Lead from brass components – phase III

This project examines the Dutch drinking water sector’s sampling protocol to control lead concentrations at the tap. With a tightening of the lead standard, the performance of this protocol needs to be assessed and understood under the new conditions. This can be done by comparing the result of the sampling protocol with the result of the previously developed model. The research represents phase III in this research programme, and focusses on the application of the model (developed in phase I) and the comparison with measurements made in phase II.

Tightening of drinking water lead standard

Starting in 2023, the lead standard for drinking water in the Dutch Drinking Water Regulations was decreased from 10 to 5 µg/L. This concentration standard represents a maximum permissible dose of lead related to a weekly intake.

As a result of this tightening of the standard, the Dutch drinking water sector is confronted with the question as to whether copper pipes with lead solders and brass components can cause an exceedance of the 5 µg/L concentration standard. One model, validated in practice, can throw light on this question.

Modelling framework validation

This project comprises the following activities:

  1. Validation model: determining the suitability of the current modelling framework.
  2. Estimation of the effect of the brass components and lead solder.
  3. Interpretation of the protocol: Can more information be derived from the measurement results with the help of the exposure model?
  4. Modelling of lead and sampling at child locations (nurseries and primary school).

Model application

The model will be applied in the following situations:

  1. A simulation of lead concentrations at the tap for different lead-releasing components and in different households. This will allow for a calculation of both the weekly exposure, as well as the expected value for a wide range of sampling protocols.
  2. An assessment of the contribution of brass components and lead solder to the standard exceedance. This part is specifically directed at homes. It will also involve the modelling of a layered building of four apartments with a single riser pipe. This will provide an indication of the need to actively locate and remove pipes with lead solder.
  3. An interpretation of the results of the new sampling protocol. The possible nature of the interpretation will depend in part on the form of the eventual protocol and on the measurements by the water utilities. This item is also directed at homes in particular.
  4. The child locations (nurseries and primary school) could also be modelled.

This project aims to evaluate and interpret the lead sampling protocol that is chosen by the Dutch drinking water sector. It will show whether this protocol satisfies the desires of the sector, and whether it offers sufficient operational perspective. If the protocol performs well, it would be fine for the sector to use it, and the model can thus explain this outcome. But if the protocol performs poorly, the modelling can be used to identify and understand weak points in the protocol, so that – outside the scope of this project – the protocol can be refined further.