ARC Arnot Research and Consulting, 36 Sproat Ave., Toronto, ON M4M 1W4, Canada.
Environ Sci Process Impacts. 2018 Jan 24;20(1):86-97. doi: 10.1039/c7em00539c.
The chemical dietary absorption efficiency (E) quantifies the amount of chemical absorbed by an organism relative to the amount of chemical an organism is exposed to following ingestion. In particular, E can influence the extent of bioaccumulation and biomagnification for hydrophobic chemicals. A new E model is developed to quantify chemical process rates in the gastrointestinal tract (GIT). The new model is calibrated with critically evaluated measured E values (n = 250) for 80 hydrophobic persistent chemicals. The new E model is subsequently used to estimate chemical reaction rate constants (k) assumed to occur in the lumen of the GIT from experimental dietary exposure tests (n = 255) for 165 chemicals. The new k estimates are corroborated with k estimates for the same chemicals from the same data derived previously by other methods. The roles of k and the biotransformation rate constant (k) on biomagnification factors (BMFs) determined under laboratory test conditions and on BMFs and bioaccumulation factors (BAFs) in the environment are examined with the new model. In this regard, differences in lab and field BMFs are highlighted. Recommendations to address uncertainty in E and k data are provided.
化学膳食吸收效率 (E) 量化了生物体吸收的化学物质的量与生物体摄入后接触到的化学物质的量之比。特别是，E 可以影响疏水性化学物质的生物积累和生物放大程度。开发了一种新的 E 模型来量化胃肠道 (GIT) 中的化学过程速率。该新模型使用 80 种疏水性持久性化学物质的经过严格评估的实测 E 值（n = 250）进行校准。随后，该新 E 模型用于根据 165 种化学物质的实验膳食暴露测试（n = 255）估算假定在 GIT 腔中发生的化学反应速率常数 (k)。新的 k 估计值与先前使用其他方法从相同数据中为相同化学物质得出的 k 估计值相吻合。新模型研究了 k 和生物转化速率常数 (k) 对实验室测试条件下确定的生物放大因子 (BMFs) 以及环境中 BMFs 和生物积累因子 (BAFs) 的影响。在这方面，突出了实验室和现场 BMFs 的差异。提供了针对 E 和 k 数据不确定性的建议。
