inventories and evaluation of
substances using models based on
Quantitative Structure Activity
Relationships.
Ongoing fish and wildlife research
and ambient monitoring also has
been effective in identifying new
5.2
chemical classes in the Great Lakes.
Polybrominated diphenyl ethers
(PBDEs), perfluorosulfonates (PFOS)
and carboxylates, chlorinated
paraffins and naphthalenes, various
pharmaceuticals and personal care
products, phenolic substances and
approximately 20 current-use
pesticides have been identified.
scientific challenge of addressing them.  For example, the
New Effects
issue of invasive species is not new, but it has been acceler-
ating in recent years because of globalization and the
In the past, the identification of effects was largely based on
vulnerability of the Great Lakes to invasions. The current
a combination of field observation and scientific judgement
number of known invaders stands at 162, with many more
by resource managers and biologists.  New effects can be
“surprises” anticipated as long as effective action is not
observed at different levels of biological organization
taken. The ultimate non-chemical stressor is the economy,
ranging from the cellular to the ecosystem level, though
since all stressors result from human economic activity.
most are first seen at the organism level.   Systematic
surveys are currently being undertaken in a limited way in
In terms of ecosystem science, the most critical factors
the Great Lakes. They are limited in the sense that the
dominating ecological processes in the Great Lakes
studies are short term and selective in terms of species and
originate from offshore in the open waters. Understanding
localities. In the future, new techniques, such as
the interconnections between physical, biological and
toxicogenomics that combine disciplines - in this case
chemical processes is the key to implementing a science-
Quantitative Structure Activity Relationships and toxicology
based approach to decision-making to achieve long-term
potential -  to enable predictive capabilities to be developed
management goals for large complex systems.  A major
that will allow scientists to anticipate new effects on a more
challenge is the limitations imposed by the current
comprehensive basis.
institutional structures to implement the Great Lakes Water
Quality Agreement, and to provide integrative manage-
The large surface area of the lakes makes them vulnerable
ment and oversight based on its goals.
to atmospheric deposition of chemical stressors, and the
large volumes of the lakes may result in long residence
New Chemicals
times for these substances.
Substantial progress has been made over the past few
decades in reducing or eliminating releases of critical
The Existing Substance Inventories of the United
pollutants identified under the Great Lakes Water Quality
Agreement and achieving reductions in the ecosystem.
States and Canada are approximately 80,000 and
While these trends are encouraging, other classes of
25,000  substances,  respectively,  many  of  which
chemicals are emerging as potential pollutants in the basin.
The Existing Substance Inventories of the United States and
have had no formal assessment of risk to human
Canada are approximately 80,000 and 25,000 substances,
health and the environment and may be present in
respectively, many of which have had no formal assessment
very low levels in both environmental media and
of risk to human health and the environment and may be
present in very low levels in both environmental media and
biota.
biota.  There are two major activities relevant to the
identification of new chemicals of interest -- release
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