Cumulative dietary exposure assessment¶
Introduction¶
The goal of this exercise is to perform a probabilistic cumulative dietary exposure assessment, illustrating all data needed. In Example 1 we will upload and use nine different files containing the data. In Example 2 we will upload and use a single zip file for the same purpose. In the example the exposure will be characterised by upper tail percentiles, and the risk driving substances and foods can be examined. In Example 3 an uncertainty analysis is added.
Preparation¶
If you haven’t done so, in the workspace browser (use the icon), create a new workspace named Examples, using the button in the right-hand bottom corner.
The data files used in the example(s) in this section, are located in MCRA in the data folder Documentation-Examples / Exercise Dietary Exposure Assessment.
Example 1¶
In this example, try and calculate a cummulative chronic dietary exposure according to EFSA 2012 Optimistic settings. Use liver steatosis as a focal effect and Cyproconazole as an index substance. Also, use the DNFCS survey as a consumptions data source.
Detailed steps are as follows.
In the Examples workspace, create a new action (using )
Then select Dietary exposures
Name it Dietary exposures
Use as Dietary exposures settings
Tier: EFSA 2012 Optimistic
Risk type Chronic
Press Create
Then go to the actions settings of this action (path: Dietary exposures)
At Scope, click Effects (path: Dietary exposures / Effects)
At Effects data source with browse to the file Effect - Steatosis.xlsx and Select
At Effect Settings for focal effect select Steatosis-liver and press Save Changes
In the green navigation bar, click Dietary exposures to go up one level.
At Scope, click Foods (path: Dietary exposures / Foods)
At Foods data source with browse to the file Foods.xlsx and Select
In the green navigation bar, click Dietary exposures to go up one level
At Scope, click Populations (optional) (path: Dietary exposures / Populations)
At Populations data source with browse to the file Populations.xlsx and Select
This file contains two populations, only one is allowed. So deselect everything by clicking on the first line, next to the word Code
Now select NL_2006, then press Save (the red warning should now be gone)
In the green navigation bar, click Dietary exposures to go up one level.
At Scope, click Substances (path: Dietary exposures / Substances)
At Substances data source with browse to the file Substances - Triazoles.xlsx and Select
At Substance settings for Index substance select Cyproconazole and press Save Changes
In the green navigation bar, click Dietary exposures to go up one level
At Inputs, click Consumptions by food as measured (path: Dietary exposures / Consumptions by food as measured)
At Inputs, click Consumptions (path: Dietary exposures / Consumptions by food as measured / Consumptions)
At Consumptions data source with browse to the file FoodConsumptions.xlsx and Select
At Consumptions data selection with open the food consumption surveys selection.
The file contains two surveys, but only one is allowed. So deselect everything by clicking on the first line, next to the word Code
Now select DNFCS_2003 and press Save (the red warning should now be gone)
In the green navigation bar, click Consumptions by food as measured to go up one level
At Inputs, click Food conversions (path: Dietary exposures / Consumptions by food as measured / Food conversions)
At Inputs, click Foods as measured (path: Dietary exposures / Consumptions by food as measured / Food conversions / Foods as measured)
At Inputs, click Concentrations (path: Dietary exposures / Consumptions by food as measured / Food conversions / Foods as measured / Concentrations)
At Concentrations data source with browse to the file ConcentrationData.xlsx and Select
In the green navigation bar, click Food conversions to go up two levels
At Inputs, click Food recipes (path: Dietary exposures / Consumptions by food as measured / Food conversions / Food recipes)
At Food recipes data source, with browse to the file FoodTranslations.xlsx
In the green navigation bar, click Dietary exposures to go up three levels
At Inputs, click Concentration models (path: Dietary exposures / Concentration models)
At Inputs, click Relative potency factors (path: Dietary exposures / Concentration models / Relative potency factors)
At Relative potency data source with browse to the file RPFs.xlsx and Select
In the green navigation bar, click Dietary exposures to go up two levels
At Inputs, click Processing factors (path: Dietary exposures / Processing factors)
At Processing factors data source with browse to the file ProcessingFactors.xlsx and Select
In the green navigation bar, click Dietary exposures to go up one level
At Inputs, click Active substances (optional) (path: Dietary exposures / Active substances)
At Inputs, click Points of departure (path: Dietary exposures / Active substances / Points of departure)
At Points of departure data source, with browse to the file PODs Triazoles.xlsx
In the green navigation bar, click Dietary exposures to go up two levels
Now run the model, by pressing the run icon in the grey bar.
Find the following results:
The 99% exposure percentile
The substance(s) with highest contribution to the total exposure distribution
The food(s)-as-measured with the highest contribution to the upper tail of the exposure distribution
Answers:
In the grey bar, browse to the results panel by clicking the icon and click on the latest output (path: Results / Dietary exposures)
In the Dietary exposures tab, browse in the tree (unfold by clicking where necessary) to Dietary exposures Distribution (daily intakes) Percentiles
In the table it states that the 99% exposure percentile is at an exposure of 0.02127 µg/kg bw/day.
In the Dietary exposures tab, browse in the tree (unfold by clicking where necessary) to Dietary exposures Details Exposures by substance Total distribution
From the pie chart it is clear that Tebuconazole contributes the most to the total exposure distribution with 32.7%. In the table below the graph more details can be found.
In the Dietary exposures tab, browse in the tree (unfold by clicking where necessary) to Dietary exposures Details Exposures by food and substance Risk drivers upper tail
From the pie chart it is clear that Flusilazole in grapefruit contributes the most (16.7%) to the upper tail exposure distribution
Example 2¶
We will create a new action to demonstrate uploading all the data at once. All data is now contained within one file, MCRA-Documentation Example Dietary exposures.xlsx.
Detailed steps are as follows.
In the Examples workspace, create a new action (using )
Then select Dietary exposures
Name it Dietary exposures from one data file
Use as Dietary exposures settings
Tier: EFSA 2012 Optimistic
Risk type Chronic
Select Cumulative
Press Create
Then go to the actions settings of this action (path: Dietary exposures)
At Scope, click Effects (path: Dietary exposures / Effects)
At Effects data source with browse to the file MCRA-Documentation Example Dietary exposures.xlsx, click Toggle all, and Select. This will load all available data tables.
You still need to specify the focal effect (under Effects), index substance (under Substances), and food surveys (under Consumptions by food as measured / Consumptions).
You are still at the path: Dietary exposures / Effects
At Effect Settings for focal effect select Steatosis-liver and press Save Changes
In the green navigation bar, click Dietary exposures to go up one level.
At Scope, click Substances (path: Dietary exposures / Substances)
At Substance settings for Index substance select Cyproconazole and press Save Changes
In the green navigation bar, click Dietary exposures to go up one level
At Inputs, click Consumptions by food as measured (path: Dietary exposures / Consumptions by food as measured)
At Inputs, click Consumptions (path: Dietary exposures / Consumptions by food as measured / Consumptions)
At Consumptions data selection with open the food consumption surveys selection.
The file contains two surveys, but only one is allowed. So deselect everything by clicking on the first line, next to the word Code
Now select DNFCS_2003 and press Save (the red warning should now be gone)
In the green navigation bar, click Dietary exposures to go up two levels
You now have achieved the same as in Example 1, only with the upload of one single file. If you haven’t done Example 1, you can now run the model, by pressing the run icon in the grey bar, and then try and answer the questions at Example 1.
Example 3¶
Repeat the run of the previous task, but instead of the nominal run, now do an uncertainty analysis loop.
Click on the icon (in the grey bar) to open the uncertainty settings panel
At Uncertainty settings, check Perform uncertainty analysis
For Monte Carlo iterations per uncertainty run choose 100, and press Save Changes
Now run the model, by pressing the run icon in the grey bar.
Compare with the previous results, to find:
95% uncertainty bounds for the 99% exposure percentile
95% uncertainty bounds for the highest contribution from a substance to the total exposure distribution
95% uncertainty bounds for the highest contribution from a food to the total exposure distribution