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 Chigwell]
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newly installed; this applies to copper, zinc, iron
and also to lead.
"Water Samples:-
(a) Average results of Chemical Examination. Milligrammes per litre (unless otherwise stated):-
| Lee Bridge | Copper-mills | Chingford Mill | Waltham Abbey | |
|---|---|---|---|---|
| No. of samples taken during the year | 52 | 52 | 4 | 4 |
| Ammoniacal Nitrogen | 0.022 | 0.012 | 0.190 | 0.20 |
| Albuminoid Nitrogen | 0.096 | 0.105 | 0.019 | 0.034 |
| Nitrate Nitrogen | 5.3 | 5.6 | 0.9 | 0.5 |
| Oxygen abs. frg8m. KMnO4 hours at 27 C | 1.11 | 1.14 | 0.30 | 0.38 |
| Hardness (total) CaCO3 | 304 | 306 | 285 | 276 |
| Hardness (non-carbonate) CaCO3 | 98 | 109 | 71 | 59 |
| Magnesium as Mg | 7 | 7 | - | - |
| Sodium as Na | 35.4 | 35.4 | - | - |
| Potassium as K | 6.6 | 6.6 | - | - |
| Chloride as Cl | 48 | 50 | 27 | 28 |
| Phosphate as PO4 | 3.5 | 3.5 | - | - |
| Silicate as SiO2 | 10 | 9 | - | - |
| Sulphate as SO4 | 92 | 92 | - | - |
| Natural Fluoride as F | 0.25 | 0.25 | 0.50 | 0.70 |
| Surface-active material as Manoxol OT | 0.03 | 0.03 | - | - |
| Turbidity units | 0.2 | 0.1 | 0.1 | 0.3 |
| Colour (Burgess Units) | 13 | 10 | 6 | 4 |
| PH value | 7.9 | 7.9 | 7.4 | 7.4 |
| Electrical Conductivity (micromhos) | 640 | 640 | 530 | 540 |
/(b)
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