Fujioka R S
Water Resources Research Center, University of Hawaii, Honolulu 96822, USA.
Water Sci Technol. 2001;44(7):181-8.
The US Environmental Protection Agency (USEPA) and the World Health Organization (WHO) have established recreational water quality standards limiting the concentrations of faecal indicator bacteria (faecal coliform, E. coli, enterococci) to ensure that these waters are safe for swimming. In the application of these hygienic water quality standards, it is assumed that there are no significant environmental sources of these faecal indicator bacteria which are unrelated to direct faecal contamination. However, we previously reported that these faecal indicator bacteria are able to grow in the soil environment of humid tropical island environments such as Hawaii and Guam and are transported at high concentrations into streams and storm drains by rain. Thus, streams and storm drains in Hawaii contain consistently high concentrations of faecal indicator bacteria which routinely exceed the EPA and WHO recreational water quality standards. Since, streams and storm drains eventually flow out to coastal marine waters, we hypothesize that all the coastal beaches which receive run-off from streams and storm drains will contain elevated concentrations of faecal indicator bacteria. To test this hypothesis, we monitored the coastal waters at four beaches known to receive water from stream or storm drains for salinity, turbidity, and used the two faecal indicator bacteria (E. coli, enterococci) to establish recreational water quality standards. To determine if these coastal waters are contaminated with non-point source pollution (streams) or with point source pollution (sewage effluent), these same water samples were also assayed for spore-forming bacteria of faecal origin (Cl. perfringens) and of soil origin (Bacillus species). Using this monitoring strategy it was possible to determine when coastal marine waters were contaminated with non-point source pollution and when coastal waters were contaminated with point source pollution. The results of this study are most likely applicable to all countries in the warm and humid region of the world.
美国环境保护局（USEPA）和世界卫生组织（WHO）制定了娱乐用水水质标准，限制粪便指示菌（粪大肠菌群、大肠杆菌、肠球菌）的浓度，以确保这些水域可供游泳。在应用这些卫生水质标准时，假定这些粪便指示菌不存在与直接粪便污染无关的重要环境来源。然而，我们之前报道过，这些粪便指示菌能够在夏威夷和关岛等潮湿热带岛屿环境的土壤环境中生长，并被雨水以高浓度输送到溪流和雨水排放口。因此，夏威夷的溪流和雨水排放口中粪便指示菌的浓度一直很高，经常超过美国环境保护局和世界卫生组织的娱乐用水水质标准。由于溪流和雨水排放口最终会流入沿海水域，我们推测，所有接收溪流和雨水排放口径流的沿海海滩中粪便指示菌的浓度都会升高。为了验证这一推测，我们监测了四个已知接收溪流或雨水排放口水的海滩的沿海水域的盐度、浊度，并使用两种粪便指示菌（大肠杆菌、肠球菌）来制定娱乐用水水质标准。为了确定这些沿海水域是否受到非点源污染（溪流）或点源污染（污水排放），还对这些相同的水样进行了粪便来源的芽孢杆菌（产气荚膜梭菌）和土壤来源的芽孢杆菌的检测。采用这种监测策略，可以确定沿海水域何时受到非点源污染，何时受到点源污染。这项研究的结果很可能适用于世界上温暖潮湿地区的所有国家。
