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Last updated: June 14, 2007
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How will Everglades restoration affect mercury
risks?
Poster presented May 1999, at the South Florida Restoration Science Forum
Presenters:
Dr. Darren G. Rumbold
drumbol@sfwmd.gov
Senior Environmental Scientist
South Florida Water Management District
Water Resource Evaluation /Resource Assessment
Div.
3301 Gun Club Road
West Palm Beach Florida 33406, USA
Telephone: 561 682-2132
Field: Ecotoxicology
Experience: biomonitoring dioxins, mercury
and other metals in wildlife near solid-waste incinerator; organochlorine
pesticides in birds; Organochlorine pesticides, PAHs and n-alkanes in coral-reef
ecosystem; toxicity identification evaluation in near-shore waters from
Florida Keys; transport, fate and risk assessment of mercury in Everglades.
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Mr. Peter Rawlik
prawlik@sfwmd.gov
Staff Environmental Scientist
South Florida Water Management District
Water Resource Evaluation /Resource Assessment
Div.
3301 Gun Club Road
West Palm Beach Florida 33406, USA
Telephone: 561 682-6710
Field:Everglades Ecology and Field Sampling
Logistics
Experience: Monitoring Everglades surface
water quality; biomonitoring along an Everglades nutrient gradient for
impacts on macrophytes, periphyton and macroinvertebrates; Emergent macrophyte
transpiration rates; mercury sample collection; mercury transport, fate
and risk assessment of mercury in the Everglades.
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What Is "Risk"?
Risk is defined as the probability that
a substance or situation will produce harm under specified conditions.
Risk is a combination of two factors:
- The probability that an adverse event will occur, such as a specific
disease or type of injury.
- The consequences of the adverse event.
Source: Presidential/Congressional Commission
on Risk Assessment and Risk Management (1997).
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Ecological Risk Assessment
Risk assessment is simply a process to
organize and analyze data.
Risk assessments ask three basic questions:
- What is at risk, i.e., what can happen
- Probability that it will occur, i.e., how likely
- Consequences of occurrence, i.e., so what?
This information is then used by a
risk manager, along with information from other sources, in judging whether
the consequences require increased management or regulation.
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Click on this image to view
a larger version.
Framework for
ecological risk assessment (USEPA, 1998)
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three phases: problem formulation, analysis and risk characterization.
First, the problem is defined by identifying
what the potential stressor is (e.g., mercury), as well as what specific
environmental value or ecological entity is to be protected (e.g., humans,
panther, wading bird). The final product of problem formulation is an analysis
plan, which is a "blueprint" for using available and new data to test explicit
risk hypotheses.
Phase two is the analysis phase that includes
two principal activities: characterization of exposure and characterization
of effects.
- Exposure characterization attempts to determine
the number and kinds of ecological entities exposed to the stressor, along
with the magnitude, frequency, extent, and duration of the exposure.
- Effects characterization determines the probable
negative effects from a given level of exposure.
Risk characterization is the final
step that integrates exposure and effects using a wide range of techniques
to estimate the nature and extent of risk. All assumptions and uncertainties
are summarized.
The assessment process is meant to be flexible
and iterative as important new information and viewpoints arise.
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Disclaimer for non-USGS materials
Next: How will Everglades restoration affect
mercury risk? (Part 2)
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