SOME CONCLUDING OBSERVATIONS
(from this scientist's experience)
- For many of the pollutants of concern in the Great Lakes, we don't have enough
information to determine the relative importance of different loading pathways (e.g.,
atmospheric deposition, waterborne loading via tributaries, contaminated sediments,
etc.).
- For any significant loading pathway, it is important to determine the major contributing
sources and source regions; for the air pathway, this must be done by combining an accurate
air emissions inventory with a atmospheric fate and transport model
- However, for many of the pollutants of concern in the Great Lakes, we do not have an
accurate air emissions inventory
- When suitable inventories are available, the HYSPLIT model appears to be a useful tool to
link air emissions from sources to Great Lakes deposition, but, other models could be used as
well, as long as source-receptor linkage information is preserved during the modeling
- For dioxin and atrazine, we've obtained some idea of the importance of different
sources and source regions, but, this is primarily dependent on the accuracy of the emissions
inventory
- Atmospheric transport from both inside and outside the Great Lakes Basin appears to be important for dioxin and atrazine
- Comprehensive atmospheric modeling of toxic air contaminants is an evolving and worthwhile endeavor,
but there are uncertainties and data gaps that limit its application to the Great Lakes or any other region
- It is hoped that the work presented today demonstrates the promise of this type of analysis,
and that we will be encouraged to develop the information necessary to apply it to the
Great Lakes for all relevant pollutants of concern
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