An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to www.epa.gov. This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

CADDIS Volume 1

Figures: Laboratory Tests of Site Media

Figure 3-8a. Laboratory Tests of Site Media, Supports

The impairment (dead fish) occurs in water that is toxic (dead fish in beaker of effluent diluted in site water). Water from an unimpaired reference site with the same industry is nontoxic.

                     Figure 3-8a illustrates how fish in a positive reference site are still okay in an impairment but fish without the positive reference are dead.Figure 3-8a.  Laboratory Tests of Site Media, Supports


Figure 3-8a. Laboratory Tests of Site Media, Refutes

The impairment (dead fish) occurs in water that is not toxic (live fish in beaker of effluent diluted in site water). Water from an unimpaired reference site with the same industry is also nontoxic.

Figure 3-8b illustrates how fish in a positive reference site are still okay in an impairment but fish without the positive reference are dead.Figure 3-8b.  Laboratory Tests of Site Media, Refutes


Explanation of the Types of Evidence Illustrations

This description applies to each of the types of evidence illustrations. These illustrations provide graphic explanations of the types of evidence. They are somewhat abstract to convey that they are representative of the concept rather than illustrations of particular applications. The live fish (green and upright) represent unimpaired organisms, populations or communities of all types, not just fish. The dead fish (white and belly-up at the surface) represent all biological impairments, not just dead fish. The pipe represents all sources and the yellow effluent plume represents all causal agents (stressors), not just effluents or even chemicals. Clock faces represent the passage of time, not the particular time difference illustrated. Fish in beakers represent laboratory tests. Other graphic elements used in particular illustrations are explained in the caption.

Top of Page