National Assessment of Pulp and Paper Environmental Effects Monitoring Data: Findings from Cycles 1 through 3
- Publishing Information
- Acknowledgement
- Abstract
- 1.0 Executive Summary
- 2.0 Introduction
- 3.0 Overview of Studies Conducted in Cycle 3
- 4.0 General Methods - Data Preparation and Analysis
- 4.1 General Methods - Procedure for Determining National Response
- 5.0 Fish Survey
- 5.1 Data Processing and Study Designs
- 5.2 Summary of Effect Sizes
- 5.3 Response Patterns and Meta-analyses
- 6.0 Fisheries Resources and Usability
- 7.0 Benthic Invertebrate Community Survey
- 7.1 Data Processing and Study Designs
- 7.2 Summary of Effect Sizes
- 7.3 Response Patterns and Meta-analyses
- 8.0 Sublethal Toxicity Testing - Introduction
- 8.1 Sublethal Toxicity Testing - Monitoring Changes in Effluent Quality Among Cycles
- 8.2 Sublethal Toxicity Testing - Summary and Future Considerations
- 9.0 Summary and Conclusions
- Glossary
- Acronyms / Abbreviations
- References
8.0 Sublethal Toxicity Testing - Introduction
Under the EEM program, each Canadian pulp and paper mill is required to measure the sublethal toxicity of its final effluent discharge. Mills conduct a battery of three sublethal toxicity tests twice a year (summer and winter) for each year of the cycle, including: 1) early life stage development of fish, 2) reproduction of an invertebrate and 3) algal growth inhibition or reproduction. The sublethal toxicity testing component of EEM follows prescribed acceptable test methods and includes species choices for different receiving environments (see Environment Canada 2004a for specific test methods).
For the purposes of this national assessment, the results of sublethal toxicity testing are used to measure changes in effluent quality over time. On a site-specific basis, sublethal toxicity data can also be used to understand and estimate the relative contribution, in multiple discharge situations, to observed effects in the receiving environment.
The endpoint that was used to measure effluent quality was the inhibiting concentration for 25% effect (IC25) -- i.e., that concentration causing performance (e.g., growth, reproduction) that was 25% inferior to that of the control organisms. In a freshwater test, if full-strength effluent did not cause 25% inhibition/effect, then the endpoint was reported as =100% concentration. For estuarine/marine tests, the highest concentration range for effluents that were salinity-adjusted was summarized in a category designated =60%. Note that for estuarine/marine tests, if full-strength effluent did not cause 25 % inhibition, then the endpoint was reported as a category designated =60% because it was the highest concentration that could be tested due to the standard procedure of adding hypersaline brine to the effluent for salinity adjustments. The method for adjusting salinity has more recently been changed to the addition of dry salts. This now makes it possible to test full strength effluents.
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