View report page

49
unchanged. Until the new works are completed which will be in some
two to three years, it is impossible to express an opinion as to the amount
of softening which will be carried out."
Purity
Section III of the Public Health Act, 1936, lays it as a duty on every
Local Authority " to take, from time to time, such steps as may be necessary
for ascertaining the sufficiency and wholesomeness of the water
supplies within their district." On consideration of a circular letter
issued by the Ministry of Health relating to the purity of public water
supplies controlled by Local Authorities and Statutory Water Companies,
it was resolved "that the Medical Officer of Health be instructed
to obtain from the Colne Valley Water Company and the Rickmansworth
and Uxbridge Valley Water Company, respectively, weekly analyses of
the water supplied by them, and periodically, himself, to take samples
of the water supplied for the purpose of comparison with the analyses
submitted by the Companies." The Colne Valley Water Company
have supplied, each week, the result of an analysis undertaken at their
laboratories of samples collected at different premises within the district.
The following is a copy of the result of the analysis of a sample of
water supplied by the Colne Valley Water Company taken in May which
is typical of all the analyses (Results in parts per million):—
Appearance : Bright with a few mineral particles.
Colour : Nil. Turbidity less than 3. Odour : Nil.
Reaction pH. 7.3. Electric conductivity 670. Free Carbon dioxide 18.
Total Solids 450. Chlorine in Chlorides 54. Alkalinity as Calcium
Carbonate 245.
Hardness : Total 250. Carbonate 245. Non-carbonate 5.
Nitrate Nitrogen 4.4. Nitrite Nitrogen absent.
Ammoniacal Nitrogen 0.000. Albuminoid nitrogen 0.20.
Oxygen absorbed 0.20. Residual Chlorine absent.
Metals : Iron, less than 0 03; other metals absent.
Bacteriological Results:
No. of colonies per mil. on agar in 24 hours at 37°C.: nil.
B. Coli (absent in) : 100 mil.
B. Welchii (absent in): 100 mil.
"This sample is practically clear and bright in appearance, neutral in reaction
and free from metals apart from a negligible trace of iron. The water is hard in
character, but not to an excessive degree, contains no excess of salinity or mineral
constituents in solution and it is of very satisfactory organic quality. From the
aspect of chemical analysis these results are indicative of a pure and wholesome
water. Suitable for drinking and domestic purposes."
Some diseases are water borne. So that the Company shall know
of the occurrence of any of these, particulars are sent to them of those
households at which there are patients suffering from diseases which
might have been contracted by the consumption of infected water, even
though there was nothing to suggest that in those particular cases infection
had been contracted in this way.
Hardness. The water supplied to this district is classed as hard.
At typical analysis, for instance that of May, 1954, was that the total
hardness was 250, made up of temporary or carbonate hardness of 245
or permanent or non-carbonate hardness of 5. The accepted
D