Wednesday, November 15, 2006 - 2:15 PM

Nutrients and Bacteria Assessment in the Homochitto National Forest.

Alton Johnson1, Stanly Mason2, April Hugis3, and Carol Boll3. (1) Alcorn State Univ, Mississippi River Research Center, 1000 Asu Dr. #852, Alcorn State, MS 39096-7500, (2) Ouachita National forest, US Forest Service, P.O Box 1270, Hot Springs, AR 71902, (3) Homochitto National Forest, US Forest Service, 1200 HWY 184 E, Meadville, MS 39653

Escherichia coli (E. coli) contamination of surface water is often attributed to loading of fecal material from agricultural, urban and residential areas or warm-blooded wildlife. The US Forest Service in southwest Mississippi is developing a 1000-acre lake (Okhissa Lake) in the Porter Creek sub-basin of the Homochitto watershed. Clean, high quality water is necessary to support this use. Private residences are located along roads in the headwaters of the sub-basin where public sewage treatment is not available and many of the residences have ineffective septic systems. To evaluate the effect of land use with respect to the USEPA water quality standards for nutrients and E. coli, monitoring stations were established on tributaries supporting the lake. Water samples were collected before and after rainfall events. Nitrate and phosphate were analyzed using ion chromatography. E. coli was analyzed using colilert® substrates. Samples were enumerated by the absence or presence in Quanti-Tray™ cells and the data expressed as MPN per 100 mL. Results indicated spatial and temporal variability in nitrate and phosphate in the watershed. E. coli was spatially and temporally distributed and was consistently higher (p<0.05) in the northern tributaries than those in the south. The presence of E. coli was attributed to residences in the sub-basin. Based on the results obtained from this study, county officials were able to develop a sewage district for residences in the Porter Creek sub-basin where the lake is being established.