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 1962
[Report of the Medical Officer of Health for Lewisham Borough]
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26
Average results of the chemical and bacteriological examination of the water supply to the Borough of Lewisham for 1962
milligrams per litre (unless otherwise stated)
(a) CHEMICAL
Table 18
| Description of the sample | Ammonia nitrogen | Albuminoid nitrogen | Oxidised nitrogen (nitrate) | Chlorides as CI. | Oxygen abs. from permanganate (4 hrs. at 27°C) | Hardness (total) | Hardness (non-carbonate) | pH value | Electrical Conductivity (micromhos) |
|---|---|---|---|---|---|---|---|---|---|
| Southern Group | .042 | .076 | 31 | 1.12 | 256 | 58 | 7.8 | 550 | |
| Deptford | .009 | .029 | 36 | 0.14 | 362 | 114 | 7.2 | 720 | |
| Bexley | .011 | .031 | 5.5 | 19 | 0.10 | 318 | 68 | 7.2 | 580 |
| Darenth | .010 | .023 | 5.3 | 17 | 0.10 | 266 | 26 | 7.2 | 500 |
| Wilmington | .017 | .033 | 9.3 | 23 | 0.14 | 292 | 48 | 7.2 | 550 |
(b) BACTERIOLOGICAL
Table 19
| BEFORE TREATMENT (RAW WATER) | AFTER TREATMENT (WATER PASSING INTO SUPPLY) | |||||||
|---|---|---|---|---|---|---|---|---|
| Plate counts (average per ml.) Colonies counted on agar 37°C. | Coliform count | Plate counts (average per ml.) Colonies counted on agar 37°C. | Coliform count | |||||
| Percentage samples neg. 100 ml. | Percentage samples neg. 100 ml. | |||||||
| (20-24 hrs.) | 22°C. (3 days) | Coliform | E. Coli | (20-24 hrs.) | 22°C. (3 days) | Coliform | E. Coli | |
| Southern Group | - | - | - | - | 11.5 | - | 99.79 | 99.95 |
| Darenth well | 129 | 96.00 | 99.20 | 0.2 | 6 | 99.60 | 100.C0 | |
| Deptford | 58 | 98.80 | 99.20 | 2.2 | 216 | 99.61 | 99.61 | |
| Wilmington No 2. Well | 0.1 | 42 | 94.31 | 97.15 | 13.0 | 375 | 98.41 | 100.00 |
| Bexley | 0.1 | 44 | 98.41 | 98.80 | 0.0 | 10 | 100.00 | 100.00 |