Toxic substances are elements, chemicals or chemical compounds that can poison living plants and animals, including humans. Although Lake Champlain levels are low compared to more industrialized areas such as the Great Lakes, there is still cause for concern. A survey of Lake bottom sediments showed elevated levels of mercury in many parts of the Lake, and several other toxic substances in specific locations. Fish consumption advisories have been issued in both New York and Vermont due to elevated levels of mercury and polychlorinated biphenyls (PCBs) in some fish species' tissues. Lead has also harmed loons and other waterfowl. As of January 1, 2007, it will be illegal to use a lead sinker weighing one-half ounce or less to fish in Vermont. Visit VT's Get the Lead Out page to learn more. New York banned the sale of lead sinkers less than one oz.

The Lake Champlain Basin Program reviewed the substances found to date in Lake Champlain and ranked them as "high priority" and of "potential concern." Ranking was based on the extent and levels at which they are found, the risk that they may pose to human health, and the risk they may pose to the ecosystem. This set of priorities will be used to: 1) direct further research on presence and effects; 2) serve as a focus for source identification efforts; and 3) direct management efforts, including source reduction, treatment and remediation.

High Priority Toxics	Potential Concern Toxics
PCB's	ammonia
mercury	persistant chlorinated pesticides
arsenic	phthalates
cadmium	chlorinated phenols
chromium	chlorine
dioxins/furans	copper
lead	VOC's (benzene, acetone)
nickel	pesticides (atrazine, alachlor)
PAH's	strong acids and bases
silver	potential pollutants such as flouride
zinc

Note:

• High priority toxic substances merit highest priority for management action because they are found in Lake Champlain sediment, water or biota at levels above appropriate standards or guidelines, which indicates potential human health or ecosystem risks.
• Potential concern toxic substances do not pose a known risk to human health or the environment based upon existing standards, but they are known to have detrimental effects in other systems where chemical concentrations are greater. These substances should be monitored more extensively and their effects studied further.

Most toxic substances found to date in Lake Champlain occur at levels that do not pose a known threat to human health; however, a few areas in the Lake have toxic substances found in higher concentrations than in the rest of the Lake, or are found together at one location. The three sites are Outer Malletts Bay, Inner Burlington Harbor, and Cumberland Bay.

In 2000 a $35 million cleanup of Cumberland Bay, which was led by the NYS Department of Environmental Conservation, removed PCB-contaminated sediments and restored wetlands and beaches. Long-term monitoring will continue at the site. Ongoing pollution prevention continues at Outer Malletts Bay and ecological studies were completed in 1999 for Inner Burlington Harbor.

Reduction and prevention actions will continue to be targeted to these sites of concern. While it is understood that these areas may not be the only sites of concern, they are sites where action to reduce and prevent contamination by toxic substances should begin. Areas where future problems can be prevented will also be targeted for pollution prevention activities.

In addition to the sites noted above, the Pine Street Barge Canal is also an area of toxic contamination near Lake Champlain. However, it does not affect Lake Champlain. This federally designated superfund site is under remediation through a program led by the US Environmental Protection Agency. Visit the EPA's Pine Street Canal fact sheet for more information.

• Fish Advisories
• Mercury
• Toxic Substances Pages (LCB Atlas)