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
Hackney 1965
[Report of the Medical Officer of Health for Hackney]
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number of wells along its course. This water is filtered and chemically
treated at Stoke Newington works. The Thames water is abstracted from the
river through intakes above Teddington Weir, and, after storage, flows along
an open viaduct to works at Ashford Common, Hampton and Kempton Park, where it
is filtered and chemically treated.
Regular monitoring of the water as it passes through the Works and in the
distribution system is carried out in order to control water purification and
to detect any form of contamination. All new and repaired mains are disinfected
with chlorine and samples of water from these structures are checked in these
laboratories before the water is passed through them into service.
The table below sets out the results of bacteriological examination after treatment. The figures quoted are yearly averages.
| Source of supply | No. of samples | Agar Plate Count per ml. after 20-24 hours at 37°C | Coliform count per cent, samples negative in 100 ml. |
|---|---|---|---|
| New River - Derived | 514 | 6.4 | 100.0 |
| Lee Bridge (Lee-Derived) | 514 | 31.4 | 99.81 |
| All Thames - Derived | 3,888 | 7. 3 | 99.92 |
All samples were 100 per cent Negative in respect of Escherichia coli count.
| New River-derived | Lee Bridge (Lee-derived) | All Thames derived | |
|---|---|---|---|
| No. of samples | 104 | 52 | 363 |
| Ammoniacal Nitrogen | 0.053 | 0.028 | 0.049 |
| Albuminoid Nitrogen | 0.065 | 0.115 | 0.091 |
| Nitrate Nitrogen | 5.7 | 5.6 | 4.3 |
| Oxygen abs. from KMnO4 4 hrs. at 27oc | 0.72 | 1.52 | 1.20 |
| Hardness (total) CaCO3 | 302 | 314 | 264 |
| Hardness (non-carbonate) CaC03 | 66 | 98 | 68 |
| Magnesium as Mg | 5 | 7 | 4 |
| Chloride as Cl | • 42 | 53 | 41 |
| Phosphate as PO4 | 1.4 | 3.4 | 1.9 |
| Silicate as Si02 | * 12 | 11 | 10 |
| Sulphate as SO4 | 60 | 98 | 64 |
| Natural Fluoride as F | 0.25 | 0.25 | 0.25 |
| Surface - active material as Manoxol OT | 0.07 | 0.15 | 0.10 |
| Turbidity units | 0.1 | 0.4 | 0.1 |
| Colour (Burgess units) | 7 | 19 | 15 |
| pH Value | 7.7 | 7.8 | 7.6 |
| Electrical Conductivity (micromhos) | 610 | 680 | 560 |
FLUORIDATION
The three former Metropolitan Borough councils were in favour of the scheme
for adding fluoride to drinking water and this Council re-affirmed its opinion
that the addition of fluoride is harmless to health and effective for dental
protection.