Relationship Between Total and Bioaccessible Lead on Children’s Blood Lead Levels in Urban Residential Philadelphia Soils

Abstract

Relationships between total soil or bioaccessible lead (Pb), measured using an in vitro bioaccessibility assay, and children’s blood lead levels (BLL) were investigated in an urban neighborhood in Philadelphia, Pennsylvania, USA, with a history of soil Pb contamination. Soil samples from 38 homes were analyzed to determine whether accounting for the bioaccessible Pb fraction improves statistical relationships with children’s BLLs. Total soil Pb ranged from 58 to 2,821 mg/kg; the bioaccessible Pb fraction ranged from 47 to 2,567 mg/kg. Children’s BLLs ranged from 0.3 to 9.8 μg/dL. Hierarchical models were used to compare relationships between total or bioaccessible Pb in soil and children’s BLLs. Total soil Pb as the predictor accounted for 25% of the variability in child BLL; bioaccessible soil Pb as the predictor accounted for 28% of BLL variability. A bootstrapping analysis confirmed a significant increase in R2 for the model using bioaccessible soil Pb as the predictor with 99.3% of bootstraps showing a positive increase. Estimated increases of 1.4 μg/dL and 1.6 μg/dL in BLL per 1,000 mg/kg Pb in soil were observed for this study area using total and bioaccessible Pb, respectively. Children’s age did not contribute significantly to the prediction of BLLs.

Geologic and anthropogenic sources of contamination in settled dust of a historic mining port city in northern Chile: health risk implications

“…Fine and ultrafine particles (smaller than 2.5 μm in diameter; ≤PM 2.5 ) present a health risk due to their entrance into the bloodstream from lung alveoli, whereas larger particles (>PM 2.5 ) are momentarily retained in the bronchi and bronchiole and are then expelled from the cilia of epithelial cells in the respiratory tract. Subsequently, these particles are swallowed, and once in the stomach, gastric hydrochloric acid at pH 2.0 partially solubilize components which constitute the bioaccessible fraction of the dust used to estimate the amount available for absorption across the gastrointestinal barrier ( Bradham et al, 2017 ). Therefore, a higher bioaccessibility of a contaminant element signifies that a larger fraction will enter the human bloodstream.…”

Smelting Remains a Public Health Risk Nearly a Century Later: A Case Study in Pueblo, Colorado, USA

“…However, the Chi-Square test showed no association between soil lead levels and the age of children in this study ( p = 0.253). Bradham and co-workers also found no significant correlation between age of children and BLLs [ 51 ].…”

Environment and Human Health: The Challenge of Uncertainty in Risk Assessment

“…Nevertheless, residual contamination in the wider urban environment might still be an issue [34,35], particularly to the poorer member of a society, including migrant groups, who are over represented in the less developed and more deprived parts of the urban landscape [36,37]. Environmental conditions: Pb is still used in many industries, including construction, mining and manufacturing, particularly in lower income countries [38].…”

“…Chronic, low-level exposure continues to be a risk, particularly in rapidly industrialising situations [45,46]. Children living on lead-contaminated land show evidence of exposure to Pb [35,[47][48][49] while urban allotment contamination remains an important issue [50].…”