Science and Judgment in Risk Assessment (1994) / Chapter Skim
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8 Data Needs
8 Data Needs
Pages 144-159
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From page 144... ...
The more precisely the risk manager frames the questions to be addressed by the risk assessment at the outset, the less ambiguity there will be as to what data are required to answer the questions, the less need for judgment in datagathering, and the lower the likelihood that inappropriate or insufficient data will be gathered. As a corollary, public input into the framing of goals and questions can help to avoid public criticism and distrust of the process of risk assessment, 144
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From page 145... ...
Risk managers need to articulate clearly from the beginning who is to be protected from what, when and where, and at what cost (including how much effort and funds are to be expended to collect appropriate data) , so that risk assessors can provide relevant information.
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From page 146... ...
Section 112 of the Clean Air Act mandates that EPA consider the hazards and possible regulation of 189 specified chemicals. Considering both the effort required to carry out complete risk assessments and the resources of the agency, it is unlikely that that can be accomplished within the time constraints of the act.
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From page 147... ...
Because the emission-characterization database is extremely important for priority-setting, EPA should review the emission estimates submitted to ensure that they meet reasonable quality standards and that emission estimates from all sources within a site are submitted. Data Availability EPA plans to use emission information that is available in the Toxic Release Inventory (TRI)
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From page 148... ...
That restriction excludes smaller sources within the manufacturing sector for which risk assessments must be conducted under the Title III requirements. Instituting an emission threshold relative to the Title III requirements (e.g., 10 tpy for single compound; 25 tpy for multiple compounds)
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From page 149... ...
A thorough understanding of what happens to a chemical in the environment forms part of the basis for estimating human exposure and hence determining risk. Priorities for Collecting Data In the proposed iterative data-collection process described at the beginning of this chapter, data on environmental fate and transport would be acquired in roughly the following order: 1.
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From page 150... ...
Most commonly, ambient-air monitoring produces interval concentrations in samples averaged over a fixed time, such as 8 hr or 24 hr at fixed sampling stations. The number of stations, their times of operation, and their locations relative to known emission sources and popula
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From page 151... ...
If a toxicant produces a metabolite, enzyme alteration, or other signal that exposure has occurred and so leads to a high correlation between that marker and degree of exposure, such information can reduce the uncertainty in a predicted risk and could be useful for risk assessment. In one respect, this would be the best exposure information, because it would show that the toxicant has been absorbed and has already had some biological effect (NRC, 1987~; but it makes single-source exposure assessment difficult, because it reveals total uptake across all routes of exposure.
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From page 152... ...
Data Availability Some of the 189 chemicals on the Clean Air Act Amendments list have relatively abundant data on concentrations; some have virtually none. When concentration data are available, they are more likely to be from ambient-air monitoring or, at best, targeted fixed-point monitoring.
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From page 153... ...
In the suggested iterative data-collection process, the toxicity data listed in the first three categories below (i.e., generic and acute toxicity, acute mammalian lethality) should be collected on every chemical as a starting point, and other, more expensive, data should be collected only on chemicals that give cause for concern based on the data in those categories.
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From page 154... ...
Various combinations of negative information in the first few items of any two of the first three lists (e.g., emissions, environmental fate and transport, exposure) with positive information in the third list might lead to a medium priority.
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From page 155... ...
Acute mammalian lethality (rodent)
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From page 156... ...
There might be, for example, a numerical weighting or scoring approach based on data in the four categories of emissions, environmental fate and transport, exposure, and toxicological data. EPA should consider convening a panel of experts to develop a priority-setting process and the requisite accompanying iterative approach to data collection.
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From page 157... ...
FINDINGS AND RECOMMENDATIONS The committee's findings and recommendations follow. Insufficient Data for Risk Assessment EPA does not have sufficient data to assess fully the health risks of the 189 chemicals in Title III within the time permitted by the Clean Air Act Amendments of 1990.
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From page 158... ...
Inadequacy of TRI Database as a Source of Emission Data for Risk-Assessment Purposes The SARA 313 Toxic Release Inventory data and other readily available data used by EPA for emission characterization may be adequate for screening purposes but are not adequate for developing detailed risk assessments for specific facilities. Present processes of gathering emission data do not yield information appropriate for all risk-assessment purposes under the Clean Air Act Amendments.
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From page 159... ...
DATA NEEDS 159 Need for System of Data Management for Risk Assessment EPA needs more adequate mechanisms to compile and maintain databases for use in health-risk screening and assessment. · EPA should review its data-management systems and improve them as needed to ensure that the quality and quantity of the data are routinely updated and that the data are sufficiently accessible for risk screening and risk assessment.
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