Bacterial Source Tracking Big Cypress Creek Bacteria Assessment Project

Transcription

1 Bacterial Source Tracking Big Cypress Creek Bacteria Assessment Project Emily Martin and Terry Gentry Soil & Aquatic Microbiology Laboratory Department of Soil & Crop Sciences Texas A&M University August 26, 2010 Stakeholder Meeting Improving Life through Science and Technology.

2 What is Bacterial Source Tracking (BST)? Data collection and analysis to determine the sources of fecal contamination in a waterbody Based on uniqueness of bacteria from individual sources A variety of different methods are used Sources of bacteria Differs from modeling in that it is not a predictive tool and does not require calibration and validation of input variables 2

3 Genotypic BST Methods (Library-Dependent) Methods: DNA fingerprinting Enterobacterial repetitive intergenic consensus sequence-polymerase chain reaction (ERIC-PCR) RiboPrinting (RP) Advantages/Disadvantages: More expensive More discriminating 3

4 Library-Independent BST Approach: Genotypic detection of microorganisms based on marker genes (DNA) Does not require known-source library Most common approach targets Bacteroidales

5 What are Bacteroidales? More abundant in feces than E. coli Obligate anaerobes less likely to multiply in environment Subgroups appear to be host specific Markers available for humans, ruminants, horse, hog Not pathogens site/_images/bacteroidetes.jpg 5

6 BST for Big Cypress Creek Limited library-dependent Analyze E. coli from ~100 water samples from across the study area using both ERIC-PCR and RP fingerprinting Library will be supplemented with known-source fecal samples from the watershed Library-independent Analyze ~250 water samples from across the study area using Bacteroidales PCR for human, ruminant, horse, and hog markers 6

7 Monitoring Stations 7

8 Big Cypress BST Samples Parameter Sept Oct Nov Dec Jan Feb Mar Apr May June July Aug Oct Dec Total Collected To-Date Target Number To Collect Bacteroidales Stream (14) X X X WWTFs (2) X X X Storm - Stream (14) X Storm - WWTFs (2) X 6 8 Bacteroidales Total E. coli (ERIC-RP) Stream (14) X X X WWTFs (2) X X X 5 11 Storm - Stream (14) 11 X Storm - WWTFs (2) 2 X 2 4 E. coli Total

9 Status of BST Analyses E. coli (ERIC-PCR + RP) 58 samples analyzed (58/122= 48% complete) Base flow = 44 Storm flow = 14 Bacteroidales PCR 213 samples analyzed (213/277 = 77% complete) Base flow = 165 Storm flow = 48 Human, ruminant, hog, and horse markers 9

10 Interim Bacteroidales BST Results Base v. Storm Samples Positive Hits 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% General Human Ruminant Hog Horse Base Flow (n=165) Storm Flow (n=48) 10

11 Interim Bacteroidales BST Results Sub-Watershed Stream Samples Postive Hits 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% General Human Ruminant Hog Horse Hart Creek (n=70) Tankersley Creek (n=52) Big Cypress Creek (n=66) 11

12 Interim Bacteroidales BST Results Wastewater Treatment Plants Positive Hits 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% General Human Ruminant Hog Horse Mt. Pleasant WWTP (n=13) Pilgrim's Pride WWTP (n=12) 12

13 Interim E. coli BST Results Base + Storm Samples 3-Way Split Unidentified (n=11) 19% Human (n=3) 5% Wildlife (n=21) 36% Livestock and Pets (n=23) 40% 13

14 BST Summary Limited Library-Dependent Analysis Existing Texas E.coli BST Library appears to be working relatively well (81% of isolates identified) Major sources in watershed appear to be domestic animals (livestock and pets) and wildlife (feral hogs, deer, birds, and small mammals) Known-Source Library additions from Big Cypress Library Independent Analysis Hog/feral hog and ruminant markers most common Big spike in ruminant and hog hits during storm events 14

15 Future BST Additional data will be collected and analyzed through January E. coli isolates 44 Bacteroidales samples ~50 Known source isolates into State Library Results will change as more data is collected Final results will be presented in

16 Questions? Emily Martin and Terry Gentry 2474 TAMU Texas A&M University College Station, TX Office: (979) Lab: (979)