~ ENTERED Joint SNL / KAFB Approach to

Determining Background Concentrations of Constituents of

Concern for the KAFB Reservation

SNL / KAFB / EPA Meeting June 1, 1995

Albuquerque, New Mexico

1

KAFB1630

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Joint SNL / KAFB Approach to Determining Background

Conc·entrations of Constituents of Concern for the KAFB Reservation

• Applications of background concentrations

• Factors that affect background

• Approach to background study

• Constituents of concern

• Sources, amounts and locations of data

• Data analysis methodology

• Status of joint background effort

2

Applications of Background Concentrations

• Nature and extent of contamination

• Baseline risk assessments

• Establishing cleanup target goals

• Selection of remediation technologies

• Verify effectiveness of cleanup

3

Factors that Affect Background

• Parent geologic material

• Depositional processes

• Erosion and weathering processes

• Pedogenic processes

These factors create a distribution of values rather than a sigle value.

4

Approach

• . Provide ·necessary background characterization for decision making process

• Establish background on as large a spatial scale as is technically justified for each Coe

• Sitewide vs. unit-based approach

- Consistent definition of contamination

- Consistent baseline risk assessment

- Consistent cleanup target

- Based on larger number of values

- Higher confidence in summary statistics

- Cost-effective approach

5

,. ..-

Constituents of Concern

• SNL - Reports - Task leader interviews - Process knowledge - Waste analysis

• KAFB - Review of Draft Background Soil Study

Work Plan - Discussions to finalize list

6

List of Constituents of Concern

Media

Groundwater/ "Surface Water"

Soil (unfiltered) Air

Antimony Antimony Cesium-137 Arsenic Arsenic Lead Barium Barium Potassium-40 Beryllium Beryllium Radium-226 Cadmium Cadmium Radium-228 Cesium-137 Cesium-137 Radon-222 Chromium VI Chromium VI Strontium-90 Cobalt Cobalt Thorium-232 Copper Copper Thorium-234. Lead Lead Total Chromium Mercury Mercury Uranium-234 Nickel Nickel Uranium-235 Radium-226 Nitrate plus Nitrite Uranium-238 Radium-228 (as N) Radium-226 Selenium Radium-228 Silver Radon-222 Strontium-90 Selenium Thallium Silver Thorium-232 Strontium-90 Thorium-234 Thallium Tin Thorium-232 Total Uranium Thorium-234 Total Chromium Tin Uranium-234 Total Chromium Uranium-235 Total Uranium Uranium-238 Uranium-234 Vanadium Uranium-235 Zinc Uranium-238 Zirconium Vanadium

Zinc Zirconium

7

Sources of Data

• SNL data from Interim Report - Background investigations - On- and off-site monitoring - Focused SWMU investigations

• New SNL data - TA-1 soil - Sitewide groundwater monitoring - etc.

• KAFB IRP data - Stages 2, 2a, 2b, and 2d

• . New off-site data - 50 samples x 19 analytes from 5 off­

site locations

• Comparison with regional background investigations

8

Number of Background Data Points

• SNL Interim Background Report (14 metals, 17 radionuclides, nitrate+nitrite)

soil groundwater surface water air

11,202 1,954

85 145

• KAFB IRP Data (20 metals, 3 radionuclides, nitrate+nitrite)

soil groundwater surface water

24,660 1,827

203

• New SNL Background Data (17 metals, 7 radionuclides)

soil groundwater

>3,069 >2,000

• New SNL Off-site Data (19 metals)

soil 950

9

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______________ ._ _________________________ ____

• KAFB IRP Stage 2 & 2A Locations

• KAFB IRP Stage 2B Locations

• SNL Tech Area Locations

301462. 125.03. 000 A 1

ISLET A INDIAN RESERVATION

Location Map of Sandia National Laboratories and Kirtland Air Force Base Reservation, Albuquerque

Handling of Non-Detect Values

• Based on EPA g~idance

- If ND <15°/o, value= 1/2 DL.

- If ND >15%, use non-parametric methods.

• Historical "high NDs" > median are deleted.

20

Data Analysis Methodology (continued)

4 - Normality testing (W test)

5 - Outlier rejection (T n test)

14

Sources of Outliers

• Improper sampling, analytical error, or laboratory contamination

• Errors in transcription of data values, decimal points, or units

• The presence of actual contamination in the sample

• A true natural value that is unusually high

15

Outlier Rejection Test

Based on EPA guidance

Evaluation · of T" statistic defined as:

T = (X0 - X)/S Where:

X0 = observation that is in question X = population mean S = population standard deviation

- Compare T with T n from table at given confidence level (95%) and N

- If T > T n then Xn = outlier

- Not used for non-parametric distribution

16

, • I I

Data Analysis Methodology (continued)

6 - Comparison of subsets surface vs. depth spatial area comparison

Methods:

• Comparison of general distributions - Multiple Box-and Whisker plot

• Comparison of medians - Wilcoxon Rank Sum test - Quantile test - Kruskal-Wallis test

• Comparison of dispersion - Kolmogorov Smirnov test

17

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-,-------251h Percentile .

~Lows~Data -

...

Figure 5-2 Box-and-Whisker Plot

Multiple Box-and-Whisker Plot for Beryllium in Soil

1.2 r ···········"··"························· (n = 173) ········································t··················· ··················· ···· (n = 158) ....................................... .

1 ~··········· ·················· ························································· ······· ·········!···················································+················································· ~

C) ~ ......... ~ 0.8 1-·················································+········································ ···········I ····································· ·············•+••···············································

..._.. C .2 0. 6 ~·················································t ···· ······································· ········l··················································•+••··············································· ... ca a.. ... B o.4 r ···························· 1 i ·······························!·························· ·····-r--------,-······················· ·· ····

C 0 0 0.2 1-·······•····•···•················•·········••••••+·•••···· ·•·•••••••· ••••• ••••·•••• ••·· ·•· •· •···· ····I·················•······ ··· ····················· ··•+••···· ·•· ·•••·•· ····· ••••••·••••··· ·· ············

or································································································· .····!········· ····························· ································································

At Depth Surface

Depth

Multiple Box-and-Whisker Plot for Total Uranium in Soil

6 r · ······ ······ ·············· ··· ···l· · ······· ····· ····· ••··•• ·· ····•·• ❖••·····•·•··············•·······•· ❖ ••···• · •······ · · ·· · ······ · ···· ··· ·•········ ···· ·· · ·· ······ •·········••<·•···· · ··• ······ · ···· ······•·•··· (n=6) j (n=71) j (n=15) j (n=10) j (n=121) j (n=129)

5 - ················· ······ ····················································· ····························-··· ·················································· ··················································· ...-. C) ~ ...._ C) 4 E ._. C 0 3 ·-as ~ .., C 2 G) (,) C

81

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t 0 t- ···················· ··········· ··1················+-················r············- ·············:········· ·· ····· ······ ·············:·············-············!············ ·

II · Ill IV V Offsite Other

Technical Area

Data Analysis Methodology {continued)

7 - Summary statistics

Type of Expression of Expression of Distribution Central Background

Tendency

Normal Arithmetic 95th Upper Mean Tolerance

Limit

Log normal Geometric 95th Upper Mean Tolerance

Limit

Non- Median 95th Percentile Parametric

18

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Identification of Contaminated Samples

Main concern is identification and rejection of contaminated samples.

• Screening of data

• A priori outlier rejection

• T n outlier rejection

• Identification of multiple populations

• Surface vs. depth subset comparison

• Spatial subset comparisons

19

# I

Status of Joint Background Effort

• Interim report based on SNL data - Established methodology - Defined data gaps

• Coordin-ation with KAFB

• Off-site Samples collected

• Database completion June 30 including - SNL data - IRP data - Off-site data

20

< I

BACKGROUND CONCENTRATIONS OF CONSTITUENTS OF CONCERN TO THE SANDIA NATIONAL LABORATORIES/

NEW MEXICO ENVIRONMENTAL RESTORATION PROJECT

Phase II: Interim Report

Prepared for:

Sandia National Laboratories/New Mexico Environmental Restoration Department

Albuquerque. New Mexico

Prepared by:

IT Corporation 530 I Centtal Avenue NE, Suite 700

Albuquerque. New Mexico 87108

October 1994

·" . . '

Data Analysis Methodology

1 - Screen data for inclusion in data-base - Site and process knowledge - Exclude analyses of non-native

materials

2 - A priori rejection (extremely high values) - Anticipated ranges - Cross correlations with other metals

3 - Histogram & cumulative distribution plots - Type of distribution? - Multiple populations? - Outliers?

12

Cross Plot of Zn versus Al 30--------------------------------

28-

26-

24-

E a. 22-c. .._....

·5 20-cn C -~ 18-N

16-

14-

12-

+

+

+

+ ++

+ ++ + + +-t+ # + *

+ + + ++ -1'1-+ +

+ ++ ++ +t#++ ++-+ -t+ + + + + +

t++ + + + ++ + -tt++ + +-!n..:' * + +

: ·~ ++ + +

+ + + ++ + +

+ + + + + +

+

10 -

~

+ +

+

+

+

+ +

1000 2000 3000 4000 5000 6000 7000 8000 Al in Soil (ppm)

9000

........ E a. a. .......... -·-0 U)

C ·­·-z

Cross Plot of Ni versus Fe 10----------------------------.

9

8

7

6

5

+ 4

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++ +

+

+ + +

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-++- -H- + ++ ++ + +

+ +-tk+ 11 I + *+

+:++it-f:+ + 4 + + +H+ ·+

+ +~ :j:t ++ +

+* + + +-4- ++-t+ ++

+ -t * ~* + ++

+ · +

+ +

-fT

+

+

3-1-----....------..--------,.----------r------.-------1 4 · 6 8 10 12 14 16

Fe in soil (ppm) (Thousands)

... .

... ~ ,-

SET_1 N:200, X:5, S:1.5

SET...:..2 N:100, X:10, S:2 25.---,----.---.----T""---,-...------.------,------.--------.--,----r------.----,

20 ................. .

.l: 15 ................ .

0 It-o 0 10 z

5 ...................... .f ..

0t:: =::::::::: . . ~ ."-----I ------------- SET_1 1 2 3 4 5 6 7 8 9 1 o 11 12 13 14 15 ------------- SET 2

Concentration

112 104 96 88 80 72

en 64 .a

0 56 ....

0 48 0 z 40 32 24 16 8 0

. ~

<=0 (0,2]

Histogram of Sets 1 and 2

(2,4) (4,6) (6,8) (8,10) (10,12] (12,14] > 14

Concentration

Normal Probability Plot of SET 1 and SET 2 3.5 , , ,

I I I : : : 0

- ; ; ~~= ~~

- . 0 2 4 6 8 10 12 14 16

Observed Value

• t

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Lognonnal Problbillly Plol t01Llldlllelcl

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Figure 7a

2 2.5 3

Lognormal Probability Plot for Barium Concentrations from Building 901 LF Soil Samples.

i "'

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Normal Probabilily Plol 901 Leachlield

I I

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I 200 • 600 ICIO 1000

IBalln!Wk1

Figure 7b

Normal Probability Plot for Barium Concentrations from Building 901 LF Soil Samples.

.. ..

Determination of Statistical Distribution Type

• Importance: - Statistical methods differ - Background descriptions differ

• Types considered: - Normal - Lognormal - Non-parametric

• Distributions determined by: - Histograms - Cumulative distribution curves - Percentage of non-detects

13