T93 A Healthy Society, Geosciences, and Natural Resources I

Monday, 10 October 2011
8:00 AM - 12:00 PM
Room M100BC

ASSESSING THE ROLE OF HOUSING AGE IN ENVIRONMENTAL LEAD LEVELS AND CHILDREN'S LEAD EXPOSURE IN NORTH AMERICA'S OLDEST CITY

Paper number: T93-10
Program: Technical Sessions
Time: 10:15 AM – 10:30 AM

Authors

Abstract

During the summer and fall of 2010, more than 250 households in St. John’s, Newfoundland and Labrador, Canada, took part in a biomonitoring survey to determine whether children living in older housing have an increased exposure to lead in the residential environment. The study measured children’s blood lead levels and lead in soil, indoor dust, indoor and outdoor paint, tap water and garden produce on residential properties. Recruitment of participants from across a selected series of housing age cohorts enabled comparisons of a target population living in older (pre-1970) housing to a reference population living in younger (post-1980) housing, as well as more refined comparisons of children’s lead exposure. The measured blood lead levels (BLLs) ranged from 0.21 to 7.5 µg/dL with mean, median and 95th percentile values of 1.12, 1.04 and 2.71 µg/dL, respectively. None of the study participants had BLLs higher than the widely used threshold of concern, 10 μg/dL. These results are reassuring because the blood lead levels are generally low and they compare very favorably to other jurisdictions. Our results also demonstrate that housing age is a statistically significant predictor of mean BLLs in young children in St. John’s and that children living in houses older than 1970 have a predictably elevated BLL compared to the reference population.

With the exception of flushed tap water, the average lead content of sampled environmental media was significantly different in our pre-1970 target housing group compared to the reference group. Analysis revealed significant correlations between participant’s BLLs and lead concentrations in indoor dust, irrespective of source, flushed tapwater, and residential soil, specifically from play areas. There was no correlation between BLLs and lead levels in paint chipping from indoor or outdoor surfaces and dripline or garden soils. Preliminary results suggest that lead isotope ratios may be able to discriminate between environmental media in residential housing in St. John’s and hence may determine the source of lead in blood of any child who ingests/inhales these media. From a public health perspective, St. John’s residents should remain concerned about the potential exposure of children to lead that might occur in older homes from dust, paint, renovations and tracking of soil inside.