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
Lewisham 1947
[Report of the Medical Officer of Health for Lewisham Borough]
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Results of the Chemical and Bacteriological Examination of the water supply to the Borough of Lewisham
January - December, 1947 PARTS PER MILLION (unless otherwise stated)
| Description of the sample | No. of samples | Ammon- iacal Nitrogen | Albuminoid Nitrogen | Oxidised Nitrogen | Chlorides as CI. | Oxygen abs. from Permanganate 3 hrs. at 800 F. | Turbidity in terms of Silica | Colour m.m. brown 2ft. tube Burgess's Tintometer | Hardness (Total) | Hardness (Permanent) | PH. Value | Residual chlorine in water leaving the works | Conductivity | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Nitrite | Nitrate | |||||||||||||
| Deptford Well | 4 | 0.003 | 0.021 | 5.1 | 37.9 | 0.17 | - | 0 | 351 | 164 | 7.1 | Nil | 625 | |
| Wilmington Well | 8 | 0.010 | 0.025 | 5.8 | 21.0 | 0.20 | - | 0 | 313 | 100 | 7.1 | 0.1 | 500 | |
| Darenth Well | 0.010 | 0.020 | 4.5 | 16.9 | 0.13 | - | 0 | 307 | 101 | 7.1 | Nil | 450 | ||
| Bexley Well | 1 | 0.000 | 0.020 | 5.0 | 17.5 | 0.12 | - | 0 | 215 | 109 | 7.1 | 0.1 | 500 | |
| Shortlands Well Thames derived filtered water | 4 | 0.008 | 0.029 | 4.8 | 19.5 | 0.21 | - | 2 | 313 | 107 | 7.1 | Nil | 475 | |
| (Walton) | 253 | 0.152 | 0.092 | 3.5 | 25.5 | 1.28 | 0.9 | 21 | 236 | 70 | 7.6 | Nil to 0.35 | 450 | |
BACTERIOLOGICAL RESULTS
| No. of samples | Colony Count on Agar at 37°C. | Bact. coli Test | ||
|---|---|---|---|---|
| Percentage of samples negative per 10 ml. | Bact. coli per 100 ml. | |||
| Deptford Well | 254 | — | 100.0 | Nil |
| Wilmington Well | 502 | — | 100.0 | Nil |
| Darenth Well | 252 | — | 99.6 | 0.008 |
| Bexley Well | 249 | — | 100.0 | Nil |
| Thames derived filtered water (Walton) | 256 | 27.9 | 98.1 | 0.031 |