(An) epidemiological study on pollution of wells in Seoul city
About 30 per cent of the citizens of Seoul have no public water supply and are depending upon well water. Unfortunately such a condition will continue for many years to come.
These wells in overcrowded urban areas are easily contaminated and might serve as vehicles for the transmission of gastro-intestinal infections which threaten the health of the citizens.
The purpose of this study is to find the current status of wells in Seoul and the digree of their contamination, if any hoping that such study will ultimately lead to organized community effort for the rectification of prevailing but often
neglected public health problems.
Out of 11,004 wells in the areas where there is no public water supply in 7 Kus(except Yong Dong Po and Yong San Ku) of Seoul City, 304 wells for general survey for water quality were chosen at random for this study during the period from August 1965 to December 1965.
For the survey of the distribution of E.coli and pathogenic E.coil, 153 wells shows positive in coliform group organism among wells subjected for water quality survey in whole city included above 7 Kus and other 2 Kus(Yong San and Yong Dong Po Ku) from July 13, 1967 to August 30, 1967.
1. About 82.2% of total wells studied were dog wells and 60.5% were equipped with the cement-paved apron. Seventy seven per cent of wells studied had their depth in the range of 1-10m, and 79.1% of wells were located within the distance of 9m for privies, sewage and other sources of possible pollution. Hand-buckets were used to draw water in 76% of wells.
2. As the result of water analysis of 304 wells, 54.3% and positive reaction for oxidizable matter, 50.5% for reducible matter, 33.6% for nitrite nitrogen, 28.9% for ammonia nitrogen and 3.2% for more than 10ppm of KMn^^4 comsumed, 42.2% for
more than 150ppm of chloride ion concentration, 64.3% for more than 100 per mo. of general count of bacteria, 48.4% for the positive coliform group organisms.
Among the wells positive for coliform group organisms, E. coli were identified from 18.3% of the wells, and pathogenic E. coli were isolated from 5.9% of the wells.
3. On the bacteriological and biochemical study of pathogenic E. coli, O^^55 (1 well), O^^26 (4 wells), O^^128 :B^^12 (1 well), O^^85 (1 well), O^^111 (2 wells), O^^124 (2 wells) and O^^125 (2 wells) and O^^126 (1 well) well identified.
4. Water pollution of well is considered to originate from infiltration of polluted water from soil surface and the increasing opportunity of pollution by use of a number of households and inadequate drawing equipment.
5. Among the wells in the study area not provided with urban water supply, only 4.3% among 304 wells had potable water, 20.4% required chlorination and other 75.3% were not potable because of chemical and bacteriological pollution.