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Threats to Clean Water in Lake Champlain

CLF is working to address the threats to Lake Champlain and waterways across New England, including:

Excessive Nutrients

Excessive nutrients, namely phosphorus and nitrogen, have impaired Lake Champlain. Washing off farm fields, roads, parking lots, and eroded stream banks, these nutrients enter the lake and overfeed algal populations, resulting in toxic blue-green algae blooms. Blooms have led to several beach closures because of the public health implications. Certain toxins produced by blue-green algae cause diarrhea, vomiting, and liver damage. New research has also linked toxic blue-green algae with neurological diseases including amyotrophic lateral sclerosis (ALS) and Parkinson’s.

E. coli and Other Pathogens

In Lake Champlain, E. coli, giardia, and cryptosporidium are causes for concern. These intestinal diseases can lead to diarrhea, abdominal cramps, and fatigue. They are present in the lake because of fecal contamination from animal waste, urban runoff, and malfunctioning septic systems.

Mercury and PCBs

Combustion of coal in neighboring states has released atmospheric mercury that eventually winds its way into Lake Champlain. In Vermont’s waterways, mercury is assimilated into tiny planktonic organisms at the base of the food chain. Through bioaccumulation, organisms feeding at the top of the aquatic food web contain significant levels of mercury. Mercury is a highly toxic metal that affects the central nervous system.

Persistent organic pollutants are fairly resilient to degradation in aquatic environments. Poly-chlorinated biphenyls, or PCBs, are one such contaminant that has been found in sections of Lake Champlain. In the past, PCBs were used in the production of electrical equipment and plastics. Like mercury, PCBs also bioaccumulate, increasing in concentration with each step up the food web. PCBs are known to be carcinogenic to animals, and are considered likely human carcinogens as well.

Sewage Overflow

Every year, gallons of sewage are released into Vermont’s waterways from wastewater treatment facilities. The Vermont Department of Environmental Conservation has created a Waste Water Inventory that tracks these overflow events. Heavy rains can overwhelm combined sewer systems, which collect industrial wastewater, domestic sewage, and rainwater in the same pipe, causing the release of wastewater directly into nearby water bodies. This wastewater can contain untreated human and industrial waste, toxic materials, and debris, contributing to the already-high phosphorus loads in Lake Champlain.

Invasive Species

Invasive species such as zebra mussels, spiny water flea, sea lamprey, and Eurasian watermilfoil negatively impact Lake Champlain. In the absence of ecological controls such as disease and predators, these non-native species can out-compete natives and deplete the lake’s native biodiversity.