Discussion Regarding Community Focused Assessments
Introduction
Each day, communities are faced with contamination problems that pose, or are perceived to pose health threats to community members. While each contamination problem is unique, three brief scenarios are presented that illustrate the challenges involved in identifying the potential health risks as well as in choosing the most appropriate course of action to address those risks.
Scenario 1
A coastal community has been built around a vibrant fishery. Two marine fish species comprise the majority of the seasonal catch, and both species are sold commercially as well as consumed in significant quantities by community members. Anecdotal reports of contamination have prompted the local health department to hire a research laboratory to conduct sampling to determine whether toxicants occur in harvested fish. The laboratory results indicate that two contaminants occur in fish tissues, and their concentrations vary by species, fish size, and lipid (fat) content.
Some of the questions that might be important to this community include.
- What will the exposure be to people eating the fish? Are there specific age groups that get higher exposure? How different are exposures for people consuming different types of fish, different sizes of fish, or fish caught at different times of the year?
- What is the risk from exposure to the contaminant?
- What remediation options make a significant impact on the exposure to the community? If removing the fish from the diet is indicated, are there suitable alternatives for the fish?
Scenario 2
A large metropolitan area has recently been told that its municipal water source is located adjacent to a large, complex, abandoned hazardous waste site. The site received wastes composed of complex mixtures of solvents and electrical fluids including vinyl chloride and PCBs and metals including chromium, cadmium, and lead. There is concern that the hazardous wastes have migrated into the groundwater and are moving toward the city's drinking water source. While monitoring at the water treatment plant has not shown elevated levels of solvents or metals in source waters, there have been reports of elevated lead levels in drinking water drawn from individual residences using the municipal water.
Some of the questions that might be important to this community include.
- What contaminants exist in the municipal water and in what concentrations are they present?
- What is the exposure of the people served by this municipal water source? Does this exposure vary based on time of the year, or other demographic factor in the community?
- What is the toxicity of the contaminants? What is the risk from exposure to the contaminants in the water based upon how the community uses the water (drinking, bathing, swimming, irrigation, etc)?
- What options exist to reduce the risk to the community posed by the contaminated water? Is it feasible to clean up the water, find a new water source, or is there another option to reduce risk?
Scenario 3
Several new housing developments have sprung up along a major, north/south interstate highway in a three state area. Recently, new homeowners in each of the states have complained about odors coming from various areas within the new homes. There have also been complaints of headaches, nausea, and fatigue from homeowners, and some are beginning to claim that there is a link between the odors and the health complaints. Homeowners suspect that a new coating used on drywall to provide an additional seal and insulation is causing the odors and some have begun to pursue litigation to have the coated drywall removed and replaced. Unfortunately, the builder has gone bankrupt and has not left records of building product sources and content, including information about the sealant coating.
Some of the questions that might be important to this community include.
- What contaminants exist in the sealant coating? If contaminants exist, what will the exposure be to people?
- What is the toxicity of the contaminants? What is the risk from exposure to the contaminants? Could the health problems be linked to the contaminants, or is there another reason for the increase in health problems?
- What is the impact of reducing/removing the source of the contaminant?
These scenarios, and many like them, share two things in common:
- A presumption that the existence of a contaminant in the food, water, or environment (at any level) may cause serious health effects, and elimination of the contaminant (at any cost) is in the best interest of the community, and;
- An absence of an exposure and risk assessment demonstrating that exposure to the contaminants can or is resulting in adverse health effects among various subgroups of the community.
Each scenario also generates myriad questions, some of which we ask below, about the extent and magnitude of exposure and health risks and about decisions around how to manage those risks.
Q1: How can I assess the risks to the health of community members associated with exposure to contaminants that are identified in the environment?
Understanding health risks in an exposed population requires knowing who is exposed and to what degree, as well as the consequences (health impacts) of exposure. Accurately predicting risk begins with accurately assessing exposure. This means understanding who is exposed (age group, gender, other demographics), the magnitude of exposure for different parts of the population, the frequency and duration of the exposures and the sources of the exposure and routes of entry to the body (oral, dermal, inhalation). It also means understanding the variability and uncertainty in exposure estimates, which will aid and optimize the decision-making process.
Q2: How have exposure assessments been conducted historically?
Until recently, models used simple single-value estimates of exposure, while other important exposure information such as individual activity patterns and factors that influence exposure such as day-to-day and seasonal variation were ignored. These older models also relied heavily on assumptions about diets, activity patterns, and other factors that influence exposure, which were often derived from the U.S. "general" population - not necessarily reflecting a situation where a contaminant was affecting the health of a local population. As a result, the standard assumptions and underlying data used in these exposure models were not necessarily representative of individual community members, so an exposure assessment may not have been relevant to those individuals.
Q3: Are there better approaches to assess exposure?
Developing exposure profiles and risk estimates for specific communities requires new models, which allow the use of unique data and information reflecting the diet, lifestyles, and other factors that affect exposure and risk for those communities. For example, to assess exposure and ultimately the risk to residents in the communities described in the scenarios presented above, we should have detailed, gender- and age-specific dietary information as well as information about the extent and frequency of water-based activities such as showering, swimming, and cooking. We would also like to have information on activity profiles that represent the community as well as different groups of individuals within the community. Some specific questions that we might ask include:
What activities are individuals engaged in that could result in contact with the contaminant (eating, sleeping, watching TV, playing sports, working, shopping, etc.)?
What is the duration of the exposure? For example, occupational exposure may occur for 8 hours daily, 5 days a week while at-home exposures may occur periodically throughout the week, and vary by individual activities.
What is the likelihood that an individual would be engaged in an activity on any day that results in exposure and how long would they be engaged in that activity? While they are engaged in the activity how many times are they exposed, and how long does each exposure last?
What is the exertion level expected when a person is engaged in an activity that results in an exposure?
How and where does the contact with the contaminant occur? Is the contact through the diet (oral)? Does it touch only the hands, feet, or face, or does it contact the whole body (dermal)? Is it breathed in (inhalation)?
These and numerous other questions inform as well as complicate a comprehensive exposure assessment. However, there are databases and software (discussed below) that can help provide and analyze detailed exposure information for virtually any group of individuals based on parameters such as their activities, their occupations and age.
Q4: How can I get information on community-level dietary and activity patterns?
Dietary and activity information from studies of the affected community are the most desirable for exposure and risk assessments, although rarely is a formal scientific study of the community available. Several national data sets are readily available to the public and may be used for nationally based assessments or as a starting place for more community-focused information. Surveys like the National Health and Nutrition Examination Survey (NHANES), the Behavioral Risk Factor Surveillance Survey (BFRSS), and Canada Food Stats (CFS) are examples of this publically available information.
However, when national surveys do not meet the need and community specific studies are not available, the information can be constructed by other means. For example, fish harvest information may have been collected by fishery agencies, while information about seasonal consumption habits and availability of the fish stock may be available from local community members. Similarly, activity patterns that result in exposure to an indoor contaminant source may be ascertained from data related to the community economic status, housing data, or other public health information available within the community. The good news is that there is always available information. People know how they eat and what they do. The information may be piecemeal and may sometimes be in atypical format (narratives, health record notes, recipe books), but often can be supported with local knowledge and transformed into a format useable by LifeLine™ software.
Q5: What can community-specific information on diet and activity tell me?
All of this information, even in narrative form, can be converted into a format that can be used in new exposure and risk assessment models that provide an assessment that is relevant to the local community and the problem at hand. This assessment will, ultimately, answer the following questions:
Who in the community is exposed (by age group or gender or socioeconomic division)?
How much exposure do people in the community experience (by day or across different periods of time)?
What are the major sources of exposure (by type of food or other medium in their personal environment, activity)?
How much did assumptions about exposure influence answers to these questions?
What are the health risks that might be associated with the exposure ?
An exposure assessment can also help identify health risk and health benefit trade-offs where, for example, a dietary shift from fish to foods with higher saturated fat or sugar content occurs because of concerns with contaminants in fish tissue. In this case, the nutritional profile of the community diet, with the fish and without the fish should be considered as public health decisions are formulated and the mitigation options decided. Finally, the assessment must recognize that contaminants from sources in addition to the source of interest (e.g., sources other than fish consumption, or water consumption, or inhalation of indoor pollutants), are also likely and must be considered in the exposure and risk analyses. In fact these other sources might be making a greater contribution to the exposure than the one under scrutiny. Contaminants occur in many other places in our personal environments including the workplace, schools, play areas, and public spaces. A comprehensive exposure and risk assessment must be cognizant of, and incorporate where possible, contaminant exposures from these other sources and provide detailed assessment of comparative as well as aggregate or cumulative exposure.
Q6: Is there software that can help me analyze this information?
Yes there is.
The LifeLine Software can handle a full array of information and values, and describes how exposure and risk are distributed across a population as well as variability in exposure and risk due to day-to-day variation in contaminant or exposure levels. The LifeLine assessment can also examine health effects over the short and longer terms. The software is freely available and with appropriate expertise or assistance, can be used by communities as well as decision-makers at the local, state, provincial and national levels. Ultimately, the LifeLine Software will help assessors capture all information about how people interact with their environments and specifically the impact of these interactions on exposure to the contaminant. The output of the LifeLine assessment, in turn, provides decision-makers with exposure and risk information relevant to the community of interest so that the most appropriate mitigation options can be identified, assessed, and implemented.
We have developed LifeLine™ software - a probabilistic software tool that models exposure to chemicals in U.S. and Canadian populations as well as in sub-populations. It was the first tool to characterize population-based aggregate and cumulative exposures and risks from pesticides through their use as well as from residues in food and water. Since then, the software has been enhanced and has become a powerful tool to assess the relative contributions of a wide range of contaminants from many different sources and to determine how contributions vary among members of a community.
Among the software tools available to conduct a community- based exposure and risk assessment are the following:
Exposure and Risk Assessment Software
LifeLine v5
LifeLine Customized Dietary Assessment Software™ (CDAS™)
LifeLine Community Based Assessment Software™ (C-BAS™)
Auxiliary Software Tools
LifeLine Dietary Record Generator™ (DRG™)
LifeLine Activity Record Generator™ (ARG™)
Compendia of Customized Dietary Files
The Compendium of Alaska Traditional and Subsistence Dietary Files™
The Compendium of Traditional Dietary Files for First Nations and Inuit in Arctic Canada™
Compendium of Dietary Files for Mexican-Influenced Communities v.1™
Compendium of Dietary Files for the American Southwest™
Q7: Can I identify subpopulations (e.g., children, women, etc.) that are at greater risk than other members of the community?
Yes there is.
The LifeLine™ Community-Based Assessment Software can use a community's dietary and activity files created with the Dietary Record Generator© and Activity Record Generator© together with the contaminant residue data to present a community-specific exposure and risk assessment. Indeed, the power of the LifeLine™ software lies in its ability to focus on specific communities or subpopulations within a community. An assessor can capture valuable information about the diets, activities, and personal environments - in virtually any format - and import this information into the exposure model. The resulting exposure assessment is, therefore, based on customized information for a community or subpopulation group, allowing identification of community subpopulations at greatest risk.
Q8: Can LifeLine help me determine whether the public health measures that are in place or are proposed are adequate to reduce the risk to the community?
As an understanding of exposure and risk is achieved, evaluation of mitigation options can occur with the LifeLine software. The software allows evaluations that answer questions such as: How well does the mitigation option protect people at risk? How much does a cleanup reduce risk? What trade-offs occur as a result of contaminant mitigation? For example, if fish consumption is lowered to reduce the exposure to the contaminant, will the benefits of fish consumption also be reduced?
Q9: Can the LifeLine software help me establish priorities for cleanup or other actions to reduce risks?
A community may be presented with one or more mitigation options, often with differing costs, levels of risk reduction, and other outcomes. The LifeLine software can help answer a variety of associated questions such as:
Do the options reduce exposure for those most-exposed populations? If so, by how much?
How much are health risks reduced for the community and for subpopulations?
Is risk reduction outweighed by other quantitative factors such as nutritional benefit? If so, by how much?
By answering these and related questions, the LifeLine software allows mitigation options to be prioritized based on exposure and risk reduction as well as risk/benefit tradeoffs. Given the community's more complete understanding of the risk profile, they can also consider the benefit of social, cultural, and other and other non-quantitative parameters that impact their quality of life and well-being.
Q10: What is the role of the community in the process of assessing and managing risk?
Communities should play an active role throughout the exposure and risk assessment process as well as in the development and implementation of the risk mitigation options. When the community has no substantive role in doing the assessment or developing the risk mitigation options, it will not know whether they are relevant to the community's situation. Community members are often observers waiting for risk information to be released by an agency or other authority. Concurrently, the community is aware that it is being studied, which strengthens the perception that contaminants are, indeed, causing illness among community members. Additional anxiety among community members may result from involvement of government personnel, and that may be given.
Implementation of the action to be taken based on the risk assessment is frequently complex. There may be several levels of government involved and not all will have first-hand knowledge of the community and the ramifications of the action plan. All of this may result in conflicting information and mitigation recommendations leading to additional studies that further increase anxiety in the community.
Much of this anxiety could be reduced if there were significant involvement of the community in all phases of the risk assessment and risk management processes. The community would have a better understanding of how decisions were reached and would even be able to contribute valuable information specifically relevant to the community. Indeed, the LifeLine software was designed to incorporate detailed, community-specific information on diet and activity patterns which affect the exposure and risk estimation. Further, the LifeLine Group has extensive experience working directly with communities to apply and interpret the output of the software. Use of the LifeLine software combined with comprehensive community involvement in the risk assessment and risk management processes will provide invaluable support for mitigation decisions and their implementation.
