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EPA recently published three new guidance documents on lead that have a direct impact on lead risk assessments and cleanup goals. The documents include:
- “Update to the Adult Lead Methodology’s Default Baseline Blood Lead Concentration and Geometric Standard Deviation Parameters”
- “Recommendations for Assessing Short-Term Exposure Scenarios Involving Lead at Superfund Sites”
- “Recommendations for Using Blood Lead Data at Superfund and RCRA Corrective Action Sites”
In the first document, EPA updated two inputs to the Adult Lead Model, which increased the default cleanup goal for lead in soil from 2,240 to 2,737 mg/kg for an adult industrial scenario. This change arose from recent national evaluations of blood lead levels that showed that adult blood lead levels have continued to decrease over time. EPA also decreased the maternal blood lead level used in its blood lead model for children (the IEUBK model); however, this change will not have a material impact on soil cleanup levels for residential soil. Surprisingly, EPA did not yet decrease the target blood lead level to coincide with CDC’s reference level of 5 µg/dL used to identify children and women of child-bearing age with elevated blood lead levels.
In the second document, EPA discussed the assessment of short-term and intermittent exposures to lead, with a heightened focus on short-term increases in blood lead level that are averaged out using EPA’s traditional blood lead models. EPA prescribed the minimum exposure frequency and duration that can be used in the Adult Lead and IEUBK models, and noted that for exposures outside these guidelines, an alternative blood lead model such as the Leggett (or ICRP) model can be used. Though their use is not currently widespread, Gradient has extensive expertise with such alternative blood lead models.
In the third document, EPA distinguished between blood lead data collected by a state or local health department vs. blood lead data collected from a site-specific study. EPA noted that such data should not be used to make adjustments to parameters in the child blood lead model.
See the updated guidance.
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