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are forwarded to the Warren Spring Laboratory of the Ministry of
Technology, who are conducting a five-year survey of air pollution
on a national basis. The object of the survey is to enable valid
conclusions to be drawn concerning the level and distribution of
air pollution. It has already been reported that there has been a
marked reduction in the concentration of smoke in the Greater
London Area, which is directly attributable to the establishment
of smoke control areas throughout the area.
RADIOACTIVE SUBSTANCES ACT
Although the main burden of the supervision of premises at
which radioactive isotopes are stored or used falls upon the staff
of the Ministry of Housing and Local Government certain duties
devolve on the Local Authority.
The premises concerned are mainly places where scientific
research is undertaken but senior schools may also use sealed
sources of radiation.
During the year the use of luminous paint which was applied
to the skin on the back of the hands of patrons at a certain dance
establishment as a "check out" system was investigated. This substance
was found to possess carcinogenic properties and might have
presented danger particularly to those applying the paint. The
proprietors undertook to cease using the paint.
PREVENTION OF DAMAGE BY PESTS ACT, 1949
RODENT CONTROL
The problem of rat and mouse infestation is a continuing one.
Theoretically, if all sources of infestation were reported immeddiately
and we were able to cope with the huge initial volume of
work expeditiously the rodent population could be practically
eliminated by the use of modern methods and poisons. In practice,
however, notification is rarely given at the first sign of infestation
and a mating pair can very quickly become a large family. A doe
can become a mother at three months and as the gestation period
tor a rat is approximately three weeks it is not difficult to appreciate
how this happens.
Compared with last year there was a fall of almost 17% in
the number of notifications of rat infestation but the factors likely
to influence this number are too numerous to attempt to suggest a
reason for the reduction. One hopes, however, that it was due
mainly to our efforts in the previous year!
Considering the vast network of soil sewers in the borough
our problem with rat infestation is very slight indeed. Two poison