Abstracts: ISEE 21st Annual Conference, Dublin, Ireland, August 25-29, 2009: Poster Presentations
Background and Objective:
High levels of particulate matter (PM) were previously found in northern Cali. The area limits with an industrial zone with main emissions coming from metals smelting and batteries production factories. As part of the exposure assessment in a prevalence study of respiratory symptoms in children, we determined outdoors levels of PM2.5 and heavy metals in a school located 2.5 km down-wind of the industrial zone.
Twenty-four hours samples of PM2.5 were collected from January-March 2009 with a low-volume sampler on Teflon filters. Samples were gravimetrically analyzed for mass concentration and via EDXRF to determine presence and mass concentration of heavy metals (Cu, Cr, As, Cd, Pb). Pair wise correlation coefficients were estimated for PM2.5 and metals, and also between all metals. Additionally, linear regression analysis was performed for PM2.5 and Pb.
Mean concentration of PM2.5 was 43.38 ug/m3. Among all samples 73% were found with Cr at a mean concentration of 0.005 ug/m3; 31% with As at 0,010 ug/m3; 82% with Cd at 0,057 ug/m3; 71% with Cu at 0,024 ug/m3; and 100% with Pb at 0.814 ug/m3. We only found a significant correlation between Pb and As levels (r = 0.90, P < 0.001). Regression analysis demonstrated a statistically significant association between Pb and PM2.5 (P = 0.05) although it only explained 8% of the PM variation.
Although levels of PM2.5 did not exceed daily limits, there was a trend to exceed annual limits. Heavy metals concentrations, mainly Pb, represent a threat for human health, and the correlation observed between Pb and as suggests that main potential sources are local factories. Based on these results, we will conduct indoor and personal exposure assessments and blood-lead testing in these school children.