Report - Agence canadienne d'évaluation environnementale

Impact of storage tank installation
Impacts on the natural environment
The MRNF is concerned about the physicochemical quality of the groundwater likely
to be pumped during the digging of basins required to install storage tanks and then,
to keep them dry during project operations. This concern is due to the high
concentration in iron and manganese. The temperature and quality of these waters is
also a cause of concern for Fisheries and Oceans Canada (DFO) which is of the view
that these should respect the Environmental Discharge Objectives 1 (EDO) so as not
to affect fish habitat. Both ministries believe that a system such as a settling tank
should be set up to capture pumped water before it is discharged in the local
environment (DQ5.1, p. 4; DQ62.1).
Water discharge from vaporizers
While the terminal is in operation, regasifying LNG would require vaporizers
discharging water in the St. Lawrence River at an approximate rate of 0.003 m 3 /s. At
an average of 30 o C, the temperature of this discharge would be several degrees
higher than that of the surrounding environment, which varies between 20 o C in the
summer and 1 o C in the winter 2 . Although at this stage of the project the proponent has
not determined the outfall location of vaporizer discharges, he nevertheless believes
that the temperature increase due to the discharge would be barely noticeable starting
at 25 m from the discharge point and that installing a diffuser would not be necessary.
The Canadian Council of Ministers of the Environment (CCME) has communicated a
provisional recommendation with regard to the temperature of the water discharged in
a water body. Based on this recommendation, human activities must not cause a
variation of more than 1 o C of the ambient marine and estuarine water temperatures in
a given point, and the maximum rate of any anthropogenic thermal variation should
not exceed 0.5 o C per hour (CCME, 1996).
According to the MDDEP’s surface water quality criteria, anthropogenic temperature
increase must not modify the water temperature to the point of causing a foreseeable
displacement or modification of present or potential aquatic populations. Also, it must
not alter certain localized sensitive areas such as a spawning ground, nor kill
organisms living close to a discharge site. Moreover, the environment must not
1. Calculation and interpretation of the Environmental Discharge Objectives (EDO) for contaminants in the
aquatic environment [On-line (March 31, 2007):www.mddep.gouv.qc.ca/eau/oer/Calcul_interpretation_OER.pdf].
2. Shipboard Thermosalinographs [On-line (March 31, 2007): www.osl.gc.ca/tsg/index-e.html].
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