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 1951
[Report of the Medical Officer of Health for Lewisham Borough]
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Average results of the examination of the water supply to the Borough of Lewisham for 1951
parts per million (unless otherwise stated)
(a) CHEMICAL Table 17
| Description of the sample | No. of samples | Ammoniacal nitrogen | Albuminoid nitrogen | Oxidised nitrogen (nitrate) | Chlorides as CI. | Oxygen abs. from permanganate (3 hrs. at 80°F) | Hardness (total) | Hardness (non. carbonate) | pH value | Conductivity |
|---|---|---|---|---|---|---|---|---|---|---|
| Deptford well | 6 | 0.014 | 0.038 | 7.2 | 33.2 | 0.14 | 363 | 124 | 7.1 | 600 |
| Wilmington well | 6 | 0.015 | 0.033 | 7.9 | 19.8 | 0.12 | 291 | 54 | 7.2 | 475 |
| Darenth well | 3 | 0.007 | 0.023 | 5.2 | 15.8 | 0.12 | 264 | 32 | 7.4 | 400 |
| Bexley well | 6 | 0.009 | 0.053 | 5.8 | 17.3 | 0.16 | 295 | 61 | 7.3 | 450 |
| Shortlands well | 6 | 0.005 | 0.022 | 5.1 | 16 3 | 005 | 295 | 77 | 7.3 | 450 |
| River Thames derived filtered water | 1749 | 0.022 | 0.085 | 40 | 22.5 | 1.34 | 264 | 63 | 7.8 | 450 |
(b) BACTERIOLOGICAL Table 18
| No. of samples | Agar colony count (average per millilitre) | Percentage of samples negative to Bad. coli in 100 ml. | Bact. coli per 100 ml. | ||
|---|---|---|---|---|---|
| 22°C 3 days | 37 °C (20-24 hrs.) | ||||
| Deptford well | 244 | 11.2 | 1.2 | 99.6 | 0.008 |
| Wilmington well | 268 | 32.3 | 1.4 | 99.6 | 0.005 |
| Darenth well | 241 | 1.6 | 0.3 | 100.0 | nil |
| Bexley well | 247 | 2.0 | 0.5 | 99.6 | 0.004 |
| Shortlands well | 256 | 7.8 | 0.1 | 100.0 | nil |
| River Thames derived filtered water | 3321 | - | 20.0 | 99.9 | 0.002 |