London's Pulse: Medical Officer of Health reports 1848-1972
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Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
Enfield 1965
[Report of the Medical Officer of Health for Enfield]
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WATER SUPPLY
| Average Results in Milligrammes per litre where applicable | |||||
|---|---|---|---|---|---|
| Thames derived North of River | New River derived | Hoe Lane Well derived | Hadley Road Well derived | Waltham Abbey Well derived | |
| No. of Samples | 207 | 104 | 3 | 4 | 4 |
| Albuminoid Nitrogen | 0.091 | 0.065 | 0.043 | 0.023 | 0.042 |
| Ammoniacal Nitrogen | 0.060 | 0.053 | 0.155 | 0.150 | 0.190 |
| Nitrate Nitrogen | 4.2 | 5.7 | 0.1 | 0.2 | 0.1 |
| Oxygen abs. from KMnO4 4hrs at 27º C | 1.20 | 0.72 | 0.38 | 0.22 | 0.42 |
| Hardness (total) CaCO3 | 272 | 302 | 440 | 276 | 274 |
| Hardness (non-carbonate) CaCO3 | 68 | 66 | 144 | 34 | 50 |
| Magnesium as Mg. | 4 | 5 | — | — | — |
| Chloride as CI | 41 | 42 | 32 | 23 | 26 |
| Phosphate as PO4 | 1.9 | 1.4 | — | — | — |
| Silicate as SiO2 | 10 | 12 | — | — | — |
| Sulphate as SO4 | 64 | 60 | — | — | — |
| Natural Flouride as F | 0.25 | 0.25 | 0.55 | 1.15 | 0.65 |
| Surface-active material as Manoxol OT | 0.11 | 0.7 | — | — | — |
| Turbidity Units | 0.1 | 0.1 | 1.1 | 1.2 | 0.6 |
| Colour (Burgess units) | 15 | 7 | 14 | 5 | 8 |
| pH Value | 7.6 | 7.7 | 7.2 | 7.4 | 7.3 |
| Electrical Conductivity (micromhos | 570 | 610 | 770 | 560 | 540 |
| Thames derived North of River | New River derived | Hoe Lane Well derived | Hadley Road Well derived | Waltham Abbey Well derived | |
|---|---|---|---|---|---|
| Number of Samples | — | — | 134 | 273 | 247 |
| Agar Plate Count per ml. 20-24 hrs. at 37°C. | — | — | 0.1 | 0.1 | 0.0 |
| 3 days at 22° C. | — | — | 5 | 9 | 2 |
| Coliform Count % samples neg. in 100 ml. | —_ | — | 98.51 | 94.14 | 96.36 |
| Count per 100 ml. | — | — | 0.2 | 0.3 | 0.1 |
| Escherichia coli Count % samples neg. in 100 ml. | — | —_ | 100.0 | 95.24 | 92.57 |
| Count per 100 ml. | — | — | — | 0.3 | — |
| Number of Samples | 2.046 | 514 | 138 | 239 | 252 |
| Agar Plate Count per ml. 20-24 hrs. at 37°C. | 7.4 | 6.4 | — | 0.2 | 0.2 |
| 3 days at 22°C. | — | — | 2 | 4 | 2 |
| Coliform Count % samples neg. in 100 ml. | 99.95 | 100.0 | 100.0 | 99.58 | 100.0 |
| Escherichia coli Count % samples neg. in 100 ml. | 100.0 | 100.0 | 100.0 | 99.58 | 100.0 |