Modern analytical techniques have been applied to investigate the nature of lead pipe corrosion products formed in pH adjusted, orthophosphate-treated, low alkalinity water, under supply conditions. Depth profiling and surface analysis have been carried out on pipe samples obtained from the water distribution system in Glasgow, Scotland, UK. X-ray diffraction spectrometry identified basic lead carbonate, lead oxide and lead phosphate as the principal components. Scanning electron microscopy/energy-dispersive x-ray spectrometry revealed the crystalline structure within the corrosion product and also showed spatial correlations existed between calcium, iron, lead, oxygen and phosphorus. Elemental profiling, conducted by means of secondary ion mass spectrometry (SIMS) and secondary neutrals mass spectrometry (SNMS) indicated that the corrosion product was not uniform with depth. However, no clear stratification was apparent. Indeed, counts obtained for carbonate, phosphate and oxide were well correlated within the depth range probed by SIMS. SNMS showed relationships existed between carbon, calcium, iron, and phosphorus within the bulk of the scale, as well as at the surface. SIMS imaging confirmed the relationship between calcium and lead and suggested there might also be an association between chloride and phosphorus.

Corrosion products, obtained from lead service pipes carrying the public drinking water supply to the Glasgow area, have been characterised by FTIR spectrometry, powder x-ray diffraction spectrometry, flame atomic absorption spectrometry and ion chromatography. As expected, the products which formed in the presence of pH adjusted-water were mainly lead carbonate or basic lead carbonate. products from areas where the water supply had been treated with orthophosphoric acid and pH adjustment for up to eight years also contained a variable proportion (up to similar to 30% w/w) of a phosphate species. This has been identified as an apatite, most probably lead hydroxyapatite, Pb-5(PO4)(3)OH