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Home < Environment < Laboratories
Environmental Microbiology
Jason Wickstrum, Director
Forbes Field, Building 740
Topeka, KS 66620
Phone: (785) 296-1636
FAX: (785) 296-1641
Emerging infectious diseases in the United States and the rest of the world reinforce the need to carefully monitor drinking water. It is not practical to assay for each possible waterborne infectious diseases because of the time and cost required to run the numerous tests necessary to detect all possible disease-causing organisms. Scientists have found a more economical method to handle the problem by testing for "surrogate" or "indicator" organisms whose presence indicates that conditions are ripe for transmitting disease-causing organisms. Most of these organisms are common to the intestinal flora in humans and animals.
The ideal indicator organisms must be detectable in all types of water, must be found in sewage and polluted waters when pathogens are present, and must be present in greater numbers than the pathogens. The most common organisms meeting these criteria are coliforms. They are capable of living in humans and animals, but some can live on plants, leather, wood, rope, or jute, and may produce a biofilm inside water distribution systems. Tests for the general group called fecal coliforms are being replaced by tests for their more notorious member, E. coli, as a more accurate indicator organism. This organism only grows in the intestines of humans and animals and therefore is the best indicator of fecal contamination.
The Environmental Microbiology laboratory uses various media to detect these organisms. In a normal year, the laboratory staff analyze about 40,000 drinking water specimens. From fiscal year 1996 through 2001 the staff tested 236,668 public water supply samples. Of these 1.0% were coliform positive and 0.2% were fecal coliform positive. Some states report a coliform-positive rate in drinking waters as high as 10%. The rate for our state indicates that the water suppliers in Kansas are doing an excellent job of keeping the water potable.
In addition to drinking water samples, the Environmental Microbiology laboratory analyzes surface waters from lakes, rivers, and streams. Public water supplies draw their water from both surface and subsurface waters so it is important that we keep these waters safe. Laboratory staff analyze surface water for fecal coliforms using a filter technique that traps bacteria on a membrane so that the number of organisms (colony-forming units or CFUs) in the raw water to be counted. In a normal year, the Environmental Microbiology laboratory will analyze over 4,000 specimens of surface water.
