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 Bexley]
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Source of supply | BEFORE TREATMENT | AFTER TREATMENT | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Number of samples | Agar plate count per ml. | Coliform count | Escherichia coli count | Number of samples | Agar plate count per ml. | Coliform count | E. coli 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. | |||
River Thames - Derived | 8,154 | 53.9 | — | 40.37 | 12.2 | 54.91 | 5.1 | 3,901 | 8.4 | 99.51 | 99.97 | |
Bexley | 263 | 0.1 | 8 | 100.0 | — | 100.0 | — | 254 | 0.1 | 12 | 100.0 | 100.0 |
Crayford No. 1 | 161 | 0.0 | 2 | 99.38 | — | 99.38 | — | 256 | ||||
Crayford No. 2 | 153 | 0.8 | 53 | 99.35 | 0.1 | 99.35 | 0.1 | 0.0 | 7 | 100.0 | 100.0 | |
Crayford No. 3 | 101 | 0.0 | 1 | 99.01 | — | 100.0 | — | |||||
Darenth | 250 | 0.0 | 14 | 99.20 | — | 100.0 | — | 256 | 0.0 | 4 | 100.0 | 100.0 |
(a) Eynsford Well | 161 | 0.0 | 10 | 98.14 | — | 98.14 | — | 255 | ||||
(b) Eynsford Borehole | 197 | 0.0 | 3 | 99.49 | 0.1 | 99.49 | 0.1 | 0.1 | 13 | 100.0 | 100.0 | |
(a) Horton Kirby No. 1 | 134 | 0.0 | 29 | 88.81 | 0.3 | 95.52 | 0.1 | 251 | ||||
(b) Horton Kirby No. 2 | 169 | 0.0 | 5 | 98.22 | — | 98.82 | — | 0.1 | 3 | 100.0 | 100.0 | |
(a) Wansunt Borehole | 249 | 0.1 | 14 | 99.60 | — | 100.0 | — | 254 | 1.2 | 8 | 100.0 | 100.0 |
(b) Wansunt Well | 232 | 6.0 | 129 | 99.57 | — | 99.57 | — | |||||
Wilmington | 248 | 0.8 | 74 | 97.18 | 0.2 | 100.0 | — | 245 | 0.3 | 13 | 99.18 | 100.0 |