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 Chislehurst]
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Milligrammes per litre (unless otherwise stated).
Description of the Sample | Bexley Well | Orpington Well | North Orping ton Well | Short-lands No. 1 | Short-lands No. 2 | Eyns-ford Well | Eyns-ford Bore Hole | Horton kirby | Wilming ton No.1 | Wilmington No. 2 | Darenth Well | Darenth Bore Hole | Thames-derived |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Number of Samples | 3 | 5 | 4 | 3 | 2 | 4 | 4 | 2 | 4 | 4 | 4 | 4 | 1882 |
Ammonia Nitrogen | 0.007 | 0.002 | 0.002 | 0.005 | 0.002 | 0.001 | 0.001 | 0.005 | 0.002 | 0.001 | 0.001 | 0.006 | 0.027 |
Albuminoid Nitrogen | 0.018 | 0.018 | 0.019 | 0.026 | 0.010 | 0.020 | 0.019 | 0.023 | 0.025 | 0.030 | 0.020 | 0.020 | 0.074 |
Oxidised Nitrogen—Nitrite | — | — | — | — | — | — | — | — | — | — | — | — | — |
Oxidised Nitrogen—Nitrate | 6.5 | 5.8 | 4.4 | 4.3 | 4.5 | 3.2 | 3.3 | 4.5 | 6.2 | 7.4 | 4.6 | 5.0 | 3.9 |
Chlorides as Cl | 17 | 15 | 13 | 17 | 18 | 16 | 16 | 17 | 22 | 22 | 16 | 17 | 29 |
Oxygen abs. from Perman ganate 4 hrs. at 27°C. | 0.06 | 0.08 | 0.08 | 0.03 | 0.02 | 0.10 | 0.06 | 0.05 | 0.14 | 0.10 | 0.06 | 0.11 | 1.16 |
Turbidity in terms of Silica | Nil | Nil | Nil | Nil | Nil | 0.2 | Nil | 0.3 | Nil | Nil | Nil | Nil | 0.3 |
Colour, m.m. brown 2 ft. Tube Burgess's Tintometer | Nil | Nil | Nil | Nil | Nil | Nil | Nil | Nil | Nil | Nil | Nil | Nil | 11 |
Hardness (Total) | 304 | 272 | 258 | 275 | 278 | 256 | 250 | 250 | 278 | 286 | 255 | 272 | 260 |
Hardness (non-carbonate) | 66 | 30 | 21 | 54 | 57 | 24 | 24 | 38 | 44 | 49 | 22 | 36 | 56 |
pH Value | 7.1 | 7.2 | 7.3 | 7.2 | 7.3 | 7.2 | 7.3 | 7.3 | 7.2 | 7.2 | 7.2 | 7.2 | 7.9 |
Phosphate as PO4 | — | — | — | — | — | — | — | — | — | — | — | — | 0.90 |
Silicate as SiO2 | - | - | - | - | - | - | - | - | - | - | - | - | 10 |
B.O.D. 5 days at 20°C. | - | - | - | - | - | - | - | - | - | - | - | - | - |
Electrical Conductivity (gemm-hos) | 575 | 525 | 475 | 525 | 525 | 475 | 475 | 475 | 525 | 550 | 500 | 525 | 550 |