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Arroyo Seco

Kevin C. Figueroa, Carineh Ghafafian, Hannah E. Holland-Moritz, Melinda Reynolds, Ramon Rodriguez, Valeria G. Sosa, Brian Travis July 24, 2009 Summer Research Connection Seminar Oak Crest Institute of Science Mentor: Dr. Marc Baum. Arroyo Seco.

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Arroyo Seco

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  1. Kevin C. Figueroa, Carineh Ghafafian, Hannah E. Holland-Moritz, Melinda Reynolds, Ramon Rodriguez, Valeria G. Sosa, Brian Travis July 24, 2009 Summer Research Connection Seminar Oak Crest Institute of Science Mentor: Dr. Marc Baum

  2. Arroyo Seco • Used for recreation (swimming, hiking, dog-walking, fishing)‏ • Possible future source of drinking water • Unique urban watershed • Used to replenish groundwater supply • Wildlife re-introduction area

  3. Arroyo Seco Foundation Studies • Watershed Feasibility Study in 2002: Broad-reaching study, including • Habitat restoration • Recreation and open spaces • Water quality • 2006 North East Trees study • Continuous research done by Arroyo Seco Stream Team • pH, turbidity, nitrate, total coliform, E. coli

  4. Stables Golf Course Stables Our Study • Fewer sites, more substances • Determine input locations • Project goal: contribute baseline data for future stream quality studies Map adapted from Arroyo Seco Foundation website

  5. Stables Golf Course Stables Water Quality Data • Temperature • pH • Turbidity • Coliforms (including E. coli)‏ Gases and Ions • Dissolved oxygen • Sulfide (S2-)‏ • Ammonia (NH3)‏ • Nitrite (NO2-)‏ • Nitrate (NO3- )‏ • Phosphate (PO43- )‏ Metals • Arsenic (As)‏ • Chromium (Cr)‏ • Copper (Cu)‏ • Iron II (Fe) • Lead (Pb)‏ • Vanadium (V)‏

  6. Sample Collection • Collect from running water • Rinse bottle with stream water, then cap it under water with no air bubbles • Collected heavy metal samples in pre-treated bottles • Sent heavy metals to be tested by Inductively Coupled Plasma – Mass Spectrometry (EPA method #200.8)‏ • Measured samples on site with colorimeter and nephelometer

  7. Nephelometer • Shines a light through the sample • Measures the scattering of light in NTUs (Nephelometric Turbidity Units)‏ From http://www.fondriest.com/images/hach_2100p_lg.jpg From Hach Turbidimeter instruction manual

  8. Colorimeter • Measures the light absorbance of a solution • Prepare a solution with known solutes and measure its light absorbance • Uses Beer-Lambert Law of light absorbance • 90 stored assays Light Source Sample Cell Absorbance detector

  9. Coliforms • Collect 100 mL in running water and store in ice chest • Use vacuum filtration to filter sample through a membrane under sterile conditions • Remove filter and place on petri dish with selected media for coliforms and E. coli • Incubate at 35 °C overnight • Total coliforms = red + blue colonies • E. coli = blue colonies

  10. Stables Golf Course Stables Nitrogenous Compounds • Useful for ecosystem analysis (used by plants for nutrients)‏ • Comes from fertilizers and animal wastes Lethal dose = 2000 mg/L EPA drinking water standard = 10 mg/L EPA drinking water standard = 1 mg/L

  11. Stables Golf Course Stables Phosphate • Important indicator for ecosystem analysis • Comes from detergents and fertilizers • Responsible for algae blooms • Eutrophication – lowering of dissolved oxygen in water from the decay of algae blooms EPA recommended level < 0.1 mg/L

  12. Stables Golf Course Stables Dissolved Oxygen • Important in determining whether the stream can support aquatic life • When dissolved oxygen < 5 mg/L fish cannot survive • Low levels the result of eutrophication, high temperatures and low salinity • Can vary a lot over the course of a day 5 = Minimum level of dissolved oxygen that can sustain a healthy aquatic ecosystem

  13. Stables Golf Course Stables Coliforms • Coliforms – bacteria commonly found in mammalian intestines • Indication of fecal contamination • Used to indicate whether other potentially harmful bacteria might be present but not harmful on its own • High levels of coliforms Site A Site E

  14. Copper, Zinc and Lead Stables Golf Course Stables • All three come from electronic wastes • All can biomagnify to toxic levels • High levels of each cause decreases in plant growth and are harmful to decomposers EPA drinking water standard = 15 ppb EPA drinking water standard = 1300 ppb EPA drinking water standard = 5000 ppb

  15. Vanadium, Chromium and Arsenic Stables Golf Course Stables • Arsenic from natural sources – high levels in the rocks • Vanadium and chromium are used in steel alloys and are found in coal mines • All can biomagnify to toxic levels which kill fish and other wildlife • Vanadium and arsenic are highly toxic; chromium is toxic in high oxidation states [e.g. Chromium (VI)] EPA drinking water standard = 10 ppb EPA drinking water standard = 100 ppb Lethal dose = 59 mg/L

  16. Stables Golf Course Stables Sulfide and Iron (II)‏ • Both come from natural deposits, microbial activity and industry • Iron (II) is not a significant environmental threat from large concentrations in water • Sulfide compounds (such as hydrogen sulfide) can be toxic to fish and humans and are an indicator of low dissolved oxygen levels WHO recommended level < 0.5 mg/L EPA drinking water standard = 0.3 mg/L

  17. Stables Golf Course Stables pH and Turbidity • Turbidity – the measure of the cloudiness of a solution • pH measures the acidity of a solution • General indicators, not specific EPA drinking water standard = 6.5-8.5 EPA drinking water standard = 0.3 NTU

  18. Results vs. Standards

  19. Stables Golf Course Stables Conclusions • Very high levels of phosphate • High level of coliform contamination • Increase in nitrogen compounds • Copper, zinc and lead increase as you go downstream • Arsenic and chromium levels generally decrease downstream while vanadium increases

  20. Future Directions Stables Golf Course Stables • Explore fluctuations of dissolved oxygen • Test for more chemicals: perchlorate, aluminum, manganese; expand number of sites tested (further north and south)‏ • Conduct more trials at different times of the day & during the year • Determine the source of contaminants

  21. Acknowledgements • Marc Baum • John Moss and Manjula Gunawardana • Sherry Tsai and James Maloney • Oak Crest Institute of Science • Caltech • Wendie Johnston and Pasadena Bioscience Collaborative • The Arroyo Seco Foundation • Exova • Howard Hughes Medical Institute • Siemens Foundation • Pasadena Independent Schools Foundation • You 

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