1 |PagePublished Studies Assessing the Effects of Multiple Applications of ULV Mosquito AdulticidesND = Not Detected.ActiveIngredientProduct SampleTypeTimesampledResults Notes ReferencePyrethrinsand PBOPyrenone25-5Sediment within 12hrs afterthe 5thand 11thsprayeventsNo evidence foraccumulation. In 6treated tanks sampledafter 5 biweekly sprayspyrethrins levels wereND in 4 tanks, 23.1 &33.1 ppb in 2 others,after 11 sprays:pyrethrins ND in 4tanks, 4.03 and 34.5ppbin 2 others,6 stock tanks under 11 biweekly ULVapplications Sediment in tanks sampledfor pyrethrins and PBO after 5th& 11thbiweekly spray events eventsaLawler et al. 2008Pyrethrinsand PBOEvergreen6-60Water middepth10 sitesunder anaerialapplication12-16hours8 daysPyrethrins were ND 16h post app at any site.In “next day” samples,PBO incr in conc at 2sites, but decr or wasND at 8 sites.Decrease to ND 8 daysafter spraying ceased3-4 consecutive spray events occurringevery 2nddayLarry Walker Assoc.2006SYVCD reportPBO Pyrenone25-5Sediment within 12hrs of the5thand11thsprayeventsNo evidence foraccumulation. In 2 outof 6 treated tanks afterthe 5thand 11thspray:PBO ND to 14.911thspray: PBO ND to2.55Sediment in 2 out of 6 treated tanksafter 5th& 11thspray eventsaPBOwas detected less frequently as thenumber of biweekly sprays increasedLawler et al. 2008PBO Pyrenone Water + 12 h Under RL 1 wk after 8th8 spray events Amweg et al. 20062 |Page25-5 sediment 1 wkspray eventSampled 1 wk after last treatmentbNotes:aLawler et al. (2008)found no accumulation of pyrethrins or PBO in sediment after multiple spray events by truck mounted equipment.Pyrethrinswere not detectable in sediment in 4 of 6treated tanks after 5 and 11 biweekly spray events.After 5 sprays, pyrethrins were present in 2 ofthe 6 treated tanks, at 23.1 and 33.1 ppb, respectively.After 11 sprays, pyrethrins were detectedat 4.03 and 34.05 ppb in 2 of 6 treated tanks.Concentrations of pyrethrins in sediment were not higher after the 11thspray event than after the 5thone, and in some cases were actually lower afterthe 11thevent.PBOwas detected less frequently as the number of biweekly spraysincreased. Five of six tanks had detectable PBO after 5 sprays,but only 2 of 6tanks were found to have PBO after 11 biweekly spray events.Concentrations of PBO were lower after the 11thevent than after only 5 events.After the 11thspray, four of 6 tanks had no detectable PBO.PBO-synergized pyrethrin had no detectable effect on the survival of Daphnia or mayflylarvae held in tanks in the spray area,even after 11 biweeklyspray eventsbAmweg et al. (2006)reported that levels of Pyrethrins and PBO in water or sediment were below reporting limits when sampled 1 week after thelast of 8 weekly spray events.ReferencesAmweg, EL, DP Weston, CS Johnson, J You and MJ Lydy. 2006. Effect ofpiperonyl butoxide on permethrin toxicity in the amphipodHyalellaazteca. Environmental Toxicologyand Chemistry 25 (7):1817-1825Larry Walker and Associates 2006. SYMVCD Pyrethrin Water Quality Monitoring Data Summary. Larry Walker and Associates.Lawler, S.P., D.A. Dritz, C.S. Johnson, and M. Wolder. 2008. Does synergized pyrethrin applied overwetlands for mosquito control affectDaphniamagnazooplankton orCallibaetis californicusmayflies?Pest Manag Sci64: 843-847.