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 Greenwich Borough]
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METROPOLITAN WATER BOARD—Water Examination Department Bacteriological Results—Yearly averages, 1971, of Water Supplied to the London Borough of Greenwich
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. | |||
Thames-derived, | 8,154 | 53.9 | — | 40•37 | 12•2 | 54•91 | 5•1 | 3,901 | 8•4 | _ | 99•51 | 99-97 |
Bexley Well | 263 | 0•1 | 8 | 100•00 | — | 100•00 | — | 254 | 0•1 | 12 | 100•00 | 100•00 |
(a) Crayford No. 1 | 161 | 0•0 | 2 | 99•38 | — | 99•38 | — | |||||
(b) Crayford No. 2 | 153 | 0•8 | 53 | 99•35 | 0•1 | 99•35 | 0•1 | 256 | 0•0 | 7 | 100•00 | 100•00 |
(c) Crayford No. 3 | 101 | 0•0 | 1 | 99•01 | — | 100•00 | — | |||||
Darenth Well | 250 | 0•0 | 14 | 99•20 | — | 100•00 | — | 256 | 0•0 | 4 | 100•00 | 100•00 |
Deptford Well | 214 | 3•4 | 52 | 99•07 | 0•1 | 99•53 | — | 216 | 0•1 | 18 | 100•00 | 100•00 |
(a) Wansunt Borehole | 249 | 0•1 | 14 | 99•60 | -- | 100•00 | - | 254 | 1•2 | 8 | 100•00 | 100•00 |
(b) Wansunt Well | 232 | 6•0 | 129 | 99•57 | - | 99•57 | - | |||||
Wilmington Well | 248 | 0•8 | 74 | 97•18 | 0•2 | 100•00 | — | 245 | 0•3 | 13 | 99•18 | 100•00 |