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 Lewisham Borough]
This page requires JavaScript
Average results of the examination of the water supply to the Borough of Lewisham for 1951
parts per million (unless otherwise stated)
(a) CHEMICAL Table 17
Description of the sample | No. of samples | Ammoniacal nitrogen | Albuminoid nitrogen | Oxidised nitrogen (nitrate) | Chlorides as CI. | Oxygen abs. from permanganate (3 hrs. at 80°F) | Hardness (total) | Hardness (non. carbonate) | pH value | Conductivity |
---|---|---|---|---|---|---|---|---|---|---|
Deptford well | 6 | 0.014 | 0.038 | 7.2 | 33.2 | 0.14 | 363 | 124 | 7.1 | 600 |
Wilmington well | 6 | 0.015 | 0.033 | 7.9 | 19.8 | 0.12 | 291 | 54 | 7.2 | 475 |
Darenth well | 3 | 0.007 | 0.023 | 5.2 | 15.8 | 0.12 | 264 | 32 | 7.4 | 400 |
Bexley well | 6 | 0.009 | 0.053 | 5.8 | 17.3 | 0.16 | 295 | 61 | 7.3 | 450 |
Shortlands well | 6 | 0.005 | 0.022 | 5.1 | 16 3 | 005 | 295 | 77 | 7.3 | 450 |
River Thames derived filtered water | 1749 | 0.022 | 0.085 | 40 | 22.5 | 1.34 | 264 | 63 | 7.8 | 450 |
(b) BACTERIOLOGICAL Table 18
No. of samples | Agar colony count (average per millilitre) | Percentage of samples negative to Bad. coli in 100 ml. | Bact. coli per 100 ml. | ||
---|---|---|---|---|---|
22°C 3 days | 37 °C (20-24 hrs.) | ||||
Deptford well | 244 | 11.2 | 1.2 | 99.6 | 0.008 |
Wilmington well | 268 | 32.3 | 1.4 | 99.6 | 0.005 |
Darenth well | 241 | 1.6 | 0.3 | 100.0 | nil |
Bexley well | 247 | 2.0 | 0.5 | 99.6 | 0.004 |
Shortlands well | 256 | 7.8 | 0.1 | 100.0 | nil |
River Thames derived filtered water | 3321 | - | 20.0 | 99.9 | 0.002 |