(Montana State University - Bozeman, College of Agriculture, 2007) Davis, Ryan Scott; Chairperson, Graduate Committee: Robert K. D. Peterson.
West Nile Virus (WNV) has been a concern for people across the North America since the disease was observed in the summer of 1999. WNV has caused the largest arboviral encephalitis epidemic in U.S. history. In response, vector management programs have been implemented. Concerns have been raised about these programs My ecological risk assessments focused on six common mosquito adulticides used in vector management, including 3 pyrethroids, pyrethrins, 2 organophosphates, a synergist, and 4 larvicides. Both aquatic and terrestrial non-target organisms were considered for acute and chronic exposures to the adulticides and larvicides. Tier I exposure estimates for adulticides were derived using modeling software. A probabilistic assessment was conducted for the adulticides to account for variability within the exposure models. The larvicide risk assessment included an even settling model into a standard farm pond. Risk quotients (RQ) were obtained by comparing exposure to toxic endpoints. Organophosphates breached a risk quotient (RQ) level of concern (LOC) for amphipods.
