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Eastmain 1-A and Rupert River Diversion Hydropower Project

Mercury and Health


The Crees’ exposure to mercury present in the environment through fish consumption has been a relatively well-known phenomenon since the 1970s. The phenomenon is based on contamination by atmospheric industrial emissions transported over long distances and the natural presence of inorganic mercury in the area. In the early 1980s, the proponent became a significant player on managing this public health issue, as reservoirs in the La Grande complex were found to be favourable to the bioaccumulation of methylmercury in the flesh of fish. Even though knowledge of the geochemical phenomena surrounding the release of mercury and its methylation still leaves considerable room for scientific debate, it is recognized that the primary consequence of this release of mercury is the marked increase in fish mercury concentrations.

In recent decades, the proponent has carried out a thorough follow-up of mercury levels in various types of fish and has developed an information guide containing information on frequency of consumption by fishing site and species captured. The proponent also participated in estimating acceptable daily doses of methylmercury for different population groups (children, adults, women of child-bearing age), on which consumption recommendations are based. In 1986, the proponent and the Québec government signed the Mercury Agreement with the Crees. The objective of this agreement was to reduce the potential effects of mercury on Crees’ health as much as possible, as well as on their traditional way of life and their traditional hunting and fishing activities.

However, in recent years, changes in eating habits, combined with restrictions on fish consumption, have resulted in a significant drop in fish consumption. In a certain part of the population, we now see a marked reluctance to eat fish, no matter its source. Generally, it seems that fish consumption and, therefore, exposure to mercury diminished considerably between 1986 and 1996. Since this time, the data available regarding mercury levels in the Cree population indicate that fish consumption has continued to decrease.

Ten years after the end of the first Mercury Agreement, the health benefits of fish consumption are being recognized, while respecting the rules for consumption concerning mercury set out for the various species and different bodies of water. We observe, however, that the proponent has, in the past, made decisions regarding public health, while it was the responsibility of the CBHSSJB to protect the health of the Crees and pilot initiatives in this area, as well as develop and implement effective methods to spread the information.

The project and mercury concentrations: the issue of consumption

The issue of the bioaccumulation of mercury is part of the negative impacts of the Eastmain-1-A Powerhouse and Rupert Diversion project. The project will cause mercury increases in the fish in six areas:

  • The Eastmain-1 reservoir;

  • The Rupert forebay;

  • The Rupert tailbay;

  • The Rupert River, immediately downstream from the control structure;

  • The Lemare River, immediately downstream from the flow release structure;

  • The Nemiscau River, immediately downstream from the two flow release structures.

With respect to fish consumption recommendations, there will be an additional consumption restriction for adults in general, compared with the baseline, for the six above-mentioned areas, except in the Rupert River, immediately downstream from the control structure, where anticipated mercury levels will remain within the actual mercury concentrations in this river section. In the case of the Eastmain-1 reservoir, fish consumption restrictions will be extended by one year. It should be noted that this aquatic area, created in 2005, will already have been subjected to specific restrictive consumption measures during the diversion bay impoundment planned for 2009.

The proponent expects that the consumption recommendations will return to baseline levels between 2016 and 2021 for lake whitefish, 2024 or 2025 for northern pike, 2026 or 2028 for walleye and 2028 for lake trout. According to the proponent, by 2028, fish consumption recommendations will have reached baseline levels for all types of fish in the six areas affected by the project.

With the $3M Eastmain-1-A/Rupert Mercury Fund, which will last 12 years, the proponent has committed to continue following up on the changes in fish mercury levels in the various study area sections and to update data on Cree contamination levels. Moreover, it would be difficult to implement mitigation measures at the source, such as stripping or total clearing of certain vegetation layers, throughout the project.

Conditions to be fulfilled by the proponent

Following the authorization of the project, the proponent will provide data on changes in fish mercury levels and will ensure technical and scientific support to the Cree Board of Health and Social Services of James Bay (CBHSSJB). In addition, in collaboration with the CBHSSJB, a governing body dedicated to the protection of Cree public health, the proponent must present a report on the progress made in researching the mercury issue with respect to overall health and on the effectiveness of information campaigns regarding mercury and fish consumption.

In addition, given that the duration of the new Mercury Agreement, signed in 2001, is much longer than the estimated time of the agreement regarding changes in fish mercury levels in reservoirs, from the initial increase until levels comparable with those of natural water bodies are reached, the proponent must submit an overview of the activities governed by the agreement, as well as a progress report on changes in mercury levels, to the ministère du Développement durable, de l’Environnement et des Parcs within the context of the northern environmental impact assessment procedure . The report must take into account the justifications for whether to renew the agreement and for specifying, where appropriate, the objectives and guidelines contained in the new agreement.

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