Toxic. Long-lasting. Dense.
What are heavy metals?
Heavy metals exist naturally in the environment, and some were used abundantly as production materials in the industrial era. Some uses like leaded gasoline have been banned, but heavy metals still exist in a variety of products. Past and current sources include...
- Mercury: thermometers, light bulbs
- Lead: gasoline, paint, pipes, ammunition, batteries
- Arsenic: wood preservation, organic pesticides
- Cadmium: pigments, batteries, plastics
- Chromium: steel, chrome plating, dyes and pigments, leather and wood preservation
How do heavy metals enter our environment?
Burning coal releases mercury into the air, which then settles out onto land and into the water. Lead pipes release lead into drinking water, while past oil spills deposited lead into sediment. Smelting and mining release cadmium into waterbodies. Sawing or sanding arsenic-treated wood releases arsenic into the air. And leather tanning or dying clothing releases chromium. These are just a few of the ways heavy metals are still being introduced into our waterways.
How are people exposed to heavy metals?
You can be exposed to heavy metals in a variety of ways. You ingest some mercury whenever you eat large, predatory fish like northern pike, walleye, or largemouth bass. While digging for food, mercury is eaten by macroinvertebrates, which are eaten by minnows, which are eaten by bigger fish. Mercury concentrations increase through the food chain. Your state issues fish consumption advisories to help you know how much fish is safe to eat.
Exposure to lead, arsenic, cadmium, and chromium comes mostly through sources other than contaminated sediment, such as lead paint chips or cigarette smoke. However, physical contact with contaminated sediment, like the kind you get wading in water, can expose you to contamination.
Can heavy metals harm my health?
Heavy metals cause a variety of negative health effects, especially among children. Scientific studies overwhelmingly show links between heavy metals and neurological diseases, reproductive problems, respiratory problems, immune system damage, liver and kidney damage, and delayed youth development, among others. Learn more about the human health effects of lead, mercury, arsenic, cadmium, and chromium.
*Great Lakes Environmental Assessment and Mapping Project. Mercury in Great Lakes Sediments | GLEAM. University of Michigan, n.d. Web. 15 Dec. 2016.