IEAC Recommendation #1, issued September 22, 2017
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.
This feasibility study will inform IEAC discussions about whether soil and further vegetation removal is determined to be an effective and desirable mitigation measure. Such a study should focus on engineering, using the new data on soil types, volumes and depths and should determine how much of the organic soil layer can be removed safely. It should consider the impact of heavy equipment, the time of year that the work is best conducted, the time frame and storage options. The study results should be available to the IEAC as soon as possible and certainly no later than December 20, 2017.
Topsoil removal is one way to reduce the amount of carbon that is available for the bacteria to ‘eat’ thus resulting the in production of less MeHg. Recently, Nalcor has mapped the deposits of organic carbon in the soils of the reservoir area – so they have a very good idea of how big the areas are and how deep. It is important to know how much of this carbon can be removed. Although this topic has been discussed in other, earlier, forums no detailed feasibility study has been undertaken – the IEC feels that such a study is critical.
The IEAC recommends that Nalcor implement the changes described in the report entitled “Recommendations on changes to the scope and quality of the Muskrat Falls Aquatic Monitoring Program”.
The goal of monitoring is to understand the current amounts of mercury and methylmercury particularly in the water and biota – especially those organisms that people use for food. No environment is free from these compounds so baseline data provide critical insight as to the concentrations of mercury/methylmercury that occur naturally. Such information is necessary to be able to identify changes that may be due to the construction/operation of the hydroelectric facility. Similarly, a robust monitoring program will be able to detect changes as they occur and, hopefully, serve as an early warning prior to increases in the amounts of methylmercury in the food that people consume. It is necessary to use laboratory analytical methods that can ‘see’ mercury/methylmercury at levels that are meaningful – i.e. the detection limit, DL, (in simplest terms this is the lowest amount that can be reliably measured). The DL has to be low enough to detect changes. For example, there could be changes in the methylmercury concentrations but if these are occurring below the detection limit they cannot be ‘seen’.
The IEC conducted a detailed analysis of the aquatic effects environmental monitoring program (EMP). SEE THE FULL REPORT HERE.
The IEAC recommends that Nalcor expedite the finalization of their current methylmercury modelling project, and complete the work no later than February 15, 2018.
Since full inundation of the reservoir has not yet occurred it is necessary to rely on mathematical models to predict what will happen in the future. The most detailed model to date, and the only one that includes Lake Melville, has been done by Harvard University. This model predicted that reservoir creation will increase methylmercury inputs in Lake Melville by 25 – 200%; a very large range. This range in predictions is due to uncertainties in the assumptions that have to be made. It would be a benefit to all parties if these uncertainties could be reduced. The IEAC was made aware of work, currently underway by Nalcor and its consultants, to expand and improve their modelling of the production and fate of methylmercury. This mechanistic model will include Lake Melville and will be integrated into Nalcor’s human health risk assessment. We believe that it is important that the IEAC be able to review the results of this model, and compare the outcomes to other studies dealing with these issues.