Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
[Report of the Medical Officer of Health for Orpington]
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Parts per million (unless otherwise stated)
BACTERIOLOGICAL RESULTS
Source of supply | BEFORE TREATMENT | AFTER TREATMENT | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Number of samples | Agar plate count per ml. | Coliform count | Number of samples | Agar plate count per ml. | Coliform count | |||||||
20-24 hours at 37°C. | 3 days at 22°C. | Per cent, samples negative in 100 ml. | Count per 100 ml. | Per cent, samples negative in 100 ml. | Count per 100 ml. | 20-24 hours at 37°C. | 3 days at 22°C | Per cent, samples negative in 100 ml. | Per cent, samples negative in 100 ml. | |||
Orpington | 252 | 0-2 | 3 | 93-25 | 0-2 | 99-60 | 257 | 0-1 | 7 | 99-22 | 99-6 | |
North Orpington | 245 | 2-3 | 23 | 17-55 | 20-0 | 33-47 | 100 | 250 | 0-9 | 2 | 100 | 100 |
Eynsford Well | 229 | 0-1 | 9 | 81-22 | 1-4 | 99-13 | — | } 258 | 0-1 | 25 | 100 | 100 |
Eynsford Borehole | 175 | 01 | 3 | 100 | — | 100 | _ | |||||
Lullingstone | 252 | 0-1 | 3 | 99-60 | 100 | — | 257 | 0-3 | 25 | 100 | 100 | |
Sundridge No.2 | 250 | 0-1 | 3 | 100 | 100 | — | } 253 | 0-1 | 6 | 100 | 100 | |
Sundridge No.4 | 45 | — | 3 | 100 | — | 100 | — | |||||
Westerham | 250 | 01 | 41 | 100 | — | 100 | — | 255 | 0-1 | 9 | 98-04 | 100 |
Thames derived | - | - | - | — | - | — | 3,344 | 9-8 | 99-46 | 99-97 |