Watershed-Scale Fate and Transport of Bacteria Using SWAT

Transcription

1 Watershed-Scale Fate and Transport of Bacteria Using SWAT Mehran Niazi Dr. Christopher Obropta, P.E. Dr. Robert Miskewitz August 6, 2009 Department of Environmental Sciences, Rutgers University

2 Outline Hypothesis Background Pathogen pollution in the US & NJ Watershed characterization TMDL Bacterial source tracking (BST) Methods SWAT model Host specific molecular marker Results Hydrologic simulation Laboratory experiment BST Continuing work Acknowledgements

3 Hypothesis We can quantify the bovine contribution of fecal contamination to the Salem River by determining the fate and transport of fecal contamination using bacterial source tracking and SWAT

4 Major Causes of Water Impairment in the US 25,000 # of causes of impairment reported 20,000 15,000 10,000 5,000 10,222 9,245 7,155 6,540 6,479 5,868 0 Pathogens Mercury Metals Nutrients Sediments Org. Enrich. Ref.: USEPA website (

5 Impaired Rivers & Streams in New Jersey, Reported Year % of rivers and streams (miles) are assessed 86% of assessed streams & rivers are impaired Pathogens are the cause of impairment for 825 miles of streams & rivers Ref.: USEPA website ( Photo: Passaic River, NJ

6 Watershed Characterization Area: 3,325 ha 52 km river length Highest ele. 45 m asl Located in Salem County & made up of three towns: Woodstown Borough, Pilesgrove Township & Upper Pilesgrove Township fbfdfhdfblfgsfdgsfdgfgxdfgxdfgxfgxfgxfbfdgdfgdhj

7 Land Use Characterization Agriculture: 68% Barren land: ~0% Forest: 11% Urban: 9% Water: 1% Wetlands: 11% CAFO Sites adjacent to stream

8 Total Maximum Daily Load (TMDL) for Pathogens in the Salem River Watershed The United States Environmental Protection Agency (EPA) approved the proposed TMDL by The New Jersey Department of Environmental Protection (NJDEP) for the Upper Salem River Watershed. The TMDL mandates 84% reduction in the load of pathogens to the river. Photo: The Salem River taken by Katie Giacalone

9 So, what are the sources and how much is each source contributing?

10 Types of Source Tracking Types Example Advantage Disadvantage Microbiological Methods Fecal col. /Fecal Streptococcus Ratio Rapid result & minimal expertise Variation in detection methods Phenotypic Methods MAR Analysis Successful in discriminating E. coli isolated from wildlife, livestock & humans AR is carried on plasmids, which can be lost from cells via cultivation & storage Genotypic Methods Host-Specific Molecular Markers No need for a culturing step; Bacteroides spp. is anaerobic therefore less likely to reproduce once introduce in the environment Little is known about survival & persistence of Bacteroides spp. in the environment Chemical Methods Caffeine Presence of caffeine in the environment would indicate the presence of human sewage Little is known about the fate of caffeine in the environment

11 What are Bacteroides? Gram-negative, anaerobic bacteria Bacteroides have shown to significantly correlate with human enteric viruses; they are found in all warm blooded animals Their abundance in feces makes them an excellent indicator organism for direct detection by molecular methods.

12 Sampling Program June 2007 to May 2009 Water flow, biweekly Water quality (fecal coliform, E. coli, temperature & conductivity, dissolved oxygen, ph, total phosphorus, total nitrogen, total Kjeldahl nitrogen, dissolved orthophosphate phosphorus and total suspended solids, BST), biweekly Biological (benthic macro-invertebrate), once

13 USGS Gauge Station Sampling Stations

14 Methods: SWAT Model Objective: SWAT is a watershed-scale, continuous-time model that operates on a daily time step & is designated to predict the impact of management on water, sediment, nutrient and pesticide yields in ungauged watersheds.

15 Methods: Input Data and Layers in Soil (STATSGO) DEM (NJDEP) Land Use (NJDEP) Stream (NJDEP) Lake (NJDEP) SWAT Precipitation (NJ weather & climate network) Max. & Min. Temperature (NJ weather & climate network)

16 Methods: Hydrologic Response Units in the Salem River Watershed

17 Methods: Quantitative Polymerase Chain Reaction (qpcr) Total biomass is collected from a water quality sample; DNA from fecal bacteria is extracted; PCR is used to amplify the DNA in the samples; Measures PCR amplification as it occurs, cycle-by-cycle; The amount of DNA is measured after each cycle of PCR by use of fluorescent markers; This allows quantitative measurements to be made in the highly reproducible exponential phase of PCR;

18 Results Hydrologic Calibration for the Sampling Points Laboratory experiment effects of temperature on persistence of bovine Bacteroides Example of BST Results

19 Result: Hydrologic Calibration Flow at S10 Flow (ft3/s) E = /1/2006 8/1/ /1/ /1/2006 2/1/2007 4/1/2007 6/1/2007 8/1/ /1/ /1/2007 2/1/2008 4/1/2008 observed predicted

20 Result: Hydrologic Calibration Flow at S E=0.31 ft3/s /8/2007 7/8/2007 8/8/2007 9/8/ /8/ /8/ /8/2007 1/8/2008 2/8/2008 3/8/2008 4/8/2008 5/8/2008 observed predicted

21 Result: Laboratory Experiment SWAT uses a simple first-order decay equation (Chin et., al. 2009): M t = M 0 exp (-kt) M t = microbial concentration at time t M 0 = initial microbial concentration t = time k = the first order rate coefficient

22 Result: Laboratory Experiment Species Temperature R 2 Coefficient rate E. coli (Wang et al., 2003) Equine fecal Bacteriodes (Bell et al., 2009) Bovine Bacteriodes 4ºC d -1 27ºC d -1 47ºC d -1 5ºC d -1 10ºC d -1 15ºC d -1 35ºC d -1 4ºC d -1 20ºC d -1 30ºC d -1

23 Example of BST Results 8.0E E+08 October 24, 2007 #1 AllBac HuBac BoBac # of Bacteroides 6.0E E E E E E E+00 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 Station

24 Continuing work Hydrology validation Lab experiment to identify coefficient for Allbac Bacteroides calibration and validation

25 Acknowledgments: This project was funded through: USDA- CSREES NRI grant # NJDEP, Watershed Restoration Plan for the Upper Salem River Watershed Dr. Craig Phelps Dr. Peter Strom Dr. John Reinfelder Dr. Chris Uchrin Cumberland-Salem Conservation District Rutgers Water Resource Program

26 Thank you!

27 Recommendation for the Salem River Watershed in the TMDL report There are horse farms, dairy farms, a poultry farm, an agricultural products operation, and a rodeo in the watershed. Cattle were observed in the stream. Both Woodstown Lake and Avis Mill Pond attract large Canada Goose population. The Township of Woodstown receives sewer service; the remainder of the watershed is on septic systems.

28 Why do we need sound and scientific approach for pathogen source tracking? Non-point source pollution: Is difficult to quantify Sources are difficult to determine Opposing interest groups often point to others for causing the problems

29 SWAT Model Applications Application category Calibration &/or sensitivity anal. Hydrologic only Hydrologic and pollutant only Pollutant loss only Climate change impact Hydrologic assessment Variation in configuration Comparison with other models Interface with other models GIS interface Pollutant assessment

30 What are the ideal indicators? Nonpathogenic Rapidly detected Easily enumerated Have survival characteristics that are similar to those of the pathogens of concern Can be strongly associated with the presence of pathogenic microorganisms