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PRODID:-//University of Illinois//Web Services Calendar//EN
VERSION:2.0
CALSCALE:GREGORIAN
BEGIN:VEVENT
DTSTAMP:20120214T142605Z
DTSTART;TZID=America/Chicago:20091117T120000
DTEND;TZID=America/Chicago:20091117T120000
SUMMARY:Water Quality Seminar Series
CREATED:20090828T130000Z
DESCRIPTION:Indicators of Arsenic in Groundwater Tom Holm\, Center for Gr
 oundwater Science\, Illinois State Water Survey  Most of my presentation
  will be on (what else?) arsenic (As) in groundwater. Some wells in Taze
 well County have As concentrations above the USEPA maximum contaminant l
 evel (MCL) of 10 ppb. The source is dissolution of iron oxide coatings o
 n sand grains which releases sorbedAs\, the same process that has poison
 ed thousands of wells in south Asia. In some areas\, As is removed from 
 groundwater by co-precipitation with ferrous sulfide. There are characte
 ristic relationships between As and redox-sensitive substances (Fe\, Mn\
 , SO42-\, etc.). A simple two-step procedure with parameters derived fro
 m data collected in a recent project accurately predicts which wells stu
 died in other recent projects exceed the As MCL. The procedure may be us
 eful in screening water samples. Does it work for other parts of the sta
 te? Come to the seminar and find out.  The second part of the seminar wi
 ll deal with oxidation-reduction potential (ORP) measurements. The ORP i
 s sometimes a useful\, if qualitative\, indicator of redoxconditions. An
  ORP probe is typically calibrated using a redoxbuffer with a standard p
 otential of +428 (ZoBell) to +675 (Light) mV\, which is outside the rang
 e of potentials measured in anoxic groundwaters\, typically -50 to +150 
 mV. I am working on a redoxbuffer with a well-defined potential of ~60 m
 V\, which is within this range.
LAST-MODIFIED:20091111T140000Z
LOCATION:Natural Resources Building (map)607 E Peabody DriveChampaign\, I
 LRoom 101
CATEGORIES:Speaker
ORGANIZER:snolson@illinois.edu
URL:http://illinois.edu/calendar/detail/2130?key=2000010120000101136294
UID:136294@illinois.edu
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