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Preliminary continental-scale geochemistry P li i i l l h i from the North American Soil Geochemical Landscapes Project L d P j t Illinois in September National Environmental Monitoring Conference National Environmental Monitoring

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SLIDE 1

P li i i l l h i Preliminary continental-scale geochemistry from the North American Soil Geochemical L d P j t Landscapes Project

National Environmental Monitoring Conference National Environmental Monitoring Conference Bellevue, Washington Bellevue, Washington

Illinois in September

, g , g August 2011 August 2011

Laurel Laurel G Woodruff G Woodruff USGS USGS St Paul St Paul Minnesota Minnesota Laurel Laurel G. Woodruff,

  • G. Woodruff, USGS,

USGS, St. Paul,

  • St. Paul, Minnesota

Minnesota David David B. Smith,

  • B. Smith, USGS,

USGS, Denver, Denver, Colorado Colorado

U.S. Department of the Interior U.S. Department of the Interior U.S. Geological U.S. Geological Survey Survey

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SLIDE 2

US Spatial Sample Sites

~4800 sites at a sampling density of b t 1 it /1600 k

2

about 1 site/1600 km2

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SLIDE 3

US Spatial Sample Sites

To date, ~ 1600 sites in 23 states have complete chemistry complete chemistry

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SLIDE 4

Three samples collected at each site

  • 1. 0 to 5 cm depth,

regardless of horizon regardless of horizon 1614 samples 2 C it f A

  • 2. Composite of A

horizon 1613 samples

  • 3. Deeper subsoil ~ 1 m
  • 3. Deeper subsoil 1 m

depth, B or C horizon 1606 samples

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SLIDE 5

Sample analyses on < 2 mm fraction

  • Near-total extraction for 42 major and trace elements

(combined ICP-MS/ICP-AES)

  • Mercury Selenium and Arsenic by single element
  • Mercury, Selenium and Arsenic by single element

methods

  • Total and Inorganic carbon (A and C horizons)
  • Quantitative XRD mineralogy (A and C horizons)
  • Quantitative XRD mineralogy (A and C horizons)

T t l f 1600 it 3 l 46 l t Total of ~1600 sites x 3 samples x 46 elements = ~221,000 elements in geochemical data array, to date.

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SLIDE 6

Major soil chemistry influences

  • Parent material
  • Weathered bedrock of many types

Weathered bedrock of many types

  • Transported and sorted materials
  • Alluvium
  • Colluvium
  • Glacial deposits
  • Windblown deposits
  • Time
  • Soils developed over millions to thousands of years
  • Soils developed over millions to thousands of years
  • Climate
  • Strong gradients of both temperature and precipitation
  • Anthropogenic influences
  • Anthropogenic influences
  • Agriculture
  • Industrialization/Mining/Mineral Processing
  • Historic land use
  • Historic land use
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SLIDE 7

Parent Materials – Soil Age Climate annual precipitation Climate – annual precipitation

Range in cm

PRISM Group, Oregon State University, http://www prismclimate org

Topography

a ge c

http://www.prismclimate.org

Topography

Elevation in meters

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SLIDE 8

Major Land Resource Areas (MLRAs)

USDA, 2006, Handbook 296, Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin.

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SLIDE 9

Sodium (Na) in C horizon

High Na in volcanic rocks Variable Na in young glacial soils Uniform Na in young loess High Na in volcanic rocks Uniform Na in older loess in older loess

%

Na leached from Rocky Mountains Colorado Plateau Low Na in carbonate parent

Na in wt. %

  • ld, highly

weathered soils Mississippi River carbonate parent materials Mississippi River alluvial plain

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SLIDE 10

Arsenic (As) in C horizon

As in ppm

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SLIDE 11

Arsenic (As) in 0 to 5 cm soils

As = 72.2 ppm

As in ppm

pp Pb = 325 ppm

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SLIDE 12

Tungsten (W) in C horizon

W in ppm

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SLIDE 13

Tungsten (W) in A horizon

W in ppm

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SLIDE 14

As As Ag Ag Bi Bi Cu Cu Pb Pb Sb Sb Te Te W W Zn Zn O-

  • 5 cm

5 cm 417 417 >10 >10 694 694 616 >10,000 616 >10,000 73 73 50.5 1150 >10,000 50.5 1150 >10,000 A 195 195 >10 >10 129 129 88 2200 88 2200 33 33 10 0 198 2130 10 0 198 2130 A 195 195 >10 >10 129 129 88 2200 88 2200 33 33 10.0 198 2130 10.0 198 2130 C 193 193 <1 <1 5 5 35 35 80 80 28 28 <0.1 <0.1 12 12 145 145

NV 847

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SLIDE 15

Cadmium (Cd) in C horizon

Cd in ppm

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SLIDE 16

Cadmium (Cd) in 0 to 5 cm soils

Cd in ppm

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SLIDE 17

Mercury (Hg) in C horizon Mercury (Hg) in C horizon

Hg in ppm

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SLIDE 18

Mercury (Hg) in 0 to 5 cm soils Mercury (Hg) in 0 to 5 cm soils

0 to 5 56.40 A 8.24 C 0.40 0 to 5 4.43 A 6 24

Hg in ppm

A 6.24 C 0.02

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SLIDE 19

Mercury in NE Mercury in NE topsoils topsoils and and subsoils subsoils

0 to 5 cm soils C horizon

Hg in ppm Hg in ppm

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SLIDE 20

Phosphorus (P) in A horizon

High P in single site in Nebraska Sand Hills

P in ppm

0 to 5 4010 A 2860 A 2860 C 3940

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SLIDE 21

P in A-horizon soils in 3 NE Sand Hills sites

NE 11547

3 NE Sand Hills sites

P = 270 ppm P = 270 ppm P = 160 ppm P = 160 ppm

10 km

NE 8987 NE 3355

P = 2540 ppm P = 2540 ppm

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SLIDE 22

Conclusions from Preliminary Spatial S li Sampling

  • The

The geochemical data geochemical data generated by the NASLGP generated by the NASLGP are creating are creating a robust database of soil geochemistry for the United States a robust database of soil geochemistry for the United States a robust database of soil geochemistry for the United States a robust database of soil geochemistry for the United States

  • Low density (1 sample/~1600 km

Low density (1 sample/~1600 km2) sampling provides soil ) sampling provides soil geochemical and mineralogical data that display coherent geochemical and mineralogical data that display coherent geochemical and mineralogical data that display coherent geochemical and mineralogical data that display coherent continental continental-

  • and

and subcontinental subcontinental-

  • scale element patterns

scale element patterns

  • These

hese patterns reflect profound differences in soil parent patterns reflect profound differences in soil parent t i l d h i h t i l d h i h id li t ff t t ti id li t ff t t ti materials and hemisphere materials and hemisphere-

  • wide climate effects, at times

wide climate effects, at times

  • verprinted by human activity
  • verprinted by human activity
  • Spatial sampling at this scale and collecting multiple

Spatial sampling at this scale and collecting multiple Spatial sampling at this scale and collecting multiple Spatial sampling at this scale and collecting multiple samples at varying soil depths at individual sites provide samples at varying soil depths at individual sites provide detailed information about the natural variability of elements detailed information about the natural variability of elements in the environment and possible human impacts in the environment and possible human impacts in the environment and possible human impacts in the environment and possible human impacts