KWR contributes expertise to RIVM advisory note

Sampling strategy should reveal presence of lead pipes

The recent publication, ‘Advisory note on sampling strategy for the detection of lead pipes’, provides a manual for building owners for the detection of invisible lead pipes in drinking water installations. Under the direction of the National Institute for Public Health and the Environment (RIVM), KWR contributed the required expertise for the advisory note. ‘With this sampling strategy, housing associations and landlords can get to work in a targeted manner’, says KWR researcher Nellie Slaats, who contributed to the note.

Need for advice

At the end of last year, the Dutch Health Council tightened the standard for lead levels in drinking water because of public health concerns. Almost simultaneously, lead pipes were unexpectedly found in homes in an Amsterdam neighbourhood. Many questions were asked about the detection of lead pipes, and the Ministry of Infrastructure and Water Management commissioned RIVM to research the issue and recommend a suitable sampling strategy for the detection of lead pipes. The resulting advisory note was recently submitted to the ministry.

KWR’s experience

KWR drew on its many years’ experience with lead in drinking water to provide the required expertise. ‘In 1999, for example, we carried out a big study on sampling strategies for lead in drinking water,’ explains Nellie Slaats. ‘And in 2017 we conducted a citizen-science project on the question for Dunea. We have thus accumulated knowledge about the detection of lead pipes.’ The target group for the recently developed sampling strategy are the owners of buildings and homes, but also those who have to respond to questions about the presence of lead pipes, like the Municipal Health Authorities (GGDs), laboratories and samplers.’

Lead pipe detection. Method 1: Legally required (RDT); Method 2: Detection of lead pipes after maximum possible residence time, for example, one night’s standstill. Lead concentration; Method 1; Method 2; stagnation time (hours)

Work in a targeted manner

A supervisory committee, comprising representatives from the client, Vewin, Kiwa, the Ministry of the Interior and Kingdom Relations, the Municipal Health Authority (GGD), Waternet, WLN, Het Waterlaboratorium, and the Human Environment and Transport Inspectorate oversaw the preparation of the advisory note.  Slaats: ‘It’s good that this allows for a more focused look at the replacement of lead pipes. With this proposed sampling strategy, housing associations and landlords can get to work in a targeted manner. But much more additional research needs to be done, for instance, into the duration and extent of lead release through new taps in (new housing) homes, or into the possibility of using filters, a subject about which KWR recently produced a report on a commission from Waternet.’

Measuring following standstill

This sampling strategy generates a worst-case situation, because the measurements are made following a relative long stagnation time. There are two circumstances in which tap water sampling is used to detect the possible presence of lead pipes. The first concerns ‘suspicious’ locations, where lead pipes are suspected but have not been found during visual inspection. The other circumstance involves cases where routine Random Day Time (RDT) sampling done by the drinking water utility in the building or home shows lead concentrations exceeding 10 μg/L. ‘With this sampling strategy lead pipes are easily detected; that can remove much of the anxiety,’ says Slaats.