ASSESSING CONTAMINATED SEDIMENTS IN THE CONTEXT OF MULTIPLE STRESSORS

Sediments have a major role in ecosystem functioning but can also act as physical or chemical stressors Anthropogenic activities may change the chemical constituency of sediments and the rate frequency and extent of sediment transport deposition and resuspension The importance of sediments as stressors will depend on site ecosystem attributes and the magnitude and preponderance of co occurring stressors Contaminants are usually of greater ecological consequence in human modified depositional environments where other anthropogenic stressors often co occur Risk assessments and restoration strategies should better consider the role of chemical contamination in the context of multiple stressors There have been numerous advances in the temporal and spatial characterization of stressor exposures and quantification of biological responses Contaminated sediments causing biological impair ment tend to be patchy, whereas more pervasive anthropogenic stressors such as alterations to habitat and flow physical disturbance and nutrient addition may drive large scale ecosystem responses A systematic assessment of relevant ecosystem attributes and referent e conditions can assist in understanding the importance of sediments in the context of other stressors Experimental manipulations then allow for the controlled study of dominant stressors and the establishment of causal links This approach will result in more effective management of watersheds and waterways Environ Toxicol Chem 2010 29 2625-2643 (C) 2010 SETAC