Report No DWI0073

Nov 1982


Before this project there was no information, that would now be considered reliable, about the concentrations of asbestos present in UK water supplies. Although the possible effects on health of exposure to asbestos via ingestion are at present very unclear, the general concern about asbestos was the reason for investigating its presence in drinking water.

This research was carried out under contract to the Department of the Environment, during the period from April 1977 until March 1982. The work was directed towards three main objectives:

  1. to evaluate methods of sampling and measurement of asbestos in water,

  2. to determine the concentration and types of asbestos in raw and treated waters in the UK,

  3. to determine whether and in what circumstances the use of asbestos-cement pipes can contribute to asbestos levels in the consumer's supply.

Objective (a) has been achieved and previously reported (WRc Technical Report TR 100). As a consequence of that work the asbestos analyses for the following survey were sub--contracted to the Ontario Research Foundation in Canada, the same laboratory as is used by the Canadian Government and by the US Environmental Protection Agency for similar work. The methods of sampling and analysis used in this project therefore allow comparison with the latest surveys from N. America.

The survey of asbestos concentrations in UK waters comprised the examination of 144 samples from a total of 65 carefully chosen locations at different stages of supply The results of these provide the basis for reporting on (b) and (c). The results suggest that most drinking waters in the UK contain asbestos fibres in a range from 'not detectable' up to 1.5 million fibres per litre (MFL). These levels are similar to typical levels observed in N. America and are low compared with levels in areas where asbestos is present in the local rock, particularly where it is mined.

The concentrations of amphibole asbestos found in UK drinking waters were mostly less than 1 MFL. For chrysotile asbestos only 12 of the 82 samples representative of potable water contained more that 1 MFL and only four samples (three locations) contained more than 3 MFL. 95% of all the fibres counted were less than 2 Ám in length.

Levels of amphibole asbestos in potable samples drawn via asbestos cement pipe systems were higher than elsewhere but still low. Levels of chrysotile asbestos in such samples were all less than 1.5 MFL with the exception of four samples (three locations). Samples taken after deliberately disturbing deposits in asbestos cement pipe systems, however, mostly contained much higher levels, up to 58 MFL.

Three subjects were identified which may require further investigation: the use of asbestos cement tanks for potable water storage, the use of asbestos rope and graphite/asbestos rope in domestic plumbing, and the extent and effect on water supplies of asbestos waste disposal to land.

Copies of this report may be available as an Acrobat pdf download under the 'Find Completed Research' heading on the DWI website.