Concentrations

In the webpage entitled "Concentrations" one is requested to provide the concentration (one or a series) of the chemical substance in the selected foods. There are three different methods to be selected, leading to different results.

Single value   The single value is the method where only one number for the concentration is to be given (e.g the maximum from a series for a worst case calculation). That number is then used for the calculation of the intake for all consumers for all days in the survey. In the figure shown here there are 116 subjects studied for 2 days. Then the number of intake calculations will be 232 (116 subjects × 2 consumption days). The unit for the concentration and a correction for composition and processing are to be set in the fields above. Proceed by clicking [Use single value].

Series of concentrations    The second section is to be used for a series of concentrations as input for the intake by all consumers for all days. The file should be a text file; its extension should be '.txt'; each row should contain one value without empty lines between the values. The number of values is unlimited. Use decimal points, not commas; "n.d." or "#N/A" to represent non detectable concentrations are not allowed. As an example a series of cadmium concentrations in chocolate (in microgram per kg) is included. For each calculation the tool selects a concentration at random from the series. The unit for the concentrations and a correction for composition and processing are to be set in the fields above. These are then used for all calculations. Proceed by clicking [Use this file].

Monte Carlo    For a Monte Carlo calculation two inputs are expected. First a series of concentrations. These are to be provided as a text file as described in the previous section. The second is the number of repetitions. Now the tool will select a subject and a consumption day from the database and a concentration from the series, all at random, and will repeat this as many times as the number of repetitions. The unit for the concentrations and a correction for composition and processing are to be set in the fields above. These are then used for all calculations. Proceed by clicking [Monte Carlo]. A consumer will now be selected various times, for the same day, with different concentrations. So, the first two methods in the example calculate 116 subjects times 2 intakes making each intake value unique, whereas 1000 repetitions will result in a series of 1000 intake values which may contain duplicate values.