TR-528 Bacterial Source Tracking (BST) on Tributaries of Trinity and Galveston Bays

Authors: Brian Hux, John Boswell, Terry Gentry, Stephanie deVilleneuve

To better characterize sources of bacteria that are entering the Trinity and Galveston Bays a water quality monitoring regime was employed to gather information needed to address bacteria concerns in five watersheds of the bays through Bacteria Source Tracking (BST). The BST further characterized the watersheds and supports the implementation of the following watershed-based plans: Double Bayou Watershed Protection Plan (WPP), Cedar Bayou WPP, The Bacteria Implementation Group (BIG) Implementation Plan and Dickinson Bayou WPP. This information will help decision-makers determine the most appropriate management measures needed to reduce bacteria in the waterbodies. Monthly sampling was conducted by the Texas Water Resources Institute (TWRI) at one site each on Buffalo, Double, Cedar and Dickinson Bayous, and Clear Creek for one year. Samples were delivered to the Soil and Aquatic Microbiology Laboratory (SAML) for processing in preparation for BST. TWRI worked with local experts to determine how many samples were needed from various sources of bacteria. A total of 75 known source samples were collected and delivered to SAML. SAML used the samples to supplement the Texas Escherichia (E. coli) BST Library where isolates were added using the Enterobacterial Repetitive Intergenic Consensus Polymerase (ERIC-PCR) and RiboPrinting combination method. SAML also conducted library-dependent BST and analyzed 240 E. coli isolates from the 60 collected water samples. The results of the analysis indicated that over 50 percent of the collected isolates originated from wildlife.