Natural Heritage Notes from Academic Journals available at TIARA:

Cornwall Sediment Strategy. Ottawa: Environment Canada, 2007.

• This is a publication put out by Environment Canada and Ontario Ministry of the Environment. It is a public information brochure that gives a broad outline of the Remedial Action Plan currently in place for the Cornwall Area of Concern. The brochure outlines the environmental issues facing the Cornwall waterfront and the solutions that have been decided upon. The Cornwall Sediment Strategy calls for the contaminated sediment to be left in place to decontaminate over time while fresh sediment accumulates annually over top of the contaminated sediment.
• For further information beyond this brochure, consult the St. Lawrence Area of Concern site:

Canadian Remedial Action Plans - St. Lawrence Area of Concern

Dreier, S. & Richman, L. Sediment Contamination in the St. Lawrence River Along the Cornwall, Ontario Waterfront. Journal of Great Lakes Resources: 27(1):60–83.

ABSTRACT. Studies from 1970 to 1997 repeatedly showed that sediment was contaminated with mercury and zinc and, to a lesser extent, lead and copper in the north channel of the St. Lawrence River along the Cornwall, Ontario waterfront. Mercury contamination was greatest at two depositional zones: downstream of the Cornwall canal discharge near Lamoureux Park boat launch (maximum 18.0 μg/g, 1975) and downstream of Windmill Point (maximum 44.0 μg/g, 1975). Contaminant concentrations decreased with increasing distance from local point sources. The latter depositional zone extended approximately 2 km downstream and had the highest concentrations of mercury as well as high zinc, copper, and lead concentrations. Concentrations of As, Fe, Mn, Cd, Ni, Cr, TP, TKN, and TOC showed no significant local enrichment. Patterns of sediment contamination suggest local sources of PAHs; however, concentrations were not high enough to be of concern. The studies indicated that mercury and zinc were primarily from local industrial sources, a conclusion supported by patterns of contamination in the north versus south channels and downstream into Lake St. Francis. Although mercury concentrations in surface sediment appear to be decreasing over time, contaminants remain at high concentrations in Cornwall waterfront sediment. The two major local point sources of mercury closed their Cornwall industrial operations in the 1990s, but contaminated sediment can act as an important long-term source of mercury to the aquatic food chain. Conclusions drawn from this review will be used in the development of a strategy for managing contaminated sediment in Cornwall and may be applicable to other areas of contaminated sediment for which similar assessments are required.

Ridal, Jeff; Lo, Amy; Watson, Susan & Zaitlin Beryl. Odours from pulp mill effluent treatment ponds: the origin of significant levels of geosmin and 2-methylisoborneol (MIB). Chemosphere. 51(8): 765-773. June 2003

· This article attempts to identify the source of earthy/musty tastes and odours in the water around Cornwall. While the research targets Domtar’s wastewater treatment plant as the likely source of odour and taste in the water, the researchers conclude that the earthy taste in the drinking water is likely independent of Domtar’s wastewater treatment system.

· The likely contributor to the earthy taste/smell is a group of microorganisms called cyanobacteria. The growth of cyanobacteria takes away from the growth of other microorganisms that break down sludge. Thus, earthy/musty odours can be used as an indicator of less than optimal operating conditions in wastewater treatment systems.

Ridal, J; Brownlee, B & Lean, D. Is Lake Ontario the Source of Taste and Odor Compounds to the Upper St. Lawrence River? Journal of Great Lakes Research. 26(3):315–322, 2000.

ABSTRACT. The south and east coastal currents of Lake Ontario were investigated to determine if they serve as the major source of the common odour compounds, 2-methylisoborneol (MIB) and geosmin (GM), to the St. Lawrence River (SLR). MIB and GM at low parts per trillion levels produce earthy-musty off-tastes in drinking waters. Previous investigations in 1996 and 1997 identified the presence of GM and MIB in SLR and in the southern coastal jet of Lake Ontario, which contributes the bulk of the summertime flow to the St. Lawrence River. Water samples were collected in July and September 1998 during cruises of Lake Ontario and the SLR, extracted shipboard and analyzed for MIB and GM. In July, both compounds were detected only in the SLR, but were found in both Lake Ontario and SLR stations in September. However, MIB and GM were found at higher levels in the St. Lawrence River (17 to 60 ng/L and 2 to 18 ng/L, respectively) than in samples from the Lake Ontario coastal current (0.5 to 10 ng/L and < 2 ng/L, respectively). The concentration profile of these samples from lake to river shows maximum concentrations of both MIB and GM in the St. Lawrence River near Brockville, Ontario. The data indicate sources of MIB and GM are primarily within the river (as opposed to sources from Lake Ontario). Zebra mussel infestation of the upper St. Lawrence River is particularly prevalent in the Brockville section of the St. Lawrence and they are implicated together with other benthic sources in the production oMIB and GM in the river.

St. Lawrence River at Massena Area of Concern. Environmental Protection Agency, 2008.

• The Massena AoC is closely linked to the Cornwall AoC. The Remedial Action Plan (RAP) produced by the Massena AoC Advisory Committee spells out who environmental integrity will be restored through a long-term billion dollar program. Heavy industry on the American side primarily from the operations of ALCOA and General Motors over the past fifty years has created significant environmental problems in the St. Lawrence and Grasse River, which is a tributary of the St.LR. This pollution has an impact on the river downstream of the AoC.

Great Lakes Areas of Concern (AoCs): St. Lawrence River | Great Lakes | US EPA

Water and Sediment Quality of the St. Lawrence River near Maitland, Ontario. Ministry of Environment and Energy.

• The report highlights the quality of sediment in and around Maitland, which was historically the location of two heavy industries – DuPont and Genstar Chemical. DuPont processed tetraethyl lead for gasoline until 1984 when lead was phased out of gasoline. The study involved 48 stations place 5km upstream and 12 km downstream of DuPont. Concentrations of phosphorus downstream of DuPont were higher than the upstream locations. Metal concentrations in the water did not exceed the Provincial Water Quality Objectives, which the exception of cadmium and cobalt at four and two stations respectively. Sediment samples do not indicate anything alarming aside from high concentrations of arsenic, iron, manganese and copper at a few deep water stations, which approached the Severe Effect Level. Lead concentrations have decreased over time since the closing of the DuPont tetraethyl lead plant. The report recommends that water quality in the Maitland area be monitored periodically to determine if Provincial Water Quality Objectives are routinely exceeded. If the PWQO’s are routinely exceeded, remedial action should be considered. The report does not call for remediation of sediment, as the quality will slowly improve over time.

Mercury in Fish in the St. Lawrence

• A three year program was set-up by the River Institute and other partners in 2003 to investigate levels of mercury in fish in the St. Lawrence. Researchers attempted to discover why walleye downstream of the Moses-Saunders dam experience mercury levels twice as high as those found upstream of the damn.