Extent of water pollution revealed

There are more than 1,200 places in England and Wales where groundwater is known to have been or is very likely to have been polluted by chemicals trickling down from the surface, according to the first nationwide survey of the problem by the Government's Environment Agency. Pollution from these "point sources" has contaminated the water in 114 boreholes used for the public supply and 137 private boreholes, and many of them have had to be closed because of the severity of the pollution.

The contaminated liquid emerging from landfill sites where garbage has been dumped for years is the cause of most of the known cases of groundwater pollution, but the agency identifies pollution from industrial sources as posing the greatest long term threat. Typical sources might be an old gas works, a petrol filling station or a dry cleaning plant. The agency admits there are big gaps in its knowledge of the problem, and the report is only a first stab.

Groundwater Pollution, free, Environmental Agency National Groundwater and Contaminated Land Centre, Olton Court, 10 Warwick Road, Olton, Solihull B92 7HX. Nicholas Schoon