This course will introduce the environmental/ecological risk assessment (ERA) paradigm and describe in detail the process recommended by the U.S. Environmental Protection Agency (EPA).  In addition, critical deficiencies that are often made when conducting ERAs will be identified, such as failure to adequately characterize spatial and temporal dynamics of exposure and subsequent linkages to adverse biological effects.  Case study examples ERAs will demonstrate the state-of-the-art and new approaches that are decreasing the uncertainty associated with the ERA process.  The important linkage of ERA issues to the decision-making, risk management process will be emphasized.