Consumer Exposure - User Guide
1) INTRODUCTION
The ECETOC TRA Consumer Tool allows calculation of consumer exposures to substances that are present in preparations and articles used by consumers. The tool calculates exposure via inhalation, dermal and oral routes separately, and also provides a summation of all the relevant exposure routes. It is available as a stand-alone Excel tool, and as an integrated tool that combines worker, environmental, and consumer calculations. This User Manual provides guidance only for working with the stand-alone consumer tool. To understand the underlying science, assumptions, and limitations of the tool, refer to the ECETOC Technical Report No. 93 and addendum to it, Technical Report No. 107.
2) GETTING STARTED
Upon opening the tool, the user will be presented with a Security Warning. To ensure the tool functions properly, select "Enable Macros".
The tool contains eight worksheets, each of which can be navigated via the tabs at the bottom of the tool. Table 1 below summarises these worksheets and explains the information provided within each sheet.
By default, upon opening, the "User Input" worksheet is shown because it is where all user-required entries are made. This worksheet contains colour-coded cells that identify inputs necessary for running the tool. Green cells are for information that must be entered before the tool can generate results. Grey cells are optional - if nothing is entered in these cells, the tool automatically selects default parameters listed in the "Defaults" tab. Pink cells are automatically populated based on user-made entries. Changes can be made only in the green and grey cells. All other cells are locked to protect equations from being unintentionally deleted and to prevent users from over-riding default parameters set in the tool.
3) USING THE TOOL
Exposure estimates and RCRs can be calculated for a group of consumer products (sentinel products) or for individual product subcategories.
STEP 1
First, identify which product or article to assess in the "User Input" worksheet. For sentinel products, put an "x" in column B for the respective preparation or article listed in column A. Similarly, for a specific product subcategory (column C), put an "x" in column D of the respective preparation or article. More than one sentinel product and/or product subcategory can be evaluated simultaneously. There is no limit to the number of sentinel products and subcategories that can be evaluated at the same time.
Note that if a cell in column B or D is not green, no exposure estimates or RCRs can be made for that sentinel product or product subcategory. See the Technical Report for more information.
TIP: If there is no direct match for your consumer product, you can select another preparation/article as a surrogate. However, it is important to review the exposure conditions listed in the "Defaults" worksheet to ensure that the exposure conditions for your consumer product are similar to the surrogate's exposure conditions.
STEP 2
Next, enter reference value(s) (e.g., DNEL) for the chemical being evaluated. The tool lists five reference values but only a total of four reference values can be entered. This is because the user can only enter the inhalation reference value either in units of mg/m3 or in units of mg/kg/day. When an inhalation reference value has already been entered and the user attempts to enter a second value in different units, an error message displays, informing the user that only one inhalation reference value can be entered into the tool. When this occurs, select "cancel" to exit the error message box.
A pathway-specific reference value is only needed if the exposure pathway is of significance for the selected product. Exposure pathways included for a sentinel product or product subcategory can be viewed in the "Defaults" worksheet (Columns D to I). The simplest way to avoid error messages when viewing results is to enter reference values for all exposure pathways. A worst-case reference value is generally the lowest of the pathway-specific reference values, and is compared to the sum of the relevant exposure estimates.
STEP 3
A vapour pressure is needed for inhalation exposures. Enter the vapour pressure, in units of Pascal (Pa), in cell C8. The tool automatically selects the vapour pressure band that is used to assign a default fraction released to the air (cells C2 and E4-E7). The selected default fraction released to the air is only applicable for non-sprays and if inhalation is a significant exposure pathway associated with the use of the product/article. For sprays, the default fraction released to the air is always 1 and cannot be changed. Spray products are identified by an "x" marked in column E.
Some products and all articles are never sprays (e.g., finger paint, diapers). For preparations and articles that are never sprays, column E is hatched out and the user cannot change the default setting. However, the tool does allow users to determine whether or not some preparations are sprays. Cells in column E for these products are shaded grey, which means input is optional. Marking the product as a spray (i.e., putting an "x" in column E) assigns 1 as the fraction released to air. If this column is left blank, the tool assigns the default fraction released to air based on the substance's vapour pressure.
TIP: For sentinel products, changing a product subcategory to a spray may change the worst-case product subcategory for inhalation exposures. This is because the tool calculates exposure estimates and RCRs by using the highest exposure estimate calculated for the product subcategories within each sentinel group. The worst-case product subcategory is not necessarily the same for all exposure pathways.
STEP 4
The user has the option to change default values for the "Product Ingredient Fraction by Weight", "Skin Contact Area" (both dermal and oral exposures), and the "Amount of Product used per Application" (inhalation exposure only). Parameters that can be modified are identified by red letters that define the acronyms for the parameter in an algorithm. For example, the red letters in "skin contact area" define the parameter, CA, which is used in the equation for calculating dermal exposures.
If no values are entered in columns F to K, the tool automatically assigns default values listed in the "Defaults" worksheet. Note that although these changes are made at the product subcategory level, they could result in a change to the worst-case product subcategory used to estimate exposure for sentinel products.
Table 2. Parameters for which default values can be changed by the user
Parameter | Explanatory Note |
Product Ingredient Fraction by Weight | Enter the fraction of substance (>0 to 1) in the product. This parameter is used to calculate exposure estimates for all three exposure pathways where applicable (inhalation, dermal, oral). Default values are listed in Column H of "Defaults" worksheet. |
Skin Contact Area (dermal exposure) | Enter different skin contact area in columns G or H, for the adult and child, respectively. The tool predetermines whether adult or child conditions are used, and therefore, the skin contact area can only be entered for either the adult or child, but not both. Although any value can be entered in columns G or H, user should refer to the contact areas listed in the "Defaults2" worksheet (rows 4 to 15 for dermal exposure). |
Skin Contact Area | Enter different skin contact area in column J. Oral exposures are based on a child mouthing a surface or an area of skin. Therefore, the skin contact area should be based on child rather than adult values. Same as above, user should refer to the skin contact areas listed in rows 18-21 of the "Defaults2" worksheet. |
Amount Product per Application | Enter a different value if more product-specific use information is available. This parameter only affects calculations for inhalation exposures. Default values are listed in column U of the "Defaults" worksheet. |
4) VIEWING RESULTS
Sentinel Products
For sentinel products, refer to the "Results by Sentinel Prod" worksheet for both exposure and RCR estimates. By default, the algorithms and parameters used to calculate the exposure estimates are hidden from view and the only outputs displayed are: exposure estimates, the worst-case product subcategory used to estimate these, and the RCRs. To view the hidden algorithms and parameters, click on the buttons at the top of the worksheet.
Rows for the sentinel products (previously selected in the "User Input" worksheet) are highlighted in pink. Risk characterisation ratios exceeding 1 are displayed in red. If no reference value or vapour pressure has been entered when those values are needed, error messages will be displayed, prompting the user to enter values in the "User Input" worksheet.
The total exposure in column AH is the sum of the dermal, oral, and inhalation exposures, and is compared to the worst-case reference value entered in cell B13 of the "User Input" tab. It is important to note that inhalation exposure is included in the total exposure only if it has units of mg/kg/day. To ensure inhalation exposure is included in the total exposure, enter an inhalation reference value in units of mg/kg/day in the "User Input" sheet. The tool does not convert the inhalation reference value from mg/m3 to mg/kg/day; this will have to be calculated outside of the tool by using a general population inhalation rate and body weight. In some cases, the worst-case product subcategory for inhalation exposures may change depending on the units.
TIPS: To view exposure estimates for a specific exposure pathway only, enter a "dummy" reference value for that exposure pathway. This will display the exposure concentration and not an error message that tells you the reference value is missing. You can ignore the RCRs generated using the "dummy" reference value.
Product Subcategories
Go to the "Results by Prod Subcat" worksheet to view results for product subcategories (previously selected in column D of the "User Input" sheet). Only pathway-specific exposure estimates and RCRs are displayed in this sheet. Similar to the results for sentinel products, the total exposure excludes inhalation exposure estimates unless they are calculated in units of mg/kg/day. To ensure inhalation exposure estimates are included in the total exposure estimate, enter an inhalation reference value in units of mg/kg/day (cell B10 in "User Input" sheet). If an inhalation reference value in mg/m3 has already been entered, this will have to be deleted first before an inhalation reference value in units of mg/kg/day can be entered.
To view the algorithms and parameters used to calculate route-specific exposure estimates, select either the "Dermal (Prod Subcat), Oral (Prod Subcat), or Inhalation (Prod Subcat) tab.
5) VIEWING DEFAULT PARAMETERS
Default parameters used in the exposure estimate calculations are listed in the "Defaults" and "Defaults2" worksheets. These worksheets are for information only and are therefore protected and cannot be changed by the user. Data that can be overridden can be done only in the "User Input" worksheet.
[1] The term "sentinel product" is used to describe a group of related product subcategories. An example is AC8 (paper products), which includes the following product subcategories: diapers, sanitary towels, tissues, and printed paper.