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Oxidation and mobilization of naturally O id i d bili i f ll occurring chromium in soils of the Sacramento Valley, California Chris Mills, Jean Morrison, Martin Goldhaber Chris Mills, Jean Morrison, Martin Goldhaber U.S. Department of the

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SLIDE 1

O id i d bili i f ll Oxidation and mobilization of naturally

  • ccurring chromium in soils of the

Sacramento Valley, California

Chris Mills, Jean Morrison, Martin Goldhaber Chris Mills, Jean Morrison, Martin Goldhaber

U.S. Department of the Interior U.S. Department of the Interior (cmills@usgs.gov) (cmills@usgs.gov) U.S. Geological Survey U.S. Geological Survey ( @ g g ) ( @ g g )

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SLIDE 2

Outline

  • Chromium toxicity and sources

Chromium toxicity and sources – – importance of speciation importance of speciation

  • Naturally occurring Cr(VI) in groundwater

Naturally occurring Cr(VI) in groundwater – – a global issue a global issue N l C di ib i i S V ll il N l C di ib i i S V ll il

  • Natural Cr distribution in Sacramento Valley soils

Natural Cr distribution in Sacramento Valley soils

  • Cr(VI) in vadose zone soils and sediments

Cr(VI) in vadose zone soils and sediments

  • Natural Cr(VI) generation in soils

Natural Cr(VI) generation in soils

  • Oxidation reactivity of natural versus fertilizer

Oxidation reactivity of natural versus fertilizer derived Cr(III) derived Cr(III)

  • Oxidation reactivity of natural versus fertilizer

Oxidation reactivity of natural versus fertilizer-derived Cr(III) derived Cr(III)

slide-3
SLIDE 3

C (VI) (HC O C (VI) (HC O -)

Toxicity and carcinogenesis of chromium

Cr(VI) (HCrO Cr(VI) (HCrO4

  • )

anion transporter anion transporter

Cr(VI) Cr(VI)

Oxidative Oxidative

ion ion -

  • cation

cation

( ) ( )

Cr(V) Cr(V)

Reduction by Reduction by Oxidative Oxidative DNA DNA breakage breakage

Reduct Reduct Detoxific Detoxific

Cr(IV) Cr(IV)

Reduction by Reduction by Vitamin C Vitamin C DNA adducts DNA adducts Cr Cr ligand ligand

D

Cr(III) Cr(III) Cr(III) Cr(III)

Salnikow & Zhitkovich, 2008, Chem. Res. Toxicol. Salnikow & Zhitkovich, 2008, Chem. Res. Toxicol. National Toxicology Program National Toxicology Program

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SLIDE 4

Sources of chromium in soil and water

  • Anthropogenic

Anthropogenic

– Industrial waste Industrial waste – – often

  • ften Cr(VI)

Cr(VI)

  • Primary contaminant at over ½

Primary contaminant at over ½ a y co a a a o e ½ a y co a a a o e ½

  • f Superfund sites
  • f Superfund sites
  • Tanneries

Tanneries

  • Corrosion inhibitors

Corrosion inhibitors

Leather Tanning Leather Tanning – – Morocco Morocco

  • Metal plating

Metal plating

  • Wood Preservatives

Wood Preservatives

– Fertilizers Fertilizers – – Cr(III) Cr(III)

Cr Ni As

Trace Metal Concentrations in Rock Phosphates (mg/kg)

( ) ( )

  • Inorganic

Inorganic

  • Biosolids

Biosolids

  • Natural

Natural Cr(III) Cr(III)

1 - 331 1 - 125 1-21

EPA 747-R-98-003 (1999)

  • Natural

Natural – – Cr(III) Cr(III)

– Ultramafic Rocks Ultramafic Rocks

Chromite Chromite (FeCr (FeCr2O4)

Pellerin & Booker (2000) Pellerin & Booker (2000) Environmental Health Perspectives Environmental Health Perspectives

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SLIDE 5

“Many cities in California have chromium 6 in their water at higher levels

Naturally occurring Cr(VI) in the news

Many cities in California have chromium 6 in their water at higher levels than Beachwood, says lawyer Stephen Lewis, who represents the plant's former owners. He argues that the chromium 6 in Beachwood's water could be naturally present or the result of activity unrelated to the plant.” y p y p –San Francisco Chronicle, 12-14-08 “Hexavalent chromium is not naturally occurring; though industry y g; g y lobbyists and their PR machines have done a great job making you believe it does. Hexavalent chromium is pollution;…” –Erin Brockovich, 2-15-2011, comment on CA Proposed Public Health Goal for Cr(VI) in drinking water (0.02 mg L-1) “The Cr (VI) you identified in Honolulu’s water supply as is probably the case for The Cr (VI) you identified in Honolulu s water supply, as is probably the case for every other city you tested, is not industrial “pollution” — it’s Mother Nature.” –Roger Brewer, Ph.D., 6-7-2011, letter to the Editor in response to EWG report on Cr(VI) in municipal drinking water, Norman (OK) Transcript Cr(VI) in municipal drinking water, Norman (OK) Transcript

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SLIDE 6

World Health Organization

Naturally occurring Cr(VI) in groundwater–global distribution

g MCL = 50 g L-1 La Spezia, Italy La Spezia, Italy

73 73

L 1

73 73 g L

g L-1

United Arab Emirates

Fantoni et al. (2002) Fantoni et al. (2002) Env. Geol.

  • Env. Geol.

Mojave Desert CA Mojave Desert CA

400+ g L-1

Wood et al. (2009) Ground Water

Yil C t Mojave Desert , CA Mojave Desert , CA

60 60 g L

g L-1

1

Izbicki et al. (2008) Appl. Geochem. Izbicki et al. (2008) Appl. Geochem.

Yilgarn Craton

430 g L-1

Gray (2003) Geochem. Explor.

  • Environ. Anal.

Oze et al., 2007, PNAS

  • Environ. Anal.
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SLIDE 7

Cr concentrations northern California surface soils are extremely high y g

Krevor et al., 2009, Energy Procedia S G North American Soil Geochemical Landscapes project, USGS

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SLIDE 8

Regional-scale soil geochemistry of northern California

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SLIDE 9

Regional-scale soil geochemistry of northern California

Morrison et al., 2009, Appl. Geochem. Morrison et al., 2009, Appl. Geochem.

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SLIDE 10

100000

Rock and surface soil total Cr concentrations

10000 100000

Sacram Riv

1000 10000

mg/kg)

mento ver

100

Cr (m

EPA screening level U S

10

Rock S il R k Soil Soil Soil Soil Rock

mean U.S. soil conc. West East Serpentine Serpentine Valley Great Valley

Rock Soil Rock Soil Soil Soil Soil Rock

Morrison et al., 2009, Appl. Geochem. Morrison et al., 2009, Appl. Geochem.

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SLIDE 11

Contributions of source materials to western valley soils

1

Great Valley Sequence Rocks and Soils

0.8 0.6

Li

0.4 0.2

r

Rocks and Soils

0.4

x10

0.6

Cr

UM Rocks and Soils

0.2 0.8

and Soils

0.2 0.4 0.6 0.8 1

Ti/10

1

Ti/10

Morrison et al., 2009, Appl. Geochem. Morrison et al., 2009, Appl. Geochem.

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SLIDE 12

Cr(VI) in valley groundwater is a health concern

CA MCL = 50 μg L CA MCL = 50 μg L-1

1

CA Public Health Goal = 0.02 CA Public Health Goal = 0.02 μg L

μg L-1

1

Sacramento Sacramento Davis Davis Davis Davis

M i t l 2009 A l G h M i t l 2009 A l G h Morrison et al., 2009, Appl. Geochem. Morrison et al., 2009, Appl. Geochem. Wanty et al., 2009, Appl. Geochem. Wanty et al., 2009, Appl. Geochem. Dawson et al., 2008, USGS Data Series Dawson et al., 2008, USGS Data Series

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SLIDE 13

Cr(VI) in valley groundwater is a health concern

CA MCL = 50 μg L CA MCL = 50 μg L-1

1

CA Public Health Goal = 0.06 CA Public Health Goal = 0.06 μg L

μg L-

  • 1

1

60 70 80

)

Sacramento Sacramento Davis Davis

40 50 60

VI)] (g L-1

Davis Davis

10 20 30

[Cr(V

2 4 6 8 10 12 14 16 18 20

[NO3-] (mg N L-1)

M i t l 2009 A l G h M i t l 2009 A l G h Morrison et al., 2009, Appl. Geochem. Morrison et al., 2009, Appl. Geochem. Wanty et al., 2009, Appl. Geochem. Wanty et al., 2009, Appl. Geochem. Dawson et al., 2008, USGS Data Series Dawson et al., 2008, USGS Data Series

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SLIDE 14

Cr(VI) increases with depth in shallow soils

1 2 1

(meters) (meters)

4 3

Depth Depth

5 10 15 4 5 10 15 5 10 15 5 10 15 5 10 15 5 10 15

Cr(VI) ( Cr(VI) (g kg g kg-1

1)

Mills et al., 2011, Appl. Geochem.

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SLIDE 15

Cr(VI) is elevated in deeper soils/sediments

5 15 10

h (meters) h (meters)

25 20

Depth Depth

25 50 25 50 30 25 50 25 50 25 50 25 50

Cr(VI) ( Cr(VI) (g kg g kg-1

1)

Mills et al., 2011, Appl. Geochem.

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SLIDE 16

Chromium cycling in natural environments

dissolution dissolution

Mn Oxides Mn Oxides

Cr(VI) Cr(VI)

Chromite Chromite (FeCr (FeCr2O4)

Cr(III) Cr(III)

dissolution dissolution di l ti / di l ti /

Cr(VI) Cr(VI)

e.g. HCrO e.g. HCrO4

  • , CrO

, CrO4

2-

  • e.g. Cr(OH)

e.g. Cr(OH)3, CrOH , CrOH2+

2+

dissolution/ dissolution/ precipitation precipitation

 Organic Carbon  Sulfides

 Fe2+

sorption sorption

e.g. e.g. Cr(OH) Cr(OH)3(s) (s) clays and clays and

  • xides
  • xides

 Sulfides

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SLIDE 17

Mn oxides are abundant in valley soils

5 mm

2500

Total Total Mn Mn

2000

soil

Mn Mn

1500

g per kg

Hydroxylamine Hydroxylamine-

  • reducible Mn

reducible Mn

500 1000

mg

500 Geometric Mean for Total Mn in U.S. surface soils Geometric Mean for Total Mn in U.S. surface soils (Shacklette and Boerngen, 1984) (Shacklette and Boerngen, 1984)

Mills et al., 2011, Appl. Geochem.

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SLIDE 18

Soil pH is a major control on Cr cycling

1.0 1.2

Common pH Values of Common pH Values of Sacramento Valley Soils Sacramento Valley Soils

0 4 0.6 0.8

V) CrO CrO 2- HCrO HCrO4

  • 0 0

0.2 0.4

Eh (V CrO CrO4

2

Cr Cr3+

3+

Cr(OH) Cr(OH)2+

2+

0 4

  • 0.2

0.0

Cr(OH) Cr(OH)3

2 3 4 5 6 7 8 9 10 11

  • 0.6
  • 0.4

Cr(OH) Cr(OH)2

+

pH

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SLIDE 19

Several distinct residences of Cr in valley soils

50 m

Smectite/Illite Smectite/Illite (~300 ppm Cr) (~300 ppm Cr)

0.5 m 0.5 m

Chromite Chromite (FeCr (FeCr2O4) Nano Nano-

  • crystalline

crystalline Iron oxides Iron oxides (300 (300-500 ppm Cr) 500 ppm Cr) (300 (300-500 ppm Cr) 500 ppm Cr)

Morrison, 2010, Ph.D. Thesis – Colorado School of Mines

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SLIDE 20

Concentrations of different Cr residences vary widely Cr(III) Cr(VI)

Cr

  • xidation

1000 10000

capacity

10 100

r kg soil

  • rate

stion te

0 01 0.1 1

mg per

  • metab

cid diges Citrat

0 0001 0.001 0.01

Li 4-ac

0.0001

Mills et al., 2011, Appl. Geochem.

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SLIDE 21

Cr(VI) generated during incubation of subsoil

20 9.0 15

kg-1)

8.5 10

r(VI) (g k

8.0

pH

5

Cr

7.0 7.5 20 40 60 80 100 120 140

Days

Mills et al., 2011, Appl. Geochem.

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SLIDE 22

H+ – Cr3+ exchange results in enhanced Cr(VI) generation

Soils ammended with HCl and incubated for two weeks Soils ammended with HCl and incubated for two weeks

100 9 0 40

)

80 100

g-1)

8.5 9.0 30 40

  • les kg-1)

40 60

VI) (g kg

8.0

pH

20

g2+ (mmo

20

Cr(V

7.5 10

Ca2+ + Mg

20 40 60 80

mmoles H+ kg-1

7.0

C

Mills et al., 2011, Appl. Geochem.

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SLIDE 23

Other salt additions affect Cr(VI) generation

30 35 20 25

g kg g kg-1

1)

10 15

Cr(VI) ( Cr(VI) (

5

Control Control NH NH4Cl Cl KCl KCl CaCl CaCl2

low high low high low high low high low high low high Low = 45 mequivalents kg Low = 45 mequivalents kg-1

1

High=128 mequivalents kg High=128 mequivalents kg-1

1

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SLIDE 24

Multiple effects of (NH4)2SO4 on Cr(VI)

5 10 15 20 25

Cr(VI) (g kg-1)

Cr(VI)

70 mequivalents NH4

+ kg-1

20 30 40

  • r NO3-

les kg-1)

NITRIFIERS NITRIFIERS

NH NH4

4 +

NO NO3

  • 10

20

NH4+ o (mmol

9.0 20

g2+ g-1)

NH NH4

+ + 1.5 O

+ 1.5 O2

NITRIFIERS NITRIFIERS

NO2

  • + 2 H

2 H+ + H2O Ca Ca2+

2+ + Mg

+ Mg2+

2+ 7.0 7.5 8.0 8.5

pH

4 8 12 16

Ca2+ + Mg (mmoles kg

NITROSIFIERS

NO2

  • + 0.5 O2

NO NO3

  • pH

pH

1 2

[PLFA] moles kg-1)

NO2 + 0.5 O2 NO NO3 nitirifiers nitirifiers nitrosifiers

20 40 60 80 100 120 140

Time (days) [ (m

nitirifiers nitirifiers

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SLIDE 25

Cr(VI) generation from Cr(III) in ammonium polyphosphate fertilizer

500 600

kg-1)

100

kg-1)

14 mequivalents NH4

+ kg-1

70 mequivalents NH4

+ kg-1

200 300 400 500

l Cr (g k

20 40 60 80

l Cr (g k

Total Cr Total Cr Total Cr Total Cr

25

1)

100

Tota

100

1)

20

Total

10 15 20

I) (g kg-1

40 60 80 100

) (g kg-1

Cr(VI) Cr(VI) Cr(VI) Cr(VI)

20 40 60 80 100 120 140

Days

5

Cr(VI

20 40 60 80 100 120 140

D

20

Cr(VI

Cr(VI) Cr(VI)

Days Days

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SLIDE 26

Conclusions

  • Sacramento valley soils are elevated in Cr and Mn due to

weathering of ultramafic rocks in surrounding mountains

  • Natural Cr is mostly present as Cr(III) in chromite
  • Natural Cr is mostly present as Cr(III) in chromite
  • Natural Cr(VI) generation occurs but is kinetically limited

by Cr(III) mobility

  • Addition of protons and other cations increases Cr(VI)

generation rates

  • Hi h

t ti f ti / i t h t

  • Higher concentrations of some cations/anions appear to shut

down Cr(III) oxidation mechanism

  • Organic carbon produced by nitrifying bacteria can reduce

g p y y g Cr(VI)

  • Oxidation of Cr(III) in ammonium polyphosphate occurs

faster than oxidation of natural Cr(III) faster than oxidation of natural Cr(III)

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SLIDE 27

Acknowledgements

  • Sue Fields & Andrew Fulks

Sue Fields & Andrew Fulks

University of California, Davis University of California, Davis

USGS USGS

  • Karl Ellefsen

Karl Ellefsen

  • JoAnn Holloway

JoAnn Holloway

  • Jeff Bold & Chuck Frey

Jeff Bold & Chuck Frey

Brown and Caldwell Brown and Caldwell

  • Bob Devany

Bob Devany

USGS USGS

y

  • Rich Wanty

Rich Wanty

  • Charlie Alpers

Charlie Alpers

  • Monique Adams

Monique Adams y

Weiss Associates Weiss Associates

  • Troy Bauder

Troy Bauder

Colorado State University Colorado State University

  • Monique Adams

Monique Adams

  • Valley Landowners

Valley Landowners

  • Joe Callizo

Joe Callizo

Wantrup Wildlife Sanctuary Wantrup Wildlife Sanctuary p y p y