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 Chislehurst]
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Orpington Well | North Orpington Well | Shortlands Well | Eynsford Well | Bexley Well | . Wilmington Well | Darenth Well | Thames derived filtered water | |
---|---|---|---|---|---|---|---|---|
Number of samples | 249 | 250 | 256 | 352 | 247 | 268 | 241 | 3,321 |
Plate Count (Average per millilitre) Colonies counted on Agar— | ||||||||
22° C. (3 days) | 108.7 | 104.8 | 7.8 | 181.6 | 2.0 | 32.3 | 1.6 | - |
37° C. (20-24 hrs.) | 9.7 | 5.7 | 0.1 | 42.0 | 0.5 | 1.4 | 0.3 | 20.0 |
Bact. coli test— Percentage of samples negative in 100 ml. | 99.6 | 100.0 | 100.0 | 99.2 | 99.6 | 99.6 | 100.0 | 99.9 |
Average number of Bact. coli per 100 ml. | 0.008 | — | — | 0.017 | 0.004 | 0.005 | — | 0.002 |