Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
[Report of the Medical Officer of Health for Hornsey, Borough of]
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All new and repaired mains are chlorinated before being restored to
use and samples of water from them are tested to ensure that its quality
is up to that normally supplied.
The water supplied to this area is not plumbo-solvent.
The water supply is in all cases direct to dwelling houses; none is
supplied by means of a stand-pipe.
Average Results of the Chemical and Bacteriological Examination of the water supplied to Hornsey during the year 1958.
Milligrammes per Litre (unless otherwise stated)
River Thames via Ashford Common | New River (Stoke Newington) | ||
---|---|---|---|
Ammonia Nitrogen | 0.043 | 0.038 | |
Albuminoid Nitrogen | 0.080 | 0.054 | |
Oxidised Nitrogen: Nitrate | 4.0 | 5.9 | |
Chlorides as CI | 27 | 32 | |
Oxygen abs. from permanganate 4 hrs. at 27°C. | 1.32 | 0.64 | |
Turbidity in terms of Silica | 0.3 | 0.1 | |
Colour m.m. brown 2ft. Tube Burgess's Tintometer | 12 | 6 | |
Hardness (Total) | 276 | 302 | |
Hardness (non-carbonate) | 68 | 78 | |
pH. Value | 7.8 | 7.8 | |
Phosphate as P04 | 0.85 | 0.55 | |
Silicate as SiO2 | 8 | 12 | |
Sulphate as SO4 | . | 62 | |
Fluoride as F. | . | 0.15 | |
Magnesium as Mg. | . | 5 | |
B.O.D. 5 days at 20oC. | . | . | |
Electrical Conductivity (gem mhos) | 550 | 625 | |
Bacteriological Results of Water Passing into Supply after Chlorination | Coliform test Percentage samples i negative in 100 ml. | ||
No. of Samples in each case: 259 | |||
Plate counts (Average per ml.) Colonies counted on agar 37°C. | |||
(20-24 hrs.) | Coliform | E.coli | |
River Thames via Ashford Common | 23.0 | 99.61 | 100.0 |
New River (Stoke Newington | 8.0 | 100.0 | 100.0 |