Total Risk Integrated 

Methodology (TRIM)

General Information

TRIM.FaTE

TRIM.Expo

TRIM.Risk

Peer Review and 

Publications

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General Information

Total Risk Integrated Methodology (TRIM) - 

 General Information 

The TRIM design includes three individual modules which have 

been the subject of peer review and publication: 

The Environmental Fate, Transport, and Ecological 

Exposure module, TRIM.FaTE, accounts for movement 

of a chemical through a comprehensive system of 

discrete compartments (e.g., media and biota) that 

represent possible locations of the chemical in the

physical and biological environments of the modeled ecosystem and provides an 

inventory, over time, of a chemical throughout the entire system. In addition to 

providing exposure estimates relevant to ecological risk assessment, TRIM.FaTE 

generates media concentrations relevant to human ingestion exposures that can be 

used as input to the ingestion component of the ...

... Exposure-Event module, TRIM.Expo. In TRIM.Expo, human exposures are 

evaluated by tracking either randomly selected individuals that represent an area's 

population or population groups referred to as "cohorts" and their inhalation and 

ingestion through time and space. The inhalation component is currently available.

In the Risk Characterization module, TRIM.Risk, estimates of human exposures or

doses are characterized with regard to potential risk using the corresponding 

exposure- or dose-response relationships. The TRIM.Risk module is also designed to 

characterize ecological risks from multimedia exposures. The output from TRIM.Risk is 

intended to include documentation of the input data, assumptions in the analysis, and 

measures of uncertainty, as well as the results of risk calculations and exposure 

analysis.

The uncertainty and variability features (e.g., sensitivity & Monte Carlo analysis) 

augment TRIM's capability for performing iterative analyses. For example, the user 

may perform assessments varying from simple deterministic screening analyses using 

conservative default parameters to refined and complex risk assessments where the 

impacts of parameter uncertainty and variability are assessed for critical parameters.

Given the modular design of TRIM, the user selects any one or more of the modules for an 

assessment depending on their needs. 

For example, when performing a human health risk assessment for an air pollutant for 

which multimedia distribution is not significant, it is recommended that TRIM.Expoinhalation be applied to ambient concentration data or the output from an air quality 

model external to TRIM (i.e., not TRIM.FaTE). The output from TRIM.Expo may then 

be input to TRIM.Risk (when available) to perform the desired risk analyses. 

In the case of a multimedia air pollutant, such as mercury, the user may choose to 

run all three TRIM modules (when available) to assess ecological risks posed by multipathway exposures from multiple media, as well as human ingestion risks posed by 

exposure from multiple pathways. 

In the development of TRIM, existing models and tools are being relied upon where possible. 

For example, EPA has incorporated TRIM into EPA's MIMS, a modeling framework that 

accommodates linkages among multiple models and the sharing of common tools and data.

Technology Transfer Network 

FERA (Fate, Exposure, and Risk Analysis)

http://epa.gov/ttn/fera/trim_gen.html

Last updated on Wednesday, November 10, 2010

EPA Office of Air Quality Planning & Standards - FERA - TRIM - General Information Page 1 of 1

http://epa.gov/ttn/fera/trim_gen.html 12/6/2011