1. Restoration/Remediation of Urban Soils
2nd Urban Soils Symposium
Bronx Botanical Gardens
November 29th, 2017
Dr. Mark A. Maddaloni
Toxicologist
EPA

4. CDC 2012 - Scientific Rationale for Eliminating the 10 ug/dL Blood Lead Level of Concern
Replaced with a “Reference Value” i.e., the 97.5% of NHANES distribution childhood BLLs presently 5 ug/dl (and to be updated every 4 years)
(2017) CDC Advisory Panel recommends lowering RV to 3.5 ug/dl
Recent studies reporting decrements in school age IQ among children whose peak BLLs had never exceeded 10 ug/dL
Builds upon risk assessments carried out by other regulatory and policy bodies (e.g., EPA’s Pb NAAQS review)
Collectively, these new studies and re‐interpretation of past studies have demonstrated that it is not possible to determine a threshold below which BLL is not inversely related to IQ.

5. Soil Lead PRG based on no greater than a 5% probability of exceeding
Exposure Scenario
5 µg/dL PbB
10 µg/dL PbB
Residential Sites
- Current Model Defaults
- Proposed Updated Defaults
153 ppm
173 ppm
418 ppm
525 ppm
Updates to ALM include Maternal PbB and GSD based on NHANES
For IRsd the preliminary value of 62 mg/day was used as a constant value for all ages– not likely to be appropriate— exploratory only
If central value is used for RBA (30%) P10 PRG=702 ppm and P% PRG = 233 ppm.
Smith et al., 2011 (Denver Urban Soil Study) reports soil lead concentration in US and Canada soils as 19.2 ppm (median) with a range of ppm.

6. IEUBK Model Output
Geometric mean PbB and probability of exceeding 10 µg/dL

7. “Get the Lead Out” Block Party
EPA and NYSDOH began promoting the Soil Kitchen and gave demonstrations of how samples are screened with an XRF