Modifying factors of toxicant impacts on biota

我的实验室环境毒理学项目的长期目标是：1)了解改变有毒化学物质对生物群影响的环境因素；2)开发评估污染物对自由生物影响的方法。在污染物的特定地点定量环境风险评估（QERA）期间，了解修饰因素对于将实验室毒理学数据应用于现场，或将在一个地点收集的现场数据应用于另一个地点，以保护环境至关重要。在我的职业生涯中观察各种修饰因素的影响时，很明显，我们真正关注的是环境因素如何修饰一种化学品的生物利用度；暴露浓度、时间和同化/净化动力学如何相互作用以达到生物体中的临界（毒性阈值）化学浓度。使用这种方法开发的模型在环境毒理学的假设制定和测试之间提供了确定的联系。我们已经使用这种方法来表征维多利亚湖中汞的动力学，在实验室和现场的沉积物中镉对底栖无脊椎动物的毒性，三丁基氧化锡对淡水中水生无脊椎动物的毒性，以及金属影响湖泊沉积物中金属的毒性。在未来，我们将研究金属对无脊椎动物的饮食毒性和水生毒性，预测铜对水生无脊椎动物的急性和慢性毒性的能力，纳米颗粒对水生生物群的毒性以及紫外光，燃烧产物和金属对鱼类的相互作用毒性。总的来说，这项工作有助于我们对环境污染物的影响的基本理解，并有助于健全以科学为基础的加拿大环境法规。

The long-term objectives of my laboratory's program in environmental toxicology are: 1) to understand the environmental factors that modify the impacts of toxic chemicals on biota and, 2) to develop methods to assess contaminant impacts on free-living organisms. An understanding of modifying factors is crucial for the application of laboratory toxicology data to the field, or the application of field data collected at one site to another, during site-specific quantitative environmental risk assessment (QERA) of contaminants to protect the environment. While looking at the effects of various modifying factors over my career, it has become evident that what we are really looking at is how environmental factors modify the bioavailability of a chemical; how exposure concentration, time and assimilation/depuration kinetics interact to achieve a critical (threshold of toxicity) chemical concentration in the organism. Models developed using this approach provide a deterministic link between hypothesis formulation and testing in environmental toxicology. We have used this approach to characterize the kinetics of mercury in Lake Victoria, the toxicity of Cd in sediment to benthic invertebrates in both the laboratory and the field, the toxicity of tributyl tin oxide to aquatic invertebrates in freshwater, and the toxicity of metals in sediments from metal-impacted lakes. In the future we will examine dietary vs. waterborne toxicity of metals to invertebrates, the ability to predict acute and chronic toxicity of copper to aquatic invertebrates, the toxicity of nanoparticles to aquatic biota and the interactive toxicity of ultraviolet light, products of combustion and metals to fish. Overall, the work contributes to our basic understanding of the impact of environmental contaminants, and to sound scientifically-based Canadian environmental regulations.