The Independent Expert Advisory Committee
The Independent Expert Advisory Committee (IEAC) was established as a result of an agreement reached by the Government of Newfoundland and Labrador, the Nunatsiavut Government, the Innu Nation and the NunatuKavut Community Council on October 25, 2016. The three Indigenous groups and the local population have concerns about the impact of methylmercury on country foods – which are important culturally, socially and to food security.
The IEAC consists of an oversight committee and a subcommittee called the Independent Expert Committee (IEC). The Oversight Committee (OC) has representatives from the following groups:
- Nunatsiavut Government
- Innu Nation
- NunatuKavut Community Council
- Affected Municipalities
- Provincial Government
- Federal Government
The Provincial and Federal Government, and Nalcor representatives do not have voting privileges.The Independent Expert Committee (IEC) is comprised of the Independent Chair, six scientific experts and three indigenous knowledge experts.
The Independent Chair, assisted by the Research Director, organizes and presides over meetings of the Oversight Committee (OC) and Independent Expert Committee (IEC) and ensures that the IEAC meets its objectives.
Following research and analysis of all relevant information, the members of the IEC discuss matters and provide recommendations to the OC by consensus. Where no consensus can be reached, dissenting opinions are attached to the recommendations made by a majority vote.
The Oversight Committee considers the recommendations put forward by the IEC, and decides whether or not to formally submit them to the responsible authorities (Ministers of the relevant Provincial and/or Federal Government departments). The OC operates by consensus of all members, including non-voting members. Where no consensus can be reached, dissenting opinions of all members, including the non-voting members, are attached to the majority vote. The Chair votes only in the event of a tie.
Once recommendations have been made by the Independent Expert Advisory Committee to the responsible Ministers and regulators, namely the provincial Ministers of Municipal Affairs and Environment and Service NL, and the federal Minister of Fisheries and Oceans, and any other appropriate responsible provincial or federal Minister, the Minister responsible for the matter in question has the final decision-making authority. It is ultimately up to him/her as to whether the recommendation will be accepted and implemented.
During the period of August 4, 2017 to March 31, 2018 the Independent Expert Committee (IEC) met over thirty times resulting in the creation and review of over 100 presentations, reports, technical memos and scientific papers. The IEC heard from a number of national and international experts and formulated two sets of Recommendations – one in September and the other in March. The Recommendations can be found HERE.
In its recommendations to the Minister the IEAC strongly encouraged that the IEAC (or another independent body yet to be established) oversee the monitoring program and mitigation activities and assist in the development and dissemination of communication materials.
In the seven months since the experts committee (IEC) was formed, over 30 meetings were held of the full group, in addition to numerous subcommittee meetings and exchanges. Input was received by means of scientific publications, presentations from various experts external to the committee and from reports from consultants contracted by the IEAC. These activities resulted in the creation and review of over 100 presentations, reports, technical memos and scientific papers. At the end of February, the IEC produced their recommendation ‘packages’ dealing with the topics of mitigation, monitoring and management (human health, communications). These packages consisted of a summary document supplemented with hundreds of pages of supplementary materials. All of this information can be found HERE. The results of the decision-making process (consensus or vote), together with the written opinions of the individual experts can be reviewed HERE.
The Oversight Committee (OC) met fourteen times since August 2017 to review information and to provide guidance and insight. On March 8 and 9, 2018 the group met in-person in Happy Valley-Goose Bay to review the recommendations and supplementary material produced by the IEC. A summary presentation was provided by the Chair and Research Director who also addressed questions and responded to requests for clarification. A consensus was reached on most recommendations but members asked for additional time and information to consider their decisions with respect to mitigation and to evaluate a suggestion by one of their members that consideration be given to an Impact Security Fund. The OC met several times over the next few weeks and produced a final set of recommendations that are described in a letter to the Ministers. That letter, as well as the opinions of individual representatives can be found HERE.
Mercury: the Basics
Mercury (chemical symbol Hg) is a naturally occurring metal present in soil, rocks, and water bodies. It exists in three different chemical forms: elemental, inorganic and organic.
It can be released into the environment as a result of human activities including coal-fired power generation, metal mining, and flooding related to hydro-electric development.
Methylmercury is an organic form of mercury. It is formed when inorganic mercury combines with a methyl group, which is composed of carbon and hydrogen. Microscopic organisms (bacteria) in water and soil can convert inorganic mercury into the organic form of mercury, methylmercury, which can accumulate in predatory fish and other living things at the top of the food chain, such as seals. It may be present in some types of fish and marine mammals at levels that have the potential to effect human health.
It is well documented that the flooding of land during the creation of a reservoir for hydroelectric or other purposes leads to an increase in methylmercury concentrations in the reservoir water and organisms. Whereas the increase in water concentrations happens fast (days to weeks), elevated methylmercury concentrations in organisms, particularly fish, are reliably measured only after several months or years, depending on age of the organisms and their position in the food chain. In some cases, the effects of reservoir flooding have also been documented many kilometers downstream in the river, but often downstream effects are unknown. The maximum increase in methylmercury concentrations in fish varies among reservoirs. The amount of increase depends on the size of the area being newly flooded relative to the size of the entire reservoir, the type and amount of organic soils in the newly flooded area, the water residence time in the reservoir, and several other factors.
Mercury is a naturally occurring metal found everywhere in the environment. On land, inorganic mercury is found in vegetation and soils. Naturally occurring bacteria can change inorganic mercury into methylmercury, usually in low oxygen environments, such as the sediments of lakes and wetlands. When land is flooded, the flooded soils and vegetation are broken down or decomposed by bacteria, which use the organic matter (carbon) in the flooded soils and vegetation as food. The decomposition of the organic matter reduces the amount of oxygen, especially in deeper waters, and can lead to increases in methylmercury, which is released to the water. This newly produced methylmercury can then be taken up by organisms in the reservoir, or exported to downstream waterbodies.
Mercury and Food
Inorganic mercury in the environment can be transformed by certain types of bacteria into methylmercury. Methylmercury enters the food chain when it is taken up by organisms such as algae and small zooplankton. Once part of the food chain, methylmercury bioaccumulates in organisms that are higher in the food chain. Bioaccumulation occurs when organisms cannot eliminate a substance, such as mercury, as fast as they take it up from their food or surroundings. Methylmercury also biomagnifies. For example, large predatory fish are more likely to have high levels of mercury as a result of eating many smaller fish that have acquired mercury by eating small invertebrates called plankton.
The IEC reviewed existing levels of methylmercury (MeHg) in various fish, seals and other country foods and found that they are quite low. They also contracted a human health expert to review two previous studies of people’s hair. He concluded that people living in communities around the Muskrat Falls project area have comparatively low MeHg concentrations in hair to other indigenous northern populations. He concluded that:
Current country food consumption practices are safe
To quote the report: ‘…the current practices of country food consumption in the communities…are safe and not leading to undue exposure to MeHg. This includes the most susceptible populations, young children and, most importantly, pregnant mothers.’
This conclusion was corroborated by another toxicologist who examined the summary data.
The results of the hair studies indicate that current consumption practices of country and storebought foods have resulted in MeHg exposures that are typically below Health Canada guidelines. A very small number (less than 1%) of the women of childbearing age and children exceeded the most sensitive Health Canada guideline. A similarly small number of women over 49 years of age and men exceeded the applicable guideline. The independent study concluded that current MeHg exposures are similar to, or lower than, other comparable groups in Canada.
Health Canada has a long history of the development of guidelines for methylmercury. To confirm that the current guidelines are still applicable, the committee contacted Dr. Harold Schwartz, Manager, Chemical Safety of Traditional Foods, First Nations and Inuit Health Branch, Department of Indigenous Services Canada. He confirmed the validity of the guidelines as cited in the Canadian Mercury Science Assessment Report, 2016, (Chapter 14, Mercury and Human Health).
The committee did hear from an expert from the Faroe Islands who said that new research did show health effects at lower and lower MeHg exposures, suggesting that there might be a future lowering of the guidelines. The United States Environmental Protection Agency (USEPA) regularly reviews its guidelines and it was noted that MeHg is listed as a priority for review. Contact with the agency indicated that such a review has not been initiated and it is likely to take several years to complete. Thus, North American guidelines are unlikely to be modified in the near future. It has been recommended that the IEAC, or an independent agency yet to be identified, oversee the monitoring program. This group will need to be aware of any changes in guidelines.
The Harvard model (Calder et al, 2016) predicted that median (the mid-point of a range) exposures will double for the communities that they studied (Happy Valley – Goose Bay, North West River, and Rigolet) but will be greatest (triple) in the community of Rigolet due to the greater consumption of country foods in that community. It has also been noted that, overall, relatively few individuals (less than 5%) exceed Health Canada guidelines now or in the future. The exceptions are a small group of women of child-bearing age and children who are high consumers of country food, mainly living in Rigolet.
Monitoring for Changes in Methylmercury
Yes. Nalcor is obligated to implement an Aquatic Environmental Effects Monitoring Program (AEEMP) for Muskrat Falls. The IEC reviewed this program and found it to be very good and said that it was ‘… exceptional compared to other similar monitoring programs in Canada.’ They recommended some changes to the program (Recommendation #1) to improve its effectiveness. The group agreed that the commercial analytical laboratory that conducts the analyses is one of the best of its kind. This is good because it means we have a very good idea of the levels of MeHg in water and biota prior to the flooding of the reservoir.
The IEAC also decided that an independent body should provide oversight to the monitoring program and recommend any additional changes, if needed, to ensure that any changes in MeHg levels are detected (Recommendation #5) before they can have an impact on humans.
Even if two results are different that does not mean that there has been a change in the MeHg levels in the water samples. As a general rule, they probably have to be at least 20% different from each other due to something called measurement uncertainty.
Analytical measurements such as the determination of MeHg in a water sample have uncertainty. For example, if the same sample is analyzed ten times each measurement will give a slightly different result. This is called the analytical uncertainty and the true value will fall somewhere in the range of results that are obtained. Samples with very small amounts of MeHg have a greater uncertainty that those with higher amounts. (It is easier to measure more of something). If ten samples of water collected in the same spot in the river at the same time and are analyzed, they will also give a range of values -called the field uncertainty. Together these give the measurement uncertainty. Our consultant, Dr. Koch, found that for the MeHg samples the standard uncertainties were about 20% for both tests described above.
Dr. Koch concluded that if someone wishes to compare two results from the water sampling program it is unlikely if they are different if the values are within 40%, and certainly within 20%, of each other.
The natural (or baseline) elevation of the Lower Churchill River at Muskrat Falls is approximately 17m above sea level (asl). When the reservoir is fully flooded the water level will be 39m asl. In November 2016 the water level was raised to 21.5m asl for about one month and then lowered back to baseline. In mid-February 2017 the water level was raised to 21m asl where it has generally remained. There was concern that this would result in increased levels of MeHg.
The IEAC commissioned a study (Koch 2018) to review the methylmercury (MeHg) results from water samples that had been collected between October 2016 and November 2017. The consultant also reviewed information that had been obtained regarding the performance of the analytical laboratory doing the testing.
Dr. Koch concluded that, due to something called measurement uncertainty, it is not possible to draw conclusions about changes in MeHg concentrations in the water samples taken over this period of time. The difference in MeHg concentrations would have to be greater than 40% in order to conclude that there was a real change.
It is unlikely, however, that there was any significant increase in MeHg. Very little MeHg is produced during cold weather months and the areas that have been flooded to date contain relatively low amounts of carbon.
Mitigation of Methylmercury Production
The production of MeHg is a natural process, and it is very common for MeHg levels to increase after a reservoir is flooded. The amount of the increase depends on the characteristics of the reservoir- its size and depth, the speed at which the water flows, the amount of carbon present etc.
The only way to predict what the increase might be is to use computer models. The first complete model for the Muskrat Falls reservoir was completed by a Harvard researcher Dr. Ryan Calder (Calder et al, 2016). This model predicted that there will be a 10-fold increase in MeHg in the river downstream of Muskrat Falls and a 2.6-fold increase in the surface waters of Lake Melville. It further modelled what this would mean in terms of human exposure.
Models always have some amount of uncertainty. The IEC wanted to understand the factors that most contributed to uncertainty. As well, the human exposure depends on how MeHg moves through the food chain and how long any species (fish, seal etc.) spends time in the water that might be most affected by any changes in the MeHg. The IEC Indigenous Knowledge Experts provided valuable contributions due to their knowledge of where fish live and feed. For example, it was noted that salmon stop eating when they enter Lake Melville; this means that they are unlikely to be impacted by any changes in MeHg in the water or other fish. The former Harvard modeller, Ryan Calder used this new information and it was found that human exposures were somewhat reduced compared to earlier model results.
The IEAC was also interested in seeing the predictions of another model being developed by Reed Harris for Nalcor and asked that it be made available by February 15, 2018 (Recommendation #3). Unfortunately, the model was not completed by this date but the group was able to work with Reed Harris and see his preliminary findings. One notable observation was the fact that his prediction of the methylmercury levels in the reservoir waters at the highest point of production was within the same range of values predicted by the Harvard model.
The Harvard model only predicts the maximum (peak) change in MeHg concentration, not how it varies over time. Results from other reservoirs suggest that the MeHg peak in water takes one to five years and slightly longer for it to appear in fish. The highest concentrations in fish are maintained for a few years (depending on the type of fish) but take decades to return to pre-flood concentrations.
The IEAC looked at various ways to reduce (or mitigate) the amount of methylmercury that will be produced due to flooding of the Muskrat Falls reservoir. The experts committee (IEC) could not find a single example worldwide where action had been taken to control methylmercury production at a hydroelectric reservoir but there were some studies published in the scientific literature that offered suggestions.
All soils, in addition to vegetation, naturally contain inorganic mercury (a less toxic form) as well as varying amounts of organic carbon. After flooding, the naturally occurring bacteria that are present consume the carbon, deplete the oxygen at the bottom of the reservoir and this creates conditions that allows the conversion of inorganic mercury into methylmercury. This methylmercury can then flow downstream and enter the food chain.
The removal of topsoil and vegetation is one way to reduce the amount of carbon that is available for the bacteria to ‘eat’, thus resulting in conditions less favorable for methylmercury production. It is important to know how much of this carbon can be removed safely. In order to gather site-specific information on the option of removing organic carbon from the future reservoir, the IEAC made the following recommendations to the Minister of Municipal Affairs and Environment (NL) on Sept 22, 2017:
IEAC Recommendation #1: The IEAC recommends that a feasibility study be undertaken by December 20, 2017, for the removal of soil and vegetation from the future reservoir area.”
On December 22, 2017, the IEC received the draft report “Muskrat Falls – Soil and Vegetation Removal from the Future Reservoir Area”, prepared by SNC Lavalin for Nalcor. The following observations were made by the IEC on this draft report:
The report addressed the technical and economic factors associated with the removal of all the vegetation and topsoil from the entire reservoir area, up to 42m above sea level (asl), which is 3m above the full impoundment level, and did not exclude problematic areas such as steep slopes and unstable soils.
The constructability for full soil and vegetation removal was considered feasible within the project timeline, but was described as very challenging
Points of important note for the committee included: the greater than anticipated minimum depth of soil clearance (0.5 m in summer, 1.5 m in winter), which essentially removes the full soil organic profile; the need to re-profile cleared land, even on moderate slopes (>30%), in order to maintain ground stability; and the widespread erosion potentially associated with such extensive ground disturbance, which could unintentionally stimulate MeHg production.
The IEC decided that it would be better to identify certain areas for topsoil removal in order to make the work more feasible, improve safety and reduce the potential for unwanted side-effects that might actually stimulate methylmercury production.
The IEC struck a Reservoir Subcommittee tasked with examining the characteristics of the future reservoir including its physical geography, ecological land classifications, soil types and organic carbon pools with the goal of informing options for targeted mitigation. An examination of the environmental risks associated with carrying out large-scale soil disturbances was also undertaken, which is detailed in the memo “Effects of forestry practices and similar soil disturbance on environmental mercury concentrations.” (Jansen, W., September 27, 2017.)
The committee agreed that an emphasis would be placed on practical considerations such as existing roads/tracks, slopes less than 30% etc., to reduce slope hazards, erosion and runoff (Jansen, Sept 27, 2018). In January 2018, the Subcommittee completed draft specifications for two Targeted Mitigation Scenarios, which were finalized in cooperation with Nalcor and its contractor SNC Lavalin, forming the basis of a new Statement of Work for Nalcor and its contractor SNC Lavalin. These two scenarios are summarized here:
Scenario A (Capping):
- Cap all fen and low shrub bog (but not marsh) wetlands ELC areas between 23.5 and 39 m asl with sediments that are low in total organic carbon, locally available and that will be stable (resistant to erosion from water flow) on the reservoir bed.
- Stability of sediment cap is more important than thickness, but assume 50 cm thick for this scenario. Cap should isolate the organic wetland soils, particularly peat accumulations, from the water column.
- Conduct work during frozen ground conditions to minimize ground disturbance.
Scenario B (Targeted Soil Removal):
- Remove soil from areas that have been previously cleared of trees and vegetation and are accessible by existing roads, between the 23.5 masl contour and the 39 masl contour.
- Exclude areas of slopes greater than 30% and other areas that would require re-profiling.
- Exclude areas that potentially contain sensitive clays (glaciofluvial and glaciomarine)
- Exclude riparian areas.
- Prioritize work on steeper slopes during frozen ground conditions, moving towards flatter areas during thawed ground conditions (to limit runoff from clearance activities).
On February 26, SNC Lavalin provided a brief summary of the preliminary information regarding the feasibility of the 2 Targeted Mitigation Scenarios, and provided costing estimates (SNC Lavalin, Feb 26, 2018 – 3 documents). The conclusions are summarized as follows:
- Both Scenarios A and B were considered feasible within the current July 2019 impoundment schedule
- Scenario B was described as a challenging undertaking to complete within the current July 2019 impoundment schedule.
(Note: on March 22, 2018 Nalcor distributed a report that described this information in greater detail – Muskrat Falls- Soil and Vegetation Removal from the Future Reservoir Area – Targeted Scenarios, 2018)
Some details would be worked out during the actual engineering design but some features are known.
Scenario A (capping) affects areas that are relatively small (1031 to 1756 ha; less than 1%) compared to the full mitigation originally examined. The material to be used for covering, or capping, these areas would be obtained locally, have low organic carbon content, and would cover the areas to a depth of 0.5 to 0.7m. The feasibility study noted that it would be possible to cap the areas before and, possibly after, flooding. This cap would prevent the organic carbon within these areas from being available for the production of methylmercury.
One expert had observed organic material (peat) floating to the surface in other reservoirs; preventing this at Muskrat Falls would reduce overall methylmercury production.
Scenario B (targeted topsoil removal) is a considerably greater engineering challenge as it entails volumes (5 – 9 million cubic metres) that are roughly one-third of the full mitigation option. Much of the work would have to be undertaken in cold weather to reduce the risk of unwanted production of methylmercury.
The soil being removed would have to be moved above the high-water mark of the future reservoir and properly contained so that this soil does not contaminate other watershed areas. A detailed design of the disposal areas was not provided but, according to the report, a typical soil disposal area would be approx. 200 m long, 50 m wide and 6 m deep – equivalent to two football fields end to end. It was thought that approximately 100 to 200 such areas would be needed.
We only have the models to estimate the potential reduction in methylmercury that could be achieved by capping and/or targeted soil removal. One such estimate was obtained from Dr. Ryan Calder (who developed his model while at Harvard University). This model suggested that soil removal might reduce the amount of methylmercury by approximately 20-25% (relative to the predicted increase with no mitigation). Capping seemed to be less effective (2% reduction) but this is because the model only looks at the surface area of the areas. If the organic material is allowed to float into the water, as has been seen in other reservoirs, then capping could produce a much greater reduction in overall methylmercury production over time.
There is evidence that natural events that result in large-scale soil disturbance, such as windfall events during storms and soil disturbance due to logging, can influence the production of methylmercury. Such effects may vary from site to site and depend on where the disturbance is relative to the waterbody of concern, the area topography and the soil type. It is known that projects carried out in winter months result in less impact than those carried out in times when soils are not frozen.
One expert felt that targeted soil removal, if not done correctly, may partially or fully offset the expected decrease in methylmercury concentrations in fish that mitigation was expected to accomplish; others felt that cold temperature excavation and appropriate precautions could reduce this risk of what has been called the unwanted side-effects of mitigation.