81 Environmental Geoscience; Geology and Health; Public Policy II: Environmental Geology for Public Use and Biogeochemistry (Posters)

Monday, 29 October 2007
8:00 AM - 12:00 PM

THE CORRELATION OF FECAL COLIFORM AND TURBIDITY OF THE LITTLE TALLAPOOSA RIVER IN THE WEST GEORGIA REGION

Paper number: 81-6
Program: Technical Sessions
Time: 8:00 AM – 12:00 PM

Authors

Abstract

The West Georgia Watershed Assessment of Carroll County and other local areas started in 2001. A long-term water monitoring plan was established to analyze regional streams, lakes, and rivers in 2003. This monitoring project allows students to gain experience in the field by testing parameters such as turbidity, pH, specific conductivity, and dissolved oxygen. After samples are collected students learn lab procedures, testing for ammonia, phosphorus, fecal coliform bacteria, E.coli bacteria, and nitrates. The Little Tallapoosa River is a source of drinking water for the city of Carrollton and is exposed to agricultural practices and urban sprawl. This combination contributes to fecal coliform contamination. Livestock may graze near the river, and during rain events manure runs from fields to the river playing a critical role in fecal coliform contamination. Also, due to urbanization, the Little Tallapoosa River is constantly exposed to human waste, trash, run off from roads, and leaky septic tanks. Although fecal coliform bacteria are not normally hazardous to animals or humans, their presence indicates more potentially dangerous bacteria.

Turbidity is the cloudiness of water caused by individual particles suspended in the water. A rain event or erosion elevates the amount of sediment in rivers producing an increase in turbidity. A comparison of turbidity and fecal coliform from six sites was conducted using data from 2003 to present along the Little Tallapoosa River. The study proved a direct correlation with an R2 value ranging from 0.6 to 0.8. From the six sites turbidity ranged from 5.7 to 120 NTU with a mean of 12 to 17 NTU. Fecal coliform bacteria ranged from 20 to 25000 col./100mL with a geometric mean of 180 to 340 col./100mL. The direct correlation between turbidity and fecal coliform indicates that as turbidity increases, so does fecal coliform bacteria. The result is significant in obtaining an accurate estimate for fecal coliform before waiting the 24 hour incubation time the procedure requires. As field parameters are taken at a site, increased turbidity values may be used to assume increased levels of fecal coliform bacteria. Therefore, an alert could be made to users of a recreational water body of possible high fecal coliform bacteria values.