title: Exposure to Inhalable Dust, Endotoxin, and Total Volatile Organic Carbons on Dairy Farms Using Manual and Automated Feeding Systems.
abstract: BACKGROUND
  Agricultural workers tend to have high exposures to organic dusts which may induce or exacerbate respiratory disorders. Studies investigating the effect of work tasks and farm characteristics on organic dust exposures among farm workers suggest that handling of animal feed is an important exposure determinant; however, the effect of the animal feeding system has not been explored in any detail.
  
  
  OBJECTIVE
  To measure the exposure of Irish dairy farmers to inhalable dust, endotoxin, and total volatile organic compounds (TVOCs) during parlour work and to explore whether levels of exposure to these agents depend on the applied feeding system in the farms.
  
  
  METHODS
  Thirty-eight personal exposure measurements were collected from farmers across seven dairy farms. The farms used manual, loft, or semi-automated feeding systems. Information on worker tasks and farm characteristics was collected during the surveys. Associations between exposure concentrations and feeding systems, worker tasks, and other farm characteristics were explored in linear mixed-effect regression models with farmer identity treated as a random effect.
  
  
  RESULTS
  Exposure concentrations were variable and had a geometric mean (GM; geometric standard deviation) of 1.5 mg m-3 (1.8) for inhalable dust and 128 EU m-3 (2.5) for endotoxin. More than 50% of the exposure measurements for endotoxin, and organic dust exceeded recommended health-based occupational exposure limits. Endotoxin levels were somewhat lower in farms using semi-automatic feeding systems when compared to those using manual feeding systems but in multivariate regression analysis associations were not statistically significant (β = -0.54, P = 0.4). Performance of activities related to handling and spreading of hay or straw was the strongest determinant for both inhalable dust and endotoxin exposure (β = 0.78, P ≤ 0.001; β = 0.72, P = 0.02, respectively). The level of dust exposure increased also as a consequence of a lower outdoor temperature, and higher ratio of distributed feed per cow (P = 0.01). Stationary measurements of TVOC and CO2 concentrations inside the dairy parlours had a GM of 180 ppb (1.9) and 589 ppb (1.3), respectively. The use of cow teat disinfectants and building ventilation were both strong predictors of TVOC concentrations within parlours.
  
  
  CONCLUSIONS
  Dairy farm workers can be exposed to high and variable levels of inhalable dust and endotoxin and may be at risk of respiratory disease. Results from this study suggest that exposure control strategies for organic dusts and TVOCs exposures should consider building ventilation and work tasks such as spreading of bedding material, using spray disinfectants and animal feeding. Until effective permanent engineering controls are established farm workers should be encouraged to wear respiratory protective equipment during these tasks.
authors.affiliation: Centre for Human Exposure Science, Institute of Occupational medicine, Research Avenue North, Edinburgh EH14 4AP, UK.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Basinas
authors.affiliation: School of Physics, National University of Ireland, Univeristy Road, Galway H91TK33, Ireland.
authors.forename: Garvin
authors.initials: G
authors.lastname: Cronin
authors.affiliation: School of Health Sciences, National University of Ireland, Univeristy Road, Galway H91TK33, Ireland.
authors.forename: Victoria
authors.initials: V
authors.lastname: Hogan
authors.affiliation: Department of Public Health, Section for Environment, Occupation and Health, Danish Ramazzini Center, Aarhus University, Bartholins Allé 2, bg 1260, Aarhus C 8000, Denmark.
authors.forename: Torben
authors.initials: T
authors.lastname: Sigsgaard
authors.affiliation: Royal College of Surgeons Ireland Hospital Group, Cavan & Monaghan Hospitals, Cavan, Ireland.
authors.forename: James
authors.initials: J
authors.lastname: Hayes
authors.affiliation: School of Physics, National University of Ireland, Univeristy Road, Galway H91TK33, Ireland.
authors.forename: Ann Marie
authors.initials: AM
authors.lastname: Coggins
mesh_terms: D000336:Aerosols / Q000633:toxicity; D000395:Air Pollutants, Occupational / Q000032:analysis*; D000821:Animal Feed / Q000032:analysis; D000822:Animal Husbandry / Q000379:methods*; D000818:Animals; D002245:Carbon Dioxide / Q000032:analysis; D002417:Cattle; D003612:Dairying; D004391:Dust / Q000032:analysis*; D004731:Endotoxins / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods; D000072480:Farms; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis*; D007494:Ireland; D016273:Occupational Exposure / Q000032:analysis*; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D000336:Aerosols; D000395:Air Pollutants, Occupational; D004391:Dust; D004731:Endotoxins; D055549:Volatile Organic Compounds; D002245:Carbon Dioxide
keywords: TVOCs; animal farmer; animal feeding systems; bio-aerosols; cow farmers; organic dust