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Quality of a River - Water Quality
Contaminants (pg 1 of 8)

Streams carry a staggering array of harmful artificial contaminants. These pollutants come from point sources, such as industrial plants or sewage treatment plants, and nonpoint sources, such as runoff from cities or farmland or from atmospheric deposition.

Organic pollutants include animal wastes, such as manure or feedlot runoff, and human wastes, such as untreated or partially treated sewage. Ammonia, a byproduct of these wastes and a major effluent from sewage treatment plants, is toxic at relatively low concentrations. Also, the presence of human waste (measured as fecal coliform) causes concern for disease pathogens. But the primary effect of organic pollutants on stream ecology is the consumption of dissolved oxygen from water as they degrade (see Dissolved oxygen and Nutrients).

A variety of substances can act as contaminants in streams. Two important groups are toxins and endocrine disruptors.

Jack Skrypek
Hear Jack Skrypek
Dealing with pollution in the Mississippi

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Introduction
Flow
Shape
Connections
Quality
Description
Temperature
Oxygen
Alkalinity
Nutrients
Sediment
Contaminants
Status
Life
Summary
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