Development and assessment of new risk assessment methods

Title of Research:
12_S01-01-2

Probabilistic Exposure Evaluation Model for Relatively Small-scale
Occupational Workplace
Principal Investigator:Akihiro Tokai
Collaborators:Haruko Yamaguchi, Asato Itoh, ShunKimura
Summary of Research:
The purpose of this study is to develop an exposure assessment model that assists voluntary
chemicals management by Japanese downstream industries for occupational exposure which
seems to have relatively higher risk in the industrial supply chain. We have developed aprobabilistic assessment tool for the occupational exposure in Japan based on the framework ofAdvanced REACH Tool (ART) constructed in European ART consortium. We named this tool as
SWEEs (integrated Score-based Workplace Exposure system) and validated the exposure
estimating algorithm by using limited amount of some available data of the organic solvent inJapanese industries. What we have done were model validation and building pathway of practicalapplication by industrial sectors.
First, for a validation of SWEEs, we collected the observed exposure data of the organic solvent
measured in some workplaces related to the automobile manufacturing industry in Japan. The
result indicated that the exposure estimate by SWEEs was the 0.1-873 times larger than themeasured data as a whole. When looking at each task, the 93% of estimated exposure estimate
on the paint production were within the factor of 3. These suggest that continuous effort to collectrelevant information on workplace exposure are strongly required. This also needs cooperative
actions from stakeholders.
Second, to prioritize the required collected data for SWEEs, we tried to estimate probabilisticallyestimated the exposure concentration stochastically by assuming providing the probability
distribution to each of mechanistic model parameters used in of ART and performed sensitive
analysis with the case of workers exposed to toluene in gravure printing industry in Japan. As theresult of this analysis, the average of estimated concentration of toluene in the painting industry
was 30.8 ppm, the 0.66 times of observed concentration (46.7ppm). In addition, modified factors
such as related to local control measurement and action of workers in workplace were identified asa key parameters that contributed largely to the estimated concentration by this sensitive analysis.
In parallel with this modeling study, we continue to improve model framework applicable underlimited data availability condition, up to now we have examined introduction of the model for multichemical behavior in the workplace, validation through data rich case studies. We also
continuously do socio-economic needs assessment of risk and exposure assessment of industry
sectors. Through integrating these tasks, final goal will be the participatory evolving systems ofvoluntary risk management system in industrial sectors in Japan.
Timeline: 2014.4 – 2015.6
Topics: N/A
Publications:
Yamaguchi, Haruko; Hamada, Hayato; Ito, Asato; Tokai, Akihiro、Development of probabilistic
occupational exposure assessment tool assisting voluntary chemical risk management ofindustrial sector in Japan, 2014 annual meeting of Society for Risk Analysis-Europe