Report No DWI0007

Oct l987


Between 1977 and 1980 the Water Research Centre took tap-water samples from around 1000 homes in 25 towns in Great Britain. These samples were taken in conjunction with the Regional Heart Study, a major epidemiological study of cardiovascular disease in middle-aged men. The samples were analysed for a range of trace elements, with the aim of using the information to gain further understanding of the relationship that has been previously shown to exist between water hardness and cardiovascular disease.

The objectives of this report are:

Lead, copper and zinc, not unexpectedly, were the three elements whose concentrations in drinking water were most strongly influenced by plumbing materials. There was some evidence that chromium and cadmium levels were also increased as a result of water being allowed to stand in the pipework overnight, although, in general, concentrations of these elements tended to be below the limits of detection.

The dependence of lead, copper and zinc concentrations on other water quality parameters was examined empirically. Alkalinity, pH, hardness and sulphate appeared to be the main constituents influencing the concentrations of lead after overnight standing.

Copper levels appeared to be most influenced by pH, nitrate and chloride, whilst zinc levels were dependent upon hardness, pH and alkalinity.

A study of the inter-relationships between the trace elements yielded little of interest, apart from a fairly close association between concentrations of vanadium and magnesium.

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