UK water companies opt out of lead pipe removal
UK water companies are planning to avoid spending £2Bn on lead pipe replacement to meet EC directives on lead content in drinking water. The UK's Drinking Water Inspectorate (DWI) has agreed to allow chemical treatment for many areas.
EC directive 80/778/EEC demands that drinking water contain no more than 25µg/l of lead by 2003 and 10ug/l by 2013. Estimates of the cost of wholesale lead pipe removal in the UK have ranged from £2Bn to £10Bn.
Michael Rouse, chief inspector of the Drinking Water Inspectorate (DWI) has received information from water companies on their estimates of complying with the directive and has, effectively, let the water companies avoid wide-scale lead pipe removal: “The expectation is that pH control and phosphate dosing will be sufficient in most areas to achieve 25µg/l and in some areas 10µg/l.” The addition of orthophosphate (ortho-P) could reduce the amount of lead dissolving into supply.
The DWI’s latest guidance letter on plumbosolvency (12:2000) makes clear that pipe removal is not the only option: “Recent letters to water companies concerning plumbosolvency control strategies note that there has been no agreement to any specific actions to be taken to meet the new lead standards. If a water company wishes, it can make a case for specific ad-hoc actions for which it has strong supporting evidence.” Other techniques include pipe re-lining (see Water & Waste Treatment magazine, August 1999, pg30).
To prevent plumbosolvency through chemical treatment, the DWI recommends ortho-P should be maintained as a residual in supply at 0.5-1.0 mgP/l, with the pH of the supply between 7.2 – 7.8. Concerns about the addition of phosphate to drinking water supplies have been voiced, as the phosphate burden on the UK’s receiving waters from sewage effluent is already high.
Chemical treatment may be sufficient to meet the EC’s standards in most areas of the UK but some pipe removal will be necessary: “When more than 10% of samples in any of the water supply zones supplied by a treatment works exceed 25ug/l, after plumbosolvency treatment and control has been optimised, the water company will need to consider replacement of lead pipes in these zones. This programme must be completed by 25 December 2003,” states the DWI.
Between 7-10M homes in the UK (around 40%) still have lead supply pipes. According to Junior Environment Minister Chris Mullin: “Neurotoxic effects from exposure to excessive levels of lead are known to contribute to problems in learning and behaviour and slightly lower IQs.”