2009 E. coli results

2009 E. coli results

August 27, 2009

Every other week from May through September, WRP volunteers test for E. coli bacteria at sites along the White River and its major tributaries. E. coli is a type of bacteria that lives in the intestines of all warm-blooded animals. E. coli is easy to test for, and is therefore used as an indicator for other disease-causing bacteria in the water. In other words, a high E. coli count reveals that a variety of disease-causing bacteria from numerous sources (leaking septic systems, animal waste, etc) are in the water and could make people sick.

E. coli counts can fluctuate dramatically depending on how much rain we’ve had or from the presence of dead carcasses or animal waste in the river. Because of this, the EPA recommends that a geometric mean (an average that evens out large variations in the data) be used instead of a simple average when considering multiple samples taken from the same site over time. At the end of each sampling season, we calculate the geometric mean of E. coli at each site for the year. This allows us to identify trends at sites over time.

The EPA standard for the geometric mean is 126 colonies/100 mL sample. Sites exceeding the EPA geometric mean standard are marked with an asterisk (*).

2009 E. coli geometric mean data

Main stem sites

Watson Park – 105
West Hartford bridge – 101
Mouth of Mill Brook – 45
White Brook – 150*
VLS parking lot – 108
Bethel below tx – 110
Bethel above tx – 58
Peavine Park – 53
Mouth of Locust Creek – 13
Silver Lake – 4
Gaysville Bridge – 47
Tweed at South Hill Road – 43
Lion’s Club Park – 33
Hancock Branch – 29

First Branch sites

Cilley Bridge – 82
Chelsea Rec Park – 79

Second Branch sites

Dugout Road – 144*
East Hill Road – 72

Third Branch sites

Mouth of Third Branch – 123
Stock Farm Road – 115
Golf Course Bridge – 112
Ayers Brook – 134*
Adams Brook – 15
Thresher Road – 66