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cleaning of diffuser tiles for the air supply in the activated sludge plant, and to the
publication of two papers on improved analytical methods.
The question of trade discharges into sewers was investigated in a number of
cases as to compliance with the appropriate clauses of the Public Health (London)
Act, 1936.
Safety lamps used in sewers were tested and adjusted periodically and an
officer of the Chemical Branch gave advice and assistance in training men employed
on sewerage work in the use of oxygen breathing apparatus under emergency
conditions.
The sewage treatment service is a joint function of the Chief Engineer's and
Public Health departments and special mention should be made of the cordial
relations which have so greatly helped in maintaining the efficiency of the operations.
Weekly conferences of the Divisional Engineer (Main Drainage) and the
Chemist-in-Chief and their senior officers have been of the utmost value in this
respect.
The Chemist-in-Chief was appointed in 1949, to be a member of the "Thames
Survey Committee" set up by the Department of Scientific and Industrial
Research at the request of the Port of London Authority.
Regular chemical analyses and bacteriological examinations were made of the
drinking waters derived from private wells at various Council premises and also at
a number of hospitals, this service having been continued at the request of the
various hospital committees. All these water supplies are chlorinated before use
and the dosage was periodically checked.
The air in the Council's vehicular tunnels was regularly examined in order to
ensure that the carbon monoxide content did not exceed the safety limit; in view
of the continued use of petrol containing lead compounds, the lead content of the
air was also checked occasionally and was found to be safe.
On the medical examination and diagnosis side a few cases of interest might be
mentioned. A man employed on cutting up old galvanised sheeting by the use of
an acetylene flame reported sick: on investigating the circumstances it was
suggested that the cause was zinc fume fever and this was confirmed by subsequent
analytical tests. Dermatitis was, in another case, suspected to have been caused by
the use of a paint remover: analysis showed that on dissolving the preparation in
water, caustic soda was produced by interaction: this material needs special
precautions in handling, such as the use of protective rubber gloves. Similar
precautions were advised in regard to another substance used in a print developing
process which had affected the user's hands. An apron (private property) used in
a Council's kitchen caught fire and injured the wearer: a similar article was
examined and was found to be highly inflammable and not suitable for use near
heated metal: the danger arose from a plasticiser incorporated in the coating
material.
The work done in co-operation with the Restaurants and Catering Department
was continued, and many meals were analysed as to their nutritional value by the
determination of their fat, protein, carbohydrate and mineral contents, and of their
calorific value: attention was also given to the ascorbic acid (Vitamin C) content.
Having regard to the continued difficulty in the supply position, the results showed
a reasonably good approach to the targets aimed at for the nutritional factors for
the various age groups concerned. The few whole day food intakes assessed at
residential schools were found to be up to the nutritional requirements. Other
matters which might be mentioned shortly were: (a) comparison of thermal
insulation efficiencies of different types of container: (b) devising a method for
removing stains from plastic plates : (c) comparison of different procedures for
cooking green vegetables with a view to the retention of the maximum possible
amount of the ascorbic acid (Vitamin C) content.
Public
Health
School and
other meals