Modifying factors of toxicant impacts on biota

我实验室环境毒理学项目的长期目标是：1）了解改变有毒化学品对生物群影响的环境因素，2）开发评估污染物对自由生活生物影响的方法。 在对污染物进行现场定量环境风险评估（QERA）以保护环境的过程中，了解修正因子对于将实验室毒理学数据应用于现场或将在一个现场收集的现场数据应用于另一个现场至关重要。 在我的职业生涯中，在研究各种修改因素的影响时，很明显，我们真正关注的是环境因素如何修改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提供了一个确定性的假设制定和环境毒理学测试之间的联系。 我们已经使用这种方法来表征汞的动力学在维多利亚湖，沉积物中的镉的毒性底栖无脊椎动物在实验室和现场，三丁基氧化锡的毒性淡水中的水生无脊椎动物，和沉积物中的金属的毒性金属影响的湖泊。 在未来，我们将研究饮食与水生毒性的金属无脊椎动物，预测急性和慢性毒性的铜水生无脊椎动物的能力，纳米粒子的毒性水生生物和紫外线的相互作用的毒性，燃烧产物和金属鱼类。 总体而言，这项工作有助于我们对环境污染物影响的基本理解，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.