Beware of toxins in Great Lakes

The combustion of coal is a dominant source of mercury pollution and climate change. Attend the Behrend lecture on Wednesday at 7:30 p.m. to learn about moving beyond coal.USDA FOREST SERVICE

How are the toxic chemicals accumulating in the Great Lakes ecosystem affecting wildlife and humans?

Widespread effects on fish and wildlife prompt fish consumption advisories and concern for drinking water safety.

Economies that depend on tourism, fishing and other water-related activities also suffer when water quality and ecosystem health declines.

Even with the progress in reducing active discharges of toxic chemicals from industrial and municipal sources, many chemicals from the past continue to persist in lake sediments, sometimes in high concentrations.

Furthermore, known toxins like mercury that have not been banned and contaminants of emerging awareness like plastics, pharmaceuticals and personal care products (PPCPs) are added to this toxic brew on a regular basis.

Coal-powered energy plants are responsible for the majority of mercury emissions that contaminate bodies of water.

Bacteria in soils and sediments convert mercury into a more toxic form called methylmercury, which can easily move up the food chain from small plants and animals to people.

Mercury is toxic to humans and wildlife because it can harm neurological and reproductive systems, especially in children and developing fetuses.

Exposure at high levels can also harm the brain, heart, kidneys, lungs and immune systems of all ages; that's why many states issue fish-consumption warnings.

Old pollutants in buried sediments can be resuspended by storms, ship propellers, dredging and bottom-dwelling organisms and then they re-enter food webs. PCBs, which were chemicals used as coolants and insulating fluids in transformers and electric motors, have been banned for decades but they still persist in the environment.

They are known to cause reproductive disruption, neurobehavioral and developmental deficits in children, and liver disease, diabetes, thyroid and immune-system problems, and increased cancer risks.

Contamination from the metals lead, nickel, copper, zinc and cadmium can also harm organisms at low concentrations. Aquatic organisms typically accumulate copper through their food.

Bottom-feeding invertebrates exhibit the highest concentrations of copper, which can be highly toxic at low concentrations to invertebrates and to fish in early life stages and can result in disruption of the food web.

Even small concentrations of some chemicals such as mercury, PCBs and other biomagnifying toxins can have enormous impacts, because they can be magnified by 1 million to 10 million times from small plants and animals to fish and shellfish that feed on them and then by animals that eat fish, like loons or people.

Toxic metals like copper, agricultural pesticides like Atrazine, and toxins like mercury and PCBs often exceed water quality and sediment guidelines.

To make matters worse, there are no recommended water quality and sediment guidelines for PPCPs or plastics.

Yet these contaminants are accumulating in the environment and some, like Triclosan, an antibacterial agent used in soaps and other personal care products, also bioaccumulate in the food web.

Many are endocrine disruptors and evidence is mounting that these chemicals are responsible for changing male fish into female or intersex fish and causing other problems.

What can you do to limit anthropogenic (human-added) toxins in your environment?

Use less energy, insist on replacing fossil fuels with clean energy sources (see story with details about Wednesday's "Beyond Coal" presentation at Penn State-Behrend) and learn more about your food and products you use on a daily basis, including PPCPs.

Choosing organic foods and products that do not introduce toxic ingredients into the environment will go a long way to limiting these toxins in our food and water.
