The tissue sampling is intended to provide data to compare to known critical contaminant levels to detect and predict environmental risk to the systems impacted.

It is designed to show both increases and decreases of the most relevant contaminants in the impacted areas of the Mud Slough corridor and San Joaquin River System. There exists a large scientific database from which screening level criteria or relative background contaminant levels for both biota and humans can be drawn. It is from this database that numbers produced by the tissue sampling will be compared. Evaluation of potential biological effects (adverse and beneficial) may indicate that sampling be intensified, that addition of collections be necessary, or that protocols be streamlined.