Connecticut River bank in South Deerfield, MA  - Photo credit:  U.S. Fish and Wildlife Service
Trash on Connecticut River bank in South Deerfield, MA. Credit: USFWS

"I never hope to see the Connecticut River in Connecticut suitable for bathing."

W.J. Scott, Chief Engineer, CT State Dept of Health, 1940

Pollution of streams harms the health and survival of fish and other aquatic organisms in their habitat.

Point Source Pollution

The This link opens in a new windowClean Water Act (1972) ended the most blatant and visible point source pollution discharges into the Connecticut River. However combined sewer overflows can still present problems.

Non Point Source Pollution

Contamination of waterways is still a concern from a variety of mainly non-point sources (faulty septic systems, agriculture). One of the most insidious forms of pollution today comes from the air.

Acid Rain

Acid rain caused from combustion of fuels affects the pH of water for fish. Normal rainwater has a pH of 5.6. On average, rainwater in the northeast has a pH of 4.0. Normally fish die when lake or stream water reaches 5 or below. Acid rain also leaches heavy metals out of the soil such as copper and aluminum. Copper causes damage to the kidneys, liver, and spleen. Aluminum binds to fish gills and causes suffocation. Also, high levels of ammonia results in hyperexcitability causing fish to swim in rapid movements and eventually die. Additionally, global warming and depletion of the ozone layer have the potential to change climate, altering the range and survival of many aquatic species. This is of particular concern in the Connecticut River since this river marks the southern extent of the range for Atlantic salmon in New England.


Lead is a contaminant found in fish tissue. Its known effects on fish and other aquatic life is reduced survival, impaired reproduction, and reduced growth. Lead can be found in shotgun shells and fishing sinkers. Lead shot and sinkers land in water sources where fish and wildlife accidentally ingest while feeding. The Common loon is one species that ingest lead sinkers. Loons take minnows being used as bait. The loon then breaks off the line and swallows the hook, line, swivel, and sinker. This results in lead poisoning which causes loss of balance, gasping, tremors, and impaired ability to fly. The loon will usually die within two to three weeks after eating the lead. The ingestion of lead sinkers accounted for approximately 70% of the dead adult loons found in fresh water.


Mercury is a neurotoxin and can seriously affect the quality of aquatic life. A single fever thermometer has enough mercury to contaminate a 10-acre body of water. When mercury enters rivers, streams, and lakes, it reacts with the soil and turns into methylmercury, a more toxic form, which is easily absorbed by fish. Methylmercury accounts for over 95% of the total mercury found in fish tissue.

With the exception of isolated point sources, the ultimate source of mercury to most aquatic ecosystems is deposition from the atmosphere, primarily associated with rainfall. Other sources include coal combustion, waste incineration, and metal processing. For example, in Massachusetts, most mercury pollution occurs when products containing mercury are discarded in the trash. When this trash is burned, it eventually becomes airborne returning to the earth in rain or snow.

Lead and Mercury information from Lakes and Ponds Association of Western Massachusetts and Massachusetts Division of Fish and Wildlife.

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Last updated: February 23, 2016
Connecticut River Coordinator's Office
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