Investigating the causes of mill effluent effects on fish reproduction in Canada: lessons learned

摘要

The national assessment of the first three cycles of the Canadian Environmental Effects Monitoring (EEM) Program showed that pulp/paper mill effluents were causing general nutrient enrichment in the receiving environment as well as metabolic disruption in fish. The consequence of metabolic disruption is that fish are allocating less energy towards reproduction. This is evidenced by larger condition factor and liver size as well as smaller gonads in fish inhabiting effluent-containing waters. When effects are identified, the EEM program calls for Investigation of Cause (IOC) followed possibly by Investigation of Solution (IOS) studies. In the case of metabolic disruption, the causative agent(s) were not known and intensive IOC and IOS studies were required. Various IOC and IOS studies have been conducted on metabolic disruption by different institutions over the past decade, with mill specific progress. Since 2005 a multi-agency consortium involving industry, government and academic researchers was formed around a centralized project. As the EEM Program is now being applied to metal mines and possibly municipal sewage plants in Canada, this project is serving as a model for these sectors. It may also serve as an example to South American countries (e.g. Chile and Brazil) that have expressed an interest in the EEM Program and are looking to incorporate effects-based monitoring into regulatory frameworks. A retrospective look at these investigations, including factors contributing to the most recent successes and lessons learned, will be presented.