Text Size
| |
| |
| |
Sediments
Mercury Concentrations in Sediments in the Great Lakes and the St. Lawrence River
Outlook
Sediment quality is monitored by analysing both the deep layer of sediment, considered a trap for toxic substances, and surface sediments, which are examined to characterize recent inputs of particles. To date, mercury concentrations in the Great Lakes–St. Lawrence system were found to have declined by some 50% compared to 20 or 30 years ago. This reduction comes in the wake of regulatory measures implemented by public authorities, particularly binational initiatives, and can be traced to the closure of industrial facilities, improvements in industrial processes and water cleanup operations. Indeed, for some years already, Canada and the U.S. have jointly undertaken to reduce gaseous emissions of mercury by 50 to 90% in the short term, and to work toward the rehabilitaton of contaminated sites through initiatives such as the Great Lakes Water Quality Agreement and the Great Lakes Binational Toxics Strategy.
 |
|
| Magella Pelletier, St. Lawrence Centre | |
The LIMNOS, research vessel of the National Water Research Institute in front of Detroit |
|
 |
|
Sampling with the Shipek corer |
Taking a core sample |
| Magella Pelletier, St. Lawrence Centre | |
Mercury was employed in this fact sheet as a benchmark of sediment quality. Such an assessment could be based on other substances, including the so-called emerging substances that are not yet being regulated and whose use grows every year. By gathering new information on the chemical and physical quality of sediment, we advance our understanding of the sedimentary processes in the basin, take a snapshot of its overall contamination, and define its short- and long-term trends.
To Learn More
CHAMPOUX, L. and H. SLOTERDIJK. 1988. Étude de la qualité des sédiments du lac Saint-Louis 1984-1985. Rapport technique no 1 : Géochimie et contamination. Environment Canada, Conservation and Protection, Quebec Region.
COAKLEY, J.P. and J.B. SÉRODES. 1993. Spatial and vertical trends in sediment-phase contaminants in the Upper Estuary of the St. Lawrence River. Estuaries 16(3B): 653–669.
HARDY, B, L. CHAMPOUX, H. SLOTERDIJK, and T.J. BUREAU. 1991. Caractérisation des sédiments de fond du lac Saint-Pierre, fleuve Saint-Laurent. Environment Canada, St. Lawrence Centre. 74 pp.
KENNEDY, J., R.R. RUCH, and N.F. SHIMP. 1971. Distribution of mercury in consolidated sediments from southern Lake Michigan. Illinois State Geological Survey, Environmental Geology Notes Number 44, Studies of Lake Michigan Bottom Sediments Number Seven.
MARVIN, C.H., M.N. CHARLTON, E.J. REINER, T. KOLIC, K. MACPHERSON, G.A. STERN, E. BRAKEVELT, J.F. ESTENIK, L. THEIESSEN, and S. PAINTER. 2002a. Surficial sediment contamination in lakes Erie and Ontario: A comparative analysis. Journal of Great Lakes Research 28(3): 437–450.
MARVIN, C.H., M.N. CHARLTON, G.A. STERN, E. BRAKEVELT, E.J. REINER, and S. PAINTER. 2002b. Spatial and temporal trends in sediment contamination in Lake Ontario. Journal of Great Lakes Research 79(2): 317–331.
MARVIN, C.H., S. PAINTER, and R. ROSSMANN. In press. Spatial and temporal patterns in mercury contamination in sediments of the Laurentian Great Lakes. Environmental Research.
PAINTER, S., C. MARVIN, F. ROSA, T. REYNOLDSON, T. CHARLTON, M. FOX, P.A. THIESSEN, and J.F. ESTENIK. 2001. Sediment contamination in Lake Erie: A 25-year retrospective analysis. Journal of Great Lakes Research 27(4): 434–448.
PELLETIER, M. and S. LEPAGE. 2002. Évolution spatiale et temporelle des processus sédimentaires et de la géochimie des sédiments du lac Saint-François au 20e siècle. Scientific and Technical Report ST-225. Environment Canada – Quebec Region, Environmental Conservation, St. Lawrence Centre. 86 pp.
ROSSMANN, R. 1999. Horizontal and vertical distributions of mercury in 1983 Lake Superior sediments with estimates of storage and mass flux. Journal of Great Lakes Research 25(4): 683–696.
ROSSMANN, R. 2002. Lake Michigan 1994-1996 surficial sediment mercury. Journal of Great Lakes Research 28(1): 65–76.
SLOTERDIJK, H.H. 1991. Mercury and organochlorinated hydrocarbons in surficial sediments of the St. Lawrence River (Lake St. Francis). Water Pollution Research Journal of Canada 26(1): 41–60.
SMITH, J.N. and C.T. SCHAFER. 1999. Sedimentation, bioturbation, and Hg uptake in the sediments of the estuary and Gulf of St. Lawrence. Limnology and Oceanography 44(1): 207–219.
THOMAS, R.L. 1972. The distribution of mercury in the sediments of Lake Ontario. Canadian Journal of Earth Sciences 9: 636–651.
THOMAS, R.L. 1974. The distribution and transport of mercury in the sediments of the Laurentian Great Lakes system. Proceedings of the International Conference on Transport of Persistent Chemicals in Aquatic Ecosystem, pp. I-1 to I-16.
Chris H. Marvin Magella Pelletier
|
|
|
Date modified: 2008/05/01 – Important Notices
