New in version 1.03
The environmental fate of a set of chemicals is calculated using Level III (steady-state) equations for a unit emission rate. Environmental persistence and potential for long-range transport are calculated for each chemical. A bioaccumulation food web model calculates the exposure experienced by a variety of wildlife, agricultural crops and livestock. Human exposure is then calculated for a specific diet and set of age groups following Health Canada Exposure factors.
This model is intended to be used to compare hazard between a large set of chemicals.
Although the model will address ionizing substances, its treatment of these substances is very simplistic and the user is cautioned that the estimation of partitioning, reaction and bioaccumulation of the ionic species can be in considerable error. The model is primarily designed to address non-ionizing substances.
It is hoped that this model will be useful for identifying and prioritizing those chemicals of commerce that are of greatest potential concern. Following such an assessment, selected chemicals can be more fully and accurately evaluated using monitoring data in conjunction with models describing chemical fate and effects in more detail in real regional environments, food webs, and human populations with specific attention to populations with diets that result in high exposure.
For more information Level III calculations, refer to the description of the Level III model. FHX is similar in structure to the RAIDAR model.
This program is based on the following publication:
Arnot JA, Mackay D, Sutcliffe R, Lo B. 2010. Estimating farfield organic chemical exposures, intake rates and intake fractions to human age classes. Environmental Modelling and Software 25(10):116-1175
The required input data are:
A comma separated value (.csv) file containing the following data in the order given below and with the restrictions as listed. A maximum size of a chemical set is 252 chemicals. Chemicals may be entered directly into the FHX software but this is not recommended unless the set is very small.
1. There must be exactly 29 columns (A to AC) in the file.
2. Each chemical must have a new row.
3. The Chemical Name must appear in both the second and last column.
4. The first row must contain the headings for the columns and the chemical data must start on the second row of the file.
5. Blank rows are not permitted.
6. Major modifications to the chemical data should not be done in the FHX model, but should be made in the spreadsheet program of your choice, the file saved in csv format, and imported. The FHX model is designed to handle only minor modifications to the chemical information and will not perform well for major changes or additions.
A single set of biota properties are provided in the model. They can not be changed by the user.
A single set of human properties are provided in the model. Only the Food Sources matrix can be changed by the user but any changes will not be saved.
The mode-of-entry must be specified, all chemicals in the set will be evaluated using this mode-of-entry.
Model output includes:
Notes on Environmental Properties:
The fish volume fraction and the fish lipid content are required here to maintain continuity with previously exisiting CEMC models such as EQC. They modify, very slightly, the total volume and the Z of the water column. The fish lipid content is used to calculate the fish-water partition coefficient (KFW) in the case of a Type 1 chemical, and the octanol-water partition coefficient (from the KFW) in the case of a Type 2 or 3 chemical. They are not used directly in the foodweb calculations.
Minimum system requirements:
Minimum system requirements are an IBM-compatible PC running Windows 98 or XP. This model will not run under Windows NT or 2000.
The screen resolution should a minimum of 800x600 pixels.
FHX Version 1.02, released May 2010 continues to be available.
FHX Version 1.01, released December 2008 continues to be available.
FHX Version 1.00, released November 2008 continues to be available.
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Last updated June 10, 2013.