REM-610 Exercise 7 – Ecological Risk Assessment. March 31, 2010. First Step. The first step of the risk assessment is the problem formulation. Briefly, state the problem including the rationale to conduct a risk assessment. Pollutant is discharged, wildlife exposed potential for risk
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March 31, 2010
The second step is to develop an exposure profile. Start by exploring the reported data. Determine
A) the mean concentration
B) the standard deviation of the concentration
C) explore the distribution of the data
Where R is the rankorder in %, n is the rank order and N is the total number of toxicity data evaluated.
-red line – describes a statistical population (of observations)
-the rank of the species tested (not of the real environment)
-black line – e.g. 80% of the chem. Concentration in the water is less than ~log 1.3
-two different populations (one of the lake, other of toxicity tests)
-next, have to look at whether the list of species tested is relevant to the species in our ecological risk assessment
-when setting the limit, should it matter whether a key species is at the bottom? Have to set the limit to a lower number
Merits: Takes into account many data points from the measurements around the lake and also from various species’ EC50.