What factors may lead to microbial contamination of ground water?
Ground water has traditionally been considered to be the water source least susceptible to contamination by indicator bacteria or human pathogens. This is certainly true of ground water from deep, confined aquifers. Geldreich (1990) reviewed the microbiological quality of source waters for drinking water supply, the sources of contamination to ground water environments, and the instances of waterborne disease outbreaks attributed to untreated or poorly-treated ground water which contained pathogens. If fecal indicator bacteria or pathogens commonly associated with humans are present in ground water in measureable numbers, there is most likely a nearby connection with a contaminated surface environment, such as a seepage from a waste lagoon or a contaminated surface water, or a subsurface source of contamination such as a septic tank, a broken or leaking sewer line, or an old or improperly designed landfilll. It is important to recognize that in spite of what we do know about bacteria a
