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Presence of Microbial Indicators in Reid Park Wetlands

Presence of Microbial Indicators in Reid Park Wetlands. Jepson Sutton Scott Stine SWES 574. Purpose. Determine the effect of water flow rate on microbial indicator concentration Stagnant Pond, Turbulent Pond, and Waterfall

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Presence of Microbial Indicators in Reid Park Wetlands

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  1. Presence of Microbial Indicators in Reid Park Wetlands Jepson Sutton Scott Stine SWES 574

  2. Purpose • Determine the effect of water flow rate on microbial indicator concentration • Stagnant Pond, Turbulent Pond, and Waterfall • Determine the effect of aquatic plants on microbial indicator concentrations • Open water vs. Planted area • Presence/Effect of chlorination and pH • Compare presence of coliforms and enterococci

  3. Experimental Problems • It was determined that the ponds contained a shading dye that eliminated all plant growth.

  4. Methods • Collect samples from three varied areas of constructed wetlands at Reid Park • Located at 22nd Street and Country Club • Use Colilert and Enterolert (IDEXX) to determine indicator concentrations

  5. Methods • Make dilutions and add Colilert/Enterolert reagents

  6. Methods • Pour into Quantitray (IDEXX) and seal using sealer

  7. Methods • Count number of positive wells • Enumerate using MPN table

  8. Total Coliforms • Includes Escherichia, Citrobacter, Enterobacter, and Klebsiella • Used as a standard for assessing fecal contamination of recreational and drinking water. • Problems in accuracy due to ability to replicate in environment. • Colilert positive=Yellow well

  9. Fecal Coliforms • Includes Escherichia and Klebsiella • Definitive indication of fecal contamination • Unable to replicate in the environment • Colilert can enumerate E. coli concentrations • Colilert positive=fluoresce under UV lamp

  10. Colilert

  11. Colilert (IDEXX) • Defined substrate technology (DST) simultaneous detection of total coliforms and E. coli • Contains specific indicator nutrients: ortho-nitrophenyl-beta-D-galactopyranoside (ONPG) and 4-methyl-umbellifery-beta-D-glucuronide(MUG)

  12. Colilert (IDEXX) • Total coliforms react with ONPG to form yellow color. • E. coli react with MUG to form fluorescent color • Can detect low levels of total coliforms and E. coli (1CFU/100ml)

  13. Total Coliforms

  14. E. coli

  15. Fecal Streptococci Indicators • Fecal Streptococci have advantages over coliform indicators: • they rarely multiply in water • they are more resistant to environmental stress and chlorination • they generally persist longer in the environment

  16. Enterococci • Members of Lancefield Group D of Streptoccocus (fecal streptococci subgroup) • “Enterococci” - normal colonist of the human large intestine • Streptococcus often given as genus of this group in water industry

  17. Enterococci • Includes Enterococcus species faecalis, faecium, avium, and durans • E. faecalis: • infects elderly patients undergoing surgery • urinary tract, wounds, blood, appendix, intestinal structures • emerging nosocomal opportunist due to: • rising incidence of multi-drug-resistant strains • ease of person to person transfer

  18. Enterococci • Have been suggested as indicators of: • presence of enteric viruses in environment • biosolids and seawater • risk of gastroenteritis for recreational bathers

  19. Enterolert (IDEXX)

  20. Enterolert (IDEXX) • Uses a nutrient-indicator to detect enterococci • fluoresces when metabolized by enterococci • Compared to standard membrane filtration (MF) method: • 50% fewer false positives • 95% fewer false negatives

  21. Results

  22. pH / Chlorine

  23. FC/FS Ratio • >4.0 = contamination of human origin • <0.7 = contamination of animal origin • Pond 1: FC/FS = 5 • Pond 2 : FC/FS = 15 • Waterfall : FC/FS = 0.8

  24. Discussion • Probable pathogen removal factors • temperature, natural die-off, sedimentation • sedimentation most significant • Studies have shown slower flow rates allow more settling of microorganisms • Pond 1 would be expected to have lowest numbers

  25. Discussion • The highest amount of contamination in all categories occurred in Pond 2 • Area where ducks gather • Total coliforms were present in the largest amounts in all samples • Total coliforms broadest of groups assayed • Presence of microorganisms could vary over time

  26. Discussion • Pond 1 and Pond 2 have similar distributions in all categories • Waterfall does not follow the trend • Total coliforms higher compared to other samples • Why? • Turbulence • Cycling of water

  27. Discussion • FC/FS Ratio suggests: • Pond 1 and Pond 2 contamination is of human origin • Waterfall contamination is predominantly of animal origin

  28. Discussion • Values used to calculate ratio are not completely representative of FC and FS • E. coli is not only member of FC group • Enterococci is only a subgroup of FS • Ratio only valid for recent (24 hrs) fecal pollution • Validity of ratio has been questioned

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