Environmental Monitoring at the La Grande Complex Evolution of Fish Mercury Levels Summary Report 1978-2012 OCTOBER 2013 Environmental Monitoring at the La Grande Complex Evolution of Fish Mercury Levels Summary Report 1978–2012 Joint report by: HYDRO-QUÉBEC PRODUCTION AND GENIVAR INC. OCTOBER 2013 EXECUTIVE SUMMARY Author(s) and title (for quotation purposes): SCHETAGNE, R. and J.THERRIEN, 2013. Environmental Monitoring at the La Grande Complex. Evolution of Fish Mercury Levels. Summary Report 1978–2012. GENIVAR inc. and Hydro-Québec Production. 172 p. Abstract: An environmental monitoring program was established to evaluate the physical, chemical and biological changes associated with the development of the La Grande hydroelectric complex. The monitoring of fish mercury became a regular component of the program as soon as the increase in fish mercury levels was observed. The specific objectives were to evaluate the temporal evolution of the phenomenon in the different types of modified environments, inform fish consumers and improve impact prediction methods for future projects. The main objectives of monitoring fish mercury during Phase I and II development of the La Grande complex were all achieved. The monitoring program, which involved conducting 45,000 analyses of total mercury in fish, helped establish the extent and duration of the temporary increase in fish mercury levels, the main processes at work and the physical and biological factors that control them. Reservoir impoundment caused an increase in fish mercury levels in the newly created reservoirs and the water bodies downstream of them to increase significantly, by factors generally ranging from 2 to 8 relative to the levels measured in natural environments. Levels peaked 4 to 11 years after impoundment in non-piscivorous species (0.33 to 0.72 mg/kg) and after 9 to 14 years in piscivorous species (1.65 to 4.66 mg/kg), depending on the environment. The phenomenon was temporary, however, as mercury levels generally returned to baseline values found in natural environments 10 to 20 years after impoundment in non-piscivorous species and after 20 to 30 years in piscivorous species. The Québec Crees were consistently informed of fish mercury levels in the La Grande complex, in accordance with the provisions of the two mercury-related agreements signed with the Crees of Québec in 1986 and 2001. Fish consumption guidelines for the La Grande complex were produced in 1998, 2001, 2004 and 2013 on the basis of the mercury exposure criteria established by the Cree Board of Health and Social Services of James Bay (CBHSSJB), using the data collected during the monitoring program. The development of two prediction models for fish mercury levels in reservoirs clearly demonstrates that the third objective, which was to improve impact prediction methods for future projects, was fulfilled. For the majority of fish species in most of the modified water bodies, the average mercury levels recorded during the most recent surveys once again allow for consumption similar to that recommended for the region's natural lakes. Therefore, it has been suggested that the monitoring of mercury levels in environments modified by the La Grande complex during phases I and II be discontinued except in Lac Sakami, where it will be incorporated into the monitoring of water bodies affected by Phase III. Keywords: Mercury / Fish / Hydroelectric complex / La Grande / Québec / Baie James / reservoir / reduced- flow environment / increased-flow environment / polynomial regression / northern pike / walleye / lake white- fish / longnose sucker Distribution list: Ministère du Développement durable, de l'Environnement, de la Faune et des Parcs, James Bay Advisory Committee on the Environment, Review Committee, Cree Regional Authority, Cree communities, Makivik Corporation, Société d'énergie de la Baie James, Société de développement de la Baie-James, Municipalité de Baie-James, Hunting, Fishing and Trapping Coordinating Committee, Canadian Electrical Association, Fisheries and Oceans Canada, Environment Canada, Cree Board of Health and Social Services of James Bay, Centre régional de la santé et des services sociaux de la Baie James, Health and Welfare Canada; environment and community relations units of Hydro-Québec's divisions; Hydro-Québec environment documentation centre. Final version Distribution Code: internal-external Date: October 2013 Call number at Centre de documentation Environnement d'Hydro-Québec: HQ-2013-097 iii PROJECT TEAM 20121 Hydro-Québec Production (Direction Gestion des actifs et conformité réglementaire) Study Authority : Diane Villeneuve Mercury Program Manager : Roger Schetagne GENIVAR inc. Project Manager : Jean Therrien Contributors : Christian Harvey Patrice Bégin Bernard Aubé-Maurice Fieldwork Coordinator : Jacques Mercier Cartography Coordinator : Diane Gagné Statistics and Data Processing : Jean Therrien Georges Morin Cartography Assistants : Maude Boulanger Ivana Saint-Laurent Line Savoie Chantale Landry Editing : Linette Poulin Technical Assistants (fieldwork and office) : Jacques Mercier Jean-Simon Roy Benjamin Gagnon Benoît Chabot Nathalie Guérard Gilles Baribeau Martin Bégin Christopher Cox Wayne Chakapash Hydro-Québec Reference No.: 25034-12005 Consultant Reference No.: 121-18895-00 1. For other contributors, please refer to previous annual or summary reports. v TABLE OF CONTENTS Page EXECUTIVE SUMMARY .......................................................................................................... iii PROJECT TEAM 2012 ............................................................................................................. v TABLE OF CONTENTS ........................................................................................................... vii TABLES .................................................................................................................................... xi FIGURES ................................................................................................................................ xiii APPENDICES .......................................................................................................................... xv MAPS ....................................................................................................................................... xv POCKET INSERT MAP ........................................................................................................... xv 1. INTRODUCTION .............................................................................................................. 1 1.1 Project description, general commitments and obligations ................................ 2 1.1.1 Study area and environment .......................................................................... 2 1.1.2 Hydroelectric developments in the La Grande complex ................................. 5 1.1.3 General commitments and obligations ........................................................... 5 1.2 Commitments and obligations specific to mercury ............................................. 8 1.3 Review of prior studies ......................................................................................... 11 1.4 Objectives ............................................................................................................... 11 2. METHODS ...................................................................................................................... 13 2.1 Sampling strategy, measurements and samples taken ..................................... 13 2.1.1 Sampling strategy ......................................................................................... 13 2.1.2 Fish measurement and sampling ................................................................. 21 2.2 Analytical determination ....................................................................................... 23 2.3 Statistical approach ............................................................................................... 28 2.3.1 Comparisons ................................................................................................ 28 2.3.2 Statistical procedure ..................................................................................... 29 2.4 Risk management .................................................................................................. 31 2.4.1 Search for mitigation measures .................................................................... 32 2.4.2 Implementation of compensation measures ................................................. 33 2.4.3 Production of fish consumption guidelines ................................................... 33 2.4.3.1 Recommended exposure level and tolerable daily intake .............. 34 2.4.3.2 Calculation of consumption lengths ................................................ 35 2.4.3.3 Prediction and validation of maximum levels reached ................... 36 2.4.3.4 Calculating the recommended number of meals per month ........... 40 2.4.3.5 Development of fish consumption guidelines ................................. 41 2.5 Complementary studies ........................................................................................ 43 vii TABLE OF CONTENTS (cont.) Page 3. RESULTS ....................................................................................................................... 45 3.1 Natural environments ............................................................................................ 45