What Is The Most Effective Method To Account For The Variability In Dermal Absorption Rates Of A Mixture Of Polycyclic Aromatic Hydrocarbons (PAHs) In Soil, Considering The Impact Of Soil Composition, Moisture Content, And Temperature, When Conducting A Risk Assessment For A Residential Community Living Near A Former Industrial Site With Documented Soil Contamination?

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To account for variability in dermal absorption rates of PAHs in soil during a risk assessment, a comprehensive approach should be employed, considering key environmental factors and their impact. Here's a structured strategy:

  1. Site-Specific Data Collection:

    • Soil Sampling: Collect samples from various locations and depths to measure PAH concentrations, soil composition (sandy, clayey, loamy), organic matter content, moisture levels, and temperature.

  2. Environmental Modeling:

    • Use models to predict how moisture and temperature may vary over time due to weather and seasonal changes, enhancing the understanding of dynamic conditions.

  3. Dermal Absorption Models:

    • Apply existing models (e.g., US EPA models) adjusted with site-specific data to estimate absorption rates, considering factors like soil composition and moisture.

  4. Probabilistic Modeling:

    • Utilize distributions for variables (soil composition, moisture, temperature) to assess a range of absorption rates, providing a more accurate risk quantification.

  5. Sensitivity Analysis:

    • Identify the most influential factors affecting absorption, such as soil composition, to prioritize data collection and analysis efforts.

  6. Monitoring and Data Refinement:

    • Conduct long-term monitoring to gather real-world data on PAH levels, moisture, and temperature, refining absorption models over time.

  7. Exposure Scenarios:

    • Consider different exposure levels, especially for vulnerable groups like children, to assess varying risks based on skin contact scenarios.

  8. Expert Consultation and Literature Review:

    • Engage with experts and review existing studies to validate approaches and incorporate best practices from similar sites.

By integrating these elements, the risk assessment will be robust, accounting for variability and providing a reliable foundation for protecting the community.