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 1961
[Report of the Medical Officer of Health for Lewisham Borough]
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Average results of the chemical and bacteriological examination of the water supply to the Borough of Lewisham for 1961
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 | .041 | .076 | 4.1 | 27 | 1.06 | 262 | 52 | 7.9 | 525 |
| Deptford | .028 | .035 | 6.3 | 36 | 0.12 | 374 | 124 | 7.3 | 725 |
| Bex ley | .20 | .043 | 5.9 | 17 | 0.14 | 292 | 48 | 7.2 | 550 |
| Darenth | .022 | .033 | 4.5 | 17 | 0.08 | 270 | 28 | 7.2 | 500 |
| Wilmington | .023 | .041 | 9.0 | 23 | 0.14 | 298 | 54 | 7.2 | 550 |
| BEFORE TREATMENT (RAW WATER) | AFTER TREATMENT (WATER PASSING INTO SUPPLY) | |||||||
|---|---|---|---|---|---|---|---|---|
| Plate counts (average per ml.) Colonies counted on agar | Coliform count | Plate counts (average per ml.) Colonies counted on agar | Coliform count | |||||
| 37° C. (20.24 hrs.) | 22° C. (3 days) | Percentage samples neg. 100 ml. | 37° C. (20.24 hrs.) | 22 C. (3 days) | Percentage samples neg. 100 ml. | |||
| E. Coli | E. Coli | |||||||
| Southern Group | - | - | - | - | 10.0 | - | 99.84 | 99.89 |
| Darenth well | - | 38 | 95.58 | 99.12 | 0.1 | 718 | 100.00 | 100.0 |
| Deptford | 0.2 | 178 | 98.00 | 99.20 | 0.6 | 119 | 100.00 | 100.0 |
| Wilmington No 2. Well | 0.2 | 49 | 96.94 | 100.0 | 0.1 | 2 | 100.00 | 100.0 |
| Bexley | 1.4 | 147 | 10000 | 100.0 | - | 64 | 100.00 | 100.0 |