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"Under natural conditions the surface of any water expanse 'breathes in' oxygen from the
atmosphere; fresh river water contains approximately 10 parts of oxygen per million and uncontaminated
sea water contains somewhat less due to its salinity, but the corresponding amount
is about 8/2 parts of oxygen per million. The absorbtion of atmospheric oxygen through the
surface of the water is by far the most important source of oxygen, but the tidal reaches of
the Thames receive two other sources of oxygen supply, sea water coming up and fresh river
water coming down — this is the water coming over Teddington Weir after two-thirds of London's
water supply has been abstracted from the River Thames by the Metropolitan Water Board. Yet
so great is the pollution and contamination by sewage and industrial wastes that most and
sometimes all the dissolved oxygen in that part of the Thames is used up in oxidising putrescible
and chemical matter and consequently at such times more gases like the 'rotten egg' smelling
hydrogen sulphide are given off from the River than oxygen absorbed into it, particularly at times
of drought. It is in drought periods too, that the Minister of'Health may permit the Metropolitan
Water Board (faced perhaps with a crisis in meeting the demands of their consumers) to reduce
the flow over Teddington Weir from the 'statutory minimum' of 170 million gallons per day to 90
million or even 50 million.
"At such times the odour nuisance to people who live and work on, or near the Thames may
become a serious menace to health both psychologically and physically when it leads in sensitive
persons to nausea, retching and vomiting — in practice it means for them at such times that they
are living in an atmosphere of hydrogen sulphide which, incidentally, effects material damage
also by tarnishing metal and blackening paint, factors which must be reckoned with in the
maintenance of your Worshipful Committee's launches.
"Apart from noxious odours, other dangers to healthare from paddling and bathing in the Thames
which in parts contains high concentrations of the so-called Salmonella organisms, i.e., the
germs principally concerned in outbreaks of food poisoning. Worst danger of all is the accidental
drinking of tidal water or its use for domestic purposes such as washing salads. Tidal water
may find its way by mistake into drinking water tanks or may contaminate drinking water through
accidental cross connections and back siphonage. An example of this kind of occurrence was
reported verbally by your Medical Officer at your last meeting.
"It is not known what the Editor of the "Municipal Journal" had in mind when he wrote of
"emergency measures" that might become necessary to safeguard public health, but your Medical
Officer knows of only two that are used in practice. First the London County Council may arrange
for their effluent to be chlorinated. Chlorination reduces the danger to health from the sewage
effluent, but the chlorine in turn is rapidly destroyed by the high organic content of the river.
The second emergency measure is for the Metropolitan Water Board, in an endeavour to achieve a
compromise between the demands of their customers and the reduction of the flow over Teddington
Weir, to limit the use of water for gardens, washing cars, etc.
"More hope lies in long term measures. The London County Council have a £1'3 million
scheme (1) for sewage purification which enforced limitation of capital expenditure has so far
prevented their implementing. (At the present time more or less untreated sewage from the London
County Council works passes into the Thames in its tidal reaches at Barking and Crossness at
the rate of about 300 million gallons of sewage in 24 hours. The vplume of tidal Thames water
between Barking Creek and Teddington Weir is 8,000 million gallons at low tide and 23,500
million gallons at high tide).
"Limitation of capital expenditure has also prevented the Metropolitan Water Board (2) from
going ahead with ambitious schemes for enlarging their provision of reservoirs which if established
would help to avoid their having to reduce the flow of 'fresh water' over Teddington
Weir.
"A much more remote 'long term' hope lies in the possibility that science may discover a
means for the London Electricity Board to effect their necessary cooling arrangements without
taking from the Thames every 24 hours 4,000 million gallons of water which they de-oxygenate
and heat, the heated water on return to the River having a further harmful effect in reducingthe
River's oxygen content, which varies inversely with the temperature of the water.
"The 'last word' on the subject may be expected when the reports are published from two
Committees which are already at work on the problems of Thames Pollution — The Thames
Survey Committee of the Department of Scientific and Industrial Research (appointed in 1949) and
The Heated and Other Effluents Committee of the Ministry of Housing and Local Government
(appointed in 1951 with wider terms of reference). (3)
"From these perhaps not over constructive thoughts about the problems of Thames Pollution
it may be refreshing to remember that unpolluted natural river waters are so 'super-saturated'
with oxygen that they have enough and to spare for their own economy and release spare oxygen
into the neighbouring atmosphere, so promoting a feeling of exhilaration in people nearby. In
the peroration to his paper on 'The Thames Estuary and the Problems of Sewage Disposal of
Greater London' (The 'Medical Officer', 15th January, 1938), Colonel Bitler formerly Medical
Officer (General Purposes), London County Council, wrote, 'Let us in our time have the air, the
clean river air with the something in it that betters our health, quickens if not lengthens our
town-sombred lives and in the prospect of its coming touches, perchance, the procrastinating
lethargy, in which so long we have been steeped'."
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