Successful abatement of lead exposure from water supplies in the West of Scotland.

A major problem has existed in the West of Scotland for at least the past century associated with lead uptake by water from leaden water distribution systems. Initial studies in Glasgow from 1969 to 1976 and in Ayr in 1980/1981 showed that not only were water supplies soft, acid in consequence highly plumbosolvent, and that water lead levels were, on average, unacceptably high but that blood lead concentrations were also in excess of acceptable limits. A decision was therefore made by Strathclyde Water Department to carry out remedial water treatment to adjust the water pH. The success of this venture was proven by the parallel rapid falls in blood lead and water lead concentrations in the city of Glasgow. This encouraged the Water Department to institute a similar scheme in the town of Ayr. Work on this commenced in 1981, and in a study of the participants in a previous blood lead survey, a highly significant fall in blood lead concentrations was observed. The equation linking these two parameters was found to follow a curvilinear relationship where blood lead varied as the cube root of the water lead with a highly significant coefficient of correlation. This relationship has been shown to hold across a wide range of water lead concentrations down to 1 microgram/liter. This detailed information allows accurate calculation of acceptable limits of lead exposure from specific sources based upon acceptable blood lead concentrations.