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Introduction How Rivers Run Stories Value Of A River What We Can Do
Quality of a River - Water Quality
Contaminants: Toxins (pg 2 of 8)

Toxins include a range of poisonous or otherwise harmful substances, such as heavy metals, road salts, and pesticides.

Heavy metals, including mercury, cadmium, and lead, come from a variety of sources, such as industrial processes, trash incineration, automobiles, and emissions from power plants. Concentrations of many of these metals tend to increase as rivers pass through large cities and collect urban runoff and industrial point sources. But some, such as mercury, are also dispersed in the atmosphere and reach streams through precipitation and runoff.

Many metals are toxic, even at very low concentrations. One of the greatest known threats to human health is the concentration of mercury (from mines, power plants, and paper mills) in muscle tissue of fish. Overexposure to mercury damages the brain, nervous system, kidneys, and lungs. For fish advisory information, go online and visit www.health.state.mn.us/divs/eh/fish/.

(Balogh et al., 1999)


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Quality
Description
Temperature
Oxygen
Alkalinity
Nutrients
Sediment
Contaminants
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