Human and Ecological Risk Assessment: Vol. 9, No. 1, pp. 195-211 (2003) 1080-7039/03/$.50 © 2003 by ASP A Proposed Framework for Investigation of Cause for Environmental Effects Monitoring L. Mark Hewitt, 1* Monique G. Dubé, 2 Joseph M. Culp, 2,3 Deborah L. MacLatchy, 4 and Kelly R. Munkittrick 4 1 National Water Research Institute, Aquatic Ecosystem Protection Research Branch, Burlington ON, Canada. 2 National Water Research Institute, Aquatic Ecosystem Impacts Research Branch, Saskatoon, SK, Canada. 3 Department of Biology, University of New Brunswick, Fredericton, NB, Canada. 4 Department of Biology, University of New Brunswick, Saint John, NB, Canada ABSTRACT Environmental Effects Monitoring (EEM) programs in Canada have been devel- oped for the pulp and paper and metal mining industries, and require a cyclical evaluation of the receiving environment to determine whether effects exist when the facilities are in compliance with existing regulations. Identifying the cause of environmental effects is a specific, identified stage in this monitoring program, but as yet there has not been a synthesis of what is meant by “identification of cause”. We propose a multitiered guidance framework for the identification of the cause of environmental effects after they have been detected, confirmed, and their extent and magnitude documented. As part of point source confirmation, the framework includes levels to define whether there is an effect, whether it is related to the effluent discharge facility, and whether response patterns in the receiver are char- acteristic of a particular stressor type. The next tier involves investigating individual process wastes within the facility to determine the components that are contributing to effects caused by exposure to the final effluent. The last three tiers of the framework relate to characterizing the chemical classes involved in the effect and, ultimately, to identifying the specific chemicals associated with the responses. Al- though there is increasing knowledge of specific causes of environmental effects gained as one progresses through the levels of investigation, there is a concomitant increase in effort and costs required. Stakeholder input is critical in determining the depth of the investigation as well as how to proceed once the environmental effects information is available. Key Words: environmental effects monitoring, causal investigation, framework. * Corresponding author: Tel(voice): 905-319-6924, Tel(fax): 905-336-6430; mark.hewitt@ec.gc.ca 200585.pgs 2/11/03, 12:28 PM 195