Presentation - National Water Research Institute

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The oxidant H 2 O 2 is photochemically generated in situ in surf zone waters at concentrations on the order of 100 to 300 nM, at production rates higher than expected from CDOM levels. Diel cycling in H 2 O 2 in beach waters occurs, with maxima in the afternoon after solar noon with lower concentrations during the night at 10 to 20% of daytime maxima. Production appeared to be dominated by solar intensity, with no evidence for tidal effects. Higher dark loss rates suggest larger sinks are associated with the turbulent surf zone. Evidence for dark and photochemical production from non-CDOM sources (kelp and intertidal beach sand). Concentrations are likely sufficient to cause indirect photoinactivation of fecal indicator bacteria in marine recreational waters.
Collaborators: Stanley Grant, Warren De Bruyn Site access: › Dept. of Fish and Game › California State Parks › Harry Helling, Crystal Cove Alliance Funding from: › Office of Naval Research › National Science Foundation › American Chemical Society Petroleum Research Fund › Chapman University faculty grants
Page 2 and 3: Why is peroxide important? Typical
Page 4 and 5: Microbial water quality standards f
Page 6 and 7: Endogenous conc.of 100 nM and 10 00
Page 8 and 9: Photochemical production from CDOM
Page 10 and 11: CDOM refers to a spectrum of highly
Page 12 and 13: H 2 O 2 levels had never been direc
Page 14 and 15: Change in %Fluorescence Refridgera
Page 16 and 17: Seal Beach Doheny State Beach
Page 18 and 19: [H 2 O 2 ] (nM) Measured in salt
Page 20 and 21: Production Rate (nM/s) HPPR incre
Page 22 and 23: HPPR varied significantly (5x) for
Page 24 and 25: concentration (nM) 200 180 160 140
Page 26 and 27: 24 hour diel study at HSB, 30 min i
Page 28 and 29: 4 diel studies in surf zone waters
Page 30 and 31: Field study 2 Clark et al., Marine
Page 32 and 33: Field study 4 Clark et al., Marine
Page 34 and 35: Absorption coefficients used as a p
Page 36 and 37: Prior studies: › H 2 O 2 from dec
Page 38 and 39: Measured photochemical production o
Page 40 and 41: Beach sand contained dark magnetic
Page 44: Scott Jakubowski Liannea Litz Cha

Presentation - National Water Research Institute

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