Utility of Mobile, Field-Based Artificial Streams for Assessing Effects of Pulp Mill Effluents on Fish in the Canadian Environmental Effects Monitoring (EEM) Program

Although the utility of artificial streams (mesocosms) as research tools for assessing effects of contaminants on aquatic biota has been recognized, their use in regulatory programs has been limited. We conducted three studies to examine the utility of using mobile, field-based artificial streams to assess the effects of pulp and paper effluents on fish as required in the Canadian Environmental Effects Monitoring (EEM) program. When evaluated against criteria of environmental relevance, interpretability, scientific defensibility, and cost-effectiveness, mesocosms satisfied all criteria. Measured endpoints on fish survival, energy use (growth, gonad size) and energy storage (liver size, condition) were relevant to the detection and quantification of effluent effects on fish. Response patterns were similar to those reported in the literature for field surveys showing reduced gonad size and increased liver size in adult mummichog (Fundulus heteroclitus) and decreased growth of juveniles. The flexibility of the systems to measure effects in multiple, replicated treatments under controlled effluent exposure and ambient conditions of water quality, temperature and photoperiod provided data that could not be obtained at these sites using field assessment approaches. The repeatability of using the same mobile, mesocosm system of uniform design and operation at different mill sites and for different receiving environments was unique and contributed to consistent scientific evaluation and interpretation. These studies demonstrated that mesocosms produced good quality data that fit within the required regulatory context of the Canadian EEM program.