title: Metal exposure in schoolchildren and working children. A urinary biomonitoring study from Lahore, Pakistan.
abstract: In order to document the exposure to trace metals among urban schoolchildren and rural working children, we measured the urinary concentrations of metals in schoolchildren from two areas of differing traffic intensity in Lahore, and in children working in carpet weaving or the brick industry outside Lahore. In a cross-sectional design, we recruited a convenience sample of 339 children aged 8-12 years (mean age 9.9 y, SD 1.4; 47% girls) from two elementary schools in Lahore - one situated in a high air pollution area (n=100) and one situated in an area with lower air pollution (n=79) - and from the carpet weaving industry (n=80) and brick industry (n=80). A spot urine sample was collected and concentrations of 20 metals and metalloids were measured by inductively coupled plasma-mass spectrometry (ICP-MS). Samples of drinking water were similarly analyzed. In general, the urinary concentrations of several toxic metals (including Cr, Mn, As, Mo, Cd, Pb, U) were higher than international reference values. Concentrations of As were especially elevated in children working in the brick making industry [geometric mean (GM) 118 μg/L], but they were also high among urban schoolchildren (GM 68 μg/L and 56 μg/L). Lead (Pb) was higher in urine from schoolchildren in the high air pollution area (GM 11 μg/L) than in those from the lower pollution area (GM 5.3 μg/L). Uranium (U) was high in both carpet weavers (GM 0.28 μg/L) and brick kiln workers (GM 0.45 μg/L). Concentrations of As, Pb, and U in drinking water corresponded well with urinary concentrations of metals. This descriptive study provides evidence for a high exposure to several toxic metals in this area of Pakistan. The concentrations of urinary As are in the order of those found in other regions of the world with high environmental exposure to As. The sources and pathways of exposure and the health significance of these findings need to be further investigated.
authors.affiliation: Centre for Environment and Health, Department of Public Health and Primary Care, KU Leuven, Belgium; Centre of Research for Public Health, Lahore, Pakistan; Lahore College of Pharmaceutical Sciences, Lahore, Pakistan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Sughis
authors.affiliation: Centre for Environment and Health, Department of Public Health and Primary Care, KU Leuven, Belgium; Centre for Environmental Sciences, Hasselt University, Belgium.
authors.forename: Tim S
authors.initials: TS
authors.lastname: Nawrot
authors.affiliation: Centre of Research for Public Health, Lahore, Pakistan.
authors.forename: Amir
authors.initials: A
authors.lastname: Riaz
authors.affiliation: Centre of Research for Public Health, Lahore, Pakistan.
authors.forename: Umair
authors.initials: U
authors.lastname: Ikram-Dar
authors.affiliation: Centre for the Improvement of Working Conditions & Environment, Lahore, Pakistan.
authors.forename: Arshad
authors.initials: A
authors.lastname: Mahmood
authors.affiliation: Louvain Centre for Toxicology and Applied Pharmacology, Université catholique de Louvain, Belgium.
authors.forename: Vincent
authors.initials: V
authors.lastname: Haufroid
authors.affiliation: Centre for Environment and Health, Department of Public Health and Primary Care, KU Leuven, Belgium. Electronic address: ben.nemery@med.kuleuven.be.
authors.forename: Benoit
authors.initials: B
authors.lastname: Nemery
mesh_terms: D000397:Air Pollution; D002648:Child; D003430:Cross-Sectional Studies; D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring; D005260:Female; D000075322:Heavy Metal Poisoning; D006801:Humans; D008297:Male; D066192:Manufacturing Industry; D019216:Metals, Heavy / Q000652:urine*; D016273:Occupational Exposure / Q000032:analysis*; D010154:Pakistan; D011041:Poisoning / Q000652:urine*; D012574:Schools
chemical_list: D019216:Metals, Heavy
keywords: Arsenic; Artisanal brick kilns; Biomonitoring; Carpet weaving; Children; Metals exposure