Chemical indicators for rapid assessment of human fecal pollution in - PowerPoint PPT Presentation

Chemical indicators for rapid assessment of human fecal pollution in storm drains Kilty Inafuku PI: Patricia Holden Mentor: Bram Sercu Donald Bren School of Environmental Science & Management

Beach Contamination • Historically high fecal contamination in dry weather • Human fecal pollution most likely to cause illness

Project Goals • Identify sources of human fecal pollution in storm drains • Use chemical indicators as a diagnostic Compare colorimetric, fecal indicator bacteria, & DNA-based methods

Colorimetric Method 1. Measure chemical indicators • NH 3 -N • SO 4 • NO 3 -N • PO 4 • Surfactants 2. Check accuracy of device 3. Check sample matrix interference

Microbiological Methods 1. Measure fecal indicator bacteria (FIB) 2. Human specific DNA-based method Extract DNA • Amplify DNA for Methanobrevibacter smithii nifH (Mnif) gene •

Accuracy of Colorimetric Assay NH3-N Standard Curve NH3-N Standard Additions 3.50 3.00 1.15% 3.00 unspiked Observed Concentration (ppm) 2.50 y = 0.8502x + 0.0724 spiked R² = 0.9998 expected Concentration (ppm) 2.50 2.00 2.00 1.50 1.50 1.29% 9.50% 1.00 1.00 0.50 0.50 0.00 0.00 0.00 1.00 2.00 3.00 4.00 storm storm creek M9 SC3 SC9 drain 1 drain 2 Actual Concentration (ppm)

pristine creek ground storm drain creek ocean

Variability in Chemical Indicator Concentrations 12.00 0.70 11.00 0.60 Surfactants Concentration (ppm) 10.00 9.00 Concentration (ppm) 0.50 8.00 7.00 0.40 6.00 0.30 5.00 4.00 0.20 3.00 2.00 0.10 1.00 0.00 0.00 M29 M30 M21 M2 M9 M9 M9 M13 M13 M13 M14 M15 M16 M17 M19 M23 M31 M18 M20 M22 M24 M26 M28 M32 M25 M27 storm drain pristine creek ocean creek NH3-N NO3-N ground PO4 SO4 Surfactants

Chemical indicators are higher in sewage NH3-N PO4 70 3.5 13 Concentration in Sewage (ppm) 3 60 12 Concentration (ppm) Concentration (ppm) 11 2.5 50 10 9 2 40 8 1.5 7 30 6 1 5 20 4 0.5 3 10 2 0 1 0 -0.5 0 0.5 1.5 2.5 3.5 4.5 5.5 Surfactants 2 Concentration (ppm) 1.5 1 0.5 0 -0.5

Chemical indicators NOT higher in sewage SO4 NO3-N 2500 14 12 SO4 Concentration (ppm) Concentration (ppm) 2000 10 8 1500 6 1000 4 2 500 0 0 -2

Mnif Presence

Chemical indicator concentrations vs. Mnif presence/absence NH3-N PO4 10.00 6.00 8.00 5.00 Concentration (ppm) Concentration (ppm) 6.00 4.00 4.00 3.00 2.00 2.00 0.00 1.00 -2.00 0.00 present absent present absent NO3-N Surfactants 14.00 1.6 1.4 12.00 1.2 Concentration (ppm) Concentration (ppm) 10.00 1 8.00 0.8 6.00 0.6 0.4 4.00 0.2 2.00 0 0.00 -0.2 -2.00 -0.4 present absent present absent

log (EC) log (ENT) 5.0 5.0 4.5 4.5 4.0 4.0 Concentration (ppm) Concentration (ppm) 3.5 3.5 3.0 3.0 2.5 2.5 2.0 2.0 1.5 1.5 1.0 1.0 0.5 0.5 0.0 0.0 present absent present absent

Conclusions • Improve accuracy of colorimetry • Using standard curves • Matrix interferences • Human fecal contamination in several storm drains • Highest concentrations of chemical indicators  sewage pollution

Future Work • Analyze more samples • Use quantitative PCR assay for sewage pollution • Include other sewage indicators (caffeine, cotinine)

Acknowledgements UC Leadership Excellence through Advanced Degrees (UC LEADS) Arica Lubin Matt Crossley Patricia Holden Bram Sercu Student Academic Preparation and Educational Partnerships (SAPEP) City of Santa Barbara, Creeks Division