Is there a basis for the quantitative limit of 500 kg/year for the environmental assessment?

The limit is based on the following model consideration: On the basis of the TiO2 example, a PNEC of 1 μg/L is assumed. For an estimated use of 200 L water per day for each inhabitant of Switzerland (ca. 8 million), the annual volume is considered to be 500x109 L. This, together with the accepted PNEC, results in an annual limit of 500 kg, below which no effect occurs.

This projection is very general and set at a high level for Switzerland as a whole. It should be pointed out that locally strongly different quantitative scenarios are possible. This is not however considered in the scope of the precautionary matrix. This projection will be re-evaluated and adapted according to new findings.