On 7 November, Water Minister Dan Rogerson argued in response to a written question from Chris Ruane, Labour MP for the Vale of Clwyd, that water filtering within households is unnecessary, as monitoring by drinking water regulators shows tap water quality in the UK is “equivalent to the best in Europe”. (I’m not aware of a data series that would underpin this claim).
On 9 December, a statistical study by engineer Marc Edwards was published showing that cheap water filters certified to remove lead, together with advice to run taps and consider bottled water in older buildings, prevented hundreds of miscarriages in Washington DC in 2004-2006, when a change in water treatment caused a city wide spike in lead in water levels (links below). The paper also examines a miscarriage cluster in an office undergoing renovation, where lead in water from solder on copper pipes may have been wrongly excluded as a factor, because water was tested too late.
The study compared fetal death rates and birth rates in Washington DC against a similar sized city with the same water supply (Baltimore), and the US as a whole, before, during and after two incidents when lead “rust” from lead pipes and from solder on copper pipes was disturbed. The first lead spike was caused by a change in disinfection chemicals, the second by attempts to solve the first problem by replacing sections of lead pipe work.
Appropriate domestic water filters can reduce chlorination by-products present in tap water from chemical disinfection, together with the herbicides, other farm chemicals and pharmaceutical residues present in some river water (but not in water from boreholes favoured for bottled supplies). Filtering tap water was recommended in 2010 by the US President’s Cancer Panel, along with washing fruit and vegetables to remove pesticide residues and avoiding charred meat.
Concerned over the known toxicity of disinfection by-products, the Netherlands has abandoned the use of chlorine in a water safety system which prioritizes choosing the safest raw water sources for drinking water (link below). Edwards’ statistical analysis shows that the US change in disinfection practice – initiated and persisted with in an attempt to reduce miscarriages from chlorination byproducts – did not achieve its health goal. Possibly the by-products of the replacement disinfectant regime, though less studied, are equally noxious. A troubling pattern for regulatory changes.
Edwards’ key recommendations – supported by his laboratory test simulating lead release from solder in response to physical disturbance – are that pregnant women should always receive advice to use filters, flushing or bottled water in older premises, and that everyone should receive warnings and take precautions when plumbing is disturbed. Currently no such advice is issued in the UK, despite a predominance of older properties (lead free solder was only available from the late ‘80s), on-going lead pipe replacement to meet a stricter lead in water standard from the end of this year, and programmes to retrofit water meters.
It would be interesting to review fetal death rate trends within the Netherlands, to see whether the package of changes they made to how river water was treated (areas with better water sources never used chlorination) measurably improved maternal health. There is no easy switch to the Dutch method – the need for residual disinfection here goes hand in hand with the c. 25% leakage rate from poorly maintained pipework (vs. 4% for the Netherlands). Bottled water and home/office filtration are the policy options currently available in the UK to safeguard fetal health.
Lucy Borland’s paper on Drinking Water Regulation in Rad Stats: http://www.radstats.org.uk/no109/Borland109.pdf
Hansard, Written Answers 7 Nov 2013: http://www.publications.parliament.uk/pa/cm201314/cmhansrd/cm131107/text/131107w0001.htm#13110787000006
Marc Edwards: http://www.vtnews.vt.edu/articles/2013/12/121313-engineering-edwardsnewstudylead.html; http://pubs.acs.org/doi/abs/10.1021/es4034952; Increase in miscarriages coincided with high … – Washington Post
2008-2009 – Environmental Factors in Cancer: Reducing Environmental Cancer Risk, What We Can Do Now available at http://deainfo.nci.nih.gov/advisory/pcp/annualReports/
The Dutch Secret: how to provide safe water without chlorine in the Netherlands, P. W.M. H. Smeets, G. J. Medema, J. C. van Dijk: available to download at www.drink-water-eng-sci.net/2/1/2009/dwes-2-1-2009.pdf