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During 1953, reports were received on 2,274 samples taken by local foods and
drugs authorities and of these only 7 were regarded as unsatisfactory. 140 samples were
examined chemically in the County Hall laboratory and five were unsatisfactory.
Whenever a sample was found to be unsatisfactory, ' follow-up ' samples were taken.
16 samples of powdered and condensed milk were examined and 4 were unsatisfactory.
In some cases deterioration in condition was regarded as due to prolonged storage
and a complaint of discoloration was considered to be caused by faulty processing in
manufacture.
Drinking water
Much care and attention is given to ensuring that the water supplies to Council
establishments are of satisfactory quality. Although in the majority of cases the water is
taken from a Company supply, there are a number of residential schools and other
premises at which it is drawn from private wells. In these cases continuous treatment
and supervision is given, the well supply being chlorinated before use by means of
automatic dosing apparatus. The Chemical Branch undertakes regular monthly
inspections and samples are taken of both untreated and treated water for chemical and
bacteriological examination in the laboratory ; chlorine tests are made to confirm the
adequacy of the dosage, which is also determined daily by the resident engineer at each
establishment.
The well supplies of some hospitals formerly under the control of the London
County Council have, at the request of the hospital committees, continued to be
included in the regular programme of water examination.
During 1953, the water supplies to 18 establishments were regularly examined, and
visits were made to other premises to investigate particular complaints, check the
suitability of water from various sources and give advice. In all, 1,271 samples were
taken during the year ; of these, 537 were tested for free chlorine, 64 were examined
chemically, and 670 bacteriologically.
The following are some examples of matters arising from water examination during
the year.
A case of pollution was found to be due to birds gaining access to a tower tank ;
the trouble was eliminated by the use of wire netting.
At two hospitals in the same locality sudden deterioration in the quality of the
well water occurred after a period of heavy rainfall. Contact was made with the
local water authority and it was found that the trouble was fairly widespread in this
particular area. The chlorine dosage was raised as a precautionary measure and a
sterile supply was maintained at service taps.
The private well supply of a large house in Suffolk was found to have an unusually
high content of nitrate (20 parts per million of nitrate nitrogen). There have
been a few recorded cases of cyanosis in very young infants due to methaemoglobinaemia
caused by ingestion of nitrates in water and it happens that the first
two cases reported in the United Kingdom were from the same part of the county.
Advice was, therefore, given that babies should not be exposed to any risk from this
water.
Air pollution
The Council maintains instruments for the measurement of air pollution at County
Hall, the two Outfall Works at Beckton and Crossness, seven parks and other sites within
the County, Kew Observatory and King George V Hospital at Godalming. The
work is done in conjunction with the Department of Scientific and Industrial Research
and it forms part of a long-term investigation covering the whole of the country.
At the first three sites mentioned, daily measurements are made of sulphur dioxide
and smoke concentrations and at the other sites a monthly assessment of conditions is
obtained using the deposit gauge and lead peroxide methods. In addition to these
regular observations, other individual problems were dealt with from time to time
relating to emission of black smoke and the deposition of grit and ash.