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It was considered desirable to obtain by overall test baiting a basis upon which the effectiveness
of "1081" could be judged after four "direct" controls, and this was carried out during
the period 10th - 13th September, 1956, three months after the pre-bait and final "1080" control
being repeated 19th - 22nd November, 1956, ten weeks later, and three weeks prior to the first
"1081" control.
For the first test baiting, 402 sewer entrances were baited and the baits, each 4 ounces,
were left down for three days, and on examination 103 "takes" (84 complete, 6 x ¾, 8 X ½ and
5 x ¼) were recorded. The weather, an important factor in sewer control, was favourable and the
299 test baits recorded as no "takes" were in good condition after three days.
For the purpose of the second overall test baiting, 19th - 23rd November, 403 sewer entrances
were baited and the recorded result was 174 "takes" (165 complete and 9 x ½). The weather
was again favourable, and no rain being experienced during the work or the previous three weeks,
the sewer entrances were dry and in ideal condition for the test.
The significant feature of the test result was the formidable increase in the number and
quality of the test bait "takes", indicating the rapid build-up and distribution in the period of
nine months between the last overall "direct" poisoning with "1080", for as previously mentioned
only 49 entrances were subject of poison bait in the June control.
The first "1081" "direct" control was applied in December, 1956, the procedure being
similar to the "1080" treatments, in dispensing and distribution.
The recorded result of the examination of the 394 entrances baited was 87 "takes" (8 complete,
7 x ¾, 39 x ½ and 33 x ¼ or less) and 51 bodies were recovered, the majority of which were
in the flows, a considerable distance from the baits. The weather during this control was adverse,
and heavy rain at times made examination of the baits difficult and only definite "takes" were
recorded.
To complete this record of sewer control up to the time of writing, the second treatment of
this series was carried out in March, 1957. In this instance the recorded result of 401 entrances
baited was 60 "takes" (11 complete, 7 x 18 x ½, and 24 x ¼ or less) each bait, with the exception
of eight being4 ozs each. Fight entrances where complete"takes"were recorded in the December
control were given 8 ozs. baits, and of these 4 x ¼ "takes" were obtained. A total of 34
bodies were found, all of which were in shallow and slow flows.
From close observation of these treatments and analysis of the sector recordings, the initial
introduction of Fluoracetamide as a rodenticide for sewer treatments is, so far, promising, but
a comprehensive picture of its properties will be reflected on completion of the series in September,
1957, after which overall tests will be applied.
ATMOSPHERIC POLLUTION
During 1956 the Public Health Committee received a report relative to sulphur oxides in the
neighbourhood of St. Paul's Cathedral. It was indicated there 'would be little prospect at the
present time of securing legislation or control by regulation to deal with sulphur emissions. A
contribution to the problem would be to ask developers to consider first the use of an
"authorised" fuel under the City of London (Various Powers) Act, 1954. The Improvements and
Town Planning Committee agreed to the Resolution of the Public Health Committee that when
recommending the grant of planning permissions it should be indicated to the developers that
advice should be sought from the Medical Officer of Health, in the case of alterations to old
buildings, and from the City Engineer, in the case of new developments, with reference to the
heating installations to be provided in connection with such developments.
The Clean Air Act, 1956, with its comprehensive proposals to deal with the smoke pollution
of the atmosphere, received the Royal Assent during the year. Certain provisions of the Act
became operative on the 31st December, 1956, and for record purposes the joint report of the
Medical Officer of Health and the City Engineer to the Port and City of London Health Committee
is reproduced below. The recommendations appended to the report have been adopted.
CLEAN AIR ACT, 1956
The Clean Air Act, 1956 (Appointed Day) Order, 1956
The Smoke Control Areas (Authorised Fuels) Regns. 1956
Model Building Byelaw under Section 24 in regard to heating
and cooking appliances in new buildings.
The Minister of Housing and Local Government appointed the 31st December, 1956 as the
date on which certain provisions of the Clean Air Act, 1956 came into operation. The Act gives
local authorities new powers and duties for the prevention of air pollution, and the provisions
now in force deal with the installation of new furnaces; the height of chimneys; smoke control
areas; pollution from colliery spoilbanks; research and publicity; and the making of building
byelaws. The Minister has also issued the Smoke Control Areas (Authorised Fuels) Regulations,
1956, and a Model Building Byelaw in regard to heating and cooking appliances in new buildings.
The Minister intends, at a later date, to make an Order fixing a date in the earlier part of 1958 as
the appointed day for the remaining provisions of the Act.
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