Chemical Properties Research Group, Department of Chemistry, Trent University, Peterborough, ON K9L OG2, Canada.
PER Consulting, Midland, MI 48642, USA.
Environ Sci Process Impacts. 2018 Jan 24;20(1):72-85. doi: 10.1039/c7em00485k.
We present a modelling perspective on quantifying metrics of bio-uptake of organic chemicals in fish. The models can be in concentration, partition ratio, rate constant (CKk) format or fugacity, Z and D value (fZD) format that are shown to be exactly equivalent, each having it merits. For most purposes a simple, parameter-parsimonious one compartment steady-state model containing some 13 parameters is adequate for obtaining an appreciation of the uptake equilibria and kinetics for scientific and regulatory purposes. Such a model is first applied to the bioaccumulation of a series of hypothetical, non-biotransforming chemicals with log K (octanol-water partition ratio) values of 4 to 8 in 10 g fish ranging in lipid contents to deduce wet-weight and lipid normalized concentrations, bioaccumulation and biomagnification factors. The sensitivity of biomagnification factors to relative lipid contents is discussed. Second, a hypothetical 5 species linear food chain is simulated to evaluate trophic magnification factors (TMFs) showing the critical roles of K and biotransformation rate. It is shown that lipid normalization of concentrations is most insightful for less hydrophobic chemicals (log K < 5) when bio-uptake is largely controlled by respiratory intake and equilibrium (equi-fugacity) is approached. For more hydrophobic chemicals when dietary uptake kinetics dominate, wet weight concentrations and BMFs are more insightful. Finally, a preferred strategy is proposed to advance the science of bioaccumulation using a combination of well-designed ecosystem monitoring, laboratory determinations and modelling to confirm that the perceived state of the science contained in the models is consistent with observations.
我们提出了一种量化鱼类中有机化学物质生物摄取度量的建模视角。这些模型可以采用浓度、分配比、速率常数（CKk）格式或逸度、Z 值和 D 值（fZD）格式，这些格式被证明是完全等效的，每种格式都有其优点。对于大多数目的，一个简单的、参数精简的单室稳态模型，包含约 13 个参数，足以用于科学和监管目的获得对摄取平衡和动力学的了解。该模型首先应用于一系列假设的、非生物转化的化学物质的生物累积，这些化学物质的 log K（辛醇-水分配比）值在 4 到 8 之间，在 10 克鱼类中，其脂质含量范围从湿重和脂质标准化浓度、生物累积和生物放大因子。讨论了生物放大因子对相对脂质含量的敏感性。其次，模拟了一个假设的 5 种线性食物链，以评估营养放大因子（TMFs），显示 K 和生物转化速率的关键作用。结果表明，对于疏水性较小的化学物质（log K < 5），当生物摄取主要由呼吸摄入和平衡（等逸度）控制时，浓度的脂质标准化最具洞察力。对于疏水性较大的化学物质，当饮食摄取动力学占主导地位时，湿重浓度和 BMF 更具洞察力。最后，提出了一种优选策略，通过结合精心设计的生态系统监测、实验室测定和建模，推进生物累积科学，以确认模型中包含的科学状态与观察结果一致。
