Risk Assessment Strategy Group
This group is chiefly examining how to assess the risks associated with chemical substances (strategy), with their management taken into account. Current research subjects are both a human health risk and an ecological risk. The central tasks of the group are the risk assessment of industrial nanomaterials and the development of a method for risk tradeoff analysis. The group is also studying how to collect data, estimate risks and generate risk indicators.
This group is chiefly examining how to assess the risks associated with chemical substances (strategy), with their management taken into account. Current research subjects are both a human health risk and an ecological risk.
Members of the Risk Assessment Strategy Group and research subjects
The Group consists of four researchers, three technical staff and one assistant.
The main research subjects of the group and the personnel in charge are as follows. There are also some individual research subjects.
*Risk tradeoff analysis (human health): Gamo and Hojo
*Risk tradeoff analysis (ecological risks): Naito and Kamo
*Risk assessment of manufactured nanoparticles: Gamo, Kobayashi, Saito, and Taniguchi
*Assessment of ecological risks arising from biomass utilization: Naito
What is a risk assessment strategy?
The starting point for understanding a risk assessment strategy is to decide for what purpose the assessment will be done. Naturally, the answer varies according to subjects. The following are examples of purpose of risk assessment.
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Screening: Conservative (safety side) assessment designed to pick out a risk that might be important. Assessment of a new material: Assessment based on initial decision-making and limited information Adaptive management: Data acquisition through trial risk management and data feedback for update of management methods Risk comparison: Comparison of two substances from the viewpoint of magnitude of risk for prioritization Cost effectiveness analysis: Comparison of risks and benefits of chemical substances and comparison of costs of countermeasures and reduced risk |
What is common to the methods of risk assessment in any cases would be not to simply seek the minimization of risks, but to conduct appropriate risk management considering the balance among the risks of chemical substances, their benefits, and costs of assessment and management.
The risk management strategy can be viewed broadly from two aspects. One is how to obtain data for risk assessment. In other words, to consider what data should be obtained for risk management.
The other is how to use the data obtained. The ways of using data can be classified into two: how to estimate a risk based on available (and usually limited) data and by what indicator the risk is to be expressed.
How to obtain data
It is not effective to obtain data at random: it needs to be obtained in purposeful and cost-effective ways. A study of how to obtain data is under way according to these themes and from the following viewpoints.
Minimum dataset for assessment (enough information for a particular management purpose), hierarchical approach (screening detailed testing) (testing that focuses on production and usage), a biaxial approach (designed to cover a wide range of substances by detailed testing on typical substances plus simplified testing), a monitoring plan for adaptive management (post-analysis framework for effectively gaining an understanding of the results of trial management)
How to estimate risks based on available data
Risk estimation is sometimes required, even when available data is limited. It is necessary to obtain as accurate an estimate as possible from all the information available. A model for predicting the concentration in environmental media falls into this category in a sense, but here at the Risk Assessment Strategy Group we are developing methods for estimating human health and ecological hazards. Any risk estimate based on limited information will be uncertain. To carry out risk management premised on the uncertainty of assessment, the group is also developing methods for quantitative assessment of uncertainty.
Risk indicators
Common human health risk indictors have up to now been the ratio of no observed adverse effect level to exposure level (MOE: margin of exposure) and the ratio of acceptable intake to exposure level (the hazard ratio). These indicators are effectively useful in the screening assessment and assessment for initial decision-making on new substances. However, they do not fully serve the purpose of doing a more in-depth risk comparison or cost effectiveness analysis. The group is studying the potential for using indicators such as lost life expectancy and quality adjusted life years (QALY).
The group is proposing a shift from the assessment of ecological risks that emphasize the impact on individual organisms to one that uses an ecologically meaningful indicator, namely a risk indicator focused on the survival of a population. It is also looking at an approach based on species sensitivity distribution to quantify the ratio of species in the ecosystem that are affected at certain levels of chemical substances in the environmental media.
