Swimming pools and bathing places
Et Al
American Journal of Publ Health 23: 40-49
1933
Accession: 025625465
The committee reports that state and municipal swimming-pool maintenance generally follows previous committee recommendations. Pertinent state laws or regulations are in effect in 31 states. Cl residuals of 0.2-0.5 p.p.m. should not be abandoned in the light of present information, although there is need of further study of pollution indicators. For normal operation, 0.5 p.p.m. should be the upper limit for Cl residuals, although temporarily higher doses may be necessary to destroy resistant organisms. Residual Cl tests should be supplemented by frequent bacteriological tests. The pH of the pool should be kept alkaline. Use of 0.3-0.6% available Cl solution for disinfection to prevent ringworm infection appears to be of value; results with Na thiosulphate have been erratic and no definite recommendations for its use are made. Elimination of cross-connections between swimming pools and potable water supplies and between swimming pools and sewers, in new pools, is recommended. Existing direct connections between pools and sewers, which might allow sewage to back up, should be eliminated. Extraordinary precautions should be taken to protect potable water supplies, where cross-connections exist. More definite knowledge of the sanitary quality of bathing-beach waters is being demanded; their actual role in spread of infections is uncertain. Although there is a dearth of epidemiological evidence, the conclusion appears inevitable that bathing in a sewage-polluted water may cause disease, and that some measure of control should be worked out. No accepted standard exists for classification of bathing waters. Standards for indoor pools are not directly applicable to outdoor waters; for outdoor waters, 30, 10 and 1 Bacillus coli per cc have been proposed. A survey by the Connecticut Dept. of Health classifies the Connecticut shore line into 4 groups, based on coli indexes of 0-50, 51-500, 501-1000 and over 1000 B. coli per cc. In classifying a bathing area, distances from source of pollution and effects of pollution by bathers should be considered. Emphasis should be placed on reduction of pollution, rather than on disinfection of bathing areas. Classification of bathing areas should be based on consideration of analytical results and on results of sanitary surveys. No absolute bacterial standard of safety is recommended. No method or standard tending to promote hysteria about bathing places is suggested. Extensive study of the public-health dangers of public swimming pools and bathing places is suggested.