OIA, Chino Airport, and Hexavalent Chromium

1
OIA, Chino Airport, and Hexavalent Chromium

• Water Quality Committee Meeting
• September 22, 2009

2
OIA Update
3
(No Transcript)
4
Chino Airport Update
5
(No Transcript)
6
Hexavalent Chromium Update
7
(No Transcript)
8
Outline of Discussion

• Speciation of Chromium
• Distribution of Hexavalent Chromium
• Fate and Transport
• Potential Point Sources of Hexavalent Chromium

9
(No Transcript)
10
(No Transcript)
11
Speciation of Chromium

• The geochemistry of chromium is complicated.
• Hexavalent chromium can be geogenic. Forensic
  geochemistry required to determine.
• Stable isotopes
• Ratio with other trace elements, e.g., Y
• Oxidation of Cr(III) to Cr(VI)
• 2Cr(OH)2(aq) MnO2(s) -gt 2(HCrO4-)(aq)
  3Mn2(aq)

12
Speciation of Chromium

• Natural sources
• Arid alluvial basins San Fernando Valley
• Natural brines
• Chromite ore bodies
• Serpentine ultramafic terrains Presidio,
  Livermore, Davis
• Range in natural groundwater ND to 20 ug/L.

13
(No Transcript)
14
Fate and Transport

• Cr(VI) is a strong oxidant and is reduced in the
  presence of electron donors
• Dissolved Fe(II)
• Minerals with Fe(II)
• Sulfides
• Organic Matter
• Exists as an anion with little sorption, except
  in variable charged soils

15
(No Transcript)
16
Historical Point Source

• Minutes of the June 6, 1958 Regional Board
  minutes.
• Los Angeles City Health Department surveys
  dairies that sell milk to the city. Survey
  includes source water quality.
• Water in the Lieb Dairy well was found to contain
  0.07 ppm hexavalent chromium.
• County Health and or Flood Control provided a
  1948 investigation report of the area adjacent
  and south of the Ontario sewage disposal plant.
• The sewage disposal plant operator noticed a
  large amount of yellow and green coloring present
  in the clarifiers samples confirmed it contained
  0.4 ppm hexavalent chromium.

17
Historical Point Source

• It was believed that General Electric had been
  dumping chromic acid waste into the city sewer
  system.
• Board member questioned staff whether or not
  there may be a possibility of the hexavalent
  chromium coming from a source at the Ontario
  International Airport. Staff did not believe so.
• Staff also stated that the samples of wells taken
  near OIA showed less than 0.01 parts per million
  of' hexavalent chromium.

18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
(No Transcript)
24
Questions?
25
(No Transcript)
26
(No Transcript)
27
(No Transcript)
28
(No Transcript)
29
(No Transcript)
30
(No Transcript)