Carbaryl, Carbofuran, and Methomyl - National Marine Fisheries ...

the probability of risk. In the Risk Characterization section, the distribution of the
sensitivity of salmonid prey items was used to determine selection of a survival toxicity
value used in population modeling exercises. Probabilistic techniques were not otherwise
utilized in the Opinion due to issues with data collection, paucity of data, non-normal
distributions of data, and quality assurance and quality control. For example, it was not
deemed appropriate to pair the salmonid prey responses with exposure probabilities based
on monitoring results given the limitations of that data set discussed in the Effects of the
Proposed Action. To evaluate population consequences associated with potential
lethality from pesticide exposure in salmon, NMFS selected the lowest reported salmonid
LC50 from the available information to ensure risk was not underestimated. When we
consider the data limitations coupled with the inherent complexity of EPA’s proposed
action (Figure 1) in California, Idaho, Oregon, and Washington, we find that probabilistic
assessments at population and species scales introduce an unquantifiable amount of
uncertainty that undermines confidence in derived risk estimates. These same studies do
not factor the status of the existing health and baseline conditions of the environment into
their assessment. At this time, the best available data do not support such an analysis and
conclusions from such an analysis would be highly speculative.
Action Area
The action area is defined as all areas to be affected directly or indirectly by the federal
action and not merely the immediate area involved in the action (50 CFR §402.02).
Given EPA’s nationwide authorization of these pesticides, the action area would
encompass the entire U.S. and its territories. These same geographic areas would include
all listed species and designated critical habitat under NMFS jurisdiction.
In this instance, as a result of the 2002 order in Washington Toxics Coalition v. EPA,
EPA initiated consultation on its authorization of 37 pesticide a.i.s and their effects on
listed Pacific salmonids under NMFS’ jurisdiction and associated designated critical
habitat in the states of California, Idaho, Oregon, and Washington. Consequently, for
purposes of this Opinion, the action area consists of the entire range and most life history
stages of listed salmon and steelhead and their designated critical habitat in California,
55