EPA: Bacillus subtilis Strain QST 713 (006479) BRAD - REBECA

EPA: Bacillus subtilis Strain QST 713 (006479) BRAD885.4200 44884801 FreshwaterFish Toxicity/Pathogenicity885.4240 446519B12 48-HourFreshwaterAquaticInvertebrateToxicity/PathogenicityGiven the plate count patterns observed, it isprobable that the actual concentrations troutwere exposed to were not more than 12orders of magnitude lower than the nominalconcentrations. An approximate LC 50 usingthe binomial method was 2.62 x 10 8 CFU/L(13.1 mg/L) with 95% confidence limits of1.12 x 10 8 CFU/L (5.6 mg/L) and 4.2 x 10 8CFU/L (21 mg/L). A precise LC 50 could not bedetermined because there were less than 2concentrations at which the percent deadwere between 0 and 100. The NOEC was1.12 x 10 8 CFU/L (5.6 mg/L). Since onlynecropsy of randomly chosen surviving troutoccurred at study termination, we can not atthis time conclude that only toxicity wasinvolved in the mortality observed sincepathogenicity was not ruled out byappropriate analysis. CLASSIFICATION:Acceptable with required confirmatory data.Data considered confirmatory becauseBacillus subtilis is very well studied and noevidence of fish toxicity or pathogenicity wasfound in published literature. In addition,exposure to aquatic organisms are minimal tonon-existent ( no aquatic use sites andapplication methods are restricted to groundsprays).An estimated environmental concentration(EEC) was calculated to be 2.5 x 10 4 CFU/L.The acute aquatic risk quotient wascalculated to be 0.00083, well below the levelof concern.The study is considered Acceptable, althougha confirmatory study is required to determinethe pathogenicity using attenuated and filtersterilized controls. Data consideredconfirmatory because Bacillus subtilis is verywell studied and no evidence of aquaticinvertebrate toxicity or pathogenicity wasfound in published literature. In addition,exposure to aquatic organisms are minimal tonon-existent ( no aquatic use sites andapplication methods are restricted to groundsprays)file:///J|/REBECA/Meetings/1.%20Conference/REBECA%...up%20work%20bacteria%20fungi/epaprintonly.cgi.html (12 von 29)13.09.2006 18:40:13