title: Assessment of nonoccupational exposure to DDT in the tropics and the north: relevance of uptake via inhalation from indoor residual spraying.
abstract: BACKGROUND
  People who live in dwellings treated with indoor residual spraying (IRS) of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] for disease-vector control in the tropics and indigenous populations in the Arctic who consume marine mammals experience high nonoccupational exposure to DDT. Although the use of DDT in IRS is rising, the resulting nonoccupational exposure is poorly characterized.
  
  
  OBJECTIVE
  We have provided a comparative assessment of exposure to DDT and its metabolites in the general population of the tropical and northern regions and in highly exposed populations in these regions.
  
  
  METHODS
  We compiled > 600 average or median DDT concentrations from the peer-reviewed literature, representing > 23,000 individual measurements in humans, food, air, soil, and dust. We use Monte Carlo sampling of distributions based on these data to estimate distributions of population- and route-specific uptake. We evaluate our exposure estimates by comparing them with biomonitoring data.
  
  
  RESULTS
  DDT concentrations are highest in people living in IRS-treated houses and lowest in the northern general population, differing by a factor of about 60. Inuits and the general population in the tropics have similar concentrations. Inhalation exposure explains most of the difference in concentration between the highly exposed and the general population in the Tropics. Calculated exposure levels are consistent with human biomonitoring data.
  
  
  CONCLUSIONS
  Nonoccupational inhalation exposure is a relevant exposure pathway for people living in homes treated by IRS of DDT. Continued monitoring of time trends and DDE to DDT ratios in the Tropics and in the North is needed to identify a possible slowdown in concentration decline and the influence of ongoing DDT use.
authors.affiliation: Safety and Environmental Technology Group, ETH Zurich, Zurich, Switzerland.
authors.forename: Roland
authors.initials: R
authors.lastname: Ritter
authors.forename: Martin
authors.initials: M
authors.lastname: Scheringer
authors.forename: Matthew
authors.initials: M
authors.lastname: MacLeod
authors.forename: Konrad
authors.initials: K
authors.lastname: Hungerbühler
mesh_terms: D003634:DDT / Q000633:toxicity*; D004784:Environmental Monitoring; D006801:Humans; D019570:Inhalation Exposure / Q000009:adverse effects; D010573:Pesticide Residues / Q000633:toxicity
chemical_list: D010573:Pesticide Residues; D003634:DDT