Clean Water


Some toxic substances and contaminants are present in Lake Champlain and its tributaries, but their effects and prevalence are not well understood.

A number of pollutants are of potential concern in Lake Champlain; these include microplastics, pharmaceuticals, road salt, pesticides, PCBs, mercury, and other bioaccumulating toxic substances. Many of these substances are often not detected when tested for or are sometimes found at very low concentration levels. The long-term effects of low-concentration toxic substances on ecosystem and human health are not well understood. Efforts to better understand the prevalence of contaminants in Lake Champlain and its tributaries are currently underway.

Long-term chloride concentration increases in the Basin’s lakes and rivers are well documented and can be attributed to winter road deicing.

Deicing salts applied to road surfaces during the winter contain chloride, which can be transported to the Lake throughout the year by snowmelt or rain runoff and by groundwater inputs to rivers and streams. This makes rivers and lakes saltier, a process known as salinization. Recent human-caused salinization of freshwater systems has been found throughout the Lake Champlain region and the world. Negative effects of low- and high-level salinization can impact all levels of an ecosystem, including primary producers, zooplankton, macroinvertebrates, amphibians, and fish communities.

Figure: Annual average chloride concentration in Lake Champlain
Figure 10 | Annual average chloride concentration in Lake Champlain

Although chloride concentrations found in Lake Champlain remain well below established benchmark levels for drinking water and aquatic life toxicity (250 mg/L and 230 mg/L, respectively), chloride concentration in the Lake is increasing (Figure 10). This upward trend is driven by long-term increasing trends of chloride loading from nearly all Lake Champlain Basin rivers. For example, the Winooski River alone delivered roughly 20,000 metric tons of chloride per year when monitoring began in the early 1990s; in recent years, it delivered approximately twice that amount annually.

Scientists taking a discharge measurement at the outlet of Mirror Lake.
Scientists are studying the impact of deicing salts used on roads and sidewalks in waterways in the Lake Placid area. Photo: Ausable River Association

LCBP partners and public works departments across the Basin are taking initiatives to safely reduce winter deicing salt application and to educate individuals and property managers on best deicing practices to reduce impact to Lake Champlain and other water bodies. Reducing the amount of deicing salt applied to our parking lots and roadways should reduce the amount of chloride measured in the Lake.

Microplastics are present in Lake Champlain, but their effects are not well understood.

Microplastics, small pieces of plastic less than 5 mm in diameter, are a growing concern in Lake Champlain. Microplastics come from a variety of sources and come in different forms; microbeads are found in some personal care products, microfibers from synthetic clothing, and eroded pieces of material from litter and other human sources. These materials often pass through wastewater treatment systems. Research conducted by SUNY Plattsburgh found that between 10,000 and 15,000 microplastic particles were discharged every day at monitored treatment facilities in the Lake Champlain Basin.

Microplastics can be ingested by fish and other wildlife and can cause digestive blockage and altered feeding behavior, which can in turn affect reproduction and overall health. Harmful bioaccumulating chemicals have been found in microplastics around the world; heavy metals and PCBs have been found in microplastics in Lake Champlain. The SUNY Plattsburgh study found fibers to be the most common plastics ingested by the bird and fish species upon which the research focused. The study also found greater amounts of plastics in organisms higher in the food chain, particularly cormorants, bowfin, and lake trout.

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What You Can Do

Don’t trash toxics. Take toxic waste and hazardous items to designated waste drop-off centers. This includes electronics, paint, pesticides, herbicides, motor oil, and items that contain mercury, such as non-digital thermometers and compact fluorescent light bulbs (CFLs).

Check for leaks. Repair leaking cars, trucks, boats, and other machinery to reduce oil and gas pollution.

Properly dispose of unused medications. Don’t flush medications. Instead, return them to a pharmacy or authorized drug collection site.

Reduce or eliminate pesticides and herbicides. Choose natural alternatives for pest and weed control.

Clean greener. Use less toxic household cleaners. Toxic substances may not be removed in the wastewater treatment process.

Avoid single-use plastics. Reduce plastic pollution by investing in reusable coffee mugs, water bottles, grocery bags, utensils, straws, and takeout containers. Reduce microplastics by choosing alternatives to fleece and by using a microfiber catcher in the laundry.

Hold the salt. The chloride compounds used to deice sidewalks and driveways wash into waterways, harming wildlife and plants. Use as little salt as possible, and try alternatives like sand for increased traction.

Scoop the poop. Rain and snowmelt wash pet waste into waterways, creating public health issues. Pet owners should always carry a scoop bag and carry it out.