title: Determinants of manganese levels in house dust samples from the CHAMACOS cohort.
abstract: BACKGROUND
  Manganese (Mn) is an essential nutrient, but at high exposure levels Mn is a neurotoxicant. The fungicides maneb and mancozeb are approximately 21% Mn by weight and more than 150,000 kg are applied each year to crops in the Salinas Valley, California. It is not clear, however, whether agricultural use of these fungicides increases Mn levels in homes.
  
  
  METHODS
  We collected house dust samples from 378 residences enrolled in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study with a second sample collected approximately nine months later from 90 of the residences. House dust samples were analyzed for Mn using inductively coupled plasma optical emission spectroscopy. Information from interviews, home inspections, and pesticide use reports was used to identify potential predictors of Mn dust concentrations and loadings.
  
  
  RESULTS
  Mn was detectable in all dust samples. The median Mn concentration was 171 μg/g and median Mn loading was 1,910 μg/m(2) at first visit. In multivariable models, Mn dust concentrations and loadings increased with the number of farmworkers in the home and the amount of agricultural Mn fungicides applied within three kilometers of the residence during the month prior to dust sample collection. Dust concentrations of Mn and other metals (lead, cadmium and chromium) were higher in residences located in the southern Salinas Valley compared those located in other areas of the Salinas Valley. Dust loadings of Mn and other metals were also higher in residences located on Antioch Loam soil than other soil types, and in homes with poor or average housekeeping practices.
  
  
  CONCLUSIONS
  Agricultural use of Mn containing fungicides was associated with Mn dust concentrations and loadings in nearby residences and farmworker homes. Housekeeping practices and soil type at residence were also important factors related to dust metal concentrations and loadings.
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, Berkeley, CA, USA. Electronic address: gunier@berkeley.edu.
authors.forename: R B
authors.initials: RB
authors.lastname: Gunier
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, Berkeley, CA, USA.
authors.forename: M
authors.initials: M
authors.lastname: Jerrett
authors.affiliation: Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA, USA.
authors.forename: D R
authors.initials: DR
authors.lastname: Smith
authors.affiliation: Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA, USA.
authors.forename: T
authors.initials: T
authors.lastname: Jursa
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, Berkeley, CA, USA.
authors.forename: P
authors.initials: P
authors.lastname: Yousefi
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, Berkeley, CA, USA.
authors.forename: J
authors.initials: J
authors.lastname: Camacho
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, Berkeley, CA, USA.
authors.forename: A
authors.initials: A
authors.lastname: Hubbard
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, Berkeley, CA, USA.
authors.forename: B
authors.initials: B
authors.lastname: Eskenazi
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, Berkeley, CA, USA.
authors.forename: A
authors.initials: A
authors.lastname: Bradman
mesh_terms: D016902:Air Pollution, Indoor / Q000032:analysis*; D002140:California; D004391:Dust / Q000032:analysis*; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D006801:Humans; D008345:Manganese / Q000032:analysis*
chemical_list: D004391:Dust; D008345:Manganese
keywords: GIS; exposure science; house dust; manganese; metals; pesticides