Report No DWI0207

Leaching of Lead from Blue uPVC Pipe FINAL REPORT

DWI0207

Feb 1994

EXECUTIVE SUMMARY

Consultants in Environmental Sciences Ltd (CES) was commissioned in August 1993 by the Department of the Environment (DoE) to conduct a research project into the leaching of lead from blue unplasticised polyvinylchloride (uPVC) pipes. The project was managed by the Drinking Water Inspectorate, (DWI).

Samples were taken from sampling taps and hydrants connected directly to blue uPVC pipe which had been installed in the drinking water supply network. No samples were taken at the consumer's tap. Sampling was undertaken at 37 locations, with one "upstream" and two "downstream" samples being generated for each location. The locations were chosen to allow sampling from blue uPVC pipes supplied by three different manufacturers and water of different composition, including a range of different hardnesses. Samples were generally taken between 05.00 hours and 07.00 hours to maximise the residence period of water in the pipes. A physical description of each sample was made and an estimate of the turbidity given. Although every effort was made to avoid disturbing sediments within the pipework sampled, the method of sampling at fire hydrants made this difficult and many of the samples contained suspended material.

Chemical analysis of samples for total lead and total iron was carried out. Average water quality data for parameters relating to plumbosolvency were obtained from the relevant water company's public register for each supply zone from which samples were taken.

The results of the analysis were reported according to manufacturer of pipe, diameter and length of pipe and water supply type. The supply location and water company were not identified in the report.

Samples were drawn from pipes produced by three manufacturers. The relationship between pipe manufacturer and water type was as follows:

Hepworth Industrial Pipes manufactured the blue uPVC pipe used in 3 of the sampling locations. All were designated by the relevant water companies as soft water;

Unidare Plastics Ltd manufactured the blue uPVC pipe used in 9 locations. Of these locations, 6 were designated by the relevant water companies as being soft water areas and 2 were designated as medium. One location was designated as a blend which could vary between hard and soft.

Uponor Ltd manufactured the blue uPVC pipe used in 25 locations. Of these locations 10 were of normal uPVC pipe in locations designated by the relevant water companies as soft water areas and 15 were of mo-PVC and were all situated in locations designated as hard water areas.

The range of the analysis results were as follows:

lead concentrations ranged from less than 1 µg/l to 778.4 µg/l

iron concentrations ranged from less than 20 µg/l to 155 000 µg/l

There appears to be a clear relationship between the elevated lead concentrations, iron concentration and sediment in the samples, indicating that sampling at fire hydrants may have caused sediments in the pipework to be disturbed and influence the sample results. It is considered unlikely, however, that the lead and iron concentrations determined in samples are representative of those at the consumer's tap.

Copies of this report may be available as an Acrobat pdf download under the 'Pre 2000 Reports' heading on the DWI website.