Developing statistical methods to estimate the number of domestic properties with internal lead piping in Scotland

About the Project

For more information on this E4 DTP project please visit

https://www.ed.ac.uk/e4-dtp/how-to-apply/supervisor-led-projects/project?item=1313

Summary

Legacy lead (Pb) in tap water continues to be a major human health concern. This exciting interdisciplinary project will investigate the source of lead in water samples and develop statistical methods to estimate the number of Scottish houses requiring plumbing replacement, aiding the Scottish Government in improving health.

Project background

Lead is ubiquitous in UK household plumbing systems. Exposure to lead in drinking water can have serious effects on human health and cause neurodevelopmental problems in children. The Scottish Government, working via the Drinking Water Quality Regulator for Scotland (DWQR) and Scottish Water (SW), has reduced the number of lead pipes in the Scottish water distribution network, but a large number of houses still have internal lead (piping, solder, storage tanks) resulting in tap water contamination. Working with DWQR and SW, this project will use water sampling data to create a spatially explicit statistical model estimating number of houses in Scotland with internal lead piping based on a modelling framework developed during a previous consultancy project with DWQR (1). This study will also design a new water sampling regime to validate model predictions by measuring lead concentration in tap water samples and identifying the source of lead using isotope analysis. The aim of this project is to develop novel statistical methods that improve the current model by accounting for spatial autocorrelation and zero-inflated count data and validate the model by carrying out further tap water sampling and using isotope ratio analysis to determine the source of lead in tap water (e.g. from internal plumbing, external water distribution pipes, or other sources). In addition to those in the Schools of Mathematics and GeoSciences, this interdisciplinary project will include collaborators in the water industry who will provide access to new datasets for model development. The project will allow the DWQR to better estimate the current extent of internal lead piping in properties across Scotland, estimate the scale of work involved with removing lead piping from residential properties and the effect this will have on improving health in Scotland.

1. Robertson et al. (2019) Estimating number of homes in Scotland with internal lead piping. Report for the Drinking Water Quality Regulator for Scotland https://dwqr.scot/media/buffgevx/estimating-the-number-of-homes-in-scotland-with-internal-lead-piping-summary-report.pdf

Specific Questions:

1. How well does the current statistical model fit available sampling data (collected from two previous sampling rounds carried out in 2020)?

2. To what extent do improvements made to the model improve predictions?

3. How can uncertainty in the model be quantified? Use statistical methods to identify and quantify different sources of uncertainty in model predictions in order to identify where uncertainty can be reduced.

4. Is it possible to determine the source of lead in tap water samples? Use data collected from tap water sampling to explore whether it is possible to distinguish between lead that enters drinking water from lead soldering or from internal fittings.

CASE partner: Drinking Water Quality Regulator for Scotland

For information on how to apply visit https://www.ed.ac.uk/e4-dtp/how-to-apply/application-process