Leachate Geochemical Results for Ash Samples from the 

June 2007 Angora Wildfire Near Lake Tahoe in Northern 

California 

By Philip L. Hageman, Geoffrey S. Plumlee, Deborah A. Martin, Todd M. Hoefen, Monique Adams, 

Paul J. Lamothe, Todor Todorov, and Michael W. Anthony 

Open-File Report 2008–1170 

U.S. Department of the Interior 

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

DIRK KEMPTHORNE, Secretary 

U.S. Geological Survey 

Mark D. Myers, Director 

U.S. Geological Survey, Reston, Virginia 2008 

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Suggested citation: 

Hageman, Philip L., Plumlee, Geoffrey S., Martin, Deborah A., Hoefen, Todd M., Adams, Monique, Lamothe, 

Paul J., Todorov, Todor, and Anthony, Michael W., Leachate Geochemical Results for Ash Samples from the 

June 2007 Angora Wildfire near Lake Tahoe in Northern California, 2008: U.S. Geological Survey Open-File

Report 2008-1170. 14 p. This publication is available online at http://pubs.usgs.gov/of/2008/1170/ 

Any use of trade, product, or firm names is for descriptive purposes only and does not imply 

endorsement by the U.S. Government. 

Although this report is in the public domain, permission must be secured from the individual 

copyright owners to reproduce any copyrighted material contained within this report. 

ii
iii

Contents 

Overview ................................................................................................................................................................................1

Introduction............................................................................................................................................................................1

Sample Collection and Preparation.......................................................................................................................................1

USGS Field Leach Test (FLT)..................................................................................................................................................2

Analytical Methods ...............................................................................................................................................................3 

Acknowledgments .................................................................................................................................................................3

USGS Contacts.......................................................................................................................................................................3

References .............................................................................................................................................................................4

 Tables 

1. Sample names, locations, elevations, and site descriptions for 19 ash samples collected for

 this study.........................................................................................................................................................................2

2. FLT leachate geochemical data for ash samples....................................................................................................5
Leachate Geochemical Results for Ash Samples from 

the June 2007 Angora Wildfire Near Lake Tahoe in 

Northern California 

By Philip L. Hageman, Geoffrey S. Plumlee, Deborah A. Martin, Todd M. Hoefen, Monique Adams, 

Paul J. Lamothe, Todor Todorov, and Michael W. Anthony 

Overview 

This report releases leachate geochemical data for ash samples produced by the Angora wildfire 

that burned from June 24 to July 2, 2007, near Lake Tahoe in northern California. The leaching studies 

are part of a larger interdisciplinary study whose goal is to identify geochemical characteristics and 

properties of the ash that may adversely affect human health, water quality, air quality, animal habitat, 

endangered species, debris flows, and flooding hazards. 

The leaching study helps characterize and understand the interactions that occur when the ash 

comes in contact with rain or snowmelt, and helps identify the constituents that may be mobilized as 

run-off from these materials. Similar leaching studies were conducted on ash and burned soils from the 

October 2007 southern California wildfires (Hageman and others, 2008; Plumlee and others, 2007). 

Introduction 

 On July 30, 2007, personnel from the U.S. Geological Survey (USGS) collected ash samples 

from forest and suburban residential areas in El Dorado County, California, that were burned by the 

Angora wildfire. All nineteen samples were leached using the USGS Field Leach Test (FLT) (Hageman, 

2007). After leaching, aliquots of the leachate were analyzed for pH and specific conductance. Another 

portion of the leachate was filtered, and aliquots were preserved for geochemical analysis. This report 

presents leachate geochemical data for pH, specific conductance, anions by ion chromatography (I.C.), 

major elements by inductively coupled plasma—emission spectrometry (ICP-AES), cations by 

inductively coupled plasma—atomic mass spectrometry (ICP-MS), and mercury by continuous flow 

injection—cold vapor—atomic fluorescence (CVAFS). 

Sample Collection and Preparation

Altogether, 19 ash samples were collected for this study (table 1). Surficial ash was collected 

from each sampling site from plots approximately 12 by 12 inches square using a clean plastic spoon or 

trowel and placed in clean plastic bags. A layer of soil up to two inches deep underlying the plots was 

collected separately and saved for future analysis. In addition to wildland burn areas, samples were also 

collected from burned residential areas. GPS coordinates and other information was collected and 

recorded for each sampling site. 

1
Table 1. Sample names, locations, elevations, and site descriptions for 19 ash samples collected for this study. 

[Angora10 was collected as two grab samples and combined into a single sample] 

___________________________________________________________________________________ 

Sample Latitude Longitude Elevation (ft.) Site Description

Angora01 38o 51.832 120o 03.121 6,660 Forest

Angora02 38o 52.172 120o 03.043 6,546 Forest

Angora03 38o 52.399 120o 02.907 6,537 Forest

Angora04 38o 52.411 120o 03.326 6,793 Forest

Angora05 38o 52.448 120o 03.115 6,599 Forest

Angora06 38o 52.514 120o 02.817 6,483 Forest

Angora07 38o 52.669 120o 02.654 6,406 Forest

Angora08 38o 52.910 120o 02.917 6,512 Forest

Angora09 38o 52.905 120o 02.422 6,373 Residential

Angora10 38o 53.10

38o 53.19

120o 02.4

120o 02.39

6,420

6,486

Residential

Angora11 38o 53.3 120o 02.15 6,450 Residential

Angora12 38o 53.3 120o 02.1 6,350 Residential

Angora13 38o 53.7 120o 02.0 6,540 Forest

Angora14 38o 53.85 120o 01.9 6,630 Residential

Angora15 38o 53.9 120o 01.8 6,580 Residential

Angora16 38o 54.1 120o 01.7 6,790 Forest

Angora17 38o 54.2 120o 01.7 6,970 Forest

Angora18 38o 54.25 120o 01.7 7,010 Forest

Angora19 38o 54.4 120o 01.9 7,040 Forest 

______________________________________________________________________________ 

After collection, splits of the original samples were sent to the USGS Mineral Resources 

Program laboratories in Denver, Colorado, for processing and analysis. To prepare the samples, the bulk 

composite samples were split. One fourth of each sample was archived, and the remainder was 

distributed for further preparation or sent to the laboratories for analysis. 

USGS Field Leach Test (FLT) 

The FLT leaching procedure is used to rapidly identify and characterize the water-leachable, 

water-reactive phase of samples. The procedure uses deionized water (DI) to leach unground, <2 mm 

splits of geologic or environmental samples. For this study, 6.25 grams of each sample were weighed 

into 125 mL wide-mouth plastic bottles. Then, 125 mL (DI) water was added slowly to each bottle so 

that no sample was lost. The bottles were tightly capped and vigorously shaken for 5 minutes on a 

horizontal shaking table. After shaking, the contents were allowed to settle for 10 minutes. After 

settling, unfiltered sub-samples of the leachate were dispensed into disposable plastic beakers and 

measured for pH and specific conductance. Another portion of leachate was filtered using a 60-cc (cubic 

centimeter) syringe and a 0.45-micrometer (μm) pore-size nitrocellulose filter. If filtration was difficult, 

a 0.70-μm glass fiber pre-filter was used in conjunction with the 0.45-μm filter in a serial manner. Subsamples of filtrate (15 mL) for ICP-AES and ICP-MS analysis were filtered into acid-washed bottles 

and preserved to pH <1.5 by acidification with ultra-pure nitric acid (HNO3). Another split (40 mL) 

of filtrate was collected in plastic bottles and refrigerated for ion chromatography analysis. A third 

sub-sample of filtrate (30 mL) was collected and preserved for mercury analysis. This split was filtered 

into acid-washed borosilicate glass bottles with Teflon-lined caps and preserved with 1.0 mL mercuryfree concentrated hydrochloric acid per 30 mL of sample. 

2
Analytical Methods 

Brief descriptions of the analytical methods used in this study are listed below. Complete details 

for all of these methods can be found online (Taggart, 2002). Leachate geochemical data for all methods 

are in table 2. 

1. pH and specific conductance were determined using hand-held meters. Analysis was conducted on 

unfiltered leachate. 

2. Major elements (calcium (Ca), potassium (K), magnesium (Mg), sodium (Na), and silica (SiO2) )were 

determined using ICP-AES. Analysis was conducted on filtered leachate preserved with Ultrex HNO3 to 

a pH <1.5. 

3. Cations, metals, and sulfate (SO4) were determined using ICP-MS for a 44-element suite. Analysis 

was conducted on filtered leachate preserved with Ultrex HNO3 to a pH <1.5. 

4. Fluoride (F), chloride (Cl), and nitrate (NO3) were determined using I.C. Analysis was conducted on 

filtered leachate preserved by refrigeration. 

5. Mercury (Hg) was determined using CVAFS. Analysis was conducted on filtered leachate preserved 

with HCl. 

In addition to this leaching study, splits of these samples are currently being analyzed by an 

assortment of other techniques including total bulk chemistry on solids, X-ray diffraction for 

mineralogy, bioaccessibility of metals and metalloids in simulated biofluids, and particle size 

distribution. Results of these analyses will be published when completed. 

Acknowledgments 

This study is funded by the USGS Mineral Resources Program. The authors wish to 

acknowledge USGS personnel Gerald Rockwell, Jim Howle, and Kevin Bazar, from the Carnelian Bay 

Field Office and Nancy Alvarez, Tim Rowe, and Jason Reichelt from the Carson City Field office for 

logistics and collection of the samples. 

USGS Contacts 

Geoffrey S. Plumlee, gplumlee@usgs.gov 

Deborah A. Martin (logistics and sample collection), damartin@usgs.gov 

Todd Hoefen (Denver sample preparation), thoefen@usgs.gov 

Ray Kokaly (remote sensing), raymond@usgs.gov 

Phil Hageman (leach tests), phageman@usgs.gov 

Greg Meeker (SEM analysis), gmeeker@usgs.gov 

Paul Lamothe (analytical chemistry), plamothe@usgs.gov

3
4

References 

Hageman, P.L., Plumlee, G.S., Martin, D.A., Hoefen, T.M., Meeker, G.P., Adams, Monique, Lamothe,

 P.J., and Anthony, M.W., 2008, Leachate geochemical results for ash and burned soil samples 

 from the October 2007 Southern California Wildfires: U.S. Geological Survey Open-File Report

 2008-1139. Available online at http://pubs.usgs.gov/of/2008/1139/. 

Hageman, P.L., 2007, U.S. Geological Survey field leach test for assessing water reactivity and leaching

 potential of mine wastes, soils, and other geologic and environmental materials: U.S. Geological 

 Survey Techniques and Methods, book 5, chapter. D3, 14 p. Available online at 

http://pubs.usgs.gov/tm/2007/05D03/.

Plumlee, G.S., Martin, D.A., Hoefen, T., Kokaly, R., Hageman, P., Eckberg, A., Meeker, G.P., Adams, 

 M., Anthony, M., and Lamothe, P.J., 2007, Preliminary analytical results for ash and burned 

 soils from the October 2007 southern California Wildfires: U.S. Geological Survey Open-File 

 Report 2007-1407. Available online at http://pubs.usgs.gov/of/2007/1407/. 

Taggart, J.E., ed., 2002, Analytical methods for chemical analysis of geologic and other materials, U.S. 

 Geological Survey: U.S. Geological Survey Open-File Report 02-223, pages not numbered 

 consecutively: http://pubs.usgs.gov/of/2002/ofr-02-0223/. 
Table 2. FLT leachate geochemical data for ash samples. 

[F, Cl, and NO3 by ion chromatogrpahy; elements: B, Ca, K, Mg, Na, and SiO2 by ICP-AES (itallics in table), cations,

metals and SO4 by ICP-MS; Hg by CVAFS]

Sample ID pH Specific Conductance Cl F (NO3) Ag Al 

(Standard Units) (μS/cm) mg/L mg/L mg/L ug/L ug/L 

Angora01Angora02Angora03Angora04

Angora05Angora06

Angora07Angora08Angora09Angora10

Angora11

Angora12Angora13Angora14Angora15

Angora16

Angora17Angora18Angora19

10.0

9.79.8

10.2

10.3

9.7

9.7

10.3

9.6

11.5

10.3

10.710.710.110.0

10.1

10.410.110.6

816638

75

120

51238223

360

64

200350140

52

45

135154140

2.21.4

<.08

1.3

1.7

1.2

<.08

1.41.2

5.0

1.3

1.91.78.20.4

1.2

1.52.11.4

0.50.50.2

0.3

0.5

0.50.2

0.12

0.2

0.2

0.2

0.20.80.40.2

0.1

1.00.60.3

0.6

<.08

0.5

0.5

<.08

<.08

0.5

1.3

0.5

0.5

0.5

<.08

0.90.60.5

0.5

0.60.60.6

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1<1<1

<1

<1<1<1

1760

1970

1470

2550

2920

1890

440

3440

230

830

1650

470

200

49001170

970

403021404780

5
Table 2—Continued.

Sample ID Ba Be Bi Ca Cd Ce Co Cr C

ug/L ug/L ug/L mg/L ug/L ug/L ug/L ug/L u

Angora01

Angora02Angora03Angora04

Angora05Angora06

Angora07Angora08Angora09Angora10Angora11Angora12Angora13Angora14

Angora15

Angora16

Angora17Angora18Angora19

396139

100210

36

7

87

8

27171578

224

3957591744

0.050.06

<0.05

0.08

<0.05<0.05<0.05<0.05

0.07

<0.05<0.05<0.05<0.05<0.05<0.05<0.05<0.05<0.05<0.05

< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2

1311

6.5

1316

9.13.79.93.5

3310

7.8

22

21

7.5

7.0

212321

<0.02<0.02<0.02<0.02<0.02<0.02

0.02

<0.02<0.02

0.24

<0.02<0.02<0.02<0.02<0.02<0.02<0.02

0.03

<0.02

< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01

0.040.02

<0.02<0.02<0.02<0.02<0.02<0.02<0.02<0.02<0.02

0.020.400.020.060.020.050.160.11

<1<1<1<1<1<1<1<1<1

12.5

<1

43.7

<1<1<1<1<1<1<1

< 0< 0< 0< 0

0

< 0< 0< 0< 0

0

< 0< 0

0

< 0< 0< 0

00

< 0

6
Table 2—Continued.

Sample ID Dy Er Eu Fe Ga Gd Ge Hg H

ug/L ug/L ug/L ug/L ug/L ug/L ug/L ng/L u

Angora01

Angora02

Angora03

Angora04

Angora05Angora06

Angora07Angora08Angora09Angora10Angora11Angora12Angora13Angora14

Angora15Angora16

Angora17Angora18Angora19

< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005

< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005

0.010.01

0.008

0.020.03

0.007

< 0.005

0.01

< 0.005

0.0090.0070.008

0.010.04

0.0050.0070.0060.007

0.01

<50<50<50<50<50<50<50<50<50<50<50<50<50<50<50<50<50<50<50

0.40.20.10.40.40.20.10.3

< 0.05

0.30.40.20.10.40.10.20.60.40.4

0.007

0.01

< 0.005< 0.005< 0.005

0.007

< 0.005

0.006

< 0.005

0.006

< 0.005

0.01

< 0.005< 0.005

0.0090.0060.005

< 0.005< 0.005

0.060.06

< 0.05< 0.05

0.05

0.05

< 0.05

< 0.05< 0.05

0.1

< 0.05

0.06

< 0.05< 0.05

< 0.05< 0.05

0.06

< 0.05< 0.05

<5<5

<5<5

<5

<5

<5

<5<5

<5

<5

<5

<5<5

<5<5

<5

<5<5

< 0< 0

< 0< 0

< 0

< 0

< 0

< 0< 0

< 0

< 0

< 0

< 0< 0

< 0< 0

< 0

< 0< 0

7
Table 2—Continued.

Sample ID La Li Lu Mg Mn Mo Na Nb N

ug/L ug/L ug/L mg/L ug/L ug/L mg/L ug/L u

Angora01

Angora02

Angora03Angora04

Angora05Angora06

Angora07Angora08Angora09Angora10Angora11Angora12Angora13Angora14

Angora15

Angora16

Angora17

Angora18Angora19

0.03

< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01

6.2

< 0.1< 0.1< 0.1< 0.1< 0.1< 0.1

0.2

< 0.1< 0.1< 0.1< 0.1

0.3

< 0.1< 0.1< 0.1< 0.1< 0.1< 0.1

< 0.1< 0.1< 0.1< 0.1< 0.1< 0.1< 0.1

< 0.1

< 0.1< 0.1< 0.1< 0.1

< 0.1

< 0.1< 0.1< 0.1< 0.1< 0.1< 0.1

0.920.860.33

0.78

1.9

0.550.270.870.34

0.4

0.55

1.09.3

2.0

0.44

0.33

1.42.7

0.84

4.3

20.427.5

8.3

14.527.918.8

4.6

12.4

1.16.07.31.4

10.3

6.58.55.8

10

6.0

< 2

< 2< 2

< 2

< 2< 2< 2

2.7

< 2

19.9

< 2

1.92.33.6

< 2< 2

16.9

5.62.3

0.19

0.28

<0.1

0.12

0.270.18

0.4

0.3

0.27

8.6

0.14

21

0.49

0.210.23

0.110.18

0.41

0.19

0.26

< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2

< 0.2

< 0.2

< 0.2

< 0.2< 0.2< 0.2

0

< < < < < < < < < < < < 

< 0

< 

< 0

< < < 

8
Table 2—Continued.

Sample ID P Pb Pr Rb Sb Sc Se SiO 2 S

mg/L ug/L ug/L ug/L ug/L ug/L ug/L mg/L u

Angora01

Angora02

Angora03Angora04

Angora05Angora06

Angora07Angora08Angora09

Angora10

Angora11Angora12Angora13Angora14

Angora15

Angora16

Angora17Angora18Angora19

0.20.10.10.20.20.20.10.20.1

< 0.01

0.20.30.1

0.07

0.20.2

0.09

0.4

0.07

<0.05<0.05<0.05<0.05<0.05<0.05<0.05<0.05<0.05

4.5

<0.05<0.05<0.05<0.05<0.05<0.05<0.05<0.05<0.05

0.02

< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01< 0.01

1.5

1.2

0.70

1.9

13.6

1.2

0.32

4.9

0.25

5.3

0.8010.019.1

4.41.4

0.41

6.08.87.4

2.0

2.41.51.31.52.03.01.71.26.71.91.81.61.71.71.11.62.91.5

< 0.6

< 0.6< 0.6< 0.6< 0.6< 0.6< 0.6< 0.6< 0.6< 0.6< 0.6< 0.6< 0.6< 0.6< 0.6< 0.6< 0.6< 0.6< 0.6

< 1

< 1< 1< 1< 1< 1< 1< 1< 1

1.2

< 1< 1

1.1

< 1< 1< 1< 1< 1< 1

0.270.170.32

0.640.49

0.180.430.670.37

2.4

0.440.99

1.3

0.58

0.17

0.14

1.3

0.350.90

0

< < < < < < < 

0

< < < < 

0

< < < < < 

9
Table 2—Continued.

Sample ID Sr Ta Tb Th Ti Tl Tm U 

ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L u

Angora01

Angora02Angora03Angora04

Angora05

Angora06

Angora07Angora08Angora09Angora10Angora11Angora12Angora13Angora14

Angora15

Angora16

Angora17Angora18Angora19

92

110

5686

166

6825

130

21525933

165318

7848

230308225

0.20.20.20.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.1

< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005

< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2

< 0.5< 0.5< 0.5< 0.5< 0.5< 0.5< 0.5< 0.5< 0.5< 0.5< 0.5< 0.5< 0.5< 0.5< 0.5< 0.5< 0.5< 0.5< 0.5

<0.1<0.1<0.1<0.1<0.1<0.1<0.1<0.1<0.1<0.1<0.1<0.1<0.1<0.1<0.1<0.1<0.1<0.1<0.1

< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005< 0.005

49.61.210.210.160.130.13

< 0.1

0.12

< 0.1< 0.1

0.171.44

< 0.1< 0.1

0.14

< 0.1< 0.1< 0.1< 0.1

10111111

1

3

4

61332

10
Table 2—Continued.

Sample ID Yb Zn Zr

ug/L ug/L ug/L

Angora01

Angora02Angora03Angora04

Angora05

Angora06

Angora07Angora08Angora09Angora10Angora11Angora12Angora13Angora14

Angora15

Angora16

Angora17Angora18Angora19

0.006

0.01

< 0.005< 0.005

0.007

< 0.005

0.01

< 0.005< 0.005

0.01

0.007

< 0.005< 0.005< 0.005

0.008

< 0.005< 0.005

0.006

< 0.005

3.1

<0.5<0.5

1.2

<0.5<0.5<0.5<0.5<0.5

2.0

<0.5

0.9

<0.5<0.5<0.5<0.5<0.5<0.5<0.5

< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2

0.5

< 0.2< 0.2

< 0.2

< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< 0.2

11