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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"Water Samples:
(a) Average results of Chemical Examination. Milligrammes per litre (unless otherwise stated):-
Copper mills | Ferry Lane | Lee Bridge | Chingford Mill | Waltham Abbey | |
---|---|---|---|---|---|
No. of samples taken during the year | 33 | 3 | 52 | 4 | 4 |
Ammoniacal Nitrogen | 0.021 | 0.014 | 0.025 | 0.142 | 0.170 |
Albuminoid Nitrogen | 0.105 | 0.082 | 0.092 | 0.029 | 0.040 |
Nitrate Nitrogen | 3.3 | 4.1 | 3,7 | 0.4 | 0.2 |
Oxygen abs. from KMnO. 4 hours at 27°C | 1.24 | 1.11 | 1.15 | 0.33 | 0.18 |
Hardness (total) CaCO3 | 314 | 371 | 316 | 276 | 286 |
Hardness (non-carbonate) CaC03 | 98 | 149 | 96 | 59 | 76 |
Magnesium as Mg | 6 | 6 | 6 | - | - |
Sodium as Na | 33.5 | 33.5 | 33.5 | - | - |
Potassium as K | 7.3 | 7.3 | 7.3 | - | - |
Chloride as CI | 42 | 45 | 44 | 25 | 27 |
Phosphate as PO4 | 2.7 | 2.4 | 2.8 | - | - |
Silicate as SiO2 | 8 | 12 | 10 | - | - |
Sulphate as SO4 | 96 | 96 | 96 | - | - |
Natural Fluoride as F | 0.35 | 0.35 | 0.35 | 0.55 | 0.75 |
Surface-active material as Manoxol OT | 0.03 | 0.03 | 0.03 | - | - |
Turbidity units | 0.2 | 0.1 | 0.1 | 0.1 | 0.5 |
Colour (Burgess units) | 13 | 7 | 14 | 2 | 8 |
pH value | 8.2 | 7.7 | 8.1 | 7.5 | 7.5 |
Electrical Conductivity (microhms) | 620 | 790 | 670 | 560 | 550 |
(b)
-20-