View report page

64
If the stone is a lime stone, the arsenic acid having a greater affinity for lime than
sodium, combines with the lime to form arsenate of lime and caustic soda, this latter at
once is carbonated and is washed off as carbonate of soda. The arsenate of lime becomes
locked up with the silica both in the pores of the stone and on the surface where it
forms a firm and almost insoluble coating.
In the case of sandstone there is a possibility in the process as described above of
some arsenic being washed off in the form of arsenate of soda, but the patentees are
taking steps to remove this risk by an improved process.
The public health interest attaching to the question is mainly confined to the
possibility of well-water contamination due to the percolation of the arsenic water through
the soil to the water-bearing strata beneath.
At present the process is not much used, and even if it were, it would be attended
with no danger in the City, inasmuch as the washings of all buildings run direct into
the sewers.
Some slight risk might, however, appear to obtain in the country, but it must not
be forgotten that the number of buildings there requiring treatment would be very few,
churches probably being the only ones which would be submitted to the process under
review.
I am of opinion, therefore, that even in rural areas the question is not one which
calls for serious consideration.
REMOVAL OF FISH OFFAL.
The contract with Messrs. F. S. Hempleman and Co., for the removal of fish offal,
expired on the 21st May, 1913, and on the recommendation of the City Engineer and
your Medical Officer of Health, was renewed for a further period of 12 months.
The conditions of the contract, which was originally entered into in May, 1906,
and has since that date been in continual operation, require that the Contractors shall
collect and remove, free of charge, between the hours of 7 p.m. and 9 a.m., all fish offal
from the Corporation Markets and fishmongers' premises in the City, to the entire
satisfaction of the Medical Officer of Health, in specially constructed galvanised iron
bins of a pattern approved by that Officer, and to thoroughly cleanse and disinfect such
bins before returning them to the Markets and shops.
The undertaking of the Contractors to remove the material during the evening hours
instead of the morning in order to obviate the necessity of the offal remaining in the City
all night, has been attended with the success anticipated, no complaint having been
received this year of smells arising from all-night storing of such offensive matter.
Before arrangements were made for the removal of fish offal by a Contractor, it
was dealt with by the Corporation's own Officers in the ordinary way as trade refuse,
but the present method is both a financial and hygienic advance.