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
Barnet 1961
[Report of the Medical Officer of Health for Barnet Urban District Council]
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The Public Analyst reported upon his chemical examination of a sample of mains water as follows:—
| Parts per million | |
| Total Solid Residue left on evaporation, dried at 100°C | 427.5 |
| Loss on incineration of Residue | 42.5 |
| Chlorine present as Chloride | 28.0 |
| Equal to Sodium Chloride | 46.1 |
| Nitrate Nitrogen | 4.7 |
| Ammoniacal Nitrogen (free Ammonia) | .01 |
| Albuminoid Nitrogen | .01 |
| Oxygen absorbed by Oxidisable Organic Matter, etc., from Potassium Permanganate solution at a temperature of 27 C In 15 Minutes | .14 |
| In 4 Hours | .24 |
| Appearance | Clear |
| Total Hardness | 300 |
| Permanent Hardness (i.e. left after boiling) | 90 |
| Metallic Contamination | Satisfactorily free |
| pH (Hydrogen Ion concentration) | 7.2 |
| Free Chlorine | 0.02 |
| This calls for no special comment. |
Rainfall for the year was a little below average, precipitation at the
North Mymms Pumping Station being 24.78", 4.27% below the average, for 24 years,
of 25.89", but 22.90% under the figure of 32.14" recorded for the year 1960.
No restrictions were imposed on the use of water.
DRAINAGE AND SEWERAGE.
The town is drained and sewered on the separate system, excepting the older
portions of the district where it is a combined system. The sewage is
conveyed to a Sewage Disposal works of 56 acres, where it is screened, grit
removed in detritus tanks, thence to primary settlement tanks and thereafter
distributed over three 80 ft. diameter bacteria filters, followed by humus
removal in rectangular tanks before discharge to the Dollis Brook. Pumping
is necessary for three sewers which have their outlets at a low point on the