Eureka Lead Removal Assessment Ecology and Environment, Inc.1

Eureka Smelter SitesRemoval Assessment

Data Quality Objectives (DQO) Process DocumentObjective Outputs

Contract: EP-S5-08-01TDD No.: TO2-09-12-04-0002

Job No.: EE-002693-2177

In April 2012, the United States Environmental Protection Agency (U.S. EPA) Region IXEmergency Response Section (ERS) tasked Ecology and Environment, Inc.’s (E&E’s) SuperfundTechnical Assessment and Response Team (START) to support a U.S. EPA-funded RemovalAssessment at the Eureka Smelter Sites (the site), located in Eureka, Eureka County, Nevada(Figure 2-1). In order to support the U.S. EPA’s data collection process, these site specific dataquality objectives (DQOs) were developed as a part of the project planning phase and will directthe project objectives during preparation of the Eureka Smelter Sites Removal AssessmentSampling and Analysis Plan (SAP). This DQO documentation version reflects the projectobjectives for environmental data collection at all the areas of concern as of September 17, 2012.

1. THE PROBLEMBackground:Based upon U.S. Bureau of Land Management (BLM) documents, between 1866 and 1910, silverand lead mining occurred in several mine shafts at Ruby Hill, which is located approximately twomiles southwest of the town of Eureka, Nevada. According to available information, over onemillion tons of ore were extracted from Ruby Hill. During this period, the Eureka ConsolidatedMining Company (ECMC) and Richmond Consolidated Mining Company (RCMC) controlled themajority of mining operations in the Eureka area. Ore mined from the Ruby Hill shafts weretransported via railroad to the various ore smelters in and around Eureka. It was reported that airpollution emanating from these former smelters may have contributed to excess human-healthrisks and environmental impacts in Eureka. There were several flood events, including a majorflood event in 1874 that washed out large portions of Eureka and the smelter areas1. Additionally,1978 and 2004 United States Department of the Interior, U.S. Geological Survey reportsdocumented elevated lead and arsenic in soil samples collected from in and around the town ofEureka, Nevada. 23

1 U.S. Bureau of Land Management, 1991, A Historic View of the BLM Shosone-Eureka Resource Area, Nevada,(Technical Report 7)2 U.S. DOI, U.S. Geological Survey, 2004, Hydrogeochemical Studies of Historical Mining Areas in the HumboldtRiver Basin and Adjacent Areas, Northern Nevada, Thomas Nash, Scientific Investigations Report 2004-5236.3 U.S. Department of the Interior Geological Survey, 1978, Geochemical Analyses of Rock and Soil Samples, EurekaMining District and Vicinity, Eureka and White Pine Counties, Nevada, (Open-File Report 78-790).

SDMS DOCID#1141233

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There are a number of identified former ore smelter and milling operations located within or in theimmediate vicinity of Eureka. These former operations include:

Eureka Consolidated Furnace Lemon Mill Metamoras Furnace Hoosac Furnace Atlas Furnace Richmond Company Furnace Jackson Furnace Silver West Furnace McCoys Mill Taylor Mill

As a result of processing at these former ore smelters and mills, waste products known as slagwere produced and consolidated into two separate piles located on the north and south ends ofEureka. The following large consolidated slag piles (CSPs) were identified in Eureka (Figure 2-4aand 2-4b):

Eureka Company Richmond Company

The former ore smelter and milling operations likely deposited waste materials at the two CSPlocations and potentially contributed to aerial contamination of soil within and/or in the vicinity ofEureka (Figure 2-4a and 2-4b). There are also several smaller CSPs that have been identified atother locations in town.

There have been no formal investigations of the site; however, on two separate occasions in thespring of 2012, Nevada Division of Environmental Protection (NDEP) and U.S. EPA personnelcollected a total of 38 surface soil samples from publically accessible locations within the town ofEureka. The analytical laboratory reported that 10 of the 38 samples had lead concentrationsbelow 400 milligrams per kilogram (mg/kg), 20 of the 38 samples had lead concentrationsbetween 400 mg/kg and 5,000 mg/kg, and 8 samples had lead concentrations above 5,000 mg/kg.The highest concentrations of lead were found near the CSPs on the north and south ends of townand in areas associated with former smelter sites. The U.S. EPA-recommended RegionalScreening Level (RSL) for lead in soil on residential property is 400 mg/kg. The sample resultsfor arsenic showed a distribution similar to lead. The arsenic concentration in samples rangedfrom 10 mg/kg to 6,700 mg/kg.

Based on the site background and known information, the U.S. EPA determined that acomprehensive removal assessment is required to identify whether or not surface and shallowsubsurface soils throughout Eureka area have been impacted by the former smelter and millprocesses. There is also currently a plan to conduct blood lead testing of town residents, in orderto evaluate whether there are current health impacts.

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This DQO document provides the project objectives for the assessment of the area within andaround the town of Eureka, Nevada. The U.S. EPA, NDEP, and START have identified sevenareas of investigation or areas of concern (AOCs) within the study area:

AOC 1 Public urban parks, playfields and public school properties,AOC 2 Developed urban properties,AOC 3 Undeveloped urban properties,AOC 4 Unpaved urban roads,AOC 5 Areas downwind and around of the town of Eureka,AOC 6 Eureka’s creek, creek bed creek and downstream flood plain (the creek that

transects the town of Eureka and is historically referred to as the Ditch),AOC 7 Background areas.

Conceptual Site Model:The contaminants of primary concern (COPCs) at the site are currently limited to arsenic and lead.Additional contaminants are potentially present at the site and may be identified during theremoval assessment. Contamination of surface and shallow subsurface soil at the site is believedto be directly related to the aerial dispersion of waste materials from the former ore processingoperations and the use of waste materials from ore processing as imported fill material.

Exposure Scenario:Due to contaminated soil, the potential for direct contact and exposure of residents, employees,and tourists to the arsenic- and lead-contaminated soil may occur. The exposure pathways includeboth ingestion and inhalation of particulate matter (dust).

Due to contaminated surface water, the potential for direct contact and exposure of residents,tourist and ecological receptor to the arsenic- and lead-contaminated water may occur. Theexposure pathway is ingestion.

Planning Team:Mr. Tom Dunkelman, U.S. EPA Federal On-Scene Coordinator (FOSC)Mr. Kirk Scheckel, U.S. EPAMr. Greg Lovato, and Mr. Jeff Collins NDEPMr. Howard Edwards, START Quality Assurance Officer/ Project ManagerAnalytical Laboratory – U.S. EPA Region 9 Laboratory, U.S. EPA Contract LaboratoryProgram (CLP), and/or START Basic Ordering Agreement (BOA) laboratory.

The Roles and Responsibilities for this investigation are as follows: Tom Dunkelman, U.S. EPA FOSC, will be the primary decision-maker and will direct the

project, specify tasks, and ensure that the project is proceeding on schedule and within budget.Additional duties include coordination of all preliminary and final reporting andcommunication with the START Project Manager.

Mr. Greg Lovato, and Mr. Jeff Collins of the NDEP are assisting the U.S. EPA FOSC inobtaining access, providing public relations and with other activities to support the RemovalAssessment.

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Howard Edwards, START Quality Assurance Officer and START Project Manager(PM), will provide quality assurance oversight to ensure that planning and plan implementationare in accordance with U.S. EPA regional quality assurance/quality control (QA/QC) protocol.He will provide technical direction concerning QA/QC as needed to the U.S. EPA FOSC andthe START project manager.

U.S. EPA Emergency Response Team and U.S. Coast Guard Pacific Strike Team will assistwith sampling, data collecting, and field analysis.

Available Resources:The current START budget for all environmental data collection and reporting is currently$57,263.18, which includes activities related to the planning, sampling, laboratory analysis, dataevaluation, and reporting for the site assessment.

Other Considerations and Constraints Related to Problem and Resources: The scheduling of data collection activities is determined by the U.S. EPA-funded assessment

schedule. Mobilization to the site for assessment is expected to begin in September 2012.Additional mobilizations may be necessary in order to sample all identified and potentiallycontaminated properties.

Analytical results available for assessment are not always useful for determining disposal andremediation costs. Additional waste testing of excavated soil is usually necessary to determinedisposal requirements.

Access agreements need to be obtained from the owner of each property parcel prior tosampling.

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2. THE DECISION

Primary Study Questions:Question # 1 What are the concentrations of arsenic and lead in soil at each decision unit? Are thedetected concentrations of arsenic and lead in soil at individual decision units above the initialcleanup goal?

Question # 2 What is the spatial distribution of arsenic and lead in soil at undeveloped propertieswithin and around the study area?

Actions that could Result from Resolution of the Study Questions:Question # 1

If it is determined that decision units have concentrations of arsenic and/or lead above theinitial cleanup goal, then the U.S. EPA will consider that decision unit to be a potentialcandidate for additional investigation or a U.S. EPA-funded removal action.

If it is determined that decision units have concentrations of arsenic and/or lead below theinitial cleanup goal, then the U.S. EPA will not consider that decision unit as a potentialcandidate for additional investigation or a U.S. EPA-funded removal action.

Question # 2If the spatial distribution is determined, then decisions regarding extent of contamination canbe made. If the spatial distribution is not determined, the extent of contamination can not beestimated.

Decision Statement:Question # 1 Lead and arsenic concentrations in soil will be compared with initial cleanup goaland the detected background concentrations in order to determine whether additional investigationor removal actions are necessary.

Question # 2 The spatial distribution of lead and arsenic concentrations in soil will be determinedon larger undeveloped properties in order to determine the extent of contamination.

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3. DECISION INPUTS

Sources of Information Currently Available: Eureka County Assessor’s Office parcel maps. Historical documents related to the locations of former smelters from museum archives. U.S. Department of Interior Geological Survey data on metal concentrations in Eureka

County soil.

New Environmental Data Required to Resolve the Decision Statement: Definitive laboratory analytical data for arsenic and lead concentrations in soil. Field analytical data for arsenic and lead concentrations in soil. Relationship of field analytical data for arsenic and lead to definitive laboratory analytical

data.

Sources of Information to Resolve the Decision Statements: COPC data from the proposed sampling locations. Global Positioning System (GPS) location data from the sampling locations.

Information Needed to Establish Site-Specific Action Level:The potential site-specific action levels for the COPCs may come from the following sources: May 2012 U.S. EPA RSLs – Residential Soils and Industrial Soils. Background concentrations for arsenic and lead in soil. Site-specific bioavailability or bio-accessibility data for arsenic and lead. Site specific removal and investigation levels for similar sites have been determined on a

site-specific basis based upon site-specific bio-accessibility data and background arsenicconcentration data. Final removal cleanup goals have ranged from 10 to 60 mg/kg.

Collection methodsSurface and shallow subsurface soil samples will be collected using either a stainless steel trowelor stainless steel hand auger.

Measurement Methods:Soil samples will be analyzed in the field to determine arsenic and lead concentrations using thefollowing U.S. EPA analytical method: Total metals by U.S. EPA Method 6200.

Soil samples will be definitively analyzed by a laboratory to determine arsenic and leadconcentrations (or concentrations for a extended list of metals) using the following U.S. EPAanalytical method: Soil extraction by U.S. EPA 3050B, analysis for total metals by U.S. EPA Method 6010B. Soil extraction by In vitro bio-accessibility extraction, analysis by U.S. EPA Method 6010B.

Confirm that Appropriate (Analytical) Methods Exist to Provide the Necessary Data:The indicated definitive laboratory analytical method has sufficient sensitivity, accuracy andprecision to generate data of sufficient quality for this project. The indicated field analytical

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method has sufficient sensitivity, accuracy and precision for lead concentration determination.Depending upon the selected initial cleanup goals, the field analytical method may not havesufficient sensitivity, accuracy or precision to be used for all arsenic concentration determinations.

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4. DEFINE THE STUDY BOUNDARIES

Specific Characteristics that Define the Population Being Studied:The concentrations of arsenic and lead in shallow surface at 0 to 2 inches below ground surface(bgs), surface soil at 2 to 6 inches bgs and shallow subsurface soil at 6 to 12 inches bgs soils withinspecific study boundaris and within specified temporal boundaries.

Spatial Boundaries:The study area is presented in Figures 2-2a, 2-2b, and 2-2c and Figure 4-2b.

AOC 1 – Public Urban Parks, Playfields and Public School PropertiesThe following public parks, playfields and school district properties in the town of Eureka wereidentified:Eureka County baseball facility property (multiple parcels) at 10 Tannehill Road.Eureka High School located at 1 Vandal Way.Eureka School District Athletic Complex located at 700 Holly Road.Eureka Elementary School and playground located at 1 McCoy Street (three parcels).Eureka School District propane storage facility located at 400 Carica Street.Former Eureka Elementary School at 200 North Adams Street.

The boundaries of each property, according to the Tax Assessor’s Parcel Number (APN), are thehorizontal spatial boundaries. The identified properties comprise a total estimated area of 80 acres(Figure 2-3). Vertical boundaries will be 6 inches bgs as requested by the school district.

AOC 2 –Developed Urban PropertyAll property parcels within Eureka, according to the Tax Assessor’s Parcel Number (APN), that aredeveloped with residential, commercial or public structures are the horizontal spatial boundariesfor AOC 2. For AOC 2 there are estimated to be 300 property parcels, which compriseapproximately 150 acres in the Eureka area (Figure 2-2a, 2-2b and 2-2c). Vertical boundaries willbe determined in the field during sampling but are initially estimated to be no greater than 1 footbgs.

AOC 3 –Undeveloped Urban PropertyAll property parcels within Eureka, according to the Tax Assessor’s Parcel Number (APN), that areundeveloped and without residential, commercial or public structures are the horizontal spatialboundaries for AOC 3. For AOC 3, there are estimated to be 100 property parcels, which compriseapproximately 100 acres in Eureka area (Figure 2-2a, 2-2b and 2-2c). Vertical boundaries will bedetermined in the field during sampling but are initially estimated to be no greater than 1 foot bgs.

AOC 4 –Unpaved Urban RoadsAll unpaved road within the urban boundary of Eureka are the horizontal spatial boundaries forAOC 3. Unpaved roads will be identified during the removal assessment. Vertical boundaries willbe determined in the field during sampling but are initially estimated to be no greater than 6 inchesbgs.

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AOC 5 – Areas Downwind of the Town of EurekaBased on historical wind direction information, the prevailing wind is to the north and north-northwest. However, historical data suggest the lead and arsenic deposition is also to the west,south and east of the town. Thus, the spatial boundary for the downwind sampling AOC is the areaoutside of the town of Eureka in a 360 degree perimeter around the urban town area that extendsone mile in all directions (Figure 4-2). The vertical boundaries will be determined in the fieldduring sampling but are initially estimated to be no greater than 1 foot bgs. A portion of AOC 5 tothe north of the Eureka is also a flood plain.

AOC 6 – Creek BedA narrow intermittent seasonal creek, which has historically flooded the Eureka area, flows southto north through the center of the town. The east-west boundaries of the creek will be its widthfrom bank to bank. The downstream flood plain will initially be investigated as part of AOC 5.Evaluation in the field based on analytical data and observation may expand the downstream east-west boundaries as needed. The length boundaries span approximately 2 miles to the north of thesouthern CSP. The vertical boundaries will be determined in the field during sampling but areinitially estimated to be no greater than 1 foot bgs. The approximate location of the creek is shownin Figure 4-3.

AOC 7 – BackgroundThe background for the creek will be sediment and surface water up to one mile south of thesouthern CSP. Surface soil background will be identified during the removal assessment and isexpected to be an undeveloped area located at greater than one mile south, southwest, or southeastof the town of Eureka. The vertical boundaries will be determined in the field during sampling butare initially estimated to be no greater than 1 foot bgs. Because the areal deposition of lead andarsenic is not expected to exist in soil at depths greater that 6 inches bgs, the 6-inch to 1-footinterval samples from AOC 5 may also be considered as background.

Temporal Boundaries of Investigation:Decisions will apply to determination of human health risks associated with long-term directexposure to COPCs in mine waste. Inorganic arsenic and lead in soil media are environmentallypersistent and migrate slowly; therefore, concentrations in the mine waste will not generally varygreatly over time. However, the migration of airborne particulate matter (i.e., dust) containinginorganic arsenic and/or mercury is dependent upon weather conditions and land use. Increasedroadway or human activity use would be expected to increase the potential for exposure to arsenicand/or lead-laden dust.

Inorganic arsenic and lead in creek surface water is dependent of the concentration of arsenic andlead in sediments, creek flow rates and volumes and the chemical and physical properties ofupstream water source. Being an intermittent seasonal creek, sampling of water must coincidewith the seasonal flow.

Investigation Time-frameThe following time-frame has been proposed for removal assessment: The draft SAP will be submitted to the U.S. EPA FOSC on August 27, 2012, and should be

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reviewed, revised, and approved by the first day of proposed work. Sample collection will take place following SAP approval by the U.S. EPA and may

commence by the last week in August. Preliminary XRF data will be available immediately after field XRF analysis. Preliminary laboratory confirmation data should be available within 21 days of sample

delivery to the laboratory. Data packages and final data should be reported to project management approximately five

weeks after sample delivery to the laboratory. Laboratory data for arsenic and lead should be evaluated following U.S. EPA Region 9 Tier 2

guidance. Evaluated data should be reported to project management approximately four to sixweeks after sample delivery to the laboratory.

Field data will be evaluated and reviewed for quality assurance/quality control prior toreporting.

Scale of decision-makingAOC 1A – Public Urban Parks, Playfields and Public School Properties Utilized by ChildrenAreas of school property that are utilized by children will be determined with information to besupplied by the school district and upon visual observation. Each school property area that isutilized by children will be divided into multiple decision units based on the following factors:

Area use (for example, a playground, walking paths, playing fields, and lunch area would beseparate decision units);

Area size (for example, a 10,000-square-foot playground would be separated into four 2,500-square-foot decision units);

Area landscaping (for example, a newly landscaped playing field with imported sod would bea separate decision unit from an adjacent playing field that is on original soil);

Area topography (for example, a sloped area would be a separate decision unit from anadjacent garden area); and

Date of school structure’s construction (for example, soil at all the gutter outlets of a newlyconstructed building might be considered a separate decision unit, while thedripline around an older structure (to avoid the lead based paint bias) would beexcluded from any decision unit).

AOC 1B - Public Urban Parks, Playfields and Public School Properties Not Utilized by ChildrenSchool property areas that are not utilized by children will be determined with information to besupplied by the school district and upon visual observation. School property areas on a propertyparcel that are not utilized by children will be considered a single decision unit. There are twoknown decision units of this type. One is a large undeveloped area north of the high schoolfacility, and one is across the street from the elementary school facility.

AOC 2 – Developed Urban PropertyEach property parcel in AOC 2 that is included in the investigation will be considered a separatedecision unit.

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AOC 3 – Undeveloped Urban PropertyEach property parcel in AOC 3 that is included in the investigation will be considered a separatedecision unit.

AOC 4 –Unpaved Urban RoadsEach ¼ acre of unpaved urban roads will be considered a decision unit. A ¼ acre road is estimatedto be 300 feet in length by 30 feet in width.

AOC 5 – Areas Downwind of the Town of EurekaAOC 5 is a separate decision unit.

AOC 6 – Creek BedAOC 6 is a separate decision unit.

AOC 7 – BackgroundAOC 7 is a separate decision unit.

Practical Constraints on Data Collection:Physical Constraints: Sampling at locations may be constrained due to the steepness of terrain. The START will use

good judgment in the field during the sampling to determine if it is safe to access the proposedsample location.

Several locations are cover with piles of slag material, which will limit access to soil.

Other Constraints on Data Collection The turnaround times on data are always estimated and cannot be assured. Sample and system

problems may indiscriminately increase data turnaround times. Definitive data will undergo an EPA Region 9 Tier 2 validation review prior to final reporting.

Problems identified during this review may initiate additional data reviews, which willincrease the time needed before data are finalized.

Specific data may be qualified or rejected based on the results of the data review process. Civil constraints such as site access agreements and permit requirements may exist and, if so,

will need to be addressed prior to sampling.

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5. DECISION RULEStatistical Parameter:The average contamination concentration in each decision unit is the statistical area of interest.The average concentration will be determined either by physically composited samples fromdiscrete sampling locations (5-point composite samples) or by the calculations of mean and upperconfidence limit data from discrete sampling point data (samples from the grid nodes).

Initial Cleanup Goal:Refer to Tables 5-1 for the selected initial cleanup goal for residential and industrial soil. Refer toTable 5-2 for the selected project investigation levels for surface water.

Decision Rule:If arsenic and/or lead concentration documented by new analytical data in a decision unit exceedinitial cleanup goals, then the property will be evaluated by the U.S. EPA for a potential removalaction.

If arsenic and/or lead concentration documented by new analytical data in a decision unit at aninvestigated area do not exceed initial cleanup goals, then no further action will be taken.

If data for arsenic and/or lead in shallow surface soil (0 to 2 inches bgs) and surface soil (2 to 6inches bgs) in AOC 5 documents a contaminant release or if the data suggests a pattern ofcontamination distribution of within the AOC, then additional investigation of area may ensue.

If data for arsenic and/or lead in shallow surface soil (0 to 2 inches bgs) and surface soil (2 to 6inches bgs) in AOC 5 does not documents a contaminant release and if the data does not suggests apattern of contamination distribution of within the AOC, then there may be no further action.

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Table 5-1

Initial Cleanup GoalsEureka Smelter Sites

Removal AssessmentEureka, Eureka County, Nevada

E & E Project No.: EE-002693-2177 TDD No.: TO2-09-12-04-0002

COPC U. S. EPAResidential

RSL(mg/kg)

U. S. EPAIndustrial

RSL(mg/kg)

InitialResidential

CleanupGoals

(mg/kg)

InitialIndustrialCleanup

Goals(mg/kg)

RL forU.S. EPA(mg/kg)

Method6010B

Method6200

Lead 400 800 400 800 3 5Arsenic 0.39 1.6 60 * 60 * 2 10

Notes:RL = Reporting Limit mg/kg = milligrams per kilogramRSL = U.S. EPA Regional Screening Level (May 2012) RPD = Relative Percent Difference* = Recent Nevada Department of Environmental Protection (NDEP) and U.S. EPAremoval goals for arsenic have ranged up to 60mg/kg.

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TABLE 5-2

Surface Water Investigation LevelsEureka Smelter SitesRemoval Assessment

Eureka, Eureka County, Nevada

E & E Project No.: EE-002693-2177 TDD No.: TO2-09-12-04-0002

MCLs - Surface

Water Direct

Exposure

Investigation LevelSurface Water

Quantitation Limit

Lead 35 ug/L 35 ug/L 5 ug/L

Arsenic 10 ug/L 10 ug/L 5 ug/LNotes:MCL =maximum contaminant levels under the National Primary Drinking Water Regulationsug/L – micrograms per liter

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6. LIMITS ON DECISION ERRORS

Range of the Parameter(s) of Interest:For AOC 1, AOC 2, AOC 3, AOC 4, AOC 5 and AOC 6Concerning a decision error, the range of interest for lead in soil is 200 mg/kg to 1,200 mg/kg.Previous data for shallow surface soil in the AOCs had lead concentrations that ranged from 80mg/kg to 45,000 mg/kg.

The range of interest for arsenic in soil is generally 5 mg/kg to 200 mg/kg. Previous data forshallow surface soil in the AOCs had lead concentrations that ranged from 20 mg/kg to 12,000mg/kg.

For AOC 7 (Background Areas)Concerning a decision error, the range of interest for lead and arsenic in soil is any value greaterthan the detection limit. Previous data for surface soil in AOC 7 had lead concentrations thatranged from 20 mg/kg to 400 mg/kg. Previous data for surface soil in AOC 7 had arsenicconcentrations that ranged from less than 1 mg/kg to 100 mg/kg.

For AOC 6 - WaterThe range of interest for lead and arsenic in surface water is any detection greater than 5 ug/L.

Baseline Condition (The Null Hypothesis):The arsenic and/or lead concentrations in soils at AOCs 1 through 6 exceed the initial cleanupgoal.The arsenic and/or lead concentrations in soils at AOCs 7 (background areas) do not exceed theinitial cleanup goal.The arsenic and/or lead concentrations in surface water at AOC 6 exceed the investigation levels.

Alternative Condition (The Alternative Hypothesis):The arsenic and/or lead concentrations in soils at AOCs 1 through 6 do not exceed the initialcleanup goal.The arsenic and/or lead concentrations in soils at AOCs 7 (background areas) exceed the initialcleanup goal.The arsenic and/or lead concentrations in surface water at AOC 6 do not exceed the investigationlevels.

Decision Error:A discussion of decision error is presented in Table 6-1.

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Soil Decision Error Limit GoalsIn order to address the study questions, decisions will be made on areas where there may be noprevious sampling data; thus, there is no information on the expected sample variance or thestandard deviation for most of the decision units. The use of a multi-point composite sampling forassessing average decision unit area concentrations is based on the U.S. EPA Superfund Lead-Contaminated Residential Sites Handbook4 (Lead Handbook) guidance for sampling (U.S. EPA,2003). The proposed sampling design may not meet the objectives presented in Table 6-2 and 6-3, depending on concentration variance of the samples used to make up the multi-point composite.Therefore, a decision to conduct additional sampling in order to meet the decision error limit goalsand minimize false rejection decision errors may be made in the field based on preliminary sampleresults (see Section 7 for additional explanation).

4 U.S. EPA, Superfund Lead-Contaminated Residential Sites Handbook (OSWER 9285.7-50), August 2003

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TABLE 6-1 DECISION ERRORSEureka Smelter SitesRemoval Assessment

Eureka, Eureka County, NevadaE&E Project No.: 002693.2177.01RA TDD No.: TO2-09-12-04-0002

Decision Error Determining that a decision unit iscontaminated and requiresrestriction, mitigation, oradditional investigation when thedecision unit is not contaminated.

Determining that a decision unit is notcontaminated and requires restriction,mitigation, or additional investigationwhen the decision unit is contaminated.

True Nature ofDecision Error

The sample concentrations areeither not representative or arebiased high.

The sample concentrations are either notrepresentative or are biased low.

The Consequence ofError

The decision unit will undergomitigation or additionalinvestigation. These situationswould cost additional money,time, and resources.

Residents in the area would be exposed toexisting contaminants.

Which DecisionError Has MoreSevere ConsequencesNear the ScreeningLevel?

LESS SEVERETo human health, but withappreciable economicconsequences.

MORE SEVERESince the contaminated soil may poserisks to human health and/or theenvironment.

Error Type

Based onConsequences

False Acceptance Decisions

A decision that the decision unitis contaminated when it is not.

False Rejection Decisions

A decision that the decision unit is notcontaminated when it is.

For Backgroud(AOC 7) Error TypeBased onConsequences

False Rejection Decisions

A decision that the decision unitis contaminated when it is not.

False Acceptance Decisions

A decision that the decision unit is notcontaminated when it is.

DefinitionsFalse Acceptance Decisions = A false acceptance decision error occurs when the null hypothesis isnot rejected when it is false.False Rejection Decisions = A false rejection decision error occurs when the null hypothesis isrejected when it is true.

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TABLE 6-2 – DECISION ERROR LIMIT GOALS

AOCs 1-6Eureka Smelter SitesRemoval Assessment

Eureka, Eureka County, NevadaE&E Project No.: 002693.2177.01RA TDD No.: TO2-09-12-04-0002

TrueAverage

Concentration ofProperty or Property

Portion(% of Initial Cleanup

Goal Value)

Decision Error TypicalDecision Error

Probability Goals(Based on

ProfessionalJudgment)

Typeof

Decision Error

< 75 A decision that the area iscontaminated when it is

not.

5 % False Acceptance

75 to < 100 A decision that the area iscontaminated when it is

not.

Gray Area1 False Acceptance

100 to 150 A decision that the area isnot contaminated when it

is.

5 %2 False Rejection

> 150 A decision that the area isnot contaminated when it

is.

1% False Rejection

The goals in this table are based on professional judgment as relevant to a RemovalAssessment.

1Gray Area is where relatively large decision errors are acceptable.2The large probability for the decision error is expected when the true contaminant concentrationsare between 100% and 150% of the initial cleanup goal value. Decreasing the probability ispossible only by significantly increasing sampling number and quality assurance sampling, sincesampling and analytical uncertainties and biases can not be eliminated.

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TABLE 6-3 – DECISION ERROR LIMIT GOALSBackground Area (AOC 7)

Eureka Smelter SitesRemoval Assessment

Eureka, Eureka County, NevadaE&E Project No.: 002693.2177.01RA TDD No.: TO2-09-12-04-0002

TrueAverage Concentration of

Property or PropertyPortion

(% of Initial Cleanup GoalValue)

Decision Error TypicalDecision Error

Probability Goals(Based on

ProfessionalJudgment)

Typeof

Decision Error

< 75 A decision that thebackground area is

contaminated when it isnot.

5 % False Rejection

75 to < 100 A decision that thebackground area is

contaminated when it isnot.

Gray Area1 False Rejection

100 to 150 A decision that thebackground area is not

contaminated when it is.

5 %2 False Acceptance

> 150 A decision thebackground area is not

contaminated when it is.

1% False Acceptance

The goals in this table are based on professional judgment as relevant to a Removal Assessment.

1Gray Area is where relatively large decision errors are acceptable.2The large probability for the decision error is expected when the true contaminant concentrations arebetween 100% and 150% of the initial cleanup goal value. Decreasing the probability is possible only bysignificantly increasing sampling number and quality assurance sampling, since sampling and analyticaluncertainties and biases can not be eliminated.

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7. OPTIMIZED DESIGN FOR OBTAINING DATA

Proposed DesignThe sampling design will follow the guidance outlined in the U.S. EPA Lead Handbook for allAOC 1A and AOC 2. The remaining AOCs will be sampled based on statistical calculations ofthe number of samples required to meet decision error limit goals.

For all samples collected, duplicates and equipment blanks will be collected in accordance withU.S. EPA QC (quality control) requirements. Matrix spike and spike duplicate (MS/MSD)samples will be collected and are required by method. Data review independent of the laboratoryshall be performed on all START-generated analytical data that may be used in decision making.GPS coordinates (latitude and longitude) of each sampling location will be determined anddocumented during sampling.

An estimation of sample totals is indicated in table 7-1.

AOC 1A - Public Urban Parks, Playfields and Public School Properties Accessible toStudentsThere are six identified public facilities in Eureka, which have a total area estimated at 45acres. Approximately 30 acres are school district properties that are active school facilities,which are routinely accessible to children who attend the school. The other 15 acres arecounty-owned ball fields and a former school site that is no longer in use as a school.However, based upon visual inspection and aerial photography it is initially believed thatstructures, engineered surfaces, and pavement cover an estimated 20 acres, and exposed areasthat will requiring sampling total less than 25 acres.

The number of decision units to be investigated is estimated to be up to 50. The size of thedecision units will be determined upon on-site inspection of the properties. Decision unitswill be less than 10,000 square feet in area whenever possible and will not exceed 1 acre. Inmost situations a decision unit will be subdivided into one to five sampling sectors. Samplingsectors will not exceed ¼ acre. The dripline and gutter runoff areas around a structure, ifsampled, will be considered an additional sampling sector. Discrete sampling and analysismay also be employed at judgmental sampling locations such as beneath a drain spout or in anarea that appears to accumulate runoff. The specific locations of decision units and samplingsectors will be determined in the field. The total number of sampling sectors requiringcomposite sampling is estimated to be 125.

Once the decision areas and sampling sectors have been established, each sampling sector willbe sampled using a five-point composite design described in the Lead Handbook. Thelocations of the sampling points where the sample aliquots are collected should be equallyspaced within the area of sampling section. The sampling sectors that are structure driplineswill be sampled with a four-point composite where aliquots are collected from each of the foursides of the structure. Sample aliquots will be collected from 0 to 2 inches bgs and from 2 to 6inches bgs at each sample location. At the request of the school district, samples will not becollected from below 6 inches bgs. Samples will be collected from exposed soil, grass or

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vegetated areas and not beneath paved surfaces.

The total number of sample aliquots from discrete sampling locations is expected to be 625(125 by 5 aliquots) at 0 to 2 inches bgs, and 625 at 2 to 6 inches bgs

AOC 1B – Undeveloped or Non Student School Property AreasThe total area of undeveloped school property is approximately 35 acres. All but 0.6 acres islocated to the north and northwest of the high school facility. The undeveloped high schoolproperties will be overlaid with a 200-foot by 200-foot grid. Soil samples will be collectedfrom the grid nodes. Samples will be collected from the surface (0-2 inches bgs) and at depth(2-6 inches bgs).

Based upon an estimated area of 1,500,000 square feet, the total number of grid nodes isexpected to be approximately 40. A soil sample will be collected at each grid node at eachdepth interval for a total of up to 80 samples. Assuming the variance does not exceed 45percent of the mean, a total of 37 samples for each depth interval are required to meet thedecision error limit goals. A 200-foot grid is also capable of detecting a circularcontamination hot spot greater than 38,000 square feet with 90 percent confidence.

The 0.6 acres of school district property adjacent to the elementary school facility will beoverlaid with a 75-foot by 75-foot grid. Soil samples will be collected from the grid nodes.Samples will be collected from the surface (0-2 inches bgs) and at depth (2-6 inches bgs).

Based upon an estimated area of 27,121 square feet, the total number of grid nodes is expectedto be approximately 6 samples from each depth interval for a total of up to 12 samples.Assuming the variance does not exceed 16 percent of the mean, a total 6 samples for eachinterval are required to meet the decision error limit goals. A 75-foot grid is also capable ofdetecting a circular contamination hot spot greater than 4,000 square feet with 90 percentconfidence.

AOC 2 –Developed Urban PropertyAOC 2 is comprised of hundreds of property parcels covering over 100 acres in Eureka. Theactual number of properties that will be accessed is unknown. A developed property is definedas containing a structure or other improvement. However, an undeveloped residential propertythat is used as an activity area should be considered as a developed property. Each propertyparcel will be considered a decision unit. Each property parcel will be divided into two to fivesampling sectors. The number of sampling sectors will depend upon the size of the propertyparcel. The Lead Handbook guidance for sampling in yards less than or equal to 5,000 feetrecommends at a minimum two sampling sectors, one that encompasses the front and the otherthat encompasses the back yard. To eliminate potential bias due to lead-based paint, the dripzone surrounding the structure will be excluded in a sampling sector. For properties greaterthan 5,000 square feet, the Lead Handbook recommends that, at a minimum, compositesamples should be collected from each of the sampling sectors of the yard surrounding aresidential structure. The Lead Handbook also recommends that play areas and gardens shouldbe separate sampling sectors.

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The number of developed properties (or decision units) to be investigated is estimated to be upto 50 but could be much higher. The total number of sampling sectors requiring compositesampling, based upon 50 properties, is estimated to be 150.

Each sampling sector will be sampled using a five-point composite design as described in theLead Handbook. The locations of the sampling points where the sample aliquots are collectshould be approximately equally spaced within the area of the sampling sector. Samplealiquots will be collected from 0 to 2 inches bgs, 2 to 6 inches bgs, and 6 to 12 inches at eachsample location. Samples will be collected from exposed soil, grass or vegetated areas andnot beneath paved surfaces.

The total number of sample aliquots from discrete sampling locations is expected to be 625(125 by 5 aliquots) at 0 to 2 inches bgs, 625 at 2 to 6 inches bgs, and 625 at 6 to 12 inches bgs.

AOC 3 – Undeveloped Urban PropertyAOC 3 is comprised of undeveloped urban property parcels located in Eureka. The propertysizes vary considerably. The actual number of properties that will be accessed is unknown.Each undeveloped property parcel will be considered a decision unit.

Urban properties of more than 5 acres will be overlaid with a 200-foot by 200-foot grid. Soilsamples will be collected from the grid nodes. Samples will be collected from the surface (0-2inches bgs), 2-6 inches bgs, and at depth (6-12 inches bgs).

The total number of property parcels greater than 5 acres to be accessed is not expected toexceed 20 but could be much higher. A property that exceeds 40 acres will not be assessed asan urban property. Based on 20 properties, the total number of sampling locations at eachdepth for undeveloped properties is estimated to be approximately 120. With samples fromeach depth interval, the total will be 360 samples. Assuming the variance does not exceed 16percent of the mean, a total of 6 samples for each decision unit interval are required to meetthe decision error limit goals. Thus, a minimum of 6 samples per each decision unit intervalwill always be collected. Assuming the variance does not exceed 45 percent of the mean, 37samples would meet the requirement of the decision error limit goals. A 200-foot grid is alsocapable of detecting a circular contamination hot spot greater than 38,000 square feet with 90percent confidence.

Urban properties of less than 5 acres will be overlaid with a 75-foot by 75-foot grid. Soilsamples will be collected from the grid nodes. Samples will be collected from the surface (0-2inches bgs), 2-6 inches bgs, and at depth (6-12 inches bgs).

The total number of undeveloped property parcels less than 5 acres to be accessed is notexpected to exceed 20 but could be much higher. Based on 20 properties, the total number ofsampling locations at each depth for undeveloped properties is estimated to be approximately120. With samples from each depth interval, the total will be 360 samples. Assuming thevariance does not exceed 16 percent of the mean, a total of 6 samples for each decision unit

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interval are required to meet the decision error limit goals. Thus, a minimum of 6 samples pereach decision unit interval will always be collected. A 5-acre property would have a total of36 samples collected at each depth interval. Assuming the variance does not exceed 45 percentof the mean, 37 samples would meet the requirement of the decision error limit goals. A 75-foot grid is also capable of detecting a circular contamination hot spot greater than 4,000square feet with 90 percent confidence.

AOC 4 –Unpaved Urban RoadThe number of unpaved roads in Eureka is not known to START. Unpaved roads will beidentified during the removal assessment. Road are expected to be divided into 300-foot longsampling sectors (i.e., approximately ¼ acre). Each sampling sector will be a decision unit.Once the sampling sectors have been established, each sampling sector will be sampled usinga 5-point composite design similar to that described in the Lead Handbook. The locations ofthe sampling points where the sample aliquots are collected should be approximately equallyspaced within the roadway area. Sample aliquots will be collected from 0 to 2 inches bgs andfrom 2 to 6 inches bgs at each sample location.

The total number of decision unit/sampling sectors is estimated to be at least 20; the totalnumber of sample aliquots from discrete sampling locations is expected to be 100 (20 by 5aliquots) at 0 to 2 inches bgs and 100 at 2 to 6 inches bgs.

AOC 5 –Areas Downwind (Air Dispersion Study Area)AOC 4, which is a 1-mile perimeter around the town of Eureka, will be sampled along 14north-south transects at 1,000-foot intervals (Figure 4-2). Each transect will be spaced at 2,000foot intervals (i.e., a 2,000 by 2,000-foot grid). Samples will not be collected from newlyexcavated or developed areas. All samples will be collected from the depth intervals of 0 to 2inches bgs and from 2 to 6 inches bgs at each sample location. The total number of samplinglocations is estimated at 150 for a total of 450 samples. Sample locations north of the Eurekaand within the creek’s downstream flood plain are included in this AOC.

AOC 6 –Creek and DownstreamSediment and surface water samples will be collected at 1,000-foot intervals starting at wherethe creek passes the southern CSP to approximately 10,000 feet north and downstream of thefirst sampling location (Figure 4-3). Samples should be collected on a day that the creek isflowing. Sediment samples will be collected from submerged locations within the creek. Thesample depth will be from 0 to 2 inches bgs. Surface water samples will be collected from thesame location as the sediment sample. If the creek is not flowing the sediment samples will becollected from the center of the creek bed or where the flow path is evident. If the creek isdry, samples will be collected from the depth intervals of 0 to 2 inches bgs, 2 to 6 inches bgs,and from 6 to 12 inches at each sample location. If the creek is flowing, samples will likelyonly be collected from the 0 to 2 inch bgs interval. The total number of sampling locations isestimated at 11 for a total of 33 sediment samples and 11 water samples. Field data from floodplain areas in AOC 5 and creek sediments in flood plain area will be evaluated to determine ifadditional sampling in of flood plain is needed. If field analytical data or observationssupport additional sampling to fill data gaps, then the flood plain will be additionally sampled

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along east-west transects or systematic grids.

AOC 7 –BackgroundBackground sediment and surface water samples will be collected at 1,000-foot intervalsstarting at where the creek passes the southern CSP to approximately 5,000 feet south andupstream of the first sampling location. Samples should be collected on a day that the creek isflowing. Sediment samples will be collected from submerged locations within the creek. Thesample depths will be from 0 to 2 inches bgs, 2-6 inches bgs, and 6-12 inches bgs. Surfacewater samples will be collected from the same locations as the sediment samples. If the creekis not flowing, the sediment samples will be collected from the center of the creek bed orwhere the flow path is evident. The total number of background water samples will be five.The total number of background sediment samples is expected to be 15.

General background sampling and analysis required to determine naturally-occurring lead andarsenic concentrations in an area with similar geology and no known or suspected impactsfrom mining. The background area will be selected in the field according to the followingcriteria:• Similar elevation as the site;• Similar geology as the site;• Upwind (gradient, stream) from site;• Undisturbed with natural vegetation;• Not in drainage or area impacted by flooding;• Distance from Eureka should exceed one mile;• Accessible (by vehicle and equipment);• Should not be near a mine site or similar contaminant source;• If possible, avoid anthills and rodent holes;• Ask nearby residents about area.

There are expected to be 20 samples collected in the background area. The samples will becollected at the grid nodes of a 75-foot by 75- foot grid. Samples will be collected from the depthintervals of 0 to 2 inches bgs, 2 to 6 inches bgs, and 6 to 12 inches at each sample location. Thetotal number of sampling locations is estimated at 20 for a total of 60 soil samples.

Background samples may also be the samples collected from AOC 4 (air dispersion study area) atdepth intervals of 6 to 12 inches bgs.

Slag Piles on any AOCMaterials in CSPs located on developed or undeveloped urban property will be sampled separatelyfrom soil. Depending on the size of the CSP the material will be sampled either as a composite oras one or more discrete samples.

Sample AnalysisAll soil samples will be analyzed for lead and arsenic by U.S. EPA SW-846 Method 6200 in thefield during the sampling event. The relationship of field analytical data by U.S. EPA method6200 to laboratory data generated by U.S. EPA method 6010B was evaluated prior to performing

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removal assessment. The correlation coefficient between the two methods for lead in 0.999 andfor arsenic is 0.992. Ten percent of all collected samples will be sent to the U.S. EPA Region 9Laboratory for total metals analysis using EPA Method 6010B. Data for additional metals may begenerated by the field XRF. However, QA and QC checks will only be performed for arsenic andlead. Data for additional metals will also be generated by the U.S. EPA Region 9 Laboratory,which will include QA and QC for all reported analytes. The U.S. EPA Region 9 Laboratory willalso perform bioaccessibility extraction followed by U.S. EPA SW-846 Method 6010B analysisfor lead and arsenic on a representative portion of the collected samples.

The use of the field XRF to generate analytical data in the field immediately following samplecollection could rapidly provide data to assist the U.S. EPA and START in determining ifcontamination above the initial cleanup goal is present in the study area and will help reduce thecost of the investigation. Furthermore, the relationship of field data to laboratory data will beevaluated prior to performing any removal or remedial action where the field data would be usedto support real-time decision making.

The relationship of field analytical data by U.S. EPA method 6200 to laboratory data generated byU.S. EPA method 6010B was evaluated prior to performing removal assessment. The correlationcoefficient between the two methods for lead in 0.999 and for arsenic is 0.992.

The use of composite sampling to determine an average concentration representing an entiredecision unit and decision unit sector may introduce errors that result in the data not meeting thedecision error limit goals for accepting or rejecting the null hypothesis (Section 6, Table 6-2). Ofgreatest concern for this removal assessment is the potential for large errors resulting in falserejection of the null hypothesis (i.e., a determination that the decision unit is not contaminatedwhen it is). To minimize the false decision errors, additional data evaluation will occur in thefield if a composite sample has a lead and/or arsenic measurement by XRF that is determined tobe at concentrations between 75 percent and 99 percent of the initial cleanup goal. The procedurefor this evaluation is as follows:

1) Each aliquot of the composite sample will be analyzed by the XRF.

2) The measurement values from individual aliquots will be used to determine if the standarddeviation of the mean for measurements (i.e., concentration variance) is low enough tostatistically support a five-point composite (e.g., to meet the decision error goals the deviationshould be 14 percent of mean of less).

3) If the standard deviation of the mean for the measurements is greater than expected and doesnot support a five-point composite, then the decision error limit goals in the DQO (Table 6-2) willnot be achieved. To resolve the problem the following steps can be taken:

a) The number of aliquots for the sampling sector can be increased. This step would notincrease the total sample count but would require additional sample collection and XRFanalysis;

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b) Individual aliquots can be considered as discrete samples for decision-making purposes.This step would not require additional sampling, but would require additional XRFanalysis and increase the total sample count by four; or

c) The sampling sector can be subdivided into smaller sampling sectors that are less likely tohave a high concentration variance. This resolution would require both additionalsampling and additional XRF analysis and would increase the total sample count by one.

The determination of whether the concentration variance is low enough to support the multi-pointcomposite and the steps to take if it is not will be made in the field and may be assisted by the useof a statistical evaluation such as a one-sided t-test or a statistical sampling program such as theU.S. EPA’s Decision Error Feasibility Trials (DEFT) software. The DEFT software program canuse the site-specific XRF data generated in the field to determine if decision error limit goals forrejecting the null hypothesis have been met, or if not, how to adjust the sampling design to meetthem.

General Requirements:All activities and documentation related to the project should proceed under a Quality ManagementPlan. All sampling, analytical, and quality assurance activities will proceed under a U.S. EPA-approved SAP. A record of sampling activities and deviation from the SAP must be documented ina bound field log book. Prior to sample collection, all project sampling personnel will reviewrelevant sampling procedures and relevant QA/QC requirements for selected analytical methods.

General Consideration for Decision Error Minimization:Average ConcentrationsIn order to minimize a decision error related to data uncertainty, the decision-maker shouldconsider statistical evaluations of the data prior to making decisions.

Data from Composite Sample LocationsThe decision-maker should consider data uncertainty when making decisions using an averagevalue derived from composite sample locations. Using an average value to represent a singledecision unit can introduce data uncertainty when concentration variance is high, wherein thenumber of samples selected for the composite may not be great enough to achieve representativesampling. To minimize decision errors around the initial cleanup goal, for soil data in whichcomposite samples have a reported concentration between 75 percent and 150 percent of theinitial cleanup goal, the concentrations of the samples used to make up the composite should beevaluated individually to identify whether sample variance is within acceptable ranges. Otherwise,the area should be treated as potentially exceeding the initial cleanup goal.

Data from Individual Sample LocationsThe decision-maker should consider data uncertainty when making decisions based uponsampling data and associated estimated values based upon a single location. An individual datavalue reported below the initial cleanup goal may be biased low, while a data value reportedabove the initial cleanup goal may be biased high. The probability of decision error increaseswhen COPC concentrations are around the initial cleanup goal due to both data uncertainty anddata bias. Due to the nature of the contamination, it is unknown whether data from any individual

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sample location on a property can represent a larger area. There are insufficient data to determineconfidence of any single sampling location. Thus the decision-maker should consider discretedata points as potentially not representative of any greater area.

Estimated Concentration DataFor any reported COPC concentrations near the method detection limit, the uncertainty isrelatively large, increasing the probability of decision error. The uncertainty for estimated data(data based on extrapolations and interpolations) is typically greater than for actual data.Therefore the probability of a decision error is greatly increased when extrapolated data are used.

Contamination Distribution MapData from sampling locations can be used to create a contamination distribution map. The mappedcontaminant concentrations indicated within an area should generally be based upon the sampledata from that area and the sample data from adjacent locations (particularly if discrete sampledata are being used). The generated map model could be used to estimate the concentrations ofcontamination throughout the property. The decision-maker should consider the data source andstatistical sophistication of the distribution map prior to making decisions based upon the map.

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Table 7-1 – Sample Number EstimationEureka Smelter SitesRemoval Assessment

Eureka, Eureka County, Nevada

Area of Concern EstimatedDecisionAreas*

EstimatedSamplingSectors

Estimatedshallow 0-2inch depthaliquots or

discretesamples

Estimatedshallow 2-6inch depthaliquots or

discretesamples

Estimatedshallow 6-12inch depthaliquots or

discretesamples

UniqueSamples forAnalysis*

DuplicateSamples forField XRF*

Samples forDefinitiveAnalysis*

AOC 1AStudent Accessible

31 88** 440 440 0 176 18 21

AOC 1BNon- Student Areas

2 0 46 46 0 92 10 11

AOC 2 50 100** 500 500 500 300 30 33

AOC 3Properties less than fiveacres

20 0 120 120 120 360 36 40

AOC 3Properties greater thanfive acres

20 0 120 120 120 360 36 40

AOC 4 20 20 100 100 0 40 4 5

AOC 5 1 0 46 46 0 92 10 11

AOC 6* 1 0 11 11 11 33 4 4

AOC 7 3 0 25 35 85*** 85 9 10

Total 148 208 1408 1408 786 1538 157 175

There is expected to be a total of 18 surface water samples including two field duplicates.* = Does not include flood plain sampling or any additional sampling based on field generated data or observations.** = Based upon 2 sampling sectors per decision unit.*** = Includes collection of 10 background samples at 6 to 12 inch depth in AOC 5.

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