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 1955
[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 1955
parts per million (unless otherwise stated)
| Description of the sample | No. of samples | Ammoniacal nitrogen | Albuminoid nitrogen | Oxidised nitrogen (nitrate) | Chlorides as Cl. | Oxygen abs. from permanganate (4 hrs.at 27° C) | Hardness (total) | Hardness (noncarbonate) | PH value | Conductivity |
|---|---|---|---|---|---|---|---|---|---|---|
| Bexley Well | 4 | 0.005 | 0.017 | 5.5 | 16 | 0.12 | 286 | 56 | 7.1 | 458 |
| Darenth Well . | 8 | Nil | 0.018 | 5.5 | 16 | 0.06 | 270 | 40 | 7.2 | 440 |
| Shortlands Well | 10 | 0.002 | 0.020 | 4.5 | 17 | 0.08 | 272 | 70 | 7.1 | 450 |
| Wilmington Well | 7 | 0.006 | 0.024 | 7.1 | 21 | 0.12 | 286 | 56 | 7.2 | 450 |
| Deptford Well | 4 | 0.002 | 0.017 | 7.0 | 35 | 0.20 | 359 | 126 | 7.1 | 550 |
| River Thames - derived filtered water | 1663 | 0.014 | 0.085 | 3.8 | 26 | 1.04 | 258 | 65 | 7.8 | 450 |
| BEFORE CHLORINATION | AFTER CHLORINATION (WATER PASSING INTO SUPPLY) | |||||||
|---|---|---|---|---|---|---|---|---|
| No. of samples | Plate count (average per ml.) Colonies counted on agar 37°C. (20-24 hrs.) | 8act. coli test | No. of samples | Plate count (average per ml.) Colonies counted on agar 37°C. (20-24 hrs.) | Bact. coli test | |||
| Percentage samples neg. 100 ml. | Average number per 100 ml. | Percentage samples neg. 100 ml. | Average number per 100 ml. | |||||
| Bexley Well | 420 | 0.1 | 100.0 | — | 256 | — | 100.0 | - |
| Darenth Well | 398 | 0.2 | 99.3 | 0.01 | 251 | — | 100.0 | — |
| Shortlands Well | 499 | 0.04 | 100.0 | — | 256 | — | 100.0 | — |
| Wilmington Well | 470 | 3.0 | 99.4 | 0.01 | 255 | — | 100.0 | — |
| Deptford Well | 221 | 2.2 | 99.6 | 0.01 | 225 | — | 100.0 | — |
| River Thames - derived filtered water | 7040 | — | 60.4 | 3.73 | 3561 | 7.8 | 99.9 | 0.002 |