| Seasonality and Children's Blood Lead Levels: Developing a Predictive Model Using Climatic Variables and Blood Lead Data from Indianapolis, Indiana, Syracuse, New York, and New Orleans, Louisiana (USA) Mark A.S. Laidlaw,1 Howard W. Mielke,2 Gabriel M. Filippelli,1 David L. Johnson,3 and Christopher R. Gonzales2 1School of Population Health, University of Western Australia, Crawley, Western Australia; 2Department of Basic Pharmaceutical Sciences, College of Pharmacy, Xavier University of Louisiana, New Orleans, Louisiana, USA; 3Department of Chemistry, State University of New York, College of Environmental Science and Forestry, Syracuse, New York, USA Abstract
On a community basis, urban soil contains a potentially large reservoir of accumulated lead. This study was undertaken to explore the temporal relationship between pediatric blood lead (BPb) , weather, soil moisture, and dust in Indianapolis, Indiana ; Syracuse, New York ; and New Orleans, Louisiana. The Indianapolis, Syracuse, and New Orleans pediatric BPb data were obtained from databases of 15,969, 14,467, and 2,295 screenings, respectively, collected between December 1999 and November 2002, January 1994 and March 1998, and January 1998 and May 2003, respectively. These average monthly child BPb levels were regressed against several independent variables: average monthly soil moisture, particulate matter < 10 µm in diameter (PM10) , wind speed, and temperature. Of temporal variation in urban children's BPb, 87% in Indianapolis (R2 = 0.87, p = 0.0004) , 61% in Syracuse (R2 = 0.61, p = 0.0012) , and 59% in New Orleans (R2 = 0.59, p = 0.0000078) are explained by these variables. A conceptual model of urban Pb poisoning is suggested: When temperature is high and evapotranspiration maximized, soil moisture decreases and soil dust is deposited. Under these combined weather conditions, Pb-enriched PM10 dust disperses in the urban environment and causes elevated Pb dust loading. Thus, seasonal variation of children's Pb exposure is probably caused by inhalation and ingestion of Pb brought about by the effect of weather on soils and the resulting fluctuation in Pb loading. Key words: climate, lead dust, lead exposure seasonality, modeling, PM10, soil lead, soil moisture. Environ Health Perspect 113:793-800 (2005) . doi:10.1289/ehp.7759 available via http://dx.doi.org/ [Online 24 February 2005]
Address correspondence to M.A.S. Laidlaw, School of Population Health, M431, 35 Stirling Hwy, University of Western Australia, Crawley, Western Australia 6009. Telephone: 6488-1260. Fax: 6488-1188. E-mail: mlaidlaw@alumni.indiana.edu T. Griffin of the Louisiana Childhood Lead Poisoning Prevention Program, Office of Public Health, supplied the New Orleans blood lead data set ; the Marion County Health Department made available the Marion County (Indianapolis) blood lead data ; and the Onondaga County Health Department provided the child blood lead database for Syracuse. D. Bivin suggested the use of monthly dummy variables to increase modeling significance, and Y. Fan of the National Oceanic and Atmospheric Administration provided soil moisture data. The authors declare they have no competing financial interests. Received 15 November 2004 ; accepted 24 February 2005.
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