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 Richmond]
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AVERAGE RESULTS OF THE CHEMICAL EXAMINATION of the water supplied to the London Borough of Richmond upon
Thames during 1971. Milligrams per litre (unless otherwise stated).
Description of the Sample | Number of Samples | Ammoniacal Nitrogen | Albuminoid Nitrogen | Nitrate Nitrogen | Oxygen abs. from KMnO44 hrs. at 27° C. | B.O.D 5 days at 20° C. | Hardness (total) CaCO3 | Hardness (non-carbonate) CaC03 | Magnesium as Mg | Sodium as Na | Potassium as K | Chloride as CI | Phosphate as P04 | Silicate as SiO2 | Sulphate as S04 | Natural Fluoride as F | Surface-active material as Manoxol OT | Turbidity units | Colour (Burgess units) | pH value | Electrical Conductivity (micromhos) | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) | (11) | (12) | (13) | (14) | (15) | (16) | (17) | (18) | (19) | (20) | (21) | (22) | (23) |
River Thames-Derived | 364 | 0.029 | 0.084 | 6.1 | 1.04 | — | 281 | 90 | 5 | 23.5 | 5.1 | 34 | 2.3 | 10 | 64 | 0.15 | 0.02 | — | 0.1 | 13 | 7.8 | 580 |
BACTERIOLOGICAL RESULTS — YEARLY AVERAGES, 1971
Source of supply | BEFORE TREATMENT | AFTER TREATMENT | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
1 Agar plate count per ml. | Coliform count | Escherichia coli count | Agar plate count per ml. | Coliform count | E. coli count | |||||||
Number of samples | 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. | Number of samples | 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 |