title: Characterization of endotoxin collected on California dairies using personal and area-based sampling methods.
abstract: Endotoxin, found in the cell wall of gram negative bacteria, is an important contributor to the biological activity of agriculture particulate matter (PM). We analyzed endotoxin in PM collected on 13 California dairies and from the breathing zone of 226 workers during the summer months of 2008. Two particle size fractions were measured: PM(2.5) and inhalable PM. Recombinant factor C assays were used to analyze biologically active endotoxin, while gas chromatography coupled with mass spectrometry in tandem was used to quantify total lipopolysaccharide. Biologically active endotoxin concentrations in the inhalable PM size fraction from area-based samples ranged from 11-2095 EU/m(3) and from 45-2061 EU/m(3) for personal samples. Total endotoxin in the inhalable PM size fraction ranged from 75-10,166 pmol/m(3) for area-based samples and 34-11,689 pmol/m(3) for personal samples. Area-based geometric mean concentrations for biologically active endotoxin and total endotoxin in PM(2.5) and inhalable PM size fractions were 3 EU/m(3), 149 EU/m(3), 60 pmol/m(3), and 515 pmol/m(3), respectively. Personal geometric mean concentrations in the inhalable PM size fraction were 334 EU/m(3), and 1178 pmol/m(3). Biologically active and total endotoxin concentration variation was best explained by meteorological data, wind speed, relative humidity, and dairy waste management practices. Differences in endotoxin concentration and composition were found across locations on the dairy.
authors.affiliation: Department of Public Health Sciences and Center for Health and the Environment, University of California Davis, Davis, CA, USA.
authors.forename: John
authors.initials: J
authors.lastname: Garcia
authors.forename: Deborah H
authors.initials: DH
authors.lastname: Bennett
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Tancredi
authors.forename: Marc B
authors.initials: MB
authors.lastname: Schenker
authors.forename: Diane C
authors.initials: DC
authors.lastname: Mitchell
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Reynolds
authors.forename: Rona
authors.initials: R
authors.lastname: Silva
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Dooley
authors.forename: John
authors.initials: J
authors.lastname: Mehaffy
authors.forename: Frank M
authors.initials: FM
authors.lastname: Mitloehner
mesh_terms: D000395:Air Pollutants, Occupational / Q000032:analysis* / Q000737:chemistry; D002140:California; D003612:Dairying; D004731:Endotoxins / Q000032:analysis* / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008070:Lipopolysaccharides / Q000032:analysis / Q000737:chemistry; D016273:Occupational Exposure / Q000032:analysis* / Q000706:statistics & numerical data; D052638:Particulate Matter / Q000032:analysis* / Q000737:chemistry; D012044:Regression Analysis; D053719:Tandem Mass Spectrometry
chemical_list: D000395:Air Pollutants, Occupational; D004731:Endotoxins; D008070:Lipopolysaccharides; D052638:Particulate Matter