Hygiene and public health / by B. Arthur Whitelegge.

  • Arthur Whitelegge
Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: Hygiene and public health / by B. Arthur Whitelegge. Source: Wellcome Collection.

    72/610 (page 60)
    matter is oxidised by agitation and aeration, assisted by microbes and aqnatic plants. When, however, the sewage of hamlets, villages, and towns is poured into the river, the pollution becomes far more serious, and the self-purifying agencies are soon overpowered. Even if the sewage added at any one point be insufficient to make a perceptible difference in the whole volume of water, it will contribute to it, and the risk of specific pollution, discernible neither by optical nor chemical tests, must always render such a stream a questionable source of supply. According to the Elvers Pollution Commissioners, no river in the United Kingdom is long enough to secure the oxidation of sewage intro- duced into it at its source. Trade effluents—for example, refuse from dyeworks, paper-mills, and bleach- works—cause even more discoloration and turbidity tlian sewage proper. From these combined causes the rivers in the manufacturing districts become foul, dis- coloured, and offensive, and are little better than open sewers. Matters are made worse by the refuse from slaughter-houses, solid household refuse, and even con- tents of privy middens being cast into the river. When the pollution reaches such a pitch as this, the purifica- tion by oxidation is insignificant. Putrefaction goes on, however, and the suspended matters are slowly deposited in the bed of the stream, so that there is still a tendency to self-purification. The magnitude of the evil at the present time is due not only to the enormous increase in popidation and manufactures, but to the better water supplies and the improved drainage, which in themselves have done so much to promote the public health. Even the introduc- tion of water-carriage of excreta has added to the pollution of streams. The increasing foulness of rivers has rendered it necessary for the towns on their banks to impound pure water which formerly passed into the natural watercourses and helped to dilute the