Taken for granted : report of the Working Party on Sewage Disposal.

  • Great Britain. Working Party on Sewage Disposal
Date:
1970
Catalogue details

Licence: Public Domain Mark

Credit: Taken for granted : report of the Working Party on Sewage Disposal. Source: Wellcome Collection.

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    diseases are normally passed either as a result of the infection of persons in the close environment of a patient or carrier of the condition, or as a result of the contamina- tion of some article of food. Against this background of disease in a community it is usually hard to identify an occasional case which might be contracted from river or other inland waters. 109 Occasionally in the past cases have been reported of enteric fever resulting from the recreational use of inland waters. These are usually found by the upper reaches of rivers where it is easier to identify the same type of organism in the patient and in the water, and to trace the source of pollution. Such cases appear to be more frequently associated with contamination of the banks of a stream than with actual bathing. Similarly polluted streams have in the past given rise also to milk-borne outbreaks of disease through contamination of cow’s udders and of dairy utensils. 110 In the higher reaches of rivers the apparent purity of the water may be deceptive. A carrier of enteric disease could contaminate a small stream as a result of a discharge of crude sewage, a septic tank effluent, or a treated effluent from a small sewage works. 111 Possible association of communicable disease with pollution in the lower reaches of rivers is more difficult to demonstrate. In Chapter 5 (dealing with sewage disposal to the sea) the importance of the dilution factor will be des- cribed. Illness will usually occur only if the numbers of any specific type of pathogenic organism ingested are very considerable, and as a result, the risk associated with sea bathing is minimal. With river bathing the problem is different. In a river the proportion of crude or untreated sewage is probably relatively small, though local pockets of high pollution near to points of discharge may exist. Rivers, however, contain considerable quantities of treated effluent, and sometimes part of their length may even be wholly sewage effluent. It is known that conventional sewage works treatment, while producing an effluent which is normally chemically satisfactory, is less effective in dealing with pathogenic organisms. Although more than 90 per cent may be removed, there may still be many thousands of faecal bacteria remaining in every millilitre of treated sewage effluent. They will contain disease-producing germs and viruses if there is infection in the local population. 112 A river receiving effluent from a number of large treatment works may therefore contain numbers of patho- genic organisms and the degree of dilution in the limited amount of river water available may not be large. It is difficult therefore to weigh the chances of infection from such water. The risks are probably greatest from accidental immersion when the proportion of water ingested may be higher than when persons are swimming or paddling. In most circumstances the risk is probably very low as may be judged by the numbers of persons, and in some cases communities such as schools, who have bathed in such waters in the past without apparent ill effect. Nevertheless it is customary for public health authorities to advise against bathing in these waters, and public bathing places or school bathing stations on such rivers have usually been closed. The decision is perhaps in part an aesthetic one, since Medical Officers of Health and other people know- ledgeable about the risks, while advising against swim- ming, will agree to children paddling and playing in the river although these children also may swallow small quantities of polluted water. 113 Canal water in industrial areas is often highly polluted (partly on account of the slow rate of flow) and may often be highly offensive. Cases of spirochaetal jaundice, a rare disease whose causative organism is to be found in rat’s urine, occasionally result from immersion (usually acciden- tal) in heavily polluted canal waters or in the waters of slow moving polluted rivers in urban areas. Other recreation on rivers and canals 114 The most popular pastime of bringing the family car to a riverside to walk, picnic and view the scene is not so obviously affected by pollution unless it is visible or can be smelt. In some places overt pollution certainly spoils this kind of enjoyment, as in an example quoted in the evidence of the National Federation of Women’s Institutes, des- cribing how raw sewage from an overloaded works flowed into a mill pool which was ‘“‘a favourite picnic place for villagers and visitors alike’. Families very often like to combine car trips with a little fishing, paddling or bathing which can be impossible, or dangerous to health, in heavily polluted rivers. Rivers in industrial areas are usually easily accessible to large numbers of people, but their amenity value may be totally destroyed by pollution. 115 Although boating is apparently quite popular on polluted rivers because they are accessible, the dirty water, the smell and the sewage fungus and other objectionable matter in the water or on the banks detract from pleasure. River authorities report increasing pressure from the public for higher standards in water quality for the sake of amenity. The amenity value of rivers is already recognised by the provisions in the Water Resources Act 1963 for maintaining a minimum acceptable flow in rivers. It seems logical to set also a minimum acceptable standard for water quality, as, however adequate the flow of the river, it cannot be enjoyed if it is laden with shreds of sewage fungus and is depositing filth by its banks. 116 Special efforts to improve the environment in river valleys in order to create new centres for recreation, or for the pleasure of the local residents, should include any improvement necessary to the main attraction in a river valley—the river itself. In the Greater London Council Development Plan for instance, the Cray Valley is listed as an area of special character, because of the beauty of the countryside. The valleys of the Colne, Crane, Lee, Roding, Ravensbourne, Wandle and Hogsmill, are listed as areas of opportunity for environmental treatment. The Lee Valley Regional Park is being developed as a centre for recreation, particularly for water sports. A group of local authorities concerned is now drawing up a plan for the use of the Mersey Valley for recreation and for improving its ameni- ties. Waste from boats 117 The growing use of rivers and canals for pleasure cruising can itself impair the pleasure, if boats discharge their lavatory and kitchen waste straight into the water. Even if the overall pollution from discharges from boats does not affect the quality of the river water as a whole, this practice is aesthetically objectionable and can cause obnoxi- ous conditions where boats are concentrated, as in marinas, or on popular stretches of water. Discharges from boats in such places could also cause a risk to health because people (particularly children) might be in direct contact with faecal matter in the water surrounding their boats. 118 River authorities can make byelaws under Section 5 of the Rivers (Prevention of Pollution) Act 1951 to prohibit discharges from boats. No such byelaws are yet in force (1970), although the East Suffolk and Norfolk River Authority’s byelaws for the Norfolk Broads have been confirmed by the Ministers of Housing and Local Govern- ment, and of Agriculture, Fisheries and Food, and will be
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