ABSTRACT
The sediment environment is a major and integral component of aquatic ecosystem functioning, yet in many ways, it is very different and separate from the overlying water environment. Assessing sediment quality usually requires collection of sediment via grab, dredge, or core methods. Sediments in slow moving waters often tend to be fine grained, as opposed to the gravel and cobble found in fast flowing waters, and, because of their greater surface area and associated factors, accumulate higher concentrations of toxicants. In comparison to nonpolar organic contaminants, metal and metalloid dynamics between sediments and interstitial and overlying waters are particularly complex. Understanding of community ecology in lotic and lentic systems has progressed significantly in recent years. Disrupting the sensitive sediment environment is of major concern when collecting samples for toxicity studies, since the bioavailability and toxicity can change significantly when in-place sediments are disturbed.
