title: Arsenic exposure in drinking water: an unrecognized health threat in Peru.
abstract: OBJECTIVE
  To assess the extent of arsenic contamination of groundwater and surface water in Peru and, to evaluate the accuracy of the Arsenic Econo-Quick(™) (EQ) kit for measuring water arsenic concentrations in the field.
  
  
  METHODS
  Water samples were collected from 151 water sources in 12 districts of Peru, and arsenic concentrations were measured in the laboratory using inductively-coupled plasma mass spectrometry. The EQ field kit was validated by comparing a subset of 139 water samples analysed by laboratory measurements and the EQ kit.
  
  
  RESULTS
  In 86% (96/111) of the groundwater samples, arsenic exceeded the 10 µg/l arsenic concentration guideline given by the World Health Organization (WHO) for drinking water. In 56% (62/111) of the samples, it exceeded the Bangladeshi threshold of 50 µg/l; the mean concentration being 54.5 µg/l (range: 0.1-93.1). In the Juliaca and Caracoto districts, in 96% (27/28) of groundwater samples arsenic was above the WHO guideline; and in water samples collected from the section of the Rímac river running through Lima, all had arsenic concentrations exceeding the WHO limit. When validated against laboratory values, the EQ kit correctly identified arsenic contamination relative to the guideline in 95% (106/111) of groundwater and in 68% (19/28) of surface water samples.
  
  
  CONCLUSIONS
  In several districts of Peru, drinking water shows widespread arsenic contamination, exceeding the WHO arsenic guideline. This poses a public health threat requiring further investigation and action. For groundwater samples, the EQ kit performed well relative to the WHO arsenic limit and therefore could provide a vital tool for water arsenic surveillance.
authors.affiliation: Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe Street (E5535), Baltimore, MD 21205, United States of America (USA).
authors.forename: Christine Marie
authors.initials: CM
authors.lastname: George
authors.affiliation: Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA .
authors.forename: Laura
authors.initials: L
authors.lastname: Sima
authors.affiliation: Department of Microbiology, Universidad Peruana Cayetano Heredia, Lima, Peru .
authors.forename: M Helena Jahuira
authors.initials: MH
authors.lastname: Arias
authors.affiliation: Department of Plant and Soil Sciences, University of Delaware, Newark, USA .
authors.forename: Jana
authors.initials: J
authors.lastname: Mihalic
authors.affiliation: PRISMA, Lima, Peru .
authors.forename: Lilia Z
authors.initials: LZ
authors.lastname: Cabrera
authors.affiliation: PRISMA, Lima, Peru .
authors.forename: David
authors.initials: D
authors.lastname: Danz
authors.affiliation: Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe Street (E5535), Baltimore, MD 21205, United States of America (USA).
authors.forename: William
authors.initials: W
authors.lastname: Checkley
authors.affiliation: Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe Street (E5535), Baltimore, MD 21205, United States of America (USA).
authors.forename: Robert H
authors.initials: RH
authors.lastname: Gilman
mesh_terms: D001151:Arsenic / Q000032:analysis*; D060766:Drinking Water; D004784:Environmental Monitoring / Q000295:instrumentation*; D010568:Peru; D013054:Spectrophotometry, Atomic; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D060766:Drinking Water; D014874:Water Pollutants, Chemical; D001151:Arsenic