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 1950
[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 1950
parts per million (unless otherwise stated)
(o) 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 (permanent) | pH value | Conductivity |
|---|---|---|---|---|---|---|---|---|---|---|
| Deptford well | 3 | 0.007 | 0.023 | 7.5 | 33.8 | 0.13 | 350 | 125 | 7.1 | 550 |
| Wilmington well | 4 | 0.023 | 0.034 | 7.0 | 22.0 | 0.12 | 292 | 67 | 7.2 | 500 |
| Darenth well | 4 | 0.008 | 0.028 | 4.8 | 17.0 | 0.09 | 274 | 57 | 7.3 | 450 |
| Bexley well | 5 | 0.006 | 0.031 | 5.3 | 19.3 | 0.09 | 291 | 69 | 7.2 | 450 |
| Shortlands well | 4 | 0.004 | 0.025 | 4.3 | 18.6 | 0.13 | 298 | 90 | 7.2 | 475 |
| River Thames filtered water from : | ||||||||||
| Hampton works | _ | 0.016 | 0.091 | 4.1 | 25.8 | 1.18 | 274 | 83 | 7.9 | 475 |
| Surbiton works | — | 0.026 | 0.093 | 3.9 | 27.1 | 1.28 | 258 | 82 | 7.8 | 450 |
| Walton works | — | 0.018 | 0.097 | 5.1 | 27.6 | 1.32 | 260 | 81 | 7.8 | 450 |
(b) BACTERIOLOGICAL Table 18
| No. of samples | Agar colony count | Percentage of samples negative to Bact. coli in 100 ml. | Bact. coli per 100 ml. | |
|---|---|---|---|---|
| Deptford well | 255 | _ | 100.0 | Nil |
| Wilmington well | 248 | — | 100.0 | Nil |
| Darenth well | 256 | _ | 100.0 | Nil |
| Bexley well | 217 | _ | 100.0 | Nil |
| Shortlands well | 256 | _ | 100.0 | Nil |
| River Thames water filtered at: | ||||
| Hampton works | 817 | 6.9 | 99.9 | 0.002 |
| Surbiton works | 512 | 11 .6 | 99 8 | 0.002 |
| Walton works | 254 | 15.3 | 100.0 | Nil |