Is the sediment in our streams, rivers, and, lakes toxic to aquatic life?
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Sediment at the bottom of a stream or suspended in the water can store toxins that are harmful to animals and plants that live on stream bottoms and to fish and other organisms that eat them. Sediment contamination can also impact overall water quality by releasing these pollutants back into the water. Toxicity tests can be used to measure the level of harm that toxins in sediment can cause to aquatic organisms. In the laboratory, test organisms are exposed to sediment samples that were taken from a stream to determine if those organisms express any adverse effects, including death or changes in reproduction or growth.
The assessment of toxicity displayed here is based on methods used to summarize nine years of toxicity testing data collected by the Surface Water Ambient Monitoring Program (SWAMP) and partner programs (click here to view the report). The process used to characterize the magnitude of toxicity at each site was designed to integrate results from multiple samples taken at a site and multiple tests conducted on the samples. Note that the assessment displayed here does not completely match the SWAMP report due to differences in statistical methods and additional data assessed in this portal.