London's Pulse: Medical Officer of Health reports 1848-1972
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Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
Hornsey 1951
[Report of the Medical Officer of Health for Hornsey, Borough of]
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WATER SUPPLY
The water supply for Hornsey is provided by the Metropolitan Water
Board from two sources:—
(a) Water from the New River, treated at the Board's filtration
works at Hornsey, and Stoke Newington.
(b) River Thames water stored in Littleton Reservoir and treated
at the Board's filtration works at Kempton Park.
Water is pumped from these works into service reservoirs at Crouch
Hill.
Samples of water are collected on five days in every week, or more often
if required, at each stage of the purification process and tests include
physical, chemical and microbiological examination.
The water supply to this area is not plumbo-solvent.
All new and repaired mains are chlorinated before being restored to
use and samples of water from them are tested bacteriologically to ensure
that its quality is up to that normally supplied.
The water supply is in all cases direct to dwelling houses; none is
supplied by means of a stand pipe.
The supply has been satisfactory both in quantity and quality during
the year.
Chemical Examination
250 samples of water were taken for chemical examination from each
of the three filtration works and were found to be satisfactory.
| Filtration Works | No. of Samples | No. of microbes per ml. Colonies counted on agar after 20-24 hrs. | Bact. coli test | |
|---|---|---|---|---|
| Percentage of samples negative to Bact. coli. in 100 ml. | Bact. coli per 100 ml. | |||
| Hornsey | 257 | 36.0 | 100.0 | - |
| Stoke Newington | 256 | 35.6 | 99.6 | 0.012 |
| Kempton Park | 764 | 28.2 | 99.7 | 0.004 |
Fluoridation of Water Supply
Research has proved that an excess of fluoride above 1.5 parts per
million causes mottling of the tooth enamel. Further, that when the
fluoride content of drinking water is below 1.0 part per million the rate
of dental caries in children increases and where the fluoride is very low or
absent the incidence of dental caries is abnormally high.
The optimum fluoride content for a water supply is, it is suggested,
between 1.0 and 1.5 parts per million. Excess causes mottling, deficiency
increases the susceptibility of children's teeth to caries.
The fluoride content of the water supplied to Hornsey is 0.2 parts per
million. In Hornsey mottling of the enamel is very rare but dental caries
in children is common. The question of whether or not fluoride should
be added to the public supply is one which must be decided in the future.
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