November 9 - 10, 2005
Hilton Newark Airport
Elizabeth, New Jersey
Overall Goals
As an integrating principle, bioavailability transcends scientific disciplines and is an important factor to consider in understanding the fate and transport of contaminants; the extent to which contaminants can be internalized by microbes, wildlife and humans; and the extent to which internalized contaminants are available to tissues and organs. The goal of this workshop is to build on this principle by clarifying how these divergent disciplines approach the concept of bioavailability and how this information can then be used to better quantify exposures.
The intent is to invite a small group of academicians and practicing professionals to discuss three general topics: 1) identification of the common concepts among the different scientific disciplines; 2) examination of the relationship between bioavailability and exposure; and 3) usage of data mapping tools to elucidate exposure-health relationships.
Workshop Sessions
Common Ground
Bioavailability has important implications for risk and exposure assessment, remediation, ecotoxicology, human toxicology, and the fate and transport of contaminants in the environment. Researchers in each of these fields have gained insight into the mechanisms and impacts of bioavailability as it relates to their disciplines, yet the common and divergent aspects of bioavailability remain poorly defined. There is confusion about concepts and terminology, and a lack of consensus with respect to a research agenda. The goals of this session are:
Exploration of the dimensions of bioavailability in the different problem areas. What is common? What is unique?
Consensus building on common concepts and terms
Definition of common research questions and necessary steps for implementation for risk and exposure assessment
Environmental Exposure and Human and Ecological Health Effects
The toxicity of environmental chemicals to humans and wildlife is directly related to the amount of toxicant that reaches a target organ or tissue. People and animals are exposed to environmental chemicals through ingestion, dermal exposure, and inhalation of contaminants present in air, water, contact surfaces, and food. Many factors influence how much of the exposed dose is absorbed systemically and then distributed to target organs where toxic effects are manifest. In addition, there are species differences in these processes. These processes are particularly problematic for chemicals that are sparingly bioavailable. Consequently, human and environmental risk assessment suffers from great uncertainty about how to model human or wildlife exposure from food, water, air, and contact exposures. This session explores our knowledge and information needs. The goals are to:
Review what is known about the factors influencing the systemic uptake and organ distribution of toxicants.
Explore knowledge gaps in oral, dermal and inhalation exposure route scenarios.
Discuss new research approaches and methods, including in silico methods.
Develop research questions and discuss the implications for risk and exposure assessment.
Exposure Mapping and Data Integration
The vast number of sites contaminated with hydrophobic chemicals and other persistent contaminants makes detailed studies on each beyond the scope of current or likely future funding. New approaches to data mapping and better use of existing data are needed to explore exposure and disease relationships and provide predictive power. The objectives of this session are to:
Examine current approaches to using innovative data mapping and interpretation approaches.
Discuss the scale and sensitivity of methods needed, and validation.
Determine appropriate analytical or data end points.
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