Environmental Exposure Modeling Group
This group is developing a technology for exposure assessment, the core point of assessing the risks of chemical substances to humans and ecosystems. It is also conducting research centering on the development of exposure assessment models in the atmospheric environment, indoor environment, rivers and oceans. Exposure and risk assessments using these models are being made in cooperation with other groups so that the results of such efforts can be utilized for policies for the management of chemical substances.
The Environmental Exposure Modeling Group comprises nine members (five full-time researchers, a research fellow and three technical staff), including group leader Dr. Haruyuki Higashino. The group is mainly working on the development of models for assessing exposure in the atmospheric environment, the indoor environment, the rivers and oceans.
Regional-scale Atmospheric Dispersion Model for Exposure and Risk Assessment (ADMER)
ADMER (Official name: AIST-ADMER, the National Institute of Advanced Industrial Science and Technology — Atmospheric Dispersion Model for Exposure and Risk Assessment) is a model designed to estimate the concentration of chemical substances in the atmosphere and the exposure population from their emissions and meteorological conditions.
The latest version of this model (Ver.2.5) released in August 2008 has features that make it possible to display concentration maps on satellite photos in Google Earth™. It also has such features as enhanced calculation speeds through parallel processing, improved user-friendliness, and an in-built function for downloading Automated Meteorological Data Acquisition System (AMeDAS) data from the Japan Meteorological Agency.
ADMER users have been increasing every year because of its simple operation and easy accessibility. Another reason for the increasing popularity of ADMER is the growing availability of various emissions data following the adoption of the Pollutant Release and Transfer Register (PRTR) system. This model is used for risk assessment of atmospheric chemical substances by many organizations, including governments, municipalities, educational institutions and companies.
ADMER has been released to the public, and anyone can use it by downloading it free of charge. Access the following website for further details of ADMER and to download it: http://www.aist-riss.jp/software/admer/
Version 1.5 with an English user interface is now available. Future plans include the development of an international version which can perform simulations for all regions, both within and outside Japan.
An example of displaying atmospheric benzene concentrations map on Google Earth™
ADMER can estimate a distribution of concentrations at spatial resolutions down to 100 m x 100 m within the basic ADMER grid (5 km x 5 km).
Next-generation Regional Atmospheric Dispersion Model for Exposure and Risk Assessment (Next-generation ADMER)
In recent years, chemical substances subject to PRTR, such as VOCs used in solutions and solvents, have been increasingly substituted for non-PRTR organic chemical substances such as alcohol. Although many of these substitutes are not particularly hazardous, they are potential precursors of hazardous substances such as aldehydes and ozone in their secondary forms in the environment. There is some possibility that substitution will not necessarily lead to risk reduction. To analyze this type of risk tradeoff problem, we need to know the atmospheric concentration of decomposition products such as aldehydes that are secondarily generated by photochemical reactions in the atmosphere as well as the concentrations of emitted substances.
We are therefore developing a next-generation ADMER designed to estimate the concentrations of secondary products (mainly ozone and aldehydes) of volatile organic compounds in the atmosphere by modeling the processes of reaction and deposition of volatile organic compounds in the atmosphere and incorporating that model into a three-dimensional, Euler-type atmospheric dispersion model.
Conceptual diagram of next-generation regional Atmospheric Dispersion
Model for Exposure and Risk assessment (Next-generation ADMER)
Indoor air exposure model
In some cases, exposure to indoor chemical substances adds to human health risk more than exposure through the external atmosphere. The effect of indoor exposure should not be ignored when carrying out a risk assessment that takes total exposure into consideration. To establish a method for indoor exposure and risk assessment, we are developing a mathematical model that will enable us to clarify the dispersion of chemical substances from products and their indoor behavior and to estimate their exposure, mostly from inhalation.
Conceptual diagram of indoor air exposure model
Model for estimating the exposure concentration of chemical substances in rivers
It is necessary to know the concentration of chemical substances in river water to assess the ecological risk to aquatic life in a river. A risk assessment based on observation data only is insufficient, since observation points and frequency are restricted. For this reason, we are developing an AIST-Standardized Hydrology-based Assessment Tool for Chemical Exposure Load (abbreviated to AIST-SHANEL) to assess and manage the risks of chemical substances for detailed temporal-spatial estimation of the exposure concentration of chemical substances in the entire water system in Japan.
This model enables us to visualize the probability of a threshold concentration above which aquatic life is affected. If ecological risks need to be reduced, for instance, it is possible to quantitatively assess to what extent a risk reduction measure will be effective for cutting the concentration of chemical substances by decreasing emissions by industry and increasing the waste removal rate in sewage treatment plants.
AIST-SHANEL is released to the public and anyone can download it or copy it from a CD-ROM free of charge. Access the following AIST-SHANEL Web site for further details.
http://www.riskcenter.jp/SHANEL/
The probability of the concentration of nonylphenolethoxylate in the basins of the Tone River and the Arakawa River exceeding 5.0 mg/m3
Risk assessment model for a coastal ecosystem
To assess the environmental concentration of hazardous chemical substances in seawater and their risks to the ecosystem, this model combined the following 3 models: a three-dimensional hydrodynamic model, an ecosystem model, and a model for predicating the fate of chemical substances. This model is used to model or predict the concentration of chemical substances in seawater by making a database of the average seasonal field from the calculation results of the physical field and biological field in coastal areas throughout the year.
The model for assessing costal ecological risks has a graphic user interface (GUI) for ease of operation on Windows.
Free CDs are available of the Tokyo Bay risk assessment model (AIST-RAMTB Ver.1.3), Ise Bay risk management model (AIST-RAMIB Ver.1.3) and Seto Inland Sea risk assessment model (AIST-RAMSIS Ver.1.0). For further details, please access the following Web site:
http://www.riskcenter.jp/RAMTB/
Figure 4 TBT loading flux setup interface
Figure 5 Predicted distribution of dissolved TBT concentration
Example of TBT calculation using the Ise Bay risk assessment model
