Risk assessment conclusions for a site may differ when using site-specific versus default values for the relative bioavailability factor (RBAF) and dermal absorption fraction (ABS.d), because these inputs affect both surface soil screening levels and risk/hazard estimates. Indeed, our case study demonstrates that different conclusions may be reached as to regulatory need for remedial action to protect human health when evaluating soil sampling data for seven carcinogenic polycyclic aromatic hydrocarbons (PAHs) using site-specific versus default TCEQ and USEPA residential soil screening levels. Use of site-specific RBAF and ABS.d values increased carcinogenicity-based TCEQ and USEPA surface soil screening levels for PAHs by 4.4- and 6-fold on average, respectively. Soil screening levels for PAHs were more sensitive to changes in ingestion exposure route parameters than to changes in dermal exposure route parameters. Accordingly, site-specific RBAF and ABS.d information has important implications for screening chemicals at PAH-impacted sites, and in addition provides more realistic estimates of risks/hazards posed by PAHs in soil with reduced uncertainty compared to estimates based on default RBAF and ABS.d values. Although default values are generally deemed acceptable by regulatory agencies, use of risk/hazard estimates based on these default values may compel insufficiently justified remedial action in some instances.

中文翻译：

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特定风险的口腔相对生物利用度因子和皮肤吸收分数对粘土飞碟靶标碎片影响的表层土壤中多环芳烃的风险评估意义。

当使用相对生物利用度因子（RBAF）和皮肤吸收分数（ABS.d）的特定于站点的值与默认值时，针对某个站点的风险评估结论可能会有所不同，因为这些输入会影响地面土壤筛选水平和风险/危害估计。确实，我们的案例研究表明，在使用特定于现场的默认TCEQ和USEPA住宅土壤筛查水平评估7种致癌多环芳烃（PAH）的土壤采样数据时，就保护人类健康的补救措施的监管需求可能会得出不同的结论。 。使用特定于地点的RBAF和ABS.d值可使PAHs的基于致癌性的TCEQ和USEPA表面土壤筛选水平分别平均提高4.4倍和6倍。PAHs的土壤筛选水平对摄入暴露途径参数的变化比对皮肤暴露途径参数的变化更敏感。因此，特定地点的RBAF和ABS.d信息对于筛选受PAH影响的地点的化学物质具有重要意义，此外，与基于默认RBAF和ABS.d值。尽管默认值通常被监管机构认为是可以接受的，但在某些情况下使用基于这些默认值的风险/危害估计值可能会迫使采取充分不足的补救措施。d信息对于在受PAH影响的场所筛选化学物质具有重要意义，此外，与基于默认RBAF和ABS.d值的估计相比，不确定性降低的土壤中PAH所带来的风险/危害提供了更现实的估计。尽管默认值通常被监管机构认为是可以接受的，但在某些情况下使用基于这些默认值的风险/危害估计值可能会迫使采取充分不足的补救措施。d信息对于在受PAH影响的场所筛选化学物质具有重要意义，此外，与基于默认RBAF和ABS.d值的估计相比，不确定性降低的土壤中PAH所带来的风险/危害提供了更现实的估计。尽管默认值通常被监管机构认为是可以接受的，但在某些情况下使用基于这些默认值的风险/危害估计值可能会迫使采取充分不足的补救措施。