Annual Groundwater Monitoring Report...2019/02/22 · Annual Groundwater Monitoring Report...

Annual Groundwater Monitoring Report

Southwestern Electric Power Company H. W. Pirkey Power Plant

East Bottom Ash Pond CCR Management Unit Hallsville, Texas

January 2019

Prepared by:

American Electric Power Service Corporation 1 Riverside Plaza

Columbus, Ohio 43215

i

Page

Table of Contents I. Overview .......................................................................................................................................... 1

II. Groundwater Monitoring Well Locations and Identification Numbers ........................................... 3

III. Monitoring Wells Installed or Decommissioned ............................................................................. 4

IV. Groundwater Quality Data and Static Water Elevation Data, With Flow Rate and Direction and Discussion ........................................................................................................................................ 4

V. Statistical Evaluation of 2018 Events .............................................................................................. 4

VI. Alternate Source Demonstration ...................................................................................................... 4

VII. Discussion About Transition Between Monitoring Requirements or Alternate Monitoring Frequency ......................................................................................................................................... 4

VIII. Other Information Required ............................................................................................................. 5

IX. Description of Any Problems Encountered in 2018 and Actions Taken ......................................... 5

X. A Projection of Key Activities for the Upcoming Year ................................................................... 5

Appendix I

Appendix II

Appendix III

Appendix IV

1

I. Overview This Annual Groundwater Monitoring Report (Report) has been prepared to report the status of activities for the preceding year for an existing CCR unit at Southwestern Electric Power Company’s, a wholly-owned subsidiary of American Electric Power Company (AEP), Pirkey Power Plant. The USEPA’s CCR rules require that the Annual Groundwater Monitoring Report be posted to the operating record for the preceding year no later than January 31, 2019.

In general, the following activities were completed:

• Groundwater samples were collected and analyzed for Appendix III and Appendix IV constituents, as specified in 40 CFR 257.94 or 95 et seq. and AEP’s Groundwater Sampling and Analysis Plan (2016);

• Groundwater data underwent various validation tests, including tests for completeness, valid values, transcription errors, and consistent units;

• Statistically significant increases (SSIs) were determined for boron, calcium, chloride, total dissolved solids (TDS), and sulfate. An attempt was made to determine an alternate source but no alternate source was determined. The SSIs caused a transition in ground water monitoring program to assessment monitoring.

• Assessment Monitoring sampling was initiated;

• Groundwater Monitoring Statistical Evaluation Reports to evaluate groundwater data were prepared and certified in accordance with 40 CFR 257.93. The statistical process was guided by USEPA’s Statistical Analysis of Groundwater Monitoring Data at RCRA Facilities, Unified Guidance (“Unified Guidance”, USEPA, 2009).

The major components of this annual report, to the extent applicable at this time, are presented in sections that follow:

• A map, aerial photograph or a drawing showing the CCR management unit(s), all groundwater monitoring wells and monitoring well identification numbers;

• Identification of any monitoring wells that were installed or decommissioned during the preceding year, along with a statement as to why that happened;

• All of the monitoring data collected, including the rate and direction of groundwater flow, plus a summary showing the number of samples collected per monitoring well, the dates the samples were collected and whether the sample was collected as part of detection monitoring or assessment monitoring programs is included in Appendix I;

• A summary of any transition between monitoring programs or an alternate monitoring frequency, for example the date and circumstances for transitioning from detection monitoring to assessment monitoring, in addition to identifying the constituents detected at a statistically significant increase over background concentrations (Appendix IV).

2

• Other information required to be included in the annual report such as alternate source demonstration or assessment of corrective measures, if applicable.

In addition, this report summarizes key actions completed, and where applicable, describes any problems encountered and actions taken to resolve those problems. The report includes a projection of key activities for the upcoming year.

3

II. Groundwater Monitoring Well Locations and Identification Numbers The figure that follows depicts the PE-certified groundwater monitoring network, the monitoring well locations and their corresponding identification numbers.

East BAP Monitoring Wells Up Gradient Down Gradient AD-4 AD-2 AD-12 AD-31 AD-18 AD-32

4

III. Monitoring Wells Installed or Decommissioned There were no monitoring wells installed or decommissioned this year.

IV. Groundwater Quality Data and Static Water Elevation Data, With Flow Rate and Direction and Discussion

Appendix I contains tables showing the groundwater quality. Static water elevation data from each monitoring event are presented in Appendix I, along with the groundwater velocity, groundwater flow direction and potentiometric maps developed after each sampling event.

V. Statistical Evaluation of 2018 Events The two statistical analysis reports are included in Appendix II. Statistically significant increases (SSIs) were determined for boron, calcium, chloride, total dissolved solids (TDS), and sulfate as summarized in Groundwater Monitoring Statistical Evaluation Report (1/3/2018) in Appendix II. The SSIs caused a transition in ground water monitoring program to assessment monitoring.

Statistically significant levels (SSLs) above the groundwater protection standard were identified for cobalt and lithium as summarized in Statistical Analysis Summary East Bottom Ash Pond Report (12/26/2018) in Appendix II.

VI. Alternate Source Demonstration An alternate source investigation was conducted for the east bottom ash pond SSIs. An alternate source was not identified for boron, calcium, chloride, total dissolved solids (TDS), and sulfate those analyses and supporting information are found in Appendix III.

VII. Discussion About Transition Between Monitoring Requirements or Alternate Monitoring Frequency

The first groundwater statistical report of the year resulted in a transition of the groundwater program from detection monitoring to assessment monitoring. On January 3, 2018, it was determined that boron, calcium, chloride, total dissolved solids (TDS), and sulfate demonstrated a statistically significant increase in concentrations. See notification in Appendix IV.

Assessment monitoring will continue in 2019.

5

Regarding defining an alternate monitoring frequency, no modification of the twice-per-year detection monitoring effort is needed.

VIII. Other Information Required No other information applies at this time.

IX. Description of Any Problems Encountered in 2018 and Actions Taken No problems were encountered this year.

X. A Projection of Key Activities for the Upcoming Year Key activities for 2019 include:

• Assessment monitoring sampling will be conducted;

• Evaluation of the assessment monitoring results from a statistical analysis viewpoint, looking for any SSLs above GWPS;

• Characterize the nature and extent of groundwater for parameters that are above its GWPS and comply with 257.95(g)(3);

• Responding to any new data received in light of CCR rule requirements;

• Preparation of the third annual groundwater report.

APPENDIX I

Tables follow, showing the groundwater monitoring data collected, the rate and direction of groundwater flow, and a summary showing the number of samples collected per monitoring well. The dates that the samples were collected also is shown.

Table 1: Residence Time Calculation Summary - East Bottom Ash PondPirkey East Bottom Ash Pond

Geosyntec Consultants, Inc.

CCRManagement

Unit

MonitoringWell

Well Diameter (inches)

Groundwater Velocity (ft/year)

Groundwater Residence

Time (days)

Groundwater Velocity (ft/year)

Groundwater Residence

Time (days)

AD-2 [2] 4.0 7.1 17.0 6.5 18.7AD-4 [1] 4.0 10.2 12.0 1.4 86.8

AD-12 [1] 4.0 37.7 3.2 20.4 6.0AD-18 [1] 2.0 12.9 4.7 6.7 9.0AD-31 [2] 2.0 24.5 2.5 23.5 2.6AD-32 [2] 2.0 21.2 2.9 11.3 5.4

Notes:[1] - Background Well[2] - Downgradient Well

EastBottom Ash

Pond

2018-03 2018-08

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ClearwaterPond AD-12370.57

AD-13353.25

AD-16344.63

AD-17327.13

AD-18360.00

AD-2328.36

AD-22349.62

AD-23320.17

AD-27332.49

AD-28321.79

AD-3344.56

AD-30323.29

AD-31344.10AD-32351.42

AD-33350.10

AD-34307.61 AD-35311.17

AD-4359.04

AD-7348.46

AD-8359.04

AD-25

AD-26

AD-29

AD-10

AD-19AD-20

AD-21

W-3

335330

325320

315

310345

340

330325 355 360

365

EBAPWBAP

Landfill

StackOut Area

P:\Projects\AEP\Groundwater Statistical Evaluation - CHA8423\Groundwater Mapping\GIS Files\MXD\Pirkey\2018\AEP-Pirkey_GW_2018-03March.mxd. HDuff. 11/28/2018. Project/Phase/Task.

AEP Pirkey Power PlantHallsville, Texas

Potentiometric Contours - Uppermost AquiferMarch 2018

³

Figure1Columbus, Ohio 2018/11/28

LegendGroundwater Monitoring Wells!A Out of Network!A EBAP!A WBAP!A Landfill!A Stackout Area!A EBAP and WBAP

!!!A All CCR Unit Networks#* Piezometer

Groundwater Elevation ContourApproximate Groundwater Flow Direction

Notes- Monitoring well coordinates and water level data (collected on March 21 - 22, 2018)provided by AEP.- Site features based on information available in CCR Groundwater Monitoring WellNetwork Evaluations (Arcadis, 2016) provided by AEP.- Groundwater elevation units are feet above mean sea level.- East and West Bottom Ash Ponds have compacted cohesive soil from elevation 344 to347 ft. msl (Sargent and Lundy, 1984; AMEC, 2011).- Clearwater pond base elevation is 344 ft. msl (Sargent and Lundy, 1983).- W-3 was not gauged in March 2018

1,000 0 1,000500Feet

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ClearwaterPond AD-12357.99

AD-13349.14

AD-16340.03

AD-17324.12

AD-18353.99

AD-2326.99

AD-22344.11

AD-23320.31

AD-27328.61

AD-28319.93

AD-3343.28

AD-30321.70

AD-31342.73AD-32347.58

AD-33347.23

AD-34306.66 AD-35310.53

AD-4350.39

AD-7344.57

AD-8345.24

AD-25

AD-26

AD-29

AD-10AD-19

AD-20

AD-21

W-3

340335330325320

315310

330

325

350

345

EBAPWBAP

Landfill

StackOut Area

P:\Projects\AEP\Groundwater Statistical Evaluation - CHA8423\Groundwater Mapping\GIS Files\MXD\Pirkey\2018\AEP-Pirkey_GW_2018-08August.mxd. ARevezzo. 12/7/2018. Project/Phase/Task.

AEP Pirkey Power PlantHallsville, Texas

Potentiometric Contours - Uppermost AquiferAugust 2018

³

Figure2Columbus, Ohio 2018/12/07

LegendGroundwater Monitoring Wells!A Out of Network!A EBAP!A WBAP!A Landfill!A Stackout Area!A EBAP and WBAP

!!!A All CCR Unit Networks#* Piezometer

Groundwater Elevation ContourApproximate Groundwater Flow Direction

Notes- Monitoring well coordinates and water level data (collected on August 20-21, 2018)provided by AEP.- Site features based on information available in CCR Groundwater Monitoring WellNetwork Evaluations (Arcadis, 2016) provided by AEP.- Groundwater elevation units are feet above mean sea level.- East and West Bottom Ash Ponds have compacted cohesive soil from elevation 344 to347 ft. msl (Sargent and Lundy, 1984; AMEC, 2011).- Clearwater pond base elevation is 344 ft. msl (Sargent and Lundy, 1983).- W-3 was not gauged in August 2018

1,000 0 1,000500Feet

Table 1b: Detection Monitoring Data EvaluationPirkey Plant - East Bottom Ash Pond


8/24/2017 12/21/2017 8/23/2017 12/21/2017 8/23/2017 12/21/2017mg/L Interwell Background Value (UPL)mg/L Detection Monitring Results 1.46 1.38 0.0175 - 0.716 2.56mg/L Interwell Background Value (UPL)mg/L Detection Monitring Results 2.06 2.92 2.24 - 7.15 17.1mg/L Interwell Background Value (UPL)mg/L Detection Monitring Results 24 24 18 20 14 22mg/L Interwell Background Value (UPL)mg/L Detection Monitring Results

Table 1 – Groundwater Data SummaryPirkey – East Bottom Ash Pond


3/22/2018 8/21/2018 3/22/2018 8/21/2018 3/21/2018 8/20/2018 3/22/2018 8/21/2018 3/22/2018 8/21/2018 3/21/2018 8/21/2018 Antimony mg/L 0.005 U 0.00005 U 0.005 U 0.00005 U 0.005 U 0.00005 U 0.005 U 0.0000200 J 0.005 U 0.0000200 J 0.005 U 0.0000100 JArsenic mg/L 0.005 U 0.000520 0.005 U 0.00130 0.005 U 0.000110 0.005 U 0.00101 0.00332 J 0.00192 0.00305 J 0.00481Barium mg/L 0.0333 0.0290 0.0667 0.121 0.0258 0.0278 0.0978 0.0998 0.0708 0.0577 0.0413 0.0172

Beryllium mg/L 0.000450 J 0.000428 0.00115 0.000400 0.000160 J 0.000159 0.0000900 J 0.000129 0.00124 0.000729 0.00317 0.00370Boron mg/L 1.99 2.14 0.0331 0.0180 0.0140 0.0170 0.0164 0.0120 0.0408 0.0220 0.628 2.45

Cadmium mg/L 0.001 U 0.0000600 0.000260 J 0.0000200 J 0.001 U 0.0000100 J 0.001 U 0.0000200 J 0.000120 J 0.0000600 0.000550 J 0.000470Calcium mg/L 1.97 1.65 1.41 2.38 0.269 0.338 0.292 0.321 3.11 2.86 6.32 17.8Chloride mg/L 30.0 46.0 3.00 7.00 5.00 10.0 6.00 10.0 16.0 25.0 15.0 28.0

Chromium mg/L 0.001 U 0.000406 0.001 U 0.000198 0.00105 0.000330 0.001 U 0.000809 0.00962 0.00239 0.00538 0.000646Cobalt mg/L 0.0124 0.0136 0.00939 0.00443 0.00149 J 0.00172 0.000970 J 0.00118 0.0111 0.00929 0.0258 0.0435

Combined Radium pCi/L 1.05 1.06 1.28 1.33 0.784 1.13 0.942 1.11 2.96 4.13 4.92 6.01Fluoride mg/L 1 U 1 U 1 U 1 U 1 U 1 U 1 U 1 U 1 U 1 U 1 U 1 U

Lead mg/L 0.005 U 0.000338 0.005 U 0.0000980 0.005 U 0.0000890 0.005 U 0.000280 0.005 U 0.00141 0.005 U 0.000714Lithium mg/L 0.0538 0.0479 0.0537 0.0294 0.00722 0.0143 0.0165 0.0175 0.0973 0.0556 0.103 0.0689Mercury mg/L 0.0000420 0.0000200 J 0.000025 U 0.00000500 J 0.000025 U 0.000025 U 0.00000600 J 0.0000140 J 0.00139 0.00111 0.00640 0.00265

Molybdenum mg/L 0.005 U 0.0000600 J 0.005 U 0.0001 U 0.005 U 0.0000400 J 0.005 U 0.0000800 J 0.005 U 0.000240 0.005 U 0.0000400 JSelenium mg/L 0.00161 J 0.00110 0.00199 J 0.0000400 J 0.005 U 0.000100 0.00153 J 0.000200 0.00198 J 0.00250 0.00218 J 0.0150

Total Dissolved Solids mg/L 220 312 132 158 5 U 94.0 100 118 260 274 288 548Sulfate mg/L 105 130 23.0 21.0 3.00 4.00 6.00 8.00 76.0 72.0 113 321

Thallium mg/L 0.002 U 0.0000960 0.002 U 0.0000960 0.002 U 0.0000400 J 0.002 U 0.0000600 0.002 U 0.000113 0.002 U 0.000238pH SU 4.22 4.74 4.80 4.79 4.18 4.38 5.43 5.10 4.47 4.94 4.10 3.86

Notes:mg/L: milligrams per literpCi/L: picocuries per literSU: standard unitU: Parameter was not present in concentrations above the method detection limit and is reported as the reporting limit J: Estimated value. Parameter was detected in concentrations below the reporting limitSamples in table collected during assessment monitoring.

AD-12 AD-18 AD-31 AD-32Parameter Unit AD-2 AD-4

Table 1 - Groundwater Data SummaryPirkey Plant - East Bottom Ash Pond

5/11/2016 7/14/2016 9/7/2016 10/13/2016 11/14/2016 1/12/2017 3/1/2017 4/11/2017 8/24/2017 Detection

Antimony mg/L F


Antimony mg/LArsenic mg/LBarium mg/L

Beryllium mg/LBoron mg/L

Cadmium mg/LCalcium mg/LChloride mg/L

Chromium mg/LCobalt mg/L

Combined Radium pCi/LFluoride mg/L

Lead mg/LLithium mg/LMercury mg/L

Molybdenum mg/LSelenium mg/L

Total Dissolved Solids mg/LSulfate mg/L

Thallium mg/LpH SU

UnitParameter 5/11/2016 7/14/2016 9/8/2016 10/13/2016 11/15/2016 1/12/2017 3/1/2017 4/10/2017 8/24/2017 Detection










Thallium mg/LpH SU


APPENDIX II

Where applicable, show in this appendix the results from statistical analyses, and a description of the statistical analysis method chosen. These statistical analyses are to be conducted separately for each constituent in each monitoring well.

Purpose of Statistical Analysis Summary Report

During the initial phase of ground water monitoring, the CCR rule requires AEP to collect at

least eight independent samples from at least one up-gradient and three downgradient wells for

21 substances listed in the CCR rule. The CCR rule also requires us to select a statistical method

that will be used to evaluate the samples in the later phases of the ground water monitoring

program. The Statistical Plan, which has been posted to AEP’s CCR website, describes the

methods selected by AEP. See AEP’s Statistical Analysis Plans.

Each Statistical Analysis Summary Report is based on the results of the 8 independent samples

that were collected by October 17, 2017, and reported in the Annual Groundwater Monitoring

Report. Using the statistical methods chosen by AEP, the samples were evaluated to eliminate

outliers, determine variability and general trends in the data, and establish background values

for: boron, calcium chloride, fluoride, pH, sulfate, and total dissolved solids. Appendix IV

substances were evaluated for purposes of identifying outliers and understanding data trends.

A subsequent sample taken during the first detection monitoring sampling event was also

compared using the proper statistical methods to the background values that were established for

these seven substances from the eight independent samples. A second or third re-sampling

event occurred, and the results compared using the same methods. This work is reported in the

memorandum included in attachment A. If confirmed, AEP will be required to enter the next

phase of monitoring. The results of future sampling will be further analyzed to target any

specific substances for which ongoing monitoring or potential corrective action is required.

STATISTICAL ANALYSIS SUMMARY

EAST BOTTOM ASH POND

H.W. Pirkey Power Plant

Hallsville, Texas

Submitted to

1 Riverside Plaza

Columbus, Ohio 43215-2372

Submitted by

150 East Wilson Bridge Road

Suite 232

Worthington, Ohio 43085

January 3, 2018

CHA8423

Statistical Analysis

January 3, 2018

2017 CHA8423 20180103 Pirkey EBAP Report i

TABLE OF CONTENTS

SECTION 1 Executive Summary ............................................................................... ES-1

SECTION 2 East Bottom Ash Pond Evaluation ............................................................ 2-1

2.1 Data Validation & QA/QC ....................................................................... 2-1

2.2 Statistical Analysis .................................................................................... 2-1

2.2.1 Background Outlier Evaluation ................................................... 2-1

2.2.2 Establishment of Background Levels .......................................... 2-3

2.2.3 Certification by Qualified Professional Engineer ........................ 2-4

2.3 Conclusions ............................................................................................... 2-5

SECTION 3 References ................................................................................................. 3-1


January 3, 2018

2017 CHA8423 20180103 Pirkey EBAP Report ii

LIST OF TABLES

Table 1 Groundwater Data Summary

Table 2 Outlier Analysis Summary

Table 3 Background Level Summary

LIST OF ATTACHMENTS

Attachment A Evaluation of Detection Monitoring Data

Attachment B Statistical Analysis Output


January 3, 2018

2017 CHA8423 20180103 Pirkey EBAP Report iii

LIST OF ACRONYMS AND ABBREVIATIONS

AEP American Electric Power

ANOVA Analysis of Variance

CCR Coal Combustion Residuals

CCV Continuing Calibration Value

CFR Code of Federal Regulations

EBAP East Bottom Ash Pond

EPA Environmental Protection Agency

LFB Laboratory Fortified Blanks

LPL Lower Prediction Limit

LRB Laboratory Reagent Blanks

NELAP National Environmental Laboratory Accreditation Program

PQL Practical Quantitation Limit

QA Quality Assurance

QC Quality Control

SSI Statistically Significant Increase

SWFPR Site-Wide False-Positive Rate

TDS Total Dissolved Solids

UPL Upper Prediction Limit

USEPA United States Environmental Protection Agency


January 3, 2018

2017 CHA8423 20180103 Pirkey EBAP Report ES-1

SECTION 1

EXECUTIVE SUMMARY

In accordance with the United States Environmental Protection Agency’s (USEPA’s) regulations

regarding the disposal of coal combustion residuals (CCR) in landfills and surface impoundments

(40 CFR 257.90-257.98, “CCR rule”), groundwater monitoring has been conducted at the East

Bottom Ash Pond (EBAP), an existing CCR unit at the H.W. Pirkey Power Plant located in

Hallsville, Texas.

Eight monitoring events were completed prior to October 17, 2017 to establish background

concentrations for Appendix III and Appendix IV parameters under the CCR rule. Groundwater

data underwent several validation tests, including those for completeness, sample tracking

accuracy, transcription errors, and consistent use of measurement units. No data quality issues

were identified which would impact the usability of the data.

The monitoring data were submitted to Groundwater Stats Consulting, LLC for statistical analysis.

The background data were reviewed for outliers, which were removed (when appropriate) prior to

calculating upper prediction limits (UPLs) for each Appendix III parameter to represent

background values. Oversight on the use of statistical calculations was provided by Dr. Kirk

Cameron of MacStat Consulting, Ltd.

A groundwater sampling event occurred on August 23 and 24, 2017 at the EBAP. This sampling

event obtained the first sample for the 1-of-2 prediction interval statistical test used for detection

monitoring. The results of this sampling event are included in this report.


January 3, 2018

2017 CHA8423 20180103 Pirkey EBAP Report 2-1

SECTION 2

EAST BOTTOM ASH POND EVALUATION

2.1 Data Validation & QA/QC

During the background monitoring program, eight sets of samples were collected for analysis from

each upgradient and compliance well. A summary of data collected during background and

detection monitoring sampling may be found in Table 1.

Chemical analysis was completed by an analytical laboratory certified by the National

Environmental Laboratory Accreditation Program (NELAP). Quality assurance and quality

control (QA/QC) samples completed by the analytical laboratory included the use of laboratory

reagent blanks (LRBs), continuing calibration verification (CCV) samples, and laboratory fortified

blanks (LFBs).

The analytical data were imported into a Microsoft Access database, where checks were completed

to assess the accuracy of sample location identification and analyte identification. Where

necessary, unit conversions were applied to standardize reported units across all sampling events.

Exported data files were created for use with the Sanitas™ v.9.5.32 statistics software. The export

was checked against the analytical data for transcription errors and completeness. No QA/QC

issues were noted which would impact data usability.

2.2 Statistical Analysis

The background data used to conduct the statistical analyses and the detection monitoring data are

summarized in Table 1. Statistical analyses for the EBAP were conducted in accordance with the

January 2017 Statistical Analysis Plan (AEP, 2017), except where noted below. Results for all

completed statistical tests are provided in Attachment A.

Time series plots of Appendix III and IV parameters are included in Attachment A. Mann-Kendall

analyses (α = 0.01) were conducted to evaluate trends in the background data. Beryllium was

found to be significantly decreasing at upgradient well AD-18. Boron was found to be significantly

increasing at compliance well AD-2. No other significant increasing or decreasing trends were

observed for other parameters or at other monitoring wells.

2.2.1 Background Outlier Evaluation

Potential outliers were identified using Tukey’s outlier test; i.e., data points were considered

potential outliers if they met one of the following criteria:

𝑥𝑖 < �̃�0.25 − 3 × 𝐼𝑄𝑅 (1)

or


January 3, 2018


𝑥𝑖 > �̃�0.75 + 3 × 𝐼𝑄𝑅 (2)

where:

𝑥𝑖 = individual data point

�̃�0.25 = first quartile

�̃�0.75 = third quartile

𝐼𝑄𝑅 = the interquartile range = �̃�0.75 − �̃�0.25

Data that were evaluated as potential outliers are summarized in Attachment A. Tukey’s outlier

test identified 14 potential outliers, which are summarized in Table 2. Next, the data were

reviewed to identify possible sources of errors or discrepancies, including data recording errors,

unusual sampling conditions, laboratory quality indicators, or inconsistent sample turbidity. The

findings of this data review are summarized below.

While the reported fluoride concentration of 4.717 mg/L at upgradient well AD-12 on October 12,

2016 was not identified as an outlier by Tukey’s method, the duplicate sample was more similar

to other upgradient data and therefore considered more representative of background. This value

was replaced with the reported fluoride concentration for the duplicate sample also collected at

AD-12. The statistical analysis was rerun using the duplicate result’s reporting limit of 1.0 mg/L,

as fluoride was not detected in the duplicate. The duplicate sample was considered more

representative based on the reported concentrations from the other background sampling events.

Seven parameters (arsenic, barium, calcium, chromium, cobalt, lead, and mercury) were identified

as potential outliers during the May 11, 2016 sampling event at compliance well AD-31. These

results suggest an issue with sample collection and the values were removed from the dataset. The

reported lead value of 0.00154 mg/L at AD-31 during the October 12, 2016 sampling event was

also identified as a potential outlier. Lead was generally not detected at a reporting limit of

0.005 mg/L at AD-31. As the potential outlier was an estimated value and likely reflects

concentrations within the aquifer, this value was retained within the database.

The reported chloride concentration of 20 mg/L at compliance well AD-2 on September 7, 2016

and the reported lithium concentration of 0.016 mg/L at compliance well AD-32 on May 11, 2016

were both identified as potential outliers. Both of these values were kept in the dataset as they

reflected concentrations in nearby compliance wells.

The remaining three potential outliers did not have an apparent reason for their elevated value and

was removed as recommended by USEPA’s Unified Guidance (USEPA, 2009). The three outliers

that were removed were associated with compliance monitoring wells; therefore, their removal did

not affect the calculation of background levels presented below. Additionally, two of the outliers

were associated with Appendix IV parameters, for which background levels were not calculated.


January 3, 2018


2.2.2 Establishment of Background Levels

Analysis of variance (ANOVA) was conducted to determine whether spatial variation was present

among the three upgradient wells (Attachment A). ANOVA indicated no significant variation

among the three upgradient wells for fluoride. Consequently, interwell tests were used for fluoride.

Significant variation was observed for boron, calcium, chloride, pH, sulfate, and total dissolved

solids (TDS). Therefore, the appropriateness of using intrawell tests was evaluated for these

parameters at the Pirkey EBAP.

Intrawell tests presume that the groundwater quality in the compliance wells was not initially

impacted by the CCR unit. To test this presumption, the data from the upgradient wells were

pooled and the data from each compliance well were compared to a pooled background value.

Tolerance limits were calculated using the pooled background data for boron, calcium, chloride,

pH, sulfate, and TDS. Parametric tolerance limits with 99% confidence and 95% coverage were

calculated for boron, chloride, pH, and TDS; non-parametric tolerance limits were calculated for

calcium and sulfate, given the greater spatial variability observed for these two parameters.

Confidence intervals were calculated for each of these six parameters at each compliance

monitoring well. If the lower confidence limit from a compliance well exceeded the upper

tolerance limit for the pooled background data, it was concluded that groundwater concentrations

at compliance wells were above background concentrations. In these instances, intrawell tests

would not be appropriate. However, these analyses indicated no significant exceedances for pH;

elevated concentrations of boron, calcium, chloride, sulfate, and TDS were observed. (Non-

parametric analyses also indicated no significant exceedances for pH and elevated concentrations

of boron, chloride, and TDS in compliance wells.) Therefore, intrawell tests were used to evaluate

potential SSIs for pH. Interwell tests were used to evaluate potential SSIs for boron, calcium,

chloride, fluoride, sulfate, and TDS.

After equality of variance was tested and identified outliers were removed (where appropriate), a

parametric or non-parametric analysis was selected based on the distribution of the data and the

frequency of non-detect data. Estimated results less than the practical quantitation limit (PQL) –

i.e., “J-flagged” data – were considered detections and the estimated results were used in the

statistical analyses. Non-parametric analyses were selected for datasets with at least 50% non-

detect data or datasets that could not be normalized. Parametric analyses were selected for datasets

that passed the Shapiro-Wilk / Shapiro-Francía test for normality. The Kaplan-Meier non-detect

adjustment was applied to datasets with between 15% and 50% non-detect data. For datasets with

fewer than 15% non-detect data, non-detect data were replaced with one half of the PQL. The

selected analysis (i.e., parametric or non-parametric) for each background dataset is shown in

Attachment A.

Upper prediction limits (UPLs) were calculated for each Appendix III parameter to represent

background values. A lower prediction limit (LPL) was also calculated for pH. To conduct the

intrawell tests for pH, a separate UPL was calculated for each compliance well. To conduct the

interwell tests for boron, calcium, chloride, fluoride, sulfate, and TDS, a single prediction interval


January 3, 2018


2.3 Conclusions

Eight background monitoring events and one detection monitoring event were completed in

accordance with the CCR Rule. The laboratory and field data were reviewed prior to statistical

analysis, with no QA/QC issues identified that impacted data usability. A review of outliers

identified fourteen potential outliers, with ten values removed from the dataset without

replacement. Prediction intervals were constructed based on the remaining background data and

a one-of-two retesting procedure. Interwell tests were selected for boron, calcium, chloride,

fluoride, sulfate, and TDS, whereas intrawell tests were selected for pH.


January 3, 2018


SECTION 3

REFERENCES

American Electric Power (AEP). 2017. Statistical Analysis Plan – H. W. Pirkey Power Plant.

January 2017.

United States Environmental Protection Agency (USEPA). 2009. Statistical Analysis of

Groundwater Monitoring Data at RCRA Facilities – Unified Guidance. EPA 530/R-09-007. March

2009.

TABLES

Table 1 - Groundwater Data Summary

Pirkey Plant - East Bottom Ash Pond


5/11/2016 7/14/2016 9/7/2016 10/13/2016 11/14/2016 1/12/2017 3/1/2017 4/11/2017 8/24/2017

Detection

Antimony mg/L 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

Arsenic mg/L 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

Barium mg/L 0.038 0.038 0.039 0.039 0.034 0.037 0.037 0.037 -

Beryllium mg/L 0.00051J 0.00047J 0.00044J 0.0004J 0.00037J 0.00038J 0.00041J 0.00044J -

Boron mg/L 1.27 1.34 1.3 1.48 1.36 1.48 1.62 1.65 1.46

Cadmium mg/L 0.001U 0.001U 0.001U 0.001U 0.001U 0.001U 0.001U 0.001U -

Calcium mg/L 1.43 1.38 2.65 1.29 1.44 1.6 1.28 1.71 2.06

Chloride mg/L 28 28 20 31 28 30 28 50 24

Chromium mg/L 0.001U 0.0004J 0.00049J 0.00089J 0.001U 0.001U 0.001U 0.00024J -

Cobalt mg/L 0.01 0.011 0.01 0.011 0.01 0.01 0.01 0.011 -

Combined Radium pCi/L 1.446 0.723 1.489 2.65 2.121 1.656 1.267 0.807 -

Fluoride mg/L 1U 1U 1U 1U 1U 1U 1U 1U 1U

Lead mg/L 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

Lithium mg/L 0.001U 0.051 0.048 0.052 0.048 0.052 0.051 0.052 -

Mercury mg/L 0.0001 0.00007 0.00068 0.00005 0.00015 0.00009 0.00004 0.00003 -

Molybdenum mg/L 0.005U 0.00086J 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

Selenium mg/L 0.00208J 0.005U 0.005U 0.00138J 0.00123J 0.005U 0.005U 0.005U -

Total Dissolved Solids mg/L 238 216 216 230 240 244 262 254 200

Sulfate mg/L 68 71 49 67 72 94 80 88 64

Thallium mg/L 0.002U 0.002U 0.00126J 0.002U 0.002U 0.002U 0.002U 0.002U -

pH SU 4.37 4.2 4.18 3.56 3.89 3.93 4.12 3.98 4.27

Notes:

mg/L: milligrams per liter

pCi/L: picocuries per liter

SU: standard unit

J: Estimated value. Component was detected in concentrations below the reporting limit

-: Not sampled

U: Component was not present in concentrations above method detection limit and is reported as the reporting

limit

Background

Parameter Unit

AD-2




Antimony mg/L

Arsenic mg/L

Barium mg/L

Beryllium mg/L

Boron mg/L

Cadmium mg/L

Calcium mg/L

Chloride mg/L

Chromium mg/L

Cobalt mg/L

Combined Radium pCi/L

Fluoride mg/L

Lead mg/L

Lithium mg/L

Mercury mg/L

Molybdenum mg/L

Selenium mg/L

Total Dissolved Solids mg/L

Sulfate mg/L

Thallium mg/L

pH SU

Parameter Unit 5/11/2016 7/14/2016 9/8/2016 10/13/2016 11/15/2016 1/12/2017 3/1/2017 4/10/2017 8/24/2017

Detection

0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

0.00396J 0.008 0.005 0.011 0.005U 0.005U 0.005U 0.005U -

0.075 0.127 0.123 0.183 0.114 0.149 0.131 0.094 -

0.001 0.001 0.001 0.00083J 0.00053J 0.00041J 0.00035J 0.00092J -

0.02 0.02 0.02 0.03 0.04 0.03 0.03 0.04 0.06229

0.00013J 0.001U 0.00011J 0.001U 0.001U 0.001U 0.001U 0.00008J -

1.63 2.32 2.37 2.87 2.71 2.94 2.86 1.91 2.04

4 4 5 6 5 5 4 5 5

0.0004J 0.003 0.002 0.007 0.00045J 0.00031J 0.001U 0.00024J -

0.008 0.009 0.008 0.007 0.006 0.00451J 0.00446J 0.008 -

0.729 4.271 0.193 2.381 1.072 2.599 1.089 0.684 -

1U 1U 1U 1U 1U 1U 1U 1U 1U

0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

0.013 0.041 0.04 0.034 0.035 0.03 0.033 0.047 -

0.00001J 0.00004 0.00001J 0.00001J 0.00001J 0.00001J 0.00001J 0.00001J -

0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

0.00179J 0.00174J 0.005U 0.0016J 0.005U 0.005U 0.005U 0.005U -

148 157 136 164 152 148 148 140 94

23 20 20 19 19 18 18 21 20

0.002U 0.00187J 0.002U 0.00087J 0.002U 0.002U 0.002U 0.002U -

5.37 4.91 4.9 4.05 4.28 4.83 4.73 4.39 4.6

Notes:



SU: standard unit


-: Not sampled


limit

Background

AD-4




Antimony mg/L

Arsenic mg/L

Barium mg/L

Beryllium mg/L

Boron mg/L

Cadmium mg/L

Calcium mg/L

Chloride mg/L

Chromium mg/L

Cobalt mg/L


Fluoride mg/L

Lead mg/L

Lithium mg/L

Mercury mg/L

Molybdenum mg/L

Selenium mg/L


Sulfate mg/L

Thallium mg/L

pH SU

Parameter Unit 5/11/2016 7/13/2016 9/7/2016 10/12/2016 11/14/2016 1/11/2017 2/28/2017 4/11/2017 8/23/2017

Detection

0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

0.026 0.023 0.03 0.027 0.028 0.023 0.026 0.024 -

0.00022J 0.00019J 0.00023J 0.00015J 0.00015J 0.00013J 0.00015J 0.00016J -

0.03 0.03 0.04 0.03 0.04 0.03 0.04 0.05 0.0495

0.001U 0.001U 0.001U 0.001U 0.001U 0.001U 0.001U 0.001U -

0.362 0.26 0.343 0.271 0.331 0.315 0.434 0.299 0.245

5 6 6 7 8 7 5 6 6

0.00071J 0.00069J 0.00035J 0.00053J 0.00033J 0.00065J 0.00033J 0.00042J -

0.00158J 0.00129J 0.00167J 0.00157J 0.00147J 0.00109J 0.0013J 0.00133J -

0.2073 2.909 0.881 0.257 0.767 1.536 0.416 0.3895 -

1U 1U 1U 1 1U 1U 1U 0.2565J 0.213J

0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

0.001U 0.008 0.01 0.012 0.013 0.01 0.009 0.008 -

0.00002U 0.00002U 0.00002U 0.00002U 0.00002U 0.00002U 0.00002U 0.00001J -

0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

0.00174J 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

94 75 63 92 80 76 50 72 52

4 4 7 8 6 6 4 7 6

0.002U 0.002U 0.002U 0.002U 0.002U 0.002U 0.00099J 0.002U -

4.44 3.11 3.89 3.37 2.58 4.76 3.63 4.74 4.84

Notes:



SU: standard unit


-: Not sampled


limit

Background

AD-12




Antimony mg/L

Arsenic mg/L

Barium mg/L

Beryllium mg/L

Boron mg/L

Cadmium mg/L

Calcium mg/L

Chloride mg/L

Chromium mg/L

Cobalt mg/L


Fluoride mg/L

Lead mg/L

Lithium mg/L

Mercury mg/L

Molybdenum mg/L

Selenium mg/L


Sulfate mg/L

Thallium mg/L

pH SU

Parameter Unit 5/10/2016 7/14/2016 9/8/2016 10/13/2016 11/15/2016 1/12/2017 3/1/2017 4/10/2017 8/24/2017

Detection

0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

0.005U 0.00377J 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

0.157 0.139 0.115 0.112 0.094 0.099 0.099 0.105 -

0.00026J 0.00024J 0.00023J 0.00019J 0.00011J 0.00017J 0.00011J 0.00013J -

0.01 0.01 0.01 0.02 0.02 0.01 0.01 0.01 0.0278

0.00011J 0.001U 0.001U 0.001U 0.001U 0.001U 0.001U 0.001U -

0.548 0.409 0.343 0.56 0.59 0.415 0.224 0.304 0.435

8 8 8 7 7 7 6 7 8

0.001 0.003 0.00078J 0.00063J 0.00072J 0.00041J 0.00057J 0.00097J -

0.00183J 0.00216J 0.0011J 0.00225J 0.00166J 0.00163J 0.00098J 0.00098J -

0.847 3.264 1.105 1.161 1.486 0.976 0.468 0.648 -

1U 1U 1U 1U 1U 1U 1U 1U 1U

0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

0.004 0.02 0.019 0.026 0.017 0.026 0.017 0.019 -

0.00002J 0.00006 0.00003 0.00001J 0.00003 0.00002J 0.00001J 0.00001J -

0.005U 0.00041J 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

0.00171J 0.00245J 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

108 116 110 124 134 128 108 102 68

7 7 8 10 7 10 7 8 8

0.002U 0.002U 0.002U 0.002U 0.002U 0.002U 0.002U 0.002U -

4.53 4.65 4.67 4.14 4.43 4.67 4.06 4.1 4.9

Notes:



SU: standard unit


-: Not sampled


limit

Background

AD-18




Antimony mg/L

Arsenic mg/L

Barium mg/L

Beryllium mg/L

Boron mg/L

Cadmium mg/L

Calcium mg/L

Chloride mg/L

Chromium mg/L

Cobalt mg/L


Fluoride mg/L

Lead mg/L

Lithium mg/L

Mercury mg/L

Molybdenum mg/L

Selenium mg/L


Sulfate mg/L

Thallium mg/L

pH SU

Parameter Unit 5/11/2016 7/13/2016 9/7/2016 10/12/2016 11/14/2016 1/11/2017 2/28/2017 4/11/2017 8/23/2017

Detection

0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

0.093 0.00342J 0.00434J 0.006 0.011 0.00392J 0.005U 0.00332J -

0.712 0.069 0.088 0.076 0.125 0.077 0.044 0.073 -

0.01 0.001 0.002 0.001 0.002 0.001 0.001J 0.001 -

0.08 0.03 0.03 0.04 0.04 0.03 0.04 0.04 0.01752

0.00086J 0.001U 0.001U 0.001U 0.00017J 0.001U 0.001U 0.00009J -

10.4 4.27 3.47 4.41 4.7 4.43 3.89 3.64 2.24

18 18 18 18 18 19 14 16 18

0.212 0.01 0.015 0.014 0.03 0.012 0.003 0.012 -

0.05 0.011 0.011 0.011 0.014 0.01 0.009 0.011 -

7.32 3.38 2.345 3.88 3.202 2.725 2.684 3.521 -

1U 1U 1U 1U 1U 1U 1U 1U 1U

0.057 0.005U 0.005U 0.00154J 0.00393J 0.005U 0.005U 0.005U -

0.077 0.096 0.094 0.097 0.096 0.093 0.09 0.097 -

0.0018 0.00032 0.00028 0.00035 0.00052 0.00038 0.00014 0.00033 -

0.00089J 0.00032J 0.005U 0.005U 0.0004J 0.005U 0.005U 0.005U -

0.00184J 0.00111J 0.005U 0.005U 0.00103J 0.005U 0.005U 0.005U -

286 245 260 276 266 252 212 252 228

63 66 60 62 66 79 68 69 52

0.002U 0.002U 0.002U 0.002U 0.002U 0.00102J 0.002U 0.002U -

4.49 3.49 3.67 3.95 3.19 4.39 3.62 3.56 4.46

Notes:



SU: standard unit


-: Not sampled


limit

AD-31

Background




Antimony mg/L

Arsenic mg/L

Barium mg/L

Beryllium mg/L

Boron mg/L

Cadmium mg/L

Calcium mg/L

Chloride mg/L

Chromium mg/L

Cobalt mg/L


Fluoride mg/L

Lead mg/L

Lithium mg/L

Mercury mg/L

Molybdenum mg/L

Selenium mg/L


Sulfate mg/L

Thallium mg/L

pH SU

Parameter Unit 5/11/2016 7/13/2016 9/7/2016 10/12/2016 11/14/2016 1/11/2017 2/28/2017 4/11/2017 8/23/2017

Detection

0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

0.00377J 0.013 0.00326J 0.01 0.006 0.006 0.00456J 0.005U -

0.035 0.058 0.035 0.05 0.037 0.037 0.03 0.026 -

0.003 0.008 0.008 0.007 0.009 0.007 0.005 0.004 -

0.708 5.23 5.78 4.26 5.52 5.05 2.73 1.46 0.716

0.00029J 0.00073J 0.0006J 0.00059J 0.00079J 0.0006J 0.00039J 0.00044J -

7.41 33.9 37.4 27.1 35.9 40 18.4 11 7.15

12 32 35 29 34 35 19 15 14

0.005 0.018 0.006 0.015 0.008 0.009 0.005 0.003 -

0.027 0.074 0.07 0.065 0.075 0.069 0.045 0.035 -

2.501 6.41 4.846 17.32 3.731 4.342 4.001 4.32 -

1U 0.67J 1U 0.8585J 0.7468J 1U 1U 0.4468J 1.962

0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

0.016 0.119 0.111 0.972 0.114 0.115 0.095 0.095 -

0.00092 0.01392 0.00168 0.00728 0.00362 0.0072 0.00793 0.00276 -

0.005U 0.00076J 0.005U 0.005U 0.005U 0.005U 0.005U 0.005U -

0.005U 0.00389J 0.005U 0.00193J 0.005U 0.005U 0.00254J 0.005U -

206 835 884 720 922 894 490 372 288

124 461 479 430 621 683 285 200 115

0.002U 0.002U 0.00109J 0.002U 0.00108J 0.00099J 0.002U 0.002U -

4.34 3.3 3.11 3.26 2.99 3.89 3.11 3.23 4.29

Notes:



SU: standard unit


-: Not sampled


limit

Background

AD-32

Table 2: Outlier Analysis SummaryPirkey East Bottom Ash Pond


Location Well ID Sample Date Parameter Reported Value Units Conclusions

Compliance AD-31 5/11/2016 Arsenic 0.093 mg/LA number of parameters were identified as outliers for this sample, suggesting sampling error. This value was removed from the dataset.

Compliance AD-31 5/11/2016 Barium 0.712 mg/LA number of parameters were identified as outliers for this sample, suggesting sampling error. This value was removed from the dataset.

Compliance AD-31 5/11/2016 Calcium 10.4 mg/LA number of parameters were identified as outliers for this sample, suggesting sampling error. This value was removed from the dataset.

Compliance AD-2 9/7/2016 Chloride 20 mg/L This value was not removed from the dataset, as it reflected concentrations similar to those in neighboring wells.

Compliance AD-2 4/11/2017 Chloride 50 mg/L This value was removed from the dataset as an outlier. Its removal did not affect the calculation of background values.

Compliance AD-31 5/11/2016 Chromium 0.212 mg/LA number of parameters were identified as outliers for this sample, suggesting sampling error. This value was removed from the dataset.

Compliance AD-31 5/11/2016 Cobalt 0.05 mg/LA number of parameters were identified as outliers for this sample, suggesting sampling error. This value was removed from the dataset.

Compliance AD-32 10/12/2016 Combined Radium 17.32 pCi/L This value was removed from the dataset as an outlier. Its removal did not affect the calculation of background values.

Compliance AD-12 10/12/2016 Fluoride 4.717 mg/L This value was replaced with 1.0 mg/L (ND) - the reporting limit for a non-detect concentration in the duplicate sample.

Compliance AD-31 5/11/2016 Lead 0.057 mg/LA number of parameters were identified as outliers for this sample, suggesting sampling error. This value was removed from the dataset.

Compliance AD-31 10/12/2016 Lead 0.00154 J mg/L This value was estimated (J-flagged) and was not removed from the dataset.

Compliance AD-32 10/12/2016 Lithium 0.972 mg/L This value was removed from the dataset as an outlier. Its removal did not affect the calculation of background values.

Compliance AD-32 5/11/2016 Lithium 0.016 mg/L This value was not removed from the dataset, as it reflected concentrations similar to those in neighboring wells.

Compliance AD-31 5/11/2016 Mercury 0.001797 mg/LA number of parameters were identified as outliers for this sample, suggesting sampling error. This value was removed from the dataset.

Table 3: Background Level SummaryPirkey Plant - East Bottom Ash Pond


Parameter Units Description AD-2 AD-31 AD-32Boron mg/L Interwell Background Value (UPL)

Calcium mg/L Interwell Background Value (UPL)Chloride mg/L Interwell Background Value (UPL)Fluoride mg/L Interwell Background Value (UPL)

SU Intrawell Background Value (UPL) 4.637 4.903 4.549SU Intrawell Background Value (LPL) 3.421 2.687 2.259

Total Dissolved Solids mg/L Interwell Background Value (UPL)

Sulfate mg/L Interwell Background Value (UPL)Notes:UPL: Upper prediction limitLPL: Lower prediction limit

pH

1

174.1

23

0.048212.94

8.511

ATTACHMENT A Evaluation of Detection Monitoring Data

150 E.Wilson Bridge Road, Suite 232 Columbus, Ohio 43085

PH 614.468.0415 FAX 614.468.0416

www.geosyntec.com

CHA8423 20180227 Pirkey EBAP Addendum Memo

Memorandu m

Date: February 27, 2018

To: David Miller (AEP)

Copies to: Terence Wehling (AEP)

From: Allison Kreinberg and Bruce Sass, Ph.D. (Geosyntec)

Subject: Evaluation of Detection Monitoring Data at Pirkey Plant’s East Bottom Ash Pond (EBAP)

In accordance with the United States Environmental Protection Agency’s (USEPA’s) regulations regarding the disposal of coal combustion residuals (CCR) in landfills and surface impoundments (40 CFR 257.90-257.98, “CCR rule”), detection monitoring events were completed on August 23-24 and December 21, 2017 at the East Bottom Ash Pond (EBAP), an existing CCR unit at the Pirkey Power Plant located in Hallsville, Texas.

Eight background monitoring events were conducted at the Pirkey EBAP prior to these detection monitoring events, and upper prediction limits (UPLs) were calculated for each Appendix III parameter to represent background values. A lower prediction limit (LPL) was also calculated for pH. Details on the calculation of these background values are described in Geosyntec’s Statistical Analysis Summary report, dated January 3, 2018.

To achieve an acceptably high statistical power while maintaining a site-wide false-positive rate (SWFPR) of 10% per year or less, prediction limits were calculated based on a one-of-two retesting procedure. With this procedure, a statistically significant increase (SSI) is only concluded if both samples in a series of two exceeds the UPL. In practice, if the initial result did not exceed the UPL, a second sample was not collected or analyzed.

Detection monitoring results and the relevant background values are summarized in Table 1b.

• Boron concentrations exceeded the interwell UPL of 0.0482 mg/L in both the initial (1.46mg/L) and second (1.38 mg/L) samples collected at AD-2, and in both the initial (0.716mg/L) and second (2.56 mg/L) samples collected at AD-32. Therefore, an SSI overbackground is concluded for boron at AD-2 and AD-32.

Evaluation of Detection Monitoring Data – Pirkey EBAP February 27, 2018 Page 2

CHA8423 20180227 Pirkey EBAP Addendum Memo

• Calcium concentrations exceeded the interwell UPL of 2.94 mg/L in both the initial (7.15mg/L) and the second (17.1 mg/L) samples collected at AD-32. Therefore, an SSI overbackground is concluded for calcium at AD-32.

• Chloride concentrations exceeded the interwell UPL of 8.51 mg/L in both the initial (24mg/L) and second (24 mg/L) samples collected at AD-2, in both the initial (18 mg/L) andsecond (20 mg/L) samples collected at AD-31, and in both the initial (14 mg/L) andsecond (22 mg/L) samples collected at AD-32. Therefore, an SSIs over background isconcluded for chloride at AD-2, AD-31, and AD-32.

• Total dissolved solids (TDS) concentrations exceeded the interwell UPL of 174 mg/L inboth the initial (200 mg/L) and second (206 mg/L) samples collected at AD-2, in both theinitial (228 mg/L) and second (224 mg/L) samples collected at AD-31, and in both theinitial (288 mg/L) and second (504 mg/L) samples collected at AD-32. Therefore, an SSIover the background is concluded for TDS at AD-2, AD-31, and AD-32.

• Sulfate concentrations exceeded the interwell UPL of 23 mg/L in both the initial (64mg/L) and second (64 mg/L) samples collected at AD-2, in both the initial (52 mg/L) andsecond (58 mg/L) samples collected at AD-31, and in both the initial (115 mg/L) andsecond (324 mg/L) samples collected at AD-32. Therefore, an SSI over the backgroundis concluded for sulfate at AD-2, AD-31, and AD-32.

As a result, the Pirkey EBAP CCR unit will conduct an alternate source demonstration. No other exceedances of UPLs were observed during these detection monitoring events.

The following modifications to Geosyntec’s Statistical Analysis Summary report were incorporated after the certification date of January 3, 2018:

• Table 1 (“Groundwater Data Summary”) was revised to reflect appropriate significant digits for estimated (J-flagged) values; and,

• Figure E (“Analysis of Variance”) of Attachment A (“Statistical Analysis Output”) was revised to correct a formatting error.

* * * * *

Table 1b: Detection Monitoring Data EvaluationPirkey Plant - East Bottom Ash Pond


8/24/2017 12/21/2017 8/23/2017 12/21/2017 8/23/2017 12/21/2017mg/L Interwell Background Value (UPL)mg/L Detection Monitring Results 1.46 1.38 0.0175 - 0.716 2.56mg/L Interwell Background Value (UPL)mg/L Detection Monitring Results 2.06 2.92 2.24 - 7.15 17.1mg/L Interwell Background Value (UPL)mg/L Detection Monitring Results 24 24 18 20 14 22mg/L Interwell Background Value (UPL)mg/L Detection Monitring Results

ATTACHMENT B Statistical Analysis Output

Groundwater Stats Consulting www.groundwaterstats.com ● ph: 913.829.1470

-1-

GROUNDWATER STATS CONSULTING

November 5, 2017

Geosyntec Consultants Attn: Mr. Bruce Sass 150 E. Wilson Bridge Rd., #232 Worthington, OH 43085

Dear Mr. Sass,

Groundwater Stats Consulting, formerly the statistical consulting division of Sanitas Technologies, is pleased to provide the screening and statistical analysis of background groundwater data for American Electric Power’s East Bottom Ash Pond. The analysis complies with the federal rule for the Disposal of Coal Combustion Residuals from Electric Utilities (CCR Rule, 2015) as well as with the USEPA Unified Guidance (2009).

Sampling began at East Bottom Ash Pond for the CCR program in 2016, and 8 background samples have been collected at each of the groundwater monitoring wells. The monitoring well network, as provided by Geosyntec Consultants, consists of the following: upgradient wells AD-4, AD-12, and AD-18; and downgradient wells AD-2, AD-31, and AD-32A.

Data were sent electronically to Groundwater Stats Consulting, and the statistical analysis was reviewed by Dr. Kirk Cameron, PhD Statistician with MacStat Consulting, primary author of the USEPA Unified Guidance, and Senior Advisor to Groundwater Stats Consulting.

The following constituents were evaluated: Appendix III parameters – boron, calcium, chloride, fluoride, pH, sulfate, and TDS; and Appendix IV parameters - antimony, arsenic, barium, beryllium, cadmium, chromium, cobalt, combined radium 226 & 228, fluoride, lead, lithium, mercury, molybdenum, selenium, and thallium.

Time series plots for Appendix III and IV parameters at all wells are provided for the purpose of screening data at these wells (Figure A). Additionally, box plots are included for all constituents at upgradient and downgradient wells (Figure B). The time series plots are used to initially screen for suspected outliers and trends, while the box plots provide visual representation of variation within individual wells and between all wells.

Data at all wells were evaluated for the following: 1) outliers; 2) trends; 3) most appropriate statistical method for Appendix III parameters based on site characteristics of groundwater data upgradient of the facility; and 4) eligibility of downgradient wells when intrawell statistical methods are recommended. Power

http://www.groundwaterstats.com


-2-

curves are provided to demonstrate that the selected statistical methods for Appendix III parameters comply with the USEPA Unified Guidance recommendations as discussed below. Summary of Statistical Method:

1) Intrawell prediction limits, combined with a 1-of-2 resample plan for pH; 2) Interwell prediction limits combined with a 1-of-2 resample plan for boron, calcium, chloride,

fluoride, sulfate and TDS.

Parametric prediction limits are utilized when the screened historical data follow a normal or transformed-normal distribution. When data cannot be normalized or the majority of data are nondetects, a nonparametric test is utilized. The distribution of data is tested using the Shapiro-Wilk/Shapiro-Francia test for normality. After testing for normality and performing any adjustments as discussed below (US EPA, 2009), data are analyzed using either parametric or non-parametric prediction limits.

• No statistical analyses are required on wells and analytes containing 100% nondetects (USEPA Unified Guidance, 2009, Chapter 6).

• When data contain


-3-

flagged as outliers, such as fluoride in upgradient well AD-12. A substitution of the most recent reporting limit was applied when varying detection limits existed in data. No true seasonal patterns were observed on the time series plots for any of the detected data; therefore, no deseasonalizing adjustments were made to the data. When seasonal patterns are observed, data may be deseasonalized so that the resulting limits will correctly account for the seasonality as a predictable pattern rather than random variation or a release. While trends may be visual, a quantification of the trend and its significance is needed. The Sen’s Slope/Mann Kendall trend test was used to evaluate all data at each well to identify statistically significant increasing or decreasing trends (Figure D). In the absence of suspected contamination, significant trending data are typically not included as part of the background data used for construction of prediction limits. This step serves to eliminate the trend and, thus, reduce variation in background. When statistically significant decreasing trends are present, earlier data are evaluated to determine whether earlier concentration levels are significantly different than current reported concentrations and will be deselected as necessary. When the historical records of data are truncated for the reasons above, a summary report will be provided to show the date ranges used in construction of the statistical limits. The results of the trend analyses showed a couple statistically significant increasing and decreasing trends, as may be seen on the Trend Test Summary Table that accompanies the trend tests. These trends are relatively low in magnitude when compared to average concentrations; therefore, no adjustments were made to the data sets. Appendix III – Determination of Spatial Variation The Analysis of Variance (ANOVA) was used to statistically evaluate differences in average concentrations among upgradient wells, which assists in identifying the most appropriate statistical approach (Figure E). Interwell tests, which compare downgradient well data to statistical limits constructed from pooled upgradient well data, are appropriate when average concentrations are similar across upgradient wells. Intrawell tests, which compare compliance data from a single well to screened historical data within the same well, are appropriate when upgradient wells exhibit spatial variation; when statistical limits constructed from upgradient wells would not be conservative from a regulatory perspective; and when downgradient water quality is unimpacted compared to upgradient water quality for the same parameter. The ANOVA identified no variation for fluoride, making this constituent suitable for interwell analyses. Variation was identified in groundwater upgradient of the site for all other Appendix III parameters. Therefore, these data were further evaluated as described for the appropriateness of intrawell testing to accommodate the groundwater quality. A summary table of the ANOVA results is included with the reports. Appendix III - Statistical Limits Intrawell limits constructed from carefully screened background data from within each well serve to provide statistical limits that are conservative (i.e. lower) from a regulatory perspective, and that will rapidly identify a change in more recent compliance data from within a given well. This statistical method removes the element of variation from across wells and eliminates the chance of mistaking natural spatial variation for a release from the facility. Prior to performing intrawell prediction limits, several steps are required to



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reasonably demonstrate downgradient water quality does not have existing impacts from the practices of the facility. Exploratory data analysis was used as a general comparison of concentrations in downgradient wells for all Appendix III parameters recommended for intrawell analyses to concentrations reported in upgradient wells. Upper tolerance limits are used in conjunction with confidence intervals to determine whether the estimated averages in downgradient wells are higher than observed levels upgradient of the facility. The upper tolerance limits were constructed to represent the extreme upper range of possible background levels at the site. In cases where downgradient average concentrations are higher than observed concentrations upgradient for a given constituent, an independent study and hydrogeological investigation would be required to identify local geochemical conditions and expected groundwater quality for the region to justify an intrawell approach. Such an assessment is beyond the scope of services provided by Groundwater Stats Consulting. When there is not an obvious explanation for observed concentration differences in downgradient wells relative to reported concentrations in upgradient wells, interwell prediction limits will initially be selected for the statistical method until further evidence shows that concentrations are due to natural variation rather than a result of the facility. Parametric tolerance limits were constructed with a target of 99% confidence and 95% coverage using pooled upgradient well data for each of the Appendix III parameters recommended for intrawell analyses (Figure F). The confidence and coverage levels for nonparametric tolerance limits are dependent upon the number of background samples. As more data are collected, the background population is better represented and the confidence and coverage levels increase. Confidence intervals were constructed on downgradient wells for each of the Appendix III parameters, using the tolerance limits discussed above, to determine intrawell eligibility for parameters exhibiting spatial variation (Figure G). When the entire confidence interval is above a background standard for a given parameter, interwell methods are initially recommended as the statistical method. Therefore, only parameters with confidence intervals which did not exceed background standards are eligible for intrawell prediction limits. Confidence intervals for the above parameters were found to be within their respective background limit for pH, while the confidence intervals for all other Appendix III parameters evaluated were above the background standards for parameters exhibiting spatial variation. Therefore, intrawell methods are recommended for pH at this time, and interwell methods are recommended initially for all other Appendix III parameters. As mentioned earlier, if a demonstration supports natural variation in groundwater, intrawell methods will be considered for all parameters. All available data through April 2017 at each well were used to establish intrawell background limits based on a 1-of-2 resample plan that will be used for future comparisons (Figure H). Interwell prediction limits, combined with a 1-of-2 resample plan, were constructed from upgradient wells for the Appendix III parameters discussed above (Figure I). Downgradient measurements will be compared to these background limits during each subsequent semi-annual sampling event.



-5-

Natural systems continuously evolve due to physical changes made to the environment. Examples include capping a landfill, paving areas near a well, or lining a drainage channel to prevent erosion. Periodic updating of background statistical limits will be necessary to accommodate these types of changes In the interwell case, newer data will be included in background when a minimum of 2 new samples from each upgradient well are available. In the intrawell case, data for all wells and constituents are re-evaluated when a minimum of 4 new data points from each well are available to determine whether earlier concentrations are representative of present-day groundwater quality. In some cases, the earlier portion of data are deselected prior to construction of limits in order to provide sensitive limits that will rapidly detect changes in groundwater quality. Even though the data are excluded from the calculation, the values will continue to be reported and shown in tables and graphs. In the event of an initial exceedance of compliance well data, the 1-of-2 resample plan allows for collection of an additional sample to determine whether the initial exceedance is confirmed. When the resample confirms the initial exceedance, a statistically significant increase (SSI) is identified and further research would be required to identify the cause of the exceedance (i.e. impact from the site, natural variation, or an off-site source). If the resample falls within the statistical limit, the initial exceedance is considered to be a false positive result and, therefore, no further action is necessary. A summary table of the background prediction limits follows this letter. Appendix IV – Assessment Monitoring Program During an Assessment Monitoring program confidence intervals are constructed at all wells for detected Appendix IV parameters. A minimum of 4 samples is required to construct confidence intervals; however, 8 samples are generally recommended for better representation of the true average population. Established Maximum Contaminant Levels (MCLs) are used as the GWPS comparisons, unless background limits are higher as discussed below. Parametric confidence intervals are constructed with 99% confidence when data follow a normal or transformed-normal distribution. For all other cases, nonparametric confidence intervals are constructed, with the confidence level based on the number of samples available. The GWPS is exceeded only when the entire confidence interval exceeds its respective GWPS. Background limits are established for the Appendix IV parameters using upper tolerance limits constructed with 95% confidence/95% coverage using pooled upgradient well data, for comparison against established MCLs. When background limits, or Alternate Contaminant Levels (ACLs), are higher than established MCLs, the CCR Rule recommends using these ACLs as the GWPS for the confidence interval comparisons. Additionally, tolerance limits are also recommended to establish ACLs for Appendix IV parameters, cobalt, lithium, and molybdenum, which do not have established MCLs. Since the scope of this project included screening and development of background limits for Appendix III Detection Monitoring statistics, comparison of the Appendix IV parameters with confidence intervals was not included in this report. Recommendations

In summary, as a result of the background screening described in this letter, intrawell prediction limits combined with a 1-of-2 resample plan are recommended for pH. Interwell prediction limits combined with a 1-of-2 resample plan are recommended for boron, calcium, chloride, fluoride, sulfate, and TDS. The



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statistical analyses will be constructed according to the USEPA Unified Guidance, based on seven Appendix III parameters and three downgradient wells.

Thank you for the opportunity to assist you in the statistical analysis of groundwater quality for the East Bottom Ash Pond. If you have any questions or comments, please feel free to contact me. For Groundwater Stats Consulting,

Kristina L. Rayner Groundwater Statistician


0

0.22

0.44

0.66

0.88

1.1

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Antimony, total Analysis Run 12/14/2017 5:20 PM View: Time Series

Pirkey EBAP Client: Geosyntec Data: Pirkey EBAP

Sanitas™ v.9.6.00 Groundwater Stats Consulting. UG

mg/

L

Hollow symbols indicate censored values.

0

0.02

0.04

0.06

0.08

0.1

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Arsenic, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L


0

0.16

0.32

0.48

0.64

0.8

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Barium, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L

0

0.002

0.004

0.006

0.008

0.01

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Beryllium, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L

0

1.2

2.4

3.6

4.8

6

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Boron, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L

0

0.00022

0.00044

0.00066

0.00088

0.0011

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Cadmium, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L


0

8

16

24

32

40

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Calcium, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L

0

10

20

30

40

50

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Chloride, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L

0

0.06

0.12

0.18

0.24

0.3

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Chromium, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L


0

0.016

0.032

0.048

0.064

0.08

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Cobalt, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L

0

4

8

12

16

20

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Combined Radium 226 + 228 Analysis Run 12/14/2017 5:20 PM View: Time Series



pCi/L

0

0.2

0.4

0.6

0.8

1

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Fluoride, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L


0

0.012

0.024

0.036

0.048

0.06

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Lead, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L


0

0.2

0.4

0.6

0.8

1

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Lithium, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L


0

0.004

0.008

0.012

0.016

0.02

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Mercury, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L


0

0.001

0.002

0.003

0.004

0.005

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Molybdenum, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L


0

1.2

2.4

3.6

4.8

6

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: pH, field Analysis Run 12/14/2017 5:20 PM View: Time Series



SU

0

0.001

0.002

0.003

0.004

0.005

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Selenium, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L


0

140

280

420

560

700

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Sulfate, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L

0

0.0006

0.0012

0.0018

0.0024

0.003

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Thallium, total Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L


0

200

400

600

800

1000

5/10/16 7/16/16 9/21/16 11/27/16 2/2/17 4/11/17

AD-4 (bg)

AD-2

AD-31

AD-32

AD-18 (bg)

AD-12 (bg)

Time Series

Constituent: Total Dissolved Solids [TDS] Analysis Run 12/14/2017 5:20 PM View: Time Series



mg/

L

0

0.001

0.002

0.003

0.004

0.005

Box & Whiskers Plot

Constituent: Antimony, total Analysis Run 12/14/2017 5:21 PM View: Time Series



mg/

L

AD-4 (bg)

n=8 100%nds

______+

AD-2n=8 100%nds

______+

AD-31

n=8 100%nds

______+

AD-32

n=8 100%nds

______+

AD-18 (bg)

n=8 100%nds

______+

AD-12 (bg)

n=8 100%nds

______+

0

0.004

0.008

0.012

0.016

0.02

Box & Whiskers Plot

Constituent: Arsenic, total Analysis Run 12/14/2017 5:21 PM View: Time Series



mg/

L

AD-4 (bg)

n=8 50%nds

______+

AD-2n=8 100%nds

______+

AD-31

n=7 14%nds

______+

AD-32

n=8 12%nds

______+

AD-18 (bg)

n=8 87%nds

______+

AD-12 (bg)

n=8 100%nds

______+

0

0.04

0.08

0.12

0.16

0.2

Box & Whiskers Plot

Constituent: Barium, total Analysis Run 12/14/2017 5:21 PM View: Time Series



mg/

L

AD-4 (bg)

n=8

______+

AD-2n=8

______+

AD-31n=7

______+

AD-32n=8

______+

AD-18 (bg)

n=8

______+

AD-12 (bg)

n=8

______+

0

0.002

0.004

0.006

0.008

0.01

Box & Whiskers Plot

Constituent: Beryllium, total Analysis Run 12/14/2017 5:21 PM View: Time Series



mg/

L

AD-4 (bg)

n=8

______+

AD-2n=8

______+

AD-31n=8

______

+

AD-32n=8

______

+

AD-18 (bg)

n=8

______+

AD-12 (bg)

n=8

______+

0

1.2

2.4

3.6

4.8

6

Box & Whiskers Plot

Constituent: Boron, total Analysis Run 12/14/2017 5:21 PM View: Time Series



mg/

L

AD-4 (bg)

n=8

______+AD-2

n=8

______+

AD-31n=8

______+AD-32

n=8

______

+

AD-18 (bg)

n=8

______+AD-12 (bg)

n=8

______+ 0

0.00022

0.00044

0.00066

0.00088

0.0011

Box & Whiskers Plot

Constituent: Cadmium, total Analysis Run 12/14/2017 5:21 PM View: Time Series



mg/

L

AD-4 (bg)

n=8 62%nds

______

+

AD-2n=8 100%nds

______+

AD-31

n=8 62%nds

______

+

AD-32n=8

______+

AD-18 (bg)

n=8 87%nds

______

+

AD-12 (bg)

n=8 100%nds

______+

0

8

16

24

32

40

Box & Whiskers Plot

Constituent: Calcium, total Analysis Run 12/14/2017 5:21 PM View: Time Series



mg/

L

AD-4 (bg)

n=8

______+

AD-2n=8

______+

AD-31n=7

______+

AD-32n=8

______

+

AD-18 (bg)

n=8

______+AD-12 (bg)

n=8

______+ 0

8

16

24

32

40

Box &

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