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 1949
[Report of the Medical Officer of Health for Lewisham Borough]
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24
Average results of the examination of the water supply to the Borough of Lewisham for 1949
PARTS PER MILLION (unless otherwise stated)
(a) CHEMICAL Table 13
| 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 (permanent) | pH value | Conductivity |
|---|---|---|---|---|---|---|---|---|---|---|
| Deptford well | 4 | 0.004 | 0.026 | 6.9 | 35.0 | 0.19 | 350 | 153 | 7.1 | 600 |
| Wilmington well | 8 | 0.013 | 0.022 | 6.0 | 20.8 | 0.21 | 295 | 81 | 7.1 | 450 |
| Darenth well | 4 | 0.006 | 0.019 | 5.0 | 15.9 | 0.08 | 290 | 74 | 7.1 | 425 |
| Bexley well | 2 | 0.000 | 0.023 | 4.8 | 16.3 | 0.04 | 285 | 91 | 7.1 | 450 |
| Shortlands well | 5 | 0.001 | 0.038 | 4.7 | 22.3 | 0.40 | 261 | 95 | 7.3 | 450 |
| Hampton (Thames filtered) | 250 | 0.015 | 0.087 | 4.3 | 27.4 | 1.13 | 244 | 71 | 7.7 | 450 |
| Surbiton (Thames filtered) | 300 | 0.017 | 0.084 | 4.1 | 28.1 | 1.14 | 236 | 66 | 7.7 | 450 |
| Walton (Thames filtered) | 247 | 0.017 | 0.093 | 4.6 | 28.8 | 1.26 | 238 | 69 | 7.6 | 450 |
(b) BACTERIOLOGICAL Table 14
| No. of samples | Agar colony count | Percentage of samples negative to Bact. coli in 100 ml. | Bact. coli per 100 ml. | |
|---|---|---|---|---|
| Deptford well | 254 | -_ | 100.0 | Nil |
| Wilmington well | 422 | — | 100.0 | Nil |
| Darenth well | 254 | — | 100.0 | Nil |
| Bexley well | 234 | — | 100.0 | Nil |
| Shortlands well | 255 | — | 99.2 | 0.016 |
| Hampton (Thames filtered) | 980 | 7.5 | 99.7 | 0.006 |
| Surbiton (Thames filtered) | 512 | 10.5 | 99.4 | 0.055 |
| Walton (Thames filtered) | 255 | 20.8 | 100.0 | Nil |