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Study Measures Toxic
Chemicals Entering Presque Isle Bay from the Air Presque Isle Bay near Erie,
Pennsylvania, is one of 43 locations around the Great Lakes region to have been
designated an “Area of Concern” by the International Joint
Commission, indicating that past use and contamination of the bay has led to
impairments on the ability to fully use the bay for beneficial purposes.
Presque Isle Bay has become the first of these 43 areas to be re-designated as
an “Area of Recovery,” indicating that the bay’s management
committee has determined that allowing a natural recovery—rather than an
active remediation project—is the best course for bringing the bay back
to full health. Local, state and national officials are therefore working hard
to eliminate remaining sources of pollution to the bay and determine how long a
wait is needed until the bay will return to health on its own. Although historical pollution
of the bay was largely through industrial discharges directly into the bay’s
waters, the great majority of such releases have now been eliminated. However,
large amounts of some toxic substances may be entering the bay—and Lake
Erie to which it connects—by depositing from the atmosphere. If chemicals
are entering from the atmosphere at a significant level, it could significantly
affect the time it will take for the bay to recover and for pollution levels in
the bay’s sediment to decrease. Among the primary
contaminants causing concern in Presque Isle Bay are a group known as
Polycyclic Aromatic Hydrocarbons, or PAHs. Unlike some persistent chemicals
that can be transported across the globe in the atmosphere, PAHs are degraded
quickly enough in the atmosphere that most deposition of these chemicals is
likely to come from relatively local (within a few hundred miles) sources.
There is therefore greater potential that actions could be taken to reduce
deposition if airborne contaminants were indeed shown to be affecting the bay.
To determine the amount of these chemicals entering the bay, a study has been
undertaken by a research team at Gannon University, led by Dr. Michelle Homan
and Dr. Weslene Tallmadge, sponsored by the Great Lakes Commission’s
Great Lakes Air Deposition (GLAD) Program. This research project
monitored the levels of these chemicals in the air and in precipitation over
the course of one year in the area of Presque Isle Bay. Three monitoring
stations were established, one very near the bay and additional sites in the
city of Erie and downwind. In addition to regular samples of air and
precipitation, the researchers also directly measured the amount of chemical
depositing to surfaces. With this information, estimates are able to be made of
the amount of these chemicals reaching the bay through the atmosphere. The results of the study
allowed the research team to make some preliminary assessments of the relative
importance of various sources to the PAH concentrations and deposition to the
bay. Activities are now underway to collect additional sampling data, which is
needed to improve the results of the source identification work. The overall results
of the project will be useful in helping local managers create models of how
pollution from the atmosphere is affecting the bay, whether current levels of
contaminants in the atmosphere are contributing to continued impairment of the
bay and what might be done to decrease them. Additional information and
the project report are at: www.glc.org/glad/projects/homan04/ ---------- The Great Lakes Air
Deposition (GLAD) program is coordinated by the Great Lakes
Commission to address the deposition of toxic pollutants to the
waters of the Great Lakes region and to promote coordinate efforts to reduce
such deposition and the resulting adverse impacts on human and wildlife health.
For more information on the GLAD program, visit http://www.glc.org/glad
or contact Jon Dettling of the Great Lakes Commission at (734)971-9135 or dettling@glc.org. |