QUALITY ASSURANCE PROJECT PLAN

COMPREHENSIVE AIR EMISSIONS TESTING 

FOR 

HYDROGEN CYANIDE 

AT 

THREE NEVADA GOLD MINE SITES 

USING THE 

USEPA SURFACE ISOLATION FLUX CHAMBER TECHNOLOGY 

Prepared For:

NEVADA GOLD MINES

Prepared By:

MR. TOM CARD

Environmental Management Consulting

41125 278th Way SE

Enumclaw, Washington 98022

DR. C. E. SCHMIDT

19200 Live Oak Road

Red Bluff, California 96080

October 7, 2009
TABLE OF CONTENTS

 i

Section 1 Introduction.....................................................................................................1-1

Section 2 Project Description.........................................................................................2-1

2.1 Area Source Emissions Assessment ......................................................................2-3

Section 3 Project Organization and Responsibility.......................................................3-1

Section 4 Quality Assurance Objectives........................................................................4-1

4.1 Precision ................................................................................................................4-2

4.2 Accuracy................................................................................................................4-2

4.3 Completeness.........................................................................................................4-3

4.4 Representativeness.................................................................................................4-3

4.5 Comparability ........................................................................................................4-3

Section 5 Sampling Procedures .....................................................................................5-1

5.1 Air Sampling..........................................................................................................5-1

5.2 Liquid Sampling/Field Analysis............................................................................5-7

Section 6 Sample Custody..............................................................................................6-1

6.1 Documentation Procedures....................................................................................6-1

6.2 Chain-of-Custody Procedures................................................................................6-1

6.3 Sample Handling Procedures.................................................................................6-2

6.4 Sample Preservation ..............................................................................................6-2

Section 7 Calibration Procedures and Frequency ........................................................7-1

7.1 Laboratory Instrument Calibration ........................................................................7-1

7.2 Sampling Equipment Calibration Procedures........................................................7-1

Section 8 Data Reduction, Validation and Reporting....................................................8-1

8.1 Data Reduction ......................................................................................................8-1

8.2 Data Transfer and Verification ..............................................................................8-1

8.3 Data Validation......................................................................................................8-1

8.4 Analytical Data Reporting .....................................................................................8-2

8.5 Emissions Estimate................................................................................................8-3

8.6 Process Data Needs................................................................................................8-9

Section 9 Analytical Procedures and Calibration..........................................................9-1

9.1 Method Detection Limits.......................................................................................9-1

9.2 Laboratory Standards and Reagents ......................................................................9-1

9.3 Methods of Sorbent Analysis for Hydrogen Cyanide............................................9-1

Section 10 Internal Quality Control ................................................................................10-1
TABLE OF CONTENTS

 ii

10.1 Analytical Laboratory Quality Control Samples .................................................10-1

10.2 Field Quality Control Samples ............................................................................10-2

Section 11 Performance and Systems Audits ...............................................................11-1

11.1 Technical Systems Audit .....................................................................................11-1

11.2 Performance Audits and Data Quality Audits .....................................................11-1

Section 12 Preventative Maintenance ............................................................................12-1

12.1 Field Equipment/Instruments...............................................................................12-1

12.2 Laboratory Instruments........................................................................................12-1

Section 13 Specific Routine Procedures Used to Access Data Precision, Accuracy, and 

Completeness ...............................................................................................13-1

13.1 Blank Data Assessment .......................................................................................13-2

13.2 Accuracy..............................................................................................................13-2

13.3 Precision ..............................................................................................................13-3

13.4 Completeness.......................................................................................................13-3

13.5 Corrective Action.................................................................................................13-4

Section 14 Corrective Action..........................................................................................14-1

14.1 Reporting Malfunctions.......................................................................................14-1

Section 15 Quality Assurance Reports to Management ...............................................15-1

Section 16 Health and Safety..........................................................................................16-1
List of Tables, Figures, and Appendices

 iii

Tables

Table 2-1 Summary of the Scope of Work for the Emissions Assessment

Table 2-2 Summary of Analytical Species and Proposed Methods with Cost Information.

Table 4-1 Sample Matrix and Parameters

Table 4-2 Accuracy, Precision and Sensitivity of Analysis

Table 6-1 Parameters for Sample Preservation

Table 7-1 Calibration Frequency of Field Sampling Equipment

Table 10-1 Summary of Internal Quality Control

Figures

Figure 5-1 Surface Flux Measurement Data Form

Attachments

Attachment 1 USEPA Flux Chamber User’s Guide

Attachment 2 NIOSH Method 6010

Attachment 3 NIOSH Method 7904

Attachment 4 Mackay and Matsugu, 1973.
List of Acronyms and Abbreviations

 iv

μg/m3 microgram per cubic meter

CFR Code of Federal Regulations

CLP contract laboratory program

CSTR continuous stirred tank reactor

DQO Data Quality Objectives

EMSL Environmental Monitoring Systems Laboratory

LIMS Laboratory Information System

lpm liters per minute

m

2 meters squared

MDL method detection limit

NIST National Institute of Standards & Technology

NIOSH National Institute of Occupational Safety and Health

ppbv parts per billion, volume

ppmv parts per million, volume

psig pounds per square inch gauge

QA quality assurance

QAPP Quality Assurance Project Plan

QC quality control

RPD relative percent difference

SDG sample delivery group

SOP standard operating procedures

g microgram

UHP ultra high purity

USEPA United States Environmental Protection Agency
SECTIONONE Introduction

 1-1

SECTION 1 INTRODUCTION

The USEPA has an interest in obtaining air emissions data for hydrogen cyanide from gold mining 

operations. Hydrogen cyanide is used in gold extraction process and may be emitted at low levels from 

several area sources or gold mining unit processes, including: 

 heap leach pads, 

 mill process tanks, 

 leach solution conveyance channels and 

 tails ponds. 

Area sources will be measured by using the USEPA surface emissions isolation flux chamber 

technologies with appropriate sample collection and analytical methodologies. The results will be 

reported as pounds emitted of HCN per hour for the gold mine area sources. Preliminary annual 

emissions of HCN will also be estimated based on projected operations and/or historical operating data if 

the necessary data is available.

This Quality Assurance Project Plan (QAPP) provides the field sampling and analytical protocols needed 

to conduct the requested „comprehensive flux chamber testing programs‟ at three gold mining sites: 

Newmont Gold Quarry, Kinross Round Mountain, and Barrick Cortez. The QAPP describes the technical 

approach for the comprehensive study, assessment method including method validation components, 

quality assurance program components, and data reduction and emission estimation procedures that will 

be used to generate air emissions of hydrogen cyanide from gold mining unit processes at these three gold 

mines, and hydrogen cyanide site air emissions from the same mines. Each mine will have subsequent 

site specific protocol document prepared that will provide specific process information and sample 

locations for that site.

Dr. C. E. Schmidt and Mr. Tom Card will provide technical services to Nevada Gold Mines for the 

purpose of measuring hydrogen cyanide emissions from area sources at mining sites and estimating 

hydrogen cyanide emissions from these area sources and these three mines. 
SECTIONTWO Project Description

 2-1

SECTION 2 PROJECT DESCRIPTION

The technical approach to the project includes conducting area source testing at total of three gold mine 

sites, including Newmont Gold Quarry, Kinross Round Mountain, and Barrick Cortez. Testing will focus 

on three types of area sources that may have sub-sources within each type, including: 

1) tall, open process tanks that are located in process areas with poor access, 

2) large heap leach pads with surface material of different age under leach (wet and dry 

areas), and 

3) tailings ponds with large aqueous areas and beach (sediment pads) with wet and dry 

surfaces, open leach channels with pregnant and barren cyanide solution, and process 

ponds. 

This document focuses on area sources, and includes a detailed assessment approach following 

USEPA protocols for assessment of unique area sources using the USEPA flux chamber 

technology. The product of this assessment is a matrix table of flux data that, when used along 

with the surface area of the area sources tested or unit processes, results in a listing of air 

emissions of hydrogen cyanide from each source tested, and, by summation, the site hydrogen 

cyanide emissions from all area sources. 

Only general information is provided in the QAPP; specific frequency of testing for the 

comprehensive study will be provided in the test site specific protocol. However, based on 

experience working at mine sites and assessing hydrogen cyanide emissions from these types of 

sources, general information that is illustrative of the magnitude and distribution of samples per 

area source is provided in Table 2-1.
SECTIONTWO Project Description

 2-2

Table 2-1

Summary of the General Scope of Work Projections

Field measurements will be made using the USEPA flux chamber with sample collection and analysis of 

samples taken from the flux chamber using NIOSH Method 6010 or NIOSH Method 7904 as indicated in 

Table 2-2. Copies of Methods 6010 and 7904 are provided in Appendix B and Appendix C, respectively.

SOURCE SCOPE COMMENT

Process Tanks Two locations each on tank of 

interest; Minimum of first and last 

tank in a series of tanks.

Minimum tank type and number, 

aerated and non-aerated locations

Tailings Pond- Liquid Surface Two to four tests per zone of pond; 

number of tests TBD using spatial 

screening data of pond water (pH, 

cyanide levels)

Access limited to pier, boat or 

barge stations

Tailings Pond- Beach Two to four tests per zone of beach, 

such as wet and dry sediment layer; 

multiple beach areas recommended 

per solid component of pond source

Range of dry and wet beach 

locations available by foot

Active Leach Pad Two to four locations per zone on wet 

and dry surfaces.

Inactive Leach Pad Two to four locations on surface.

Replicate Samples Minimum of 5% per batch, one per 

day

Media Blank Samples Minimum of 5% per batch, one per 

day

Snow covered process units Weather permitting, the effects of 

snow cover will be tested 

Snow cover is expected to impede 

mass transfer.
SECTIONTWO Project Description

 2-3

Table 2-2 

Summary of Analytical Species and Proposed Methods.

Target Species Analytical Method Sample Media Analytical 

Instrument Laboratory/Manufacturer

Hydrogen Cyanide (gas 

phase) NIOSH 6010 Soda lime solid sorbent tube

Spectroscopy

ALS Laboratory Group

960 W. LeVoy Drive

Salt Lake City, UT 84123

801.266.7700

Hydrogen Cyanide (gas 

phase)

NIOSH 7904 

(modified)

0.25 N NaOH 

solution

Spectroscopy

ALS Laboratory Group

960 W. LeVoy Drive

Salt Lake City, UT 84123

801.266.7700

2.1 Area Source Emissions Assessment

For this study, assessment of hydrogen cyanide emissions will be performed using the USEPA 

recommended surface emission isolation flux chamber (flux chamber) and appropriate sample 

collection/analytical technologies. A schematic diagram of the USEPA emission flux chamber is 

provided below. 

The emission flux chamber is a dynamic environmental chamber designed for operation on land surfaces, 

but is applicable to sludge and liquid surfaces as well. The chamber qualifies as a mixed tank reactor or a 

„continuously stirred tank reactor‟ (CSTR) and has been designed to assess flux without a significant bias, 

even for diffusion-limited sources. The chamber is pressure vented and operated at 5.0 liters per minute 

(lpm) sweep air flow rate and sample gas is withdrawn from the chamber at equilibrium (5 residence 

times or 30 minutes; chamber volume is 30 liters and the flow rate of sweep air gas is 5.0 lpm). Because 

the emission chamber equipment is identical to the USEPA/Environmental Monitoring Systems 

Laboratory (EMSL) design, and because the protocol for use is followed to exact specifications, the data 

generated by this technology can be used to quantify area source emission fluxes to within the 

specifications of accuracy, precision, and repeatability of the published method. All data collected for 

this effort will be directly comparable to previously collected flux data by this technology, and will be 

within the method quality assurance/quality control specifications. 

Samples are collected from the USEPA flux chamber at equilibrium using appropriate and valid sample 

collection and analytical methodology. The analytical methods, combined with the field quality control 

testing (minimum amount of field system blank tests and replicate sample tests) will be adequate to 

demonstrate compliance with method performance. 
SECTIONTWO Project Description

 2-4

A mine site can consist of a composite of various sources of hydrogen cyanide emissions from area 

sources, which are dependent on many variables, including: operational considerations, size of the area 

source, spatial variability, diurnal factors, and seasonal factors. The various area sources can be described 

as unique „unit processes‟, which when combined in a facility assessment, can be used to estimate 

hydrogen cyanide emissions from the facility. Several studies have been conducted using the USEPA 

emission flux chamber at identical or similar sites, and the technology is applicable to this assessment 

effort. The strengths of the flux chamber technology for this application are:

1. The air emissions from a given unit process measured using flux chambers are unaffected by 

upwind sources;

2. The sensitivity (3.3 g/m3or a flux of about 0.13 g/m2, min-1) for Method 7904 using a 

sensitivity of 0.1 g/sample and a 30 liter sample volume provides for a low level flux 

assessment;

3. Other flux chamber studies (Round Mountain) have been conducted for hydrogen cyanide 

emissions from other mines, and all data collected from these studies will be directly comparable 

to the data collected in this study;

4. All data collected will be of known accuracy and precision; 

5. The technology is a direct measurement approach and no modeling is required to obtain emission 

factor information since data are reported in engineering units, for example, mass per 

time/surface area. 

6. The USEPA technology, using the USEPA/EMSL User‟s Guide (available on ceschmidt.com 

website) and specified equipment, is a verified approach producing data that can be used to 
SECTIONTWO Project Description

 2-5

estimate emissions from a process by knowing the surface area and measured flux of the test 

source.

This approach provides specific flux data from a given test location. Thus, the exact areas tested must be 

carefully selected so that they represent the unit process fugitive emissions, and air emissions from the 

gold mine site. Therefore, proper planning is needed prior to testing including: identifying all project 

variables that may affect surface emissions; identifying all significant and unique area sources which 

includes discerning significant emission sources from non-significant emission sources (note- significance 

is determined by a combination of flux potential and surface area); properly allocating project resources 

between planning/preparation efforts, field testing, and reporting. These details will be provided in the 

site-specific SOPs.

Although not specified in this conceptual approach, additional screening level data will be collected to 

assist in field sample collection. Colorimetric tubes for hydrogen cyanide will be used as needed in 

conjunction with flux chamber testing in order to „fine tune‟ sorbent sample collection. 

2.1.1 Measurement of Surface Flux

Emissions from various surfaces at the gold mine sites will be evaluated using the flux chamber. One or 

more samples will be made at the locations identified in Table 2-1, or other area source identified from 

discussions with site operators or from site inspections. Testing may also be conducted on non-operating 

sources or reclaim areas at a lower frequency of data collection in order to rule out potential sources as 

described in the site-specific SOPs.

2.1.2 Calculation of Flux Data

The flux of compounds will be calculated using data on the concentration of compounds from the flux 

chamber sample (μg/m3), the sweep air added to the chamber (lpm), and the surface area of the chamber 

(0.13 m2). The flux chamber provides a direct measure of the flux of compounds (μg/m2,min-1) from a 

given surface at a given point in time.

2.1.3 Calculation of Emission Rate Data 

The emission rate (μg/min) of compounds from the selected unit process will be calculated using the flux 

data (μg/m2,min-1) and the surface area tested (m2). The emission rate of compounds from the mining 

sites can be estimated by summing the hydrogen cyanide flux from each unique area of the unit processes 

and multiplying the representative flux by the total area for the source to provide the total estimated unit 

process emissions. Site emissions are obtained by summing all unit process emissions. Data evaluation 

and correction as needed for large area sources or other factors that affect site emissions are described in 

Section 8.
SECTIONTHREE Project Organization and Responsibility

3-1

SECTION 3 PROJECT ORGANIZATION AND RESPONSIBILITY

The organization for the program includes the team of Dr. C. E. Schmidt, and Mr. Tom Card, ALS 

Laboratory Group will provide laboratory services. Tom Card is responsible for the collection of facility 

and process operations data as well as assisting in flux chamber testing, and C. E. Schmidt is responsible 

for conducting flux chamber measurements. Tom Card is responsible for calculating unit process 

emissions and site emissions of hydrogen cyanide. 

The field sampling and analytical activities are the responsibility of Dr. C. E. Schmidt. Dr. Schmidt will: 

arrange for the field sampling, coordinate with mine site operators, coordinate with the subcontract 

laboratory for analytical services, conduct the field sampling, ship samples for analysis, receive and 

review laboratory data, and report (Technical Memorandum) the results of the field sampling. 
SECTIONFOUR Quality Assurance Objectives

 4-1

SECTION 4 QUALITY ASSURANCE OBJECTIVES

The purpose of a QA/QC program is to produce data of known quality that satisfy the project objectives 

set forth in this document. The QA/QC program shall:

 Provide a mechanism for ongoing control and evaluation of measurement data quality.

 Provide an estimate of data quality in terms of accuracy, precision, completeness, 

representativeness, and comparability for use in data interpretation.

The QA objectives for accuracy and precision are presented by sample matrix for all sampling and 

analytical parameters in Tables 4-1 and 4-2. These values are estimates of the degree of uncertainty that 

is considered acceptable in order for the data to fulfill the needs of the program area source testing. The 

QA/QC program focuses on controlling and quantifying measurement error within these limits, and 

provides a basis for understanding the uncertainty associated with these data. In the first step of data 

validation, measurement data are compared to the QA objectives to determine whether gross performance 

problems occurred.

The basis for assessing precision, accuracy, completeness, representativeness, and comparability is 

discussed in the following subsections. Specific calculations for data quality measurements are presented 

in Section 13.

Data Quality Objectives (DQOs) are qualitative and quantitative statements, which specify the quality of 

the data to satisfy the end uses of the data to be collected. As such, different data uses may require 

different levels of data quality. There are five analytical levels, which address various data uses, and the 

methods required to achieve the desired level of quality. These levels are:

 Screening (DQO Level 1): This provides the lowest data quality but the most rapid results. It is 

often used for health and safety monitoring at the site, preliminary comparison to local 

regulations or criteria, initial site characterization to locate areas for subsequent and more 

accurate analyses, and for engineering screening of alternatives. These types of data include 

those generated on-site through the use of real-time monitoring equipment at the site like the 

OVA.

 Field Analyses (DQO Level 2): This provides rapid results and better quality than in Level 1. 

This level may include mobile lab generated data depending on the level of quality control 

exercised.

 Engineering (DQO Level 3): This provides an intermediate level of data quality and is used for 

site characterization. Engineering analyses may include mobile lab generated data and some 

analytical lab methods (e.g., laboratory data with quick turnaround used for screening but without 

full quality control documentation). 

 Conformational (DQO Level 4): This provides the highest level of data quality and is used for 

purposes of risk assessment, evaluation of remedial alternatives and primary responsible party 

determination. These analyses require full Contract Laboratory Program (CLP) analytical and 

data validation procedures in accordance with USEPA recognized protocol.
SECTIONFOUR Quality Assurance Objectives

 4-2

 Non-Standard (DQO Level 5): This refers to analyses by non-standard protocols, for example, 

when exacting detection limits or analysis of an unusual chemical compound is required. These 

analyses often require method development or adaptation. The level of quality control is usually 

similar to DQO Level 4 data. 

The data collected for this testing effort include Level 2 screening data using colorometric detection tubes 

for hydrogen cyanide and Level 4 detailed offsite analysis for hydrogen cyanide. The laboratory will 

perform under DQO Level 4 analysis; however, it will not be asked to prepare or submit a CLP type data 

package. These back-up data will be archived and available upon request.

4.1 Precision

Precision measures the reproducibility of repetitive measurements. It is strictly defined as the degree of 

mutual agreement among independent measurements as the result of repeated application of the same 

process under similar conditions. Analytical precision is a measurement of the variability associated with 

duplicate (two) or replicate (more than two) analyses of the same sample in the laboratory. Total 

precision is a measurement of the variability associated with the entire sampling and analysis process. It 

is determined by analysis of duplicate or replicate field samples, and incorporates the variability caused 

by matrix variability, field sampling procedures, and analytical variability. The results of total and 

analytical precision must be interpreted by taking into consideration all possible sources of variability.

Duplicate samples will be analyzed to assess field and laboratory precision, and the results will be 

reported as the relative percent difference (RPD) between duplicate measurements. In all cases, field 

precision objectives for RPD will be less than 50 percent. Analytical precision objectives are presented 

for each method and matrix in Table 4-2. 

4.2 Accuracy

Accuracy is a statistical measurement of correctness, and includes components of random error 

(variability due to imprecision) and systematic error (bias). As such, it reflects the total error associated 

with a measurement. A measurement is accurate when the value reported does not differ from the true 

value, or known concentration, of the spike or standard. Analytical accuracy is typically measured by 

determining the percent recovery of known target analytes that are spiked at known concentrations into a 

field sample (a matrix spike) or reagent water (a method spike) before extraction at known 

concentrations. The stated accuracy limits apply to spiking levels at five times the method detection 

limits or higher. The individual methods provide equations for acceptance criteria at lower spiking 

levels.

Surrogate compound recovery is also reported and is used to assess method performance for each sample 

analyzed for volatile compounds. Sampling accuracy is assessed by evaluating results for field and trip 

blanks.

Both accuracy and precision are calculated for specific sampling or analytical batches, and the associated 

sample results must be interpreted considering these specific measures. Application of calculated 

precision and accuracy to measurement sample results will be discussed in Section 13. An additional 

consideration in applying accuracy and precision is the concentration level of the samples; a procedure 
SECTIONFOUR Quality Assurance Objectives

 4-3

capable of producing the same value within 50 percent would be considered precise for low-level (near 

the detection limit) analyses of minor constituents, but would be unacceptable, and possibly useless, for 

major constituents at high concentrations.

4.3 Completeness

Completeness, also referred to as percent data capture, is defined as the percentage of valid data reported 

compared to the total number of samples collected for analysis. Valid data are determined during the data 

assessment process and satisfy the QA objectives. Completeness is determined after precision and 

accuracy are calculated. The objective for completeness for all measurement parameters and all sample 

matrices is 90 percent.

4.4 Representativeness

Objectives for representativeness will be defined for each sampling and analysis task and will be a 

function of the investigative objectives. Representativeness will be achieved through use of the standard 

sampling and analytical procedures described in this QAPP and the frequency of testing as described in 

Section 5.

4.5 Comparability

Comparability is the confidence with which one data set can be compared to another. The objectives for 

this QA/QC program are to produce data with the greatest degree of comparability possible. The number 

of matrices sampled and the range of field conditions encountered must be considered in ultimately 

determining comparability. Comparability will be achieved by using the same (standard) methods for 

sampling and analysis, reporting data in standard units, and using standard and comprehensive reporting 

formats. Analysis of reference samples may also be used to provide additional information that can be 

used to assess comparability of analytical data produced within the program.

Table 4-1

Sample Matrix and Parameters

Parameter Method Instrument or Laboratory DQO Level

Hydrogen Cyanide Colorometric Tube Detection Colorometric Tube Detection 2

Hydrogen Cyanide

NIOSH 6010/7904

ALS Laboratory Group

960 W. LeVoy Drive

Salt Lake City, UT 84123

801.266.7700

4
SECTIONFOUR Quality Assurance Objectives

 4-4

Table 4-2

Accuracy, Precision and Sensitivity of Analysis

Parameter Method Accuracy Precision Sensitivity

Hydrogen Cyanide Colorimetric ±50% ±50%

5 ppmv (n=1)

0.5 ppmv (n=10)

Hydrogen Cyanide NIOSH 6010 +15% ±30% 0.1 g/sample

Hydrogen Cyanide NIOSH 7904 +20% ±30% 0.1 g/sample
SECTIONFIVE Sampling Procedures

 5-1

SECTION 5 SAMPLING PROCEDURES

This section contains detailed descriptions of the sample collection protocols to be used for field 

sampling. All field personnel will be familiar with the procedures they will be using and will have a copy 

of the QAPP available for reference.

Section 5.1 describes three distinct types of air sampling:

 5.1.1 Real-Time Detection of Flux Chamber Gas Air Using Colorometeric Tube Detection

 5.1.2 Surface Emission Isolation Flux Chamber Sampling

 5.1.5 Sampling for Hydrogen Cyanide in the Flux Chamber Using Sorbent Technologies

5.1 Air Sampling

5.1.1 Real-Time Portable Detection of Flux Chamber Gas Using Colorometric Tube Detection

Colorometric tube detection may be used in screening the flux chamber gas concentration in order to 

assist in quantitative gas sample collection (Section 5.1.4). For the flux chamber screening using this 

approach, a sample is drawn into the color tube using a hand plunger with a sample draw of either 50 ml 

or 100 ml. The detection is noted by color change on the tube scale. More gas sample can be drawn in 

for improved sensitivity. These screening data will be recorded in the field documentation but will not be 

used for quantitative analysis.

5.1.2 Surface Emission Isolation Flux Chamber Sampling

Isolation emission flux chamber sampling is a direct measurement of emission rates of air contaminants 

from area sources. Flux chambers can be used for measuring source emissions from:

 Liquid surface, quiescent or agitated;

 Solid land surfaces;

 Open ports in processes; and

 Cracks or vents in a process.

Flux measurements will be conducted on solid and liquid surfaces on mining sources. All flux chamber 

measurements will be conducted as per the USEPA guidance document, “Measurement of Gaseous 

Emission Rates from Land Surfaces Using an Emission Isolation Flux Chamber”, February 1986. All 

liquid and solid surface testing will be conducted by placing the chamber directly on the liquid or solid 

surfaces. The method is briefly described below.

The enclosure device, referred to as the flux chamber, is used to sample gaseous emissions from a defined 

surface area. Clean, dry sweep air is added to the chamber at a fixed, controlled rate. The chamber 

temperature and volumetric flow rate of air through the chamber is recorded and the concentration of the 

species of interest is measured at the exit of the chamber. The emission rate is calculated as:
SECTIONFIVE Sampling Procedures

 5-2

(Ci) (Q)

 ERi = A

where:

ERi = Emission rate of species i (μg/m2-min)

Ci = Measured concentration of species i (μg/l)

Q = Air flow rate (l/min)

A = Exposed Surface Area (m2)

The response time of the flux chamber is characterized by the residence time. The chamber residence 

time (t) is a function of chamber volume (V) and air flow rate (Q). The quotient of volume and flow rate 

(V/Q = t) is the theoretical residence time. Four to five residence times are normally needed to establish 

steady-state conditions in the chamber at which time representative sampling can occur. This will require 

24 to 30 minutes per sampling point.

The chamber is an acrylic topped, pressure vented, stainless steel cylinder designed to penetrate the 

sampling surface. The chamber has a 0.13 m2exposed surface area and a volume of approximately 0.03

m

3

. One 1⁄4 inch port will be used to withdraw sample gas. Sealing on hard surfaces such as heap leach 

can be accomplished by piling solid media of the area around the base sufficient to prevent ambient air 

entrainment.

Dry, hydrocarbon-free sweep air (zero grade air) will be provided from compressed gas cylinders. The 

sweep air will pass through a calibrated rotameter with a needle-valve flow control. Inlet and outlet lines 

are made of Teflon and all fittings in contact with the gas will be Teflon or stainless steel. The outlet line 

will include a sampling manifold for monitoring and/or collection of the gaseous specie of interest. This 

manifold will consist of ports for gas-canister sampling and gas-syringe collection. A thermocouple and 

readout will be used (when possible) to measure the surface and air temperatures at the sample point.

The flux chamber will be wiped clean and dried before each use and then placed over the sampling area. 

The sweep air is added to a flow rate of 5.0 liters per minute and the time noted when the chamber is 

placed on the test surface. Air temperatures inside and outside the chamber are also taken and recorded. 

Once steady state is reached (about 30 minutes), gas samples are collected. Samples will be collected 

using either solid or liquid sorbent media and calibrated sampling pumps. Note that the method 

recommends a sweep air flow rate of 5.0 lpm.

Data will be recorded on the data form shown in Figure 5-1. The following data collection steps will be 

taken:

Locate equipment at the sampling location;

 Document location of measurement, date, time, and operator;

 Initiate sampling by starting sweep air, checking the flow rate, placing the chamber on the testing 

location, and sealing the bottom of the chamber;

 Document the gas flow rate (5.0 lpm) and the initial and final temperatures of ambient air, of air 

inside the chamber, and of the bulk soil/waste;
SECTIONFIVE Sampling Procedures

 5-3

 Document any other data such as source characteristics, relevant process data if any, 

meteorological conditions, etc., for possible correlations with emission rate measurements or 

method verification;

 Monitor the chamber operation and record field data every residence time;

 Collect gas samples at steady state indicated by the number of chamber residence times (e.g., 5 

residence times or 30 minutes); and

 Fill out appropriate chain-of-custody forms and master sample log entries for sample collected.

The sample matrix given in Table 2-1 includes general flux chamber testing descriptions and typical 

quality control testing efforts (minimum blank tests 5%, replicate tests 5%). However, specific sampling 

activities will be provided in the site-specific SOPs.

5.1.3 Sampling for Hydrogen Cyanide from the Flux Chamber

Samples will be collected as grab samples from the flux chamber by colorometric tube for screening 

purposes. Integrated sample collection is required for the collection of quantitative hydrogen cyanide 

assessment. The collection media required for the integrated sample collection is either solid sorbent or 

liquid reagent in an impinger. Prior to sample collection, all sampling media will be cleaned/prepared 

according to the specific analytical methods selected.

5.1.3.1 Grab Sampling

Grab samples will be collected by colorometric tube detection from the chamber contents or exhaust gas 

line. 

To collect grab samples from the flux chamber:

 Attach sampling line from the flux chamber to the colorometric detector tube using 1⁄4” Teflon 

tubing and silicone connector; 

 Record sample time on data sheet and withdraw plunger collecting the sample; and

 After sample collection is completed, read the tube indicator results and disconnect from the 

chamber.

5.1.3.2 Integrated Sampling

Integrated samples (solid sorbent or liquid impinger) will be collected on either solid or liquid sampling 

media. The sorbent media will be used to collect exhaust gas samples after chamber equilibrium. Gas 

will be metered by using a calibrated personal (battery powered) sampling pump. The pump will be 

calibrated immediately before and after use with the sampling media in-line (note- „dummy‟ sample 

media that will not be analyzed) flow controller on the canister. Prior to sample collection, each sorbent 

will be prepared in the laboratory. 

To collect sorbent samples from the flux chamber:
SECTIONFIVE Sampling Procedures

 5-4

 Attach sampling line from the flux chamber to the sorbent media using a clean, 1⁄4-inch Teflon or 

stainless steel tube with 1⁄4-inch Swagelok fittings;

 Record start time on data sheet and turn on the calibrated sampling pump;

 The integrated sample will be collected at the method specific flow rate over a period of time that 

will allow for the collection of an adequate volume of gas to attain minimum detection limits;

 After sample collection is completed, the pump is shut off and the sample line is disconnected 

from the chamber;

 The sample collection is recorded on the chain-of-custody sheet;

 Prior to transporting to the laboratory, all media are sealed and preserved as per the sample 

collection protocol; and

 Complete appropriate chain-of-custody forms, master sample log entries, labels for samples 

collected, and ship media. 
SECTIONFIVE Sampling Procedures

 5-5

Figure 5-1

Surface Flux Measurement Data Form

SURFACE FLUX MEASUREMENT DATA FORM

DATE SAMPLERS 

LOCATION 

SURFACE DESCRIPTION 

CURRENT ACTIVITY 

INSTRUMENT TYPE I.D. NO. TYPE ID NO. 

INSTRUMENT BASELINE 

PROJECT QC: BACKGROUND MEASUREMENTS  BLANK MEASUREMENTS  REPLICATE MEASUREMENTS  

AMBIENT CONCENTRATIONS 

CHAMBER I.D. PHOTO TAKEN: Yes  No  STACK SIZE/VELOCITY 

CHAMBER SEAL CONDENSATION: Yes  No  BARM PRESS 

AMBIENT CONDITIONS: Sun  P.Sun  Cloudy  Wind at 5', mph Wind at Seal, mph

TEMP RAIN: Yes  No  Comment 

PRIOR CHAMBER CLEANING: Full Wash  Wet Wipe  Dry Wipe  None  

SAMPLE LINE: BACK FLUSHED PRIOR TO START  PURGED PRIOR TO SAMPLING  New  Used 

SWEEP AIR CC SUPPLIER PSIG START PSIG STOP 

Time Sweep Air

(L/min)

Residence

Number

Temperature (oF) Real-Time

(ppmv)

Sample 

Number Comments Chamber Ambient

 

Surf Air Surf Air

0

1

2

3

4

5

COMMENTS: SITE DIAGRAM

 
SECTIONFIVE Sampling Procedures

 5-6

5.1.4 Sampling for Hydrogen Cyanide in the Flux Chamber Using Sorbent Technologies

There are no agency-approved methods for ambient-level air sampling and analysis for hydrogen cyanide. 

Therefore, existing occupational (NIOSH) methods will be modified and adapted for use in this program. 

There are two approaches to sample collection: a solid sorbent, or a liquid sorbent (impingers, or 

bubbler). The decision to use either one depends on the objectives of the sampling. The solid sorbent is 

an easier method to use, as it does not require the use of liquid impingers, while the liquid impinger 

method allows a higher sampling flow rate and has a lower potential for clogging, thus providing the 

possibility of lower detection limits and greater reliability. While the liquid impinger method may provide 

lower detection limits and greater reliability, it uses a corrosive impinger solution which requires a high 

level of care in terms of safety and is readily subject to contamination and loss of the sample. Therefore, 

these considerations need to be taken into account. The method of choice is source and area source 

specific, and will be identified in the site-specific SOPs.

5.1.4.1 NIOSH Methods for Hydrogen Cyanide

Due to the origin of these methods, they are oriented towards occupational settings and therefore are 

designed for a much higher detection and quantification range—in ppmv vs. the ppbv levels needed in 

ambient level air sampling. However, these methods can be extended, usually by sampling at a higher 

flow rate or for a longer period of time to increase the total sampled volume, or by increasing the 

sensitivity of the analysis method. These modifications will be described below.

5.1.4.1.1 NIOSH 7904 (modified)—Impinger Sampling/ Visible Absorption Spectroscopy

This method has been modified using a liquid impinger of 0.25 N NaOH to collect the gaseous hydrogen 

cyanide. A sample is collected at 0.5 to 1 liter per minute (lpm). The resulting solution is analyzed 

spectrophotometrically. The detection limit for this method is estimated to be 0.1 g cyanide.

5.1.4.1.2 NIOSH 6010—Sorbent Sampling/Visible Absorption Spectroscopy

This method uses a soda lime (hydrated calcium, sodium, and potassium hydroxides) sorbent tube with 

600 mg in the front section and 200 mg in the back for breakthrough. Sampling is specified at 0.05 to 0.2

lpm for up to 90 liters. If the sample conditions require it, the total air volume will be increased up to 900 

liters. The analysis is performed by color development after water extraction with an oxidizing reagent 

followed by a complexing agent. The resulting solution is analyzed spectrophotometrically at 580 nm. 

The detection limit cited by the method is 0.1 g/sample. 

5.1.5 Meteorological Monitoring

The mining sites maintain permanent site meteorological monitoring stations, and local (near the air 

monitoring) meteorological monitoring may be conducted at the point of testing with a portable station.

Parameters monitored will be:

 Wind speed

 Wind direction
SECTIONFIVE Sampling Procedures

 5-7

 Temperature

 Relative humidity

 Barometric pressure

The portable monitoring station, if used, will be mounted on 3 meter towers.

5.2 Liquid Sampling/Field Analysis

Each flux chamber sample taken from a free liquid surface will have the following liquid phase 

parameters samples and analyzed:

 Solution temperature.

 Solution pH (by field pH meter).

 Free cyanide (field test kit).

 pH/WAD and free cyanide (mine process lab)

5.2.1 Temperature

Solution temperature will be by electronic thermocouple. Temperature will be taken in situ.

5.2.2 pH

Solution pH will be by portable field instrument backed up by colorimetric strips. The field instrument 

will be calibrated with pH 7 and pH 10 buffer solution prior to each sampling day.

5.2.3 Field Liquid Cyanide Concentration (free cyanide)

Field liquid phase cyanide concentration will be determined by using a Chemetrics field test kit. Two 

different test kits will be used. One for low range (colorimetric) for concentrations up to 1 mg/l and high 

range (titrimetric) with a range of 5 to 50 mg/l. For intermediate concentrations, the sample will be 

diluted with distilled water.

The Colorimetric Method. The kit employs the Isonicotinic/Barbituric Acid Method. To perform a test, 

two accessory solutions are added to the sample to convert cyanide to cyanogen chloride. The analyst 

then snaps off the tip of the reagent ampoule below the surface of the sample. The sample is 

automatically aspirated into the ampoule where the resulting cyanogen chloride reacts with the 

isonicotinic and barbituric acids to form a blue color. Test results are expressed in parts per million 

(mg/l) cyanide. Total testing time is about 20 minutes. This chemistry provides two advantages over the 

more commonly used pyridine methods: (1) The shelf-life of the reagent is extended, and (2) The analyst 

is not exposed to the noxious and hazardous fumes from the pyridine reagent. 

The Titrimetric Method. CHEMetrics employs silver nitrate as the titrant and 

dimethylaminobenzalrhodamine as the indicator. A color change from orange to yellow signals the end of 

the titration. Results are expressed as ppm (mg/L) CN
SECTIONFIVE Sampling Procedures

 5-8

5.2.4 Laboratory Liquid Cyanide Concentration

A sample will be taken for analysis by the site process laboratory using their standard analytical 

technique. This technique will be reported in the site specific protocol. Values will be reported for both 

free and WAD cyanide.
SECTIONSIX Sample Custody

 6-1

SECTION 6 SAMPLE CUSTODY

Sample possession during all testing efforts must be traceable from the time of collection until the results 

are verified and reported. Sample custody procedures provide a mechanism for documentation of all 

information related to sample collection and handling to achieve this objective.

Dr. Schmidt will be responsible for seeing that the field team adheres to proper custody and 

documentation procedures for all sampling operations. Preformatted field data and Chain-of-Custody 

forms will be used as the primary documentation mechanism to ensure that information pertaining to each 

sample is properly recorded. In addition, a master sample logbook will be maintained for all samples 

collected. Examples of these data documentation forms are presented in this section. Copies of the 

Chain-of-Custody forms and the field logs will be retained in the project file.

6.1 Documentation Procedures

6.1.1 Field Records

Field personnel will be required to keep accurate written records of their daily activities in a bound 

logbook. All entries will be legible, written in waterproof ink, and contain accurate and inclusive 

documentation of an individual's field activities, including field data and observations, any problems 

encountered, and actions taken to solve the problem. The type of data recorded in the field logbook 

includes field measurements, ambient conditions, and any other information pertinent to sample 

collection. Entry errors or changes will be crossed out with a single line, dated, and initialed by the 

person making the correction. Entries made by individuals other than the person to whom the logbook 

was assigned will be dated and signed by the individual making the entry. Field logbooks will be 

available for review. 

6.1.2 Sample Labels

Each sample collected will receive a sample label that identifies the sample by a unique sample 

identification number. These labels are affixed to the sample container prior to sample collection.

6.1.3 Sample Master Logbook

A sample master log will be maintained for all samples collected. Each sample will be assigned a unique 

identification number; a full description of the sample, its origin, and disposition will be included in the 

log entry.

6.2 Chain-of-Custody Procedures

After the samples are collected and documented in the master logbook, a Chain-of-Custody form will be 

completed and will accompany the samples to the laboratory. Figure 6-1 presents a Chain-of-Custody 

form used for samples. Team members collecting the samples are responsible for the care and custody of 

the samples until they are transferred or dispatched to the appropriate laboratory. When transferring 

samples, the individuals relinquishing and receiving the samples will sign, date, and note the time on the 

record.
SECTIONSIX Sample Custody

 6-2

This record documents sample possession from collection to the laboratory sample control center.

When the samples are received by the laboratory, the sample control officer will verify the Chain-ofCustody form against the samples received. If any discrepancies are observed, they will be recorded on 

the Chain-of-Custody form and Dr. Schmidt will be notified to correct the problem.

6.2.1 Shipment

All sample shipments will be accompanied by the Chain-of-Custody record, which identifies the contents 

of each crate. The person relinquishing the samples to the laboratory will request the signature of a 

laboratory representative to acknowledge receipt of the samples. Sample collection and shipment will be 

coordinated to ensure that the receiving laboratory has staff available to process the samples according to 

method specifications.

All shipping containers will be secured for safe transportation to the laboratory. The method of shipment, 

courier name(s), and other pertinent information is entered in the “Remarks” section when the samples are 

to be shipped (i.e., Federal Express, Express Mail, etc.) instead of hand-delivered.

6.3 Sample Handling Procedures

The objective of sample handling procedures is to ensure that samples arrive at the laboratory intact, at 

the proper temperature, and free of external contamination. Sorbent and canister samples will be shipped 

to the laboratory by field sampling personnel.

Sample packaging requirements for hazardous materials requiring interstate transport are defined in the 

Code of Federal Regulations 40 (CFR) 49, Chapter 1, Part 171. These requirements outline in detail the 

proper classification and transportation procedures for hazardous materials that will be used in the

transporting of samples.

6.4 Sample Preservation

Once the samples have been collected, the methods specify preservation, storage requirements and 

holding time limitations. Table 6-1 summarizes the preservation requirements for the type of samples 

collected during this program.

Table 6-1

Parameters for Sample Preservation

Media/Parameter Preservation and Storage 

Requirements

Maximum Holding Time 

(Days)

NIOSH 6010 Solid Sorbent Tubes Tube sealed, vials sealed, 4o C 14 Days

NIOSH 7904 Impinger Solution Glass vial, vials sealed, 4o C 5 Days
SECTIONSEVEN Calibration Procedures and Frequency

 7-1

SECTION 7 CALIBRATION PROCEDURES AND FREQUENCY

Information is presented in this section pertaining to the laboratory calibration of sampling equipment.

Included are descriptions of each procedure or references to applicable standard operating procedures 

(SOPs), the frequency of calibrations, and the calibration standards to be used.

7.1 Laboratory Instrument Calibration

Laboratory instruments are calibrated according to manufacturer's specifications and are in compliance 

with the analytical method requirements. Detailed calibration procedures and recommended frequencies 

are included along with the analytical SOPs, which can be found in the appendix to this volume. A brief 

description of the analytical methodologies, and their associated calibration procedures, is included in 

Section 9.

7.2 Sampling Equipment Calibration Procedures

An important function in maintaining data quality is the check-out and calibration of all sampling 

equipment. Using referenced procedures, the equipment will be calibrated prior to field sampling. These 

results will be properly documented and retained. If a referenced calibration technique for a particular 

piece of apparatus is not available, then state-of-the-art techniques are used. A discussion of the 

procedures used to calibrate equipment is presented below. Calibration frequency of the field sampling 

equipment is presented in Table 7-1. No other field calibration is required other than the personal 

sampling pumps.

Table 7-1

Calibration Frequency of Field Sampling Equipment

Sampling Equipment Calibration Before 

Sampling

Frequency

Daily After Sampling

pH Meter; Buffer Standards X X X

Personal Sampling Pumps X X X

Note that the personal sampling pumps are calibrated using a primary gas standard (DC Lite calibrator) 

immediately before and after each sample collection. The average of the calibration run data is used as 

the flow rate for the sample collection interval.
SECTIONEIGHT Data Reduction, Validation and Reporting

 8-1

SECTION 8 DATA REDUCTION, VALIDATION AND REPORTING

The data reduction, validation, and reporting procedures described in this section will ensure that 

complete documentation is maintained throughout the program, that transcription and data reduction 

errors are minimized, that the quality of the data is reviewed and documented, and that the reported 

results are properly qualified and in a conventional format.

8.1 Data Reduction

The reduction of raw data generated at the laboratory bench is the responsibility of the analyst producing 

it. The data interpretation that is required to calculate sample concentrations follows the methodology 

described in the specific analytical SOP. After all analyses have been completed, a preliminary 

laboratory report is generated for review by the laboratory supervisors who verify that the analyses were 

properly performed and interpreted. After the final review by the laboratory supervisor, the raw data is 

transferred to sample control and presented for review by the QA coordinator. Raw data, together with all 

supporting documentation, are stored permanently in confidential files by sample control.

The QA coordinator reviews the data for adherence to the QC method limits. In addition, the data are 

reviewed for the presence of outliers. An outlier is an unusually large (or small) value in a set of 

observations. There are many possible reasons for outliers, among which are:

 Faulty instruments or component parts.

 Inaccurate reading of a record, dialing error, etc.

 Errors in transcribing data.

 Calculation errors. 

Sometimes analysts or operators can identify outliers by noting the above types of occurrences when they 

record observations. In these instances, the errors are corrected, or if correction is not possible the suspect 

observations may be removed from the data before calculations are performed. If no such information 

exists, the Dixon Criteria are used to test suspected outliers at the 5 percent significance level if there are 

three or more points in the data set containing the outlier. Outliers identified by this method may be 

removed from the data before further processing (see W.J. Dixon, “Processing Data for Outliers,” 

Biometrics, 1953, Vol. 9, No. 1, pp. 74-89).

8.2 Data Transfer and Verification

A laboratory database is used to store and transfer analytical data from the laboratory. Sample control 

staff are responsible for entering into the system and verifying sample and result information and 

generating hard copies of the analytical results.

8.3 Data Validation

Dr. Schmidt will review field documentation and all measurement data for acceptable sample collection 

and analysis procedures, adherence to prescribed QA procedures, and agreement with the acceptance 
SECTIONEIGHT Data Reduction, Validation and Reporting

 8-2

criteria described in Section 4. Initially, the reviewer will determine whether hold times were met and 

that all required analytical QC checks were reported with the data. Then, all QC sample results will be 

reviewed to evaluate the sampling and analytical performance. Reagent blank results will be evaluated to 

identify any systematic contamination; spike and duplicate results will be compared to the QA objectives 

presented in Section 4, and the results will be used to calculate precision and accuracy for the data set.

This process will identify any analytical methods and compounds for which the QA objectives are not 

satisfied, and corresponding sample data will be qualified with a “flag” indicating the problem. Samples 

collected on the same day, analyzed in the same run or batch, or individual samples may be flagged, 

depending on the type of problem that has been identified. Reanalysis or resampling may be 

recommended at this time if data are determined to be unacceptable for the intended application.

The qualifier codes, or “flags,” will be stored with the data and printed with the data when reported or 

transferred for any purpose. The specific statistical procedures and qualifier codes used in the validation 

process are described in detail in Section 13. After data are received from the laboratory, entered, 

checked, and qualified, they are a permanent part of the database and cannot be deleted or altered.

8.4 Analytical Data Reporting

Data reporting for this project will consist of QA reporting, investigative data reporting, and QC data 

reporting.

General reporting practices for measurement data will include:

 Heading information identifying the sample batch and the analytical method.

 Unique sample identification number or code.

 Consistent units of measure.

 Consistent number of significant figures.

 No blank or dashed places reported; all spaces will contain a designation (i.e., not analyzed, not 

sampled, etc.).

 Explanation of outlier values or the cause for deviation from historical data.

 Comparison with regulatory threshold values if applicable.

 Quality assurance flags.

 Quantification of accuracy and precision for analytical data.

8.4.1 Investigative Data Reporting

Measurement data generated during the course of an investigation will be reported in tabular form from 

the computerized database. The formats of the reports will vary, depending on the objectives of the 

investigation. In general, data will be presented according to sampling location, analytical method, 

parameter, and/or matrix. All data will be reported with the qualifiers discussed above, and units will be 

specified.
SECTIONEIGHT Data Reduction, Validation and Reporting

 8-3

8.4.2 General Reporting Procedures

The procedures employed to ensure report quality involve the following:

 All calculations and measurements will be verified by recalculation by the person initially 

providing data. The calculations and measurements are then checked by another individual who 

signs and dates the calculation sheets. Any calculations and measurements that differ from the 

initial totals are resolved by both individuals. Once the calculations and measurements are 

included in an internal working copy of a document, the figures are rechecked during peer 

review. If there are many such calculations within a report, a certain percentage (10 to 50 

percent) are checked again during peer review.

 Numerical values presented in reports and comparisons of numbers appearing in text, tables, and 

appendixes will be addressed in the manner discussed above.

8.4.3 QC Data Reporting

Quality control results will be reported by sample matrix and method in tabular form. How these QC 

results influence the measurement data will be delineated. For example, matrix spike interference will 

influence specific samples, while laboratory blank contamination will influence all samples extracted or 

analyzed on a specific day or during a specific analytical run. Two levels of tables may be constructed for 

each type of QC check. The first level table will contain all QC data, and will present one line per 

parameter or analysis. First level table formats will be used in presenting duplicate samples and analyses, 

matrix and method spikes, and system blank results. First level QC data tables will be generated for all 

investigations.

Specially developed table formats will be used occasionally as an aid to interpretation of the investigative 

data. The particular format will depend on how the QC results are expected to influence the investigative 

data. This type of table might be used to identify corresponding investigative results (samples analyzed 

on corresponding dates), which may be inaccurate. Specialty tables will be generated automatically or 

manually, depending on the volume of data to be processed and the complexity of the calculations.

8.5 Emissions Estimate

8.5.1 Background

Fate modeling is an approach to quantify emissions from liquid and solid surfaces using the physical mass 

transfer characteristics of the system combined with the chemical properties of the specific compounds of 

interest. The general fate modeling equation is (EPA-453/R-94-080A)

rv KtCxA

where rv = the system emission rate (g/s), Ktis the overall mass transfer coefficient (m/s), Cxis the surface 

liquid phase concentration of constituent x (g/m3) and A is the system surface area (m2).

Ktis a function of the individual liquid phase and gas phase mass transfer coefficients. These coefficients 

are essentially a measure of the thickness of the laminar diffusion layer on the liquid side and gas side of 
SECTIONEIGHT Data Reduction, Validation and Reporting

 8-4

the interface. However, since this thickness cannot usually be measured directly, these coefficients are 

estimated by indirect means. Since they are estimated values, they will also contain the other system 

uncertainties, such as surface perturbations, area deviations, liquid phase chemistry non-equilibria, and 

gas phase concentrations inhibiting mass transfer.

The overall mass transfer, Ktis calculated from the liquid and gas phase mass transfer coefficients by

l g

t

k Hk

K

1 1

1





where klis the liquid phase mass transfer coefficient (m/s), H is the gas/liquid partition coefficient 

(Henry‟s Law Coefficient, g/m3gas per g/m3liquid), and kg is the gas phase mass transfer coefficient. 

Except for cases of extreme turbulence (packed towers, etc.) the liquid phase mass transfer is not limiting 

when the gas/liquid partition coefficient is less than 0.01. This value is around 0.005 for cyanide. These 

types of compounds are called „gas phase limited‟ compounds. Therefore, for these compounds

Kt Hkg

The concentration term, Cx, is the net positive driving force. Therefore

x

gx

x lx H

C

C  C 

where Clx is the liquid phase concentration of constituent x, Cgx is the gas phase concentration of 

constituent x, and Hxis the partition coefficient of constituent x. For small systems, Cgx, the gas phase 

concentration of the constituent, is assumed to be zero (the infinite dilution assumption). However, for 

large systems (heap pads, ponds, etc.), Cgx can be significant, due to the accumulation of the constituent in 

the gas phase. In essence, as a constituent volatilizes across a large surface, the downwind concentration 

becomes larger and larger. This increasing gas phase concentration causes a significant retardation of 

further volatilization. This effect must be taken into account when measurements from a flux chamber 

(a small system) are used as the basis for estimating the emissions from a heap pad or pond (a large 

system) or emissions may be significantly over estimated. This is normally accounted for in the 

estimation of kg by including the Fa factor described below.

8.5.2 Corrections to be Applied to Flux Chamber Data to Calculate Complete Process 

Emissions

kg is a function of gas phase turbulence (wind conditions). Wind not only controls the thickness of the 

laminar layer, it also increases overall effective surface area by the creation of surface perturbations 

(waves). As mentioned above, the presence of significant gas phase concentrations can also be accounted 

for by kg.
SECTIONEIGHT Data Reduction, Validation and Reporting

 8-5

Normally kg is measured in a surface isolation flux chamber. The flux chamber has an idealized gas 

phase environment representing relatively calm conditions (surface wind speed less than a 10 meter 

height equivalent of 3 m/s) and a relatively small surface area (0.13 m2).

In order to account for and more accurately represent the actual environmental conditions at the site, the 

value from the flux chamber must be adjusted for wind speed and process size using the following 

adjustment factors.

0.78

10

3















U

Fw

and

0.1 1

0.5

0.1 1

0.5

0.5

4

0.407

4

4*0.13

































































































 



A A

Fa

where U10 is the wind speed (m/s) a 10 meters above the process surface and A is the system surface area 

(m2). 

Both of these factors are based on work done by MacKay and Matasugu (Evaporation Rates of Liquid 

Hydrocarbon Spills On Land and Water, The Canadian Journal of Chemical Engineering, Vol. 51, 

August 1973). Their gas phase mass transfer coefficient equation is reported in EPA-453/R-94-080A and 

is used as the impoundment gas phase mass transfer correlation in WATER9. The wind factor (Fw) 

results in an upward emissions adjustment for winds above 3 m/s while the area factor (Fa) results in a 

downward emissions adjustment for large areas. In order to obtain an accurate estimate of emissions, 

both factors must be taken into account.

The Fa factor is based on the known fact that evaporation from large bodies of water is always less than 

from the small pans that generally quantify evaporation. This reduction in evaporation rate is due to the 

higher humidity on the downwind side of the impoundment that suppresses the evaporation rate.

Evaporation is a surrogate for all gas phase mass transfer because evaporation is limited by only gas 

phase resistance. As reported in MacKay and Matsugu (1973) the standard value used to account for this 

difference is 0.7; that is the evaporation from large bodies is normally around 70% of that from pans. 

Large bodies also retain heat better than pans and this tends to counteract some of the area effects. So 

from a true mass transfer (and not thermodynamic effect) the 70% value is very conservative. For the 

testing that is proposed in this plan for large surfaces, 70% would be too high a value. This is because 

that value, as reported by MacKay and Matsugu, also accounts for the effect of heat retention by larger 

bodies compared to the much smaller surfaces that are the subject of direct measurement in the underlying 

test that took place in those cases. The higher heat retention of larger bodies will result in a higher 
SECTIONEIGHT Data Reduction, Validation and Reporting

 8-6

evaporative or thermodynamic transfer of a substance into the gas phase. This is a mechanism that is 

separate and apart from a true chemical mass transfer mechanism. This effect will not be present in the 

case of the flux testing since the flux measurements will be conducted on the source itself, thereby 

accounting for the heat retention of the source being measured. In summary, an evaporation pan has two 

primary differences than a reservoir:

1. The pan has a lower humidity over it (gas phase accumulation) accelerating evaporation 

(volatilization).

2. The pan has a lower thermal mass, resulting in cooling from the water vaporization, decreasing 

evaporation (volatilization).

Since the issue in question is cyanide and not water evaporation, Item 2, the thermal mass, does not come 

into play. Therefore, the pan rate has no mitigating factors, resulting in a cyanide volatilization rate of 

much less than the standard 70% value used for water reservoirs.

MacKay and Matsugu conducted experiments to quantify how the size of the actual source/system will 

affect mass transfer rates when scaling up from a smaller area such as a flux chamber, focusing on mass 

transfer (apart from the thermodynamic mechanism) and developed the mathematical relationship 

described in the equation above. Their values also agreed with other investigators (listed in the above 

citation). Their empirical relationship for the gas phase mass transfer coefficient has been standardized 

by the USEPA in the WATER9 fate model. Their original work is proved as an attachment to this 

document. This factor will correct the flux chamber measured emissions from the large (wet) processes at 

gold mines to reflect actual conditions at the site, and is expected to result in calculated process emissions 

that are 35% to 55% less than the flux chamber measured emissions.

To provide an example of how this is intrinsically integrated into the WATER9 fate model, the emissions 

have been calculated from a small section (flux chamber sized) of a large pond (1,000 meters in diameter) 

using WATER9 algorithms. Since WATER9 cannot accommodate ionizing compounds, like cyanide, 

methanol is used as an example compound. Assume that the pond has a liquid phase methanol 

concentration of 5 mg/l and a Henry‟s Law value of 0.000148 mg/l per mg/l. At a wind speed of 3 m/s, 

using these values, WATER9 would calculate the emissions under the flux chamber of 3.56 x 10-8g/s. 

Using this flux chamber value, and multiplying by the pond area, the entire pond emissions would be 

0.215 g/s. However, if we just directly put the area (785,000 m2) of the pond in WATER9, the resulting 

emissions would be 0.091 g/s. Therefore, the value measured by the flux chamber (0.215 g/s) 

overestimated the emissions by over a factor of two, and subsequently must be corrected to produce the 

actual emissions value of 0.091 g/s. 

8.5.3 Emissions from Wet Surfaces

For wet (including covered irrigated) surfaces the flux chamber data will be used to calculate emissions 

(g/s) based on the above described approach. A gas phase mass transfer coefficient (kg) will be calculated 

for each process type (mill tanks, ponds, leach solution channels, leach pads, etc.) by the following 

equation:
SECTIONEIGHT Data Reduction, Validation and Reporting

 8-7

C HA

r

k

l

v

g

0



Where:

kg = gas phase mass transfer coefficient (m/s) 

rv = hydrogen cyanide emissions from surface (g/s) as calculated from the flux chamber concentration 

data.

αo = predicted non-ionized cyanide fraction

 









H

pKa 10 1

1

0

pKa = ionization coefficient

[H+] = hydrogen ion concentration (moles/liter)

Cl = total liquid phase cyanide (non-complexed) (g/m3). This will be free not weak acid dissociable 

(WAD) cyanide.

H = Henry‟s Law Coefficient (g/m3per g/m3),

A = Process surface area (m2), for this case the flux chamber area of 0.13 m2.

8.5.3.1 Ionization Coefficient

The ionization and gas-liquid partition (Henry‟s Law) values will be the temperature dependent values as 

reported by Yoo et al. Korean J. of Chem. Eng., 3(1) (1986) 67-72.

The ionization coefficient is calculated by

ln(K) = A + Bt + C ln(t) + D/t

where

K = the ionization coefficient (g-mole/Kg)

t = is the temperature (

oK) (273 < t < 423)

A = -12.1960, B = -0.031482, C = 3.7658, D = -6340.7

8.5.3.2 Gas/Liquid Partition Coefficient

The gas-liquid partition (Henry‟s Law) coefficient is calculated by

ln(H) = A + Bt + C ln(t) + D/t

where
SECTIONEIGHT Data Reduction, Validation and Reporting

 8-8

H = the gas-liquid partition coefficient (Kg-atm/mole)

t = the temperature (

oK) (273 < t < 373)

A = 9.5850, B = -0.03147, C = 3.1704, D = -6302.0

The partition coefficient, H can be put in the non-dimensional form by

H 

mg/l

mg/l

 = H 

Kg − atm

mole

 

1,000 g/Kg

1,000 mg

g

∗ 1,000 l

m3

∗ RT

where

R = gas constant (8.2057*10-5 m

3

-atm/(gmoleoK)

T = temperature (oK)

8.5.3.3 Emissions Calculation

The emissions (g/s) from wet surfaces will be calculated by the formula (with the parameters previously 

defined)

v g

ClHAFaFwr k  0

where the process parameters of pH, temperature, cyanide concentration, unit process area, and wind 

speed during the tests will be used to calculate emissions (g/s) for each individual process. Annual 

emissions will also be calculated based on projected (or historical) annual average pH, temperature, 

cyanide concentration, unit process area, and wind speed. Because the study will define new zones within 

each process unit, it is not likely that historical data on these parameters for each individual zone will be 

available. Thus, preliminary annual HCN emissions may have to be based on the calculated short-term 

emissions (g/s) described in the section and the annual operating schedule (e.g., 8,760 hours per year). 

Additionally, an effort will be made to account mass transfer impedance that results from annual snow 

over.

8.5.4 Emissions from Dry Surfaces

There is no equivalent method for calculating emissions from dry (non-irrigated) surfaces (e.g., inactive 

leach pads). Past measurements have shown that these emissions are a very small part of the site 

emissions. They will be estimated by taking representative flux chamber measurements of dry surfaces 

and then multiplying those measured emission rates by the representative surface areas. Those emissions 

will be assumed to be constant over the annual emission estimation period.
SECTIONEIGHT Data Reduction, Validation and Reporting

 8-9

8.5.5 Total Site Emissions from Area Sources

Total site emissions from area sources will be calculated by summing the area source emissions described 

above.

8.6 Process Data Needs

In order to complete an annual emission estimate, the following data is needed (on an annual basis) for 

each process unit zone. For pH, the hydrogen ion concentration should be averaged, not the pH value.

1. Process solution pH, cyanide (free and WAD) concentration, and temperature.

2. Area under leach for each process solution system.

3. Fraction of leach surface that is wet (including covered irrigated surfaces).

4. Pond area, beach area, tank area.

5. Atmospheric data (wind speed, temperature).

6. Process elevation above sea level.
SECTIONNINE Analytical Procedures and Calibration

 9-1

SECTION 9 ANALYTICAL PROCEDURES AND CALIBRATION

This section contains brief descriptions of calibration procedures and analytical methodology for the 

analysis of air samples that will be collected during the testing. Reproductions of the methods used 

during this program are included as an appendix to this volume. Each method is briefly described in the 

following sections.

9.1 Method Detection Limits

The method detection limit (MDL) is defined as the minimum concentration of a substance that can be 

measured and reported with 99 percent confidence that the analyte concentration is greater than zero.

Laboratories perform MDL studies on an annual or quarterly basis (depending on the method) to 

demonstrate that they can meet or exceed the method-recommended MDLs. The USEPA procedure used 

for establishing MDLs is described in Appendix B of Part 136 Definition and Procedure for the 

Determination of the Method Detection Limit -Revision 1.1, 40 CFR 136, 1984. This procedure consists 

of analyzing seven aliquots of a standard spiked at three-to-five times the expected MDL, which is taken 

through all the sample processing steps of the analytical method. The MDL is defined as three times the 

standard deviation of the mean value for the seven analyses. In the few cases where the individual 

laboratory has experimentally determined MDLs higher than recommended method detection limits, the 

method-recommended MDL is shown in parentheses in the appropriate table or text.

9.2 Laboratory Standards and Reagents

Laboratory standards and reagents are obtained from the following suppliers:

For organic analysis, analytical standards are obtained from either USEPA sources, SUPELCO, Radian 

laboratory in Austin, and MSD Isotopes. Spectral grade and reagent grade solvents and reagents are 

obtained from chemical suppliers such as Aldrich, Sigma, Burdick and Jackson, EM Science, and Baxter.

All standards and laboratory reagents, with the exception of common laboratory solvents, are dated upon 

receipt. The preparation and use of all standards are recorded in bound laboratory notebooks that 

document standard traceability to USEPA or NIST standards. Additional information recorded includes 

date of preparation, concentration, name of the preparer, and expiration date, if applicable.

9.3 Methods of Sorbent Analysis for Hydrogen Cyanide

The following subsections describe the analytical procedure to be used for the determination of hydrogen 

cyanide in the flux chamber. 

9.3.1 NIOSH Method 7904 (modified)

The method has been to modified using a liquid impinger of 0.25 N NaOH to collect the gaseous 

hydrogen cyanide. Sample is collected at 0.5 to 1 liter per minute (lpm). The resulting solution is 

analyzed with a visible absorption apectroscopy. The detection limit for this method is estimated to be 

0.1 g cyanide. Calibration is performed using standard solutions of NaCN in 0.25 N NaOH.
SECTIONNINE Analytical Procedures and Calibration

 9-2

9.3.2 NIOSH Method 6010

This method uses a soda lime (hydrated calcium, sodium, and potassium hydroxides) sorbent tube with 

600 mg in the front section and 200 mg in the back for breakthrough. Sampling is specified at 0.05 to 2 

lpm for up to 90 liters. The analysis is performed by color development after water extraction with an 

oxidizing reagent followed by a complexing agent. The resulting solution is analyzed 

spectrophotometrically using a visible absorption spectrometer operated at 580 nm. Calibration is 

performed using standard solutions of KCN in 0.1 N NaOH. The detection limit cited by the method is 

0.1 g/sample. 
SECTIONTEN Internal Quality Control

 10-1

SECTION 10 INTERNAL QUALITY CONTROL

Internal QC consists of collecting and/or analyzing a series of duplicate, replicate, blank, and matrix spike 

samples to ensure that the analytical results are within QC limits specified for the program. Laboratory 

QC samples are documented at the bench and reported with the analytical results. The QC sample results 

are used to quantify precision and accuracy, and identify any problems or limitations in the associated 

sample results. Field QC samples will be documented in field logbooks and submitted “blind” to the 

laboratory. These components of the sampling program will help produce data of known quality 

throughout the sampling and analysis component of the program.

10.1 Analytical Laboratory Quality Control Samples

Laboratory QC is necessary to control the analytical process, to assess the accuracy and precision of 

analytical results, and to identify assignable causes for atypical analytical results. The QC checks in the 

laboratory protocol are specific to the analytical method and generally include the use of one or more of 

the following QC samples.

10.1.1 Calibration Standards

Initial calibration is performed as required for each analytical method, usually using a range of calibration 

standards with the low standard near the detection limit for the compound. These standards are used to 

determine the linear dynamic range for the initial instrument calibration. Both Method 6010 and 7904 

mandate daily calibration using six standards over the working range of the samples.

10.1.2 Quality Control Check Samples

Quality control check samples are standard samples containing the analytes of interest at a specified 

concentration, usually in the mid-calibration range. These samples are prepared independent of the 

calibration standard, and are used to demonstrate that the instrument is operating within acceptable 

accuracy and precision limits. Quality control check samples will be conducted as needed during sample 

analysis, but are not required by these methods for hydrogen cyanide. 

10.1.3 Reagent Blanks

A reagent blank is a sample composed of all the reagents (in the same quantities) used in preparing a real 

sample for analysis. It is carried through the same sample preparation procedure as a real sample.

Reagent blanks are used to ensure that interferences from the analytical system, reagents, and glassware 

are under control. The required frequency for analyzing reagent blanks is specified in the analytical SOP 

for each method, and generally consists of one per day for each method/instrument and/or one per 

extraction batch.

10.1.4 Method Spike/Method Spike Duplicates

A method spike is a sample of target analytes at known concentrations that is spiked into a field sample 

before sample preparation and analysis. Two aliquots of the sample may be spiked and used for the 
SECTIONTEN Internal Quality Control

 10-2

duplicate analysis. The results of the analysis of the duplicate spiked samples are used to measure the 

percent recovery of each spiked compound and to compare the recovery between samples, which provides 

an estimate of the accuracy and precision of the method. Method spike and duplicate spike samples are 

not required for these methods.

10.1.5 Laboratory Duplicates (Duplicate Analysis)

Laboratory duplicates are repeated but independent determinations of the same sample by the same 

analyst, at essentially the same time and under the same conditions. The sample is split in the laboratory 

and each fraction is carried through all stages of sample preparation and analysis. Duplicate analyses 

measure the precision of each analytical method. Laboratory duplicate analyses are performed for 10 

percent of samples analyzed, or at least one per day.

Table 10-1 summarizes the specific internal QC checks performed as required for the analytical methods.

This table also includes information relating to the initial calibration and ongoing calibration checks. 

10.2 Field Quality Control Samples

10.2.1 Field Duplicate Samples

A field duplicate sample is a second sample collected at the same location with the original sample.

Duplicate sample results are used to assess precision, including variability associated with both the 

laboratory analysis and the sample collection process. Duplicate samples will be collected simultaneously 

or in immediate succession using identical recovery techniques, and treated in an identical manner during 

storage, transportation, and analysis.

Recovery and analysis of 5 percent or at least one duplicate sample per day for each method will be 

performed. The sample containers will be assigned a control number such that they cannot be identified 

(blind duplicate) as duplicate samples by laboratory personnel performing the analysis.

10.2.2 Field Blank

Field blanks are samples of purified air/sampling reagents that are collected and processed in the field 

using the same sampling and handling procedures as other samples. Field blanks are used to assess the 

potential introduction of contaminants to the samples during sample collection in the flux chamber and 

analysis in the laboratory. The frequency requirements for preparing field blanks will be 5 percent of the 

samples collected over the course of the sampling program with at least one field blank per day.
SECTIONTEN Internal Quality Control

 10-3

Table 10-1

Summary of Internal Quality Control

ANALYTICAL 

METHOD PARAMETER PROCEDURE QC CHECKFREQUENCY

ACCEPTANCE 

CRITERIA CORRECTIVE ACTION

NIOSH 6010 HCN Method Blank Prior To Sample 

Analysis Daily <0.1 g

1. Repeat

2. Clean System and 

Leak-Check

Linearity Check 

(Multi-Point 

Calibration)

Daily RSD <30%

1. Repeat Calibration

2. Repeat Linearity Check

Single Point 

Response Factor 

Check

As needed +30% RPD

1. Repeat RF Check

2. Repeat Calibration

Duplicate Analysis 10%, Minimum 1 Per 

Batch

+30% RPD 1. Repeat Analysis

NIOSH 7904 HCN Method Blank Prior To Sample 

Analysis Daily <0.1 g

1. Repeat

2. Clean System and 

Leak-Check

Linearity Check 

(Multi-Point 

Calibration)

Daily RSD <30%

1. Repeat Calibration

2. Repeat Linearity Check

Single Point 

Response Factor 

Check

As needed +30% RPD

1. Repeat RF Check

2. Repeat Calibration

Duplicate Analysis 10%, Minimum 1 Per 

Batch

+30% RPD 1. Repeat Analysis
SECTIONELEVEN Performance and Systems Audits

 11-1

SECTION 11 PERFORMANCE AND SYSTEMS AUDITS

Systems audits, performance audits, and data quality audits are independent assessments of sample 

collection and analysis procedures. Audit results are used to evaluate the ability of the system to produce 

data that fulfill the objectives established for the program, satisfy the quality control criteria, and identify 

any areas requiring corrective action. A systems audit is a qualitative review of the overall sampling or 

measurement system, while a performance and data quality audit is a quantitative assessment of a 

measurement system.

11.1 Technical Systems Audit

A technical systems audit is an on-site, qualitative review of the sampling or analytical system. Sampling 

systems will be inspected at the beginning of the sampling task by Dr. Schmidt. Due to the limited 

activity and adherence to standard protocols, no formal systems auditing will be performed. 

The internal laboratory systems reviews routinely include:

 Calibration procedures and documentation; 

 Completeness of data forms, notebooks, and other reporting requirements; 

 Data review and validation procedures; 

 Data storage, filing, and record-keeping procedures; 

 Sample custody procedures; 

 Quality control procedures, control limits, and documentation; 

 Operating conditions of facilities and equipment; 

 Documentation of maintenance activities; and 

 Systems and operations overview. 

The field systems review will include:

 Calibration procedures and documentation for field meters and other measurement devices. 

 Complete documentation of field logbooks and sampling data sheets. 

 Organization and minimization of potential contamination sources while in the field. 

 Proper sample collection, storage, and transportation procedures.

 Compliance with the established Chain-of-Custody procedures for sample documentation and 

transfer to the laboratory.

11.2 Performance Audits and Data Quality Audits

Performance audits and data quality audits quantitatively assess the data produced by a measurement 

system. A performance audit involves submitting accepted reference standards for analysis for each 
SECTIONELEVEN Performance and Systems Audits

 11-2

analytical method and/or analytical instrument. The standards for each matrix are selected to reflect the 

range of concentrations expected for the sampling program. The performance audit answers questions 

about whether the measurement system is within control limits and whether the data produced meet the 

analytical quality assurance specifications. The data quality audit evaluates data quality indicators, and 

identifies limitations that may be encountered in data applications.

Due to the modest size of this program and the use of standard protocols, no performance auditing is 

scheduled for this effort.
SECTIONTWELVE Preventative Maintenance

 12-1

SECTION 12 PREVENTATIVE MAINTENANCE

12.1 Field Equipment/Instruments

The field equipment for this project includes flux chamber technology equipment, personal sampling 

pumps, calibration equipment, and meteorological monitoring equipment. Specific preventative 

maintenance procedures to be followed for field equipment are those recommended by the manufacturer. 

Critical spare parts and disposable or expendable items will be kept on-site to minimize instrument down 

time. 

12.2 Laboratory Instruments

As part of their QA/QC Program, a routine preventative maintenance program will be conducted by the 

selected laboratory to minimize the occurrence of instrument failure and other system malfunctions. 

Designated laboratory personnel will be responsible for performing routine scheduled maintenance, and 

coordinate with the vendor for the repair of all instruments. All laboratory instruments are maintained in 

accordance with manufacturer's specifications and the requirements of the specific method employed. 

This maintenance will be carried out on a regular, scheduled basis, and will be documented in the 

laboratory instrument service logbook for each instrument. Emergency repair or scheduled manufacture's 

maintenance is provided under a repair and maintenance contract with factory representatives. Routine 

preventative maintenance schedules will be provided with the selected laboratories SOPs.
Specific Routine Procedures Used to Access Data

SECTIONTHIRTEEN Precision, Accuracy, and Completeness

 13-1

SECTION 13 SPECIFIC ROUTINE PROCEDURES USED TO ACCESS 

DATA PRECISION, ACCURACY, AND COMPLETENESS

The assessment of measurement data is required to ensure that the QA objectives for the project are met, 

and that quantitative measures of data quality are provided. A distinction must be made between routine 

quality control and data assessment that is conducted as a part of laboratory operations, and the projectrelated data assessment process conducted after the data have been reported. It must be assumed that the 

planning and monitoring that have gone into the sampling and analysis process have served to control the 

process as much as possible to produce data of sufficient quality for project needs. After the data have 

been reported, it is necessary to identify any part of the process that could not be controlled, and to what 

extent that may affect the quality of the reported data.

The routine QC procedures conducted in the laboratory are established in the analytical SOPs. The 

laboratory is responsible for following those procedures and operating the analytical systems within 

statistical control limits. These procedures include proper instrument maintenance, calibration checks, 

and internal QC sample analyses at the required frequencies (i.e., reagent blanks, matrix spike/matrix 

spike duplicates [MS/MSD], laboratory duplicates). One of the additional ongoing data assessment 

processes is to maintain control charts for representative QC sample analyses in order to monitor system 

performance. This provides verification that the system is in statistical control and indicates when 

performance problems occur, so the problems can be corrected as soon as possible. When reporting the 

sample data, the laboratory is required to provide the results of associated QC sample analyses.

Problems occur in spite of all precautions taken in planning and execution of the sampling and analysis 

task. In these cases, the data assessment conducted by Dr. Schmidt after the data have been reported must 

identify the problem, determine which data are affected, and state how these data may be limited for use 

in the intended applications.

The discussion of data assessment presented in this section pertains to the project-related assessment of 

data that have been reported after laboratory analyses have been completed. Data assessment procedures 

established for the testing include:

 Evaluation of blank results to identify systematic contamination.

 Statistical calculations for accuracy and precision using the appropriate QC sample results. 

 Estimation of completeness in terms of the percent of valid data. 

 Recommendations for corrective actions such as reanalysis or resampling if data are critically 

affected. 

 Assignment of data qualifier flags to the data as necessary to reflect limitations identified by the 

process.

Some basic statistical calculations used in the data assessment process are presented along with a 

discussion of specific applications to environmental sample results. 
Specific Routine Procedures Used to Access Data

SECTIONTHIRTEEN Precision, Accuracy, and Completeness

 13-2

13.1 Blank Data Assessment

Reagent blank results indicate whether any of the contaminants reported in sample results may be 

attributed to laboratory sources and, therefore, would not likely present in the sampled medium. The 

most common laboratory contaminants are methylene chloride, phthalates, acetone, and toluene. These 

are recognized as being ubiquitous in the laboratory environment and controlling them to within 

acceptable low levels is part of standard laboratory procedure.

If contamination from these compounds is reported in blank samples, the samples associated with the 

blank, either the same analytical or extraction batch, may be qualified using a data qualifier (B) to 

indicate that some or all of these compounds may be from laboratory sources. If the concentrations 

reported in the samples are similar to the blank concentrations, it is likely that all of the contamination 

was introduced; this assessment is then made in the report for the sampling task.

13.2 Accuracy

As previously defined, accuracy is associated with correctness and is a comparison between a measured 

value and a known, or „true‟, value. Accuracy is calculated from method spike (spikes of the pure matrix) 

or matrix spike results.

Spike results are reported by the laboratory as percent recovery and are compared to the accuracy 

objectives stated in Section 4. Results that do not satisfy the objectives are assigned a data qualifier flag 

(A) to indicate uncertainty associated with inaccuracy.

Method spikes are spikes of a reference material into a sample matrix (e.g., canister or cryotrap) in the 

lab. If recovery is outside the established limits, samples from the same batch may be qualified. If any 

results appear atypical and could be related, those results may also be qualified. The flagged data will be 

discussed in the report for the sampling task, and specific limitations such as poor or enhanced recovery 

for specific compounds will be stated.

The percent recovery of matrix spike samples will be calculated using Equation 13-1.

A - B

%R = ─────────── X 100 Equ. 13-1

C

Where:

A = The analyte concentration determined experimentally from the spiked sample;

B = The background level determined by a separate analysis of the unspiked sample 

and;

C = The amount of the spike added.
Specific Routine Procedures Used to Access Data

SECTIONTHIRTEEN Precision, Accuracy, and Completeness

 13-3

13.3 Precision

Precision is a measure of variability between duplicate or replicate analyses and is calculated for field and 

laboratory replicates. By definition, field precision incorporates laboratory precision. Precision is 

calculated as the RPD between duplicate analyses or MS or MSD as appropriate. The calculated RPDs 

are compared to the objectives stated in Section 4. Results that do not satisfy the objectives are assigned a 

data qualifier flag indicating uncertainty associated with imprecision (P).

An average RPD may be calculated and reported as a measure of overall analytical precision for 

compounds with multiple measurements. The specific samples collected or analyzed in duplicate are 

flagged if they do not satisfy the QA objectives. In addition, associated samples may be flagged to 

indicate variability due to poor precision. For poor field duplicate precision, samples collected by the 

same sampling team, from the same equipment, or on the same day may be affected; close evaluation of 

those results should indicate the most likely source of variability and the corresponding samples will be 

qualified as warranted. For poor laboratory precision, samples processed and analyzed in the same batch 

will be more closely evaluated, and any anomalous results will be qualified.

Dr. Schmidt is responsible for ensuring that these codes are assigned to the data as required by the 

established QC criteria, and that they are reported and understood by project staff using the data for 

specific applications. He is also responsible for initiating corrective actions for analytical problems 

identified during the QC data assessment process. These corrective actions range from verifying that the 

method was in statistical control during the analytical runs, to reanalysis of the sample, to resampling.

The relative percent difference (%RPD) will be calculated for each pair of duplicate analysis using the 

Equation 13-2.

 S - D

%RPD = ────────── X 100 Equ. 13-2

 (S + D)/2

Where: S = First sample value (original or MS value)

D = Second sample value (duplicate or MSD value)

13.4 Completeness

Completeness is determined after the QC data have been evaluated and the results applied to the 

measurement data. In addition to results identified as being outside of the QC limits established for the 

method, the occurrence of matrix effects, and lost samples, samples that could not be analyzed for any 

other reason are included in the assessment of completeness. The percentage of valid results is reported 

as completeness.
Specific Routine Procedures Used to Access Data

SECTIONTHIRTEEN Precision, Accuracy, and Completeness

 13-4

Data completeness will be calculated using Equation 13-3.

Valid Data Obtained

Completeness =─────────────── X 100 Equ. 13-3

Total Data Planned

13.5 Corrective Action

Review of sampling logs and/or analytical results may indicate problems that invalidate the results or 

critically influence their use. In these cases, corrective action may be required to ensure that valid data 

are provided. Corrective actions include: recalibration and reanalysis if the analytical system is shown to 

be out of statistical control; reanalysis if systematic contamination has occurred; resampling if sampling 

procedures or sample handling have been improper or caused contamination. The severity of the problem 

and the importance of affected samples will dictate when one of these actions will be required. 

General recommendations in any case are to follow good laboratory practice and good management 

practice for all aspects of the sampling and analysis program. These include development and strict 

adherence to SOPs for all areas, and the establishment of clear responsibilities and lines of 

communication within the sampling and analytical staff, as well as between project and laboratory staff. 
SECTIONFOURTEEN Corrective Action

 14-1

SECTION 14 CORRECTIVE ACTION

During the course of the testing program, it is the responsibility of the Dr. Schmidt to see that all 

measurement procedures are followed as specified and that measurement data meet the prescribed 

acceptance criteria. In the event a problem arises, it is imperative that prompt action be taken to correct it

14.1 Reporting Malfunctions

Problems that require corrective action will be documented by Dr. Schmidt as presented in the field log 

book. He will initiate the corrective action request in the event that QC results exceed acceptability limits 

or upon identification of some other problem or potential problem. Corrective action may also be 

initiated by the laboratory coordinator or Mr. Card based upon QC data or audit results. Depending upon 

the severity of the problem, corrective actions range from use of data qualifier flags, to reanalysis of the 

sample or samples affected, to resampling and reanalysis. 
SECTIONFIFTEEN Quality Assurance Reports to Management

 15-1

SECTION 15 QUALITY ASSURANCE REPORTS TO MANAGEMENT

Effective management of a field sampling and analytical effort requires timely assessment and review of 

field activities. This will require effective interaction between the field team members, the laboratory, 

and the client.

Dr. Schmidt will be responsible for informing team members on the status of their respective tasks and 

results of the QC activities. This will ensure that quick and effective solutions can be implemented 

should any data quality problems arise. The use of frequent, oral reporting provides an effective 

mechanism for ensuring ongoing evaluation of measurement efforts. These discussions will include the 

following:

 Summary of activities and general program status.

 Summary of calibration and QC data.

 Summary of unscheduled maintenance activities.

 Summary of corrective action activities.

 Status of any unresolved problems.

 Assessment and summary of data completeness. 

 Summary of any significant QA/QC problems, corrective action, and recommended and/or 

implemented solutions not included above.
SECTIONSIXTEEN Health and Safety

 16-1

SECTION 16 HEALTH AND SAFETY

All project personnel working at mining sites for more that five days per year are required to have a 

current mine safety training certificate issued by the US Department of Labor, Mine Safety and Heath 

Administration, OMB Number 1219-0070. In addition, site-specific Hazard Training will be required for 

each facility. It is also likely that assistance while working on the mining sites will include an escort.

Inspection of certificates and hazard training will be the first order of business at each mine site. All site 

personnel are required to comply with mine safety regulations. Compliance with traffic laws is critical, 

and there will be no access to restricted zones allowed. 
ATTACHMENT 1 Flux Chamber Users Guide

























































ATTACHMENT 2 NIOSH 6010
HYDROGEN CYANIDE 6010

HCN MW: 27.03 CAS: 74-90-8 RTECS: MW6825000

METHOD: 6010, Issue 2 EVALUATION: FULL Issue 1: 15 May 1989

Issue 2: 15 August 1994

OSHA : 10 ppm (skin)

NIOSH: STEL 4.7 ppm

ACGIH: C 10 ppm (skin)

(1 ppm = 1.105 mg/m3 @ NTP)

PROPERTIES: gas; BP 26 °C; vapor density 0.93

(air = 1.00); d(liq) 0.69 g/mL @ 20 °C;

 VP 82.7 kPa (620 mm Hg) @ 20 °C;

 explosive range 5 to 40% v/v in air

SYNONYMS: hydrocyanic acid, prussic acid, formonitrile

SAMPLING

SAMPLER: SOLID SORBENT TUBE

(soda lime, 600 mg/200 mg)

FLOW RATE: 0.05 to 0.2 L/min

VOL-MIN: 2 L @ 5 ppm

 -MAX: 90 L

SHIPMENT: routine

SAMPLE 

STABILITY: at least 2 weeks @ 25 °C [1]

BLANKS: 2 to 10 field blanks per set

MEASUREMENT

TECHNIQUE: SPECTROPHOTOMETRY,

VISIBLE ABSORPTION

ANALYTE: cyanide ion complex

DESORPTION: 10 mL deionized water; stand 60 min

COLOR DEVELOPMENT: N-chlorosuccinimide/

succinimide oxidizing agent

and barbituric acid/pyridine

coupling agent; absorption @ 

580 nm in 1-cm cuvette

CALIBRATION: standard solutions of KCN in 0.1 N

NaOH

RANGE: 10 to 300 μg CN- per sample [1]

ESTIMATED LOD: 1 μg CN- per sample [1]

PRECISION (Sr): 0.041 @ 10 to 50 mg per sample [1]

ACCURACY

RANGE STUDIED: 2 to 15 mg/m3 [1]

(3-L samples)

BIAS: Not significant

OVERALL PRECISION (Sˆ

rT): 0.076 [1]

ACCURACY: ± 15.0%

APPLICABILITY: The working range is 0.3 to 235 ppm (3 to 260 mg/m3) for a 3-L air sample. This method is applicable to STEL

measurements. Particulate cyanides are trapped by the initial glass fiber membrane disk. This method is more sensitive and

subject to fewer interferences than NIOSH Method 7904, which uses ion specific electrode analysis. The method was used t o

determine HCN in firefighting environments [2].

INTERFERENCES: A high concentration of hydrogen sulfide gives a negative interference.

OTHER METHODS: This is based on the method of Lambert, et al. [3]. NIOSH Method 7904 uses an ion specific electrode for

measurement. The method has been adapted for use with a Technicon Autoanalyzer [4].

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
HYDROGEN CYANIDE: METHOD 6010, Issue 2, dated 15 August 1994 - Page 2 of 5

SAMPLING:

REAGENTS:

1. Potassium cyanide*, reagent grade.

2. Succinimide, reagent grade.

3. N-Chlorosuccinimide, reagent grade.

4. Barbituric acid, reagent grade.

5. Pyridine, spectrophotometric quality.

6. Phenolphthalein, 1% (w/v) in ethanol or

methanol, reagent grade.

7. Hydrochloric acid, concentrated, reagent

grade.

8. Sodium hydroxide (NaOH), reagent grade.*

9. Sodium lime (CaO + 5-20% NaOH), reagent

grade (Aldrich #26,643-4 or equivalent).

Crush and sieve to 10/35 mesh. Store in

capped container.*

10. Water deionized-distilled.

11. Sodium hydroxide solution, 0.1 N.*

12. Calibration stock solution. 1 mg /mL CN-.

Dissolve 0.125 g KCN in 0.1 N NaOH in a 50-

mL volumetric flask. Dilute to mark with 0.1 N

NaOH. Standardize by titration with standard

AgNO3 solution (see APPENDIX).

13. Hydrochloric acid solution, 0.15 N.

14. N-Chlorosuccinimide/succinimide oxidizing

reagent. Dissolve 10.0 g succinimide in about

200 mL distilled water. Add 1.00 g Nchlorosuccinimide. Stir to dissolve. Adjust

volume to 1 liter with distilled water. Stable 6

months when refrigerated.

15. Barbituric acid/Pyridine reagent. Add about 30

mL distilled water to 6.0 g barbituric acid in a

100-mL Erlenmeyer flask. Slowly add 30 mL

pyridine with stirring. Adjust the volume to

100 mL with water. Stable 2 months when

refrigerated.

EQUIPMENT:

1. Sampler, glass tube, 9 cm long, 7-mm OD,

5-mm ID, with plastic caps, containing two

sections (front = 600 mg; back = 200 mg)

granular soda lime 10/35 mesh, separated and

contained with silanized glass wool plugs, with

a 5-mm diameter glass fiber filter disk placed

before the plug on inlet side. Tubes are

commerically available. (SKC, Inc. 226-28 or

equivalent.)

 2. Spectrophotometer, visible, 580 nm, with

cuvettes, 1-cm light path.

 3. Personal sampling pump, 0.05 to 0.2 L/min,

with flexible connecting tubing.

 4. Pipets, volumetric 0.1-, 0.5-, 1.0-, 2.0-,

10.0-mL.

 5. Vials, glass or plastic, 15-mL with PTFE-lined

caps.

 6. Flasks, volumetric, 25-, 50-, 100-, 1000-mL,

with stoppers.

 7. Pipets, transfer, disposable.

 8. Syringes, 10-μL, readable to 0.1 μL.

 9. Flask, Erlenmeyer, 100-mL.

10. Syringes, 10-mL, polyethylene with luer tip.

11. Filter cassette, with membrane filter, 13-mm

diameter, 0.45-μm pore size, with luer fitting.

* See SPECIAL PRECAUTIONS

 

SPECIAL PRECAUTIONS: HCN gas and cyanide

particulates are highly toxic and may be fatal if

swallowed, inhaled, or absorbed through the skin

[5]. Soda lime and NaOH are very caustic [5].

Use gloves and a fume hood for handling these

chemicals.

1. Calibrate each personal sampling pump

with a representative sampler in line.

2. Break ends of sampler immediately before

sampling. Attach sampler to personal

sampling pump with flexible tubing.

3. Sample at an accurately known flow rate between 0.05 and 0.2 L/min for a total sample size of

0.6 to 90 L.

4. Cap tube. Pack securely for shipment.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
HYDROGEN CYANIDE: METHOD 6010, Issue 2, dated 15 August 1994 - Page 3 of 5

SAMPLE PREPARATION:

5. Score each sampler with a file. Break sampler at score line.

6. Transfer front and back sorbent sections to separate vials. Discard glass wool plugs separating

and retaining sorbent sections.

NOTE: An estimate of particulate cyanide may be obtained by analyzing the initial glass fiber

filter disk as follows; however, no evaluation data are available for particulate cyanides

determined in this manner.

 (i) Transfer the glass wool plug at the tube inlet and the glass fiber filter disk

immediately behind it to a third vial.

 (ii) Add 10.0 mL 0.1 N NaOH to each vial.

(iii) Proceed with step 8.

7. Add 10.0 mL deionized-distilled water to each vial containing a sorbent section. Cap each vial.

8. Allow to stand 60 minutes, with occasional agitation. Transfer to a 10-mL plastic syringe fitted

with an in-line 0.45-μm filter. Collect the filtrate in a clean vial.

CALIBRATION AND QUALITY CONTROL:

 9. Calibrate daily with at least six working standards over the range 1 to 300 μg CN- per sample.

a. Prepare a working standard solution, 1.00 μg /mL.CN-, by diluting 100 μL of calibration stock

solution to 100 mL with 0.1 N NaOH.

 b. Pipet 0.5-, 1.00-, 1.50-, 2.00- and 2.50-mL of the working standard solution into 25-mL

volumetric flasks to make 0.50-, 1.00-, 1.50-, 2.00- and 2.50- μg CN- standards.

 c. Analyze together with field samples and blanks (steps 12 through 19).

d. Prepare calibration graph (absorbance vs. μg CN-).

10. Determine desorption efficiency (DE) at least once for each lot of soda lime used for sampling. 

Prepare at least three tubes at each of five levels plus three media blanks.

a. Remove and discard back sorbent section of a blank sampler.

b. Inject a known amount of calibration stock solution directly onto the soda lime with a

microliter syringe.

c. Cap, and allow to stand overnight.

d. Desorb (steps 5 through 8) and analyze together with working standards and blanks (steps

12 through 19).

e. Prepare a graph of DE vs. μg CN- recovered.

 11. Analyze three quality control blind spikes and three analyst spikes to ensure that the calibration

graph and DE graph are in control.

MEASUREMENT:

12. Set spectrophotometer according to manufacturer's recommendations and to conditions on p.

6010-1.

13. Pipet a sample aliquot estimated to contain 0.5 to 2.5 μg CN- into a 25-mL volumetric flask. 

Alternately, to cover an unknown sample concentration range, pipet 0.5-, 1.00-, and 3.00-mL

aliquots into separate 25-mL vol. flasks for each field sample. Larger or smaller aliquots may be

taken, based on prior knowledge of expected analyte level.

14. Pipet 0.5 mL 0.1 N NaOH into a 25-mL volumetric flask for reagent blank.

15. Add one drop phenolphthalein solution to each standard or sample.

NOTE: Add a little deionized-distilled water to increase volume for easier mixing. All solutions

should be alkaline (pink) at this point.

16. Starting with the reagent blank, add dropwise 0.15 N HCl, with mixing, until pink color just

disappears. CAUTION: HCN may be produced. Work in hood. Immediately add 1.0 mL

N-chlorosuccinimide/succinimide oxidizing reagent. Mix and let stand.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
HYDROGEN CYANIDE: METHOD 6010, Issue 2, dated 15 August 1994 - Page 4 of 5

NOTE 1: To avoid possible loss of HCN, add the oxidizing agent before proceeding to the

next sample.

 NOTE 2: Do not prepare more samples than can be analyzed within the 30-minute maximum

time for color development.

 17. After at least 5 min. standing (but not longer than 15 min), starting with the reagent blank, add

1.0-mL barbituric acid-pyridine coupling reagent. Mix.

 18. Adjust sample volume to 25 mL with deionized-distilled water and allow to stand at least 12 min

(but not longer than 30 min) for color development.

 19. Read absorbance at 580 nm in a 1-cm light path cuvette on a spectrophotometer. If sample

absorbance is outside the range of the calibration standards, take an aliquot, re-analyze (steps

12 through 19), and apply the appropriate aliquot factor in calculations.

CALCULATIONS:

20. Calculate the mass, μg, of CN- in aliquot analyzed. Apply the appropriate aliquot factor to

calculate the mass, μg, of CN- in the original 10-mL solution.

21. Determine the mass, μg CN- (corrected for DE), found in the sample front (Wf) and back (Wb)

sorbent sections and in the average media blank front (Bf) and back (Bb) sorbent sections. If

Wb > Wf/10, report breakthrough and possible sample loss.

 22. Calculate concentration, C, of HCN in the air volume sampled, V(L).

where 1.039 = conversion factor, CN- to HCN

EVALUATION OF METHOD:

The method was evaluated by sampling the test atmospheres of HCN generated from a compressed

mixture of HCN in nitrogen [1]. The range of HCN concentration was equivalent to 2 to 15

mg/m3 for a 3-L air sample. Twenty-two samples collected at 0.2 L/min for 15 minutes

indicated overall precision Sˆ

rT of 0.076 with nearly 100% recovery. Breakthrough occurred

after 40 minutes of sampling at the flow rate of 0.2 L/min at an HCN concentration of

148 mg/m3. Sample tubes spiked with solutions of KCN and analyzed after storage, indicated that the

samples of cyanide ions were stable on the tube for at least 2 weeks. Analysis of 22 tubes which were

spiked with KCN standard solutions in the range 10 to 50 μg indicated a recovery of nearly 100% with a

pooled precision of 0.041. Desorption efficiency may be poor below 10 μg CN- [6].

REFERENCES:

[1] Williamson, George. "Method Development Protocol and Backup Data Report on Hydrogen

Cyanide"

Internal NIOSH/MRSB Report, Unpubl. NIOSH (1988).

[2] Williamson, George. "Analysis of Air Samples on Project 166 (Firesmoke) on HCN; Sequence

NIOSH/MRSB-6366A, Unpubl. NIOSH, (1988).

[3] Lambert, J. L., Ramasamy, J., and J. V. Paukstelis, "Stable Reagents for the Colorimetric

Determination of Cyanide by Modified Konig Reactions," Analyt. Chem., 47, 916-918 (1975).

[4] DataChem Laboratories, NIOSH Sequence #6837-K (unpublished, March 21, 1990).

[5] NIOSH/OSHA Occupational Health Guidelines for Chemical Hazards, U.S. Department of Health

and Human Services. Publ. (NIOSH) 81-123 (1981), available as stock #PB 83-154609 form NTIS,

Springfield, VA 22161.

[6] DataChem Laboratories, User Check, NIOSH Sequence #6837-J (unpublished, March 19, 1990).

METHOD WRITTEN BY: George Williamson, NIOSH/DPSE.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
HYDROGEN CYANIDE: METHOD 6010, Issue 2, dated 15 August 1994 - Page 5 of 5

APPENDIX: STANDARDIZATION OF CALIBRATION STOCK SOLUTION

Titrate an aliquot of the cyanide standard stock solution (Reagent 12) with standard silver nitrate

(AgNO3) solution. The end point is the first formation of a white precipitate, Ag[Ag(CN) 2]. Calculate the

cyanide concentration with the following equation:

Mc = 52.04 Va (Ma/Vc)

Where Mc = cyanide concentration (mg/mL)

Va = volume (mL) of standard silver nitrate solution

Ma = concentration (moles/L) of standard silver nitrate solution

Vc = volume (mL) of calibration stock solution titrated

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
ATTACHMENT 3 NIOSH 7904
CYANIDES, aerosol and gas 7904

 HCN and salts MW: 27.03 (HCN); CAS: 74-90-8 (HCN); RTECS: MW6825000 (HCN);

 65.11 (KCN) 151-50-8 (KCN) TS8750000 (KCN)

METHOD: 7904, Issue 2 EVALUATION: FULL Issue 1: 15 February 1984

Issue 2: 15 August 1994

OSHA : 11 mg/m3; skin (HCN)

 5 mg/m3; skin (cyanides, as CN -)

NIOSH: C 5 mg/m3/10 min (as CN-)

ACGIH: C 11 mg/m3; skin (HCN);

 5 mg/m3; skin (cyanides, as CN)

PROPERTIES: HCN: gas, BP 26 °C; VP 620 mm Hg 20 °C;

 vapor density 0.94 (air = 1); KCN: solid,

 d 1.52 g/mL, MP 634 °C

SYNONYMS: HCN: hydrocyanic acid, prussic acid, formonitrile, cyanides.

SAMPLING

SAMPLER: FILTER + BUBBLER

(0.8-μm PVC membrane

+ 15 mL 0.1 N KOH) [1]

FLOW RATE: 0.5 to 1 L/min

VOL-MIN: 10 L @ 0.5 mg/m3 (as CN-)

 -MAX: 180 L @ 11 mg/m3 (as CN-)

SHIPMENT: routine

SAMPLE STABILITY: analyze within 5 days;

particulate on filter may

liberate HCN gas [2]

BLANKS: 2 to 10 field blanks per set

MEASUREMENT

TECHNIQUE: ION-SPECIFIC ELECTRODE

ANALYTE: cyanide ion (CN-)

EXTRACT FILTER: 25 mL 0.1 N KOH; 30 min

RINSE

BUBBLER: 2 mL 0.1 N KOH; dilute to 25 mL

with 0.1 N KOH

MEASURE: mV reading of cyanide ion electrode

vs. reference electrode

CALIBRATION: solutions of KCN in 0.1 N KOH

RANGE: 0.05 to 2 mg CNESTIMATED LOD: 2.5 μg CN-

 [2]

PRECISION (Sr): 0.043 (HCN) [3];

0.038 (KCN) [2]

ACCURACY

RANGE STUDIED: 5 to 21 mg/m3 (HCN) [3];

2.6 to 10 mg/m3 (KCN) [2]

BIAS: - 7.6%

OVERALL PRECISION (Sˆ

rT): 0.062 (HCN) [3];

0.103 (KCN) [2]

ACCURACY: ± 20.0%

APPLICABILITY: The working range (as CN -) is 0.5 to 15 mg/m3 for a 90-L air sample or 5 to 20 mg/m 3 for a 10-L air sample.

INTERFERENCES: Sulfide, chloride, iodide, bromide, cadmium, zinc, silver, nickel, cuprous iron and mercury interfere. In humid

atmospheres, some particulate cyanide collected on the filter will liberate hydrogen cyanide which will be trapped in th e bubbler

[2]. The method cannot distinguish between HCN formed in this manner and HCN originally present in air.

OTHER METHODS: This method combines and replaces Methods S288 [4], S250 [5], and P&CAM 116 [6]. Method 6010

(Hydrogen Cyanide) uses a soda lime tube as sampler, with colorimetric measurement.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
CYANIDES, aerosol and gas: METHOD 7904, Issue 2, dated 15 August 1994 - Page 2 of 4

REAGENTS:

1. Deionized water.

2. Potassium cyanide.*

3. Calibration stock solution, 1000 μg/mL CN -.

Dissolve 0.250 g KCN in 0.1 N KOH to make

100 mL solution. Stable for at least 1 week in

polyethylene bottle.

4. Potassium hydroxide (KOH), 0.1 N. Dissolve

5.6 g KOH in deionized water; dilute to 1000

mL.

5. Lead acetate paper.

6. Cadmium carbonate (if sulfide present).

7. Hydrogen peroxide, 30% (if sulfide present).

8. Sodium sulfite, 1 M (if sulfide present).

* See SPECIAL PRECAUTIONS.

EQUIPMENT:

1. Sampler: polyvinyl chloride membrane filter,

37-mm diameter, 0.8-μm pore size in 2-piece

filter cassette holder, followed by a glass

midget bubbler containing 15 mL 0.1 N KOH.

 2. Personal sampling pump, 0.5 to 1 L/min, with

splashover protection and flexible connecting

tubing.

 3. Vials, polyethylene, with screw caps, 20-mL,

and plastic tape for sealing.

 4. Cyanide ion electrode, (Orion 94-06 or

equivalent).

 5. Reference electrode.

 6. pH meter, readable to 0.1 mV.

 7. Magnetic stirrer and stirring bars.

 8. Jars, ointment, 60-mL, squat-form with

aluminum-lined screw caps.

 9. Pipets, 0.05- to 2 and 25-mL, with pipet bulb.

10. Volumetric flasks, 25-mL.

11. Beakers, 50-mL.

12. Analytical balance, readable to 0.1 mg.

SPECIAL PRECAUTIONS: Hydrogen cyanide gas and the cyanide particulates may be fatal if

swallowed, inhaled or absorbed through the skin. Work in a hood.

Amyl nitrite is the antidote for cyanide poisoning [7].

SAMPLING:

1. Calibrate each personal sampling pump with a representative sampler in line.

2. Sample at 0.5 to 1 L/min for a total sample size of 10 to 180 L.

NOTE: Maintain bubblers in a vertical position during sampling. Do not allow the solution level

to fall below 10 mL.

3. Remove the bubbler stem and tap it gently against the inside wall of the bubbler. Rinse the

bubbler stem with 1 to 2 mL of unused 0.1 N KOH. Add the rinse to the bubbler.

4. Quantitatively transfer the contents of the bubbler to a 20-mL vial. Close cap tightly and wrap

with plastic tape to avoid sample loss during transit. Label each vial.

SAMPLE PREPARATION:

5. Transfer the filter from the cassette filter holder to a 60-mL ointment jar.

6. Pipet 25.0 mL 0.1 N KOH into the jar. Cap and allow to stand for at least 30 min with

occasional shaking to complete extraction. Analyze within 2 h after extraction.

7. Empty the contents of the vial into a 25-mL volumetric flask using 0.1 N KOH to rinse the vial. 

Add rinse to the volumetric flask. Dilute to the mark with 0.1 N KOH.

NOTE: Sulfide ion irreversibly poisons the cyanide ion specific electrode and must be removed

if present. Check for the presence of sulfide ion by touching a drop of sample to a

piece of lead acetate paper; the paper will discolor in the presence of sulfide ion. If this

test is positive, remove sulfide by one of the following methods:

a. Add 1 mL 1 M H2O2 and 1 mL 1 M Na2SO3 to sample solutions prior to diluting to volume. 

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
CYANIDES, aerosol and gas: METHOD 7904, Issue 2, dated 15 August 1994 - Page 3 of 4

b. Add a small amount (spatula tip) of powdered cadmium carbonate to the sample. Swirl to

disperse the solid and recheck the liquid with lead acetate paper. If sulfide ion has not been

removed completely, add more cadmium carbonate. Avoid a large excess of cadmium

carbonate and long contact time with the solution. When a drop of liquid no longer discolors

a strip of lead acetate paper, filter the sample through a small plug of glass wool in a

Pasteur pipette and proceed with the analysis.

CALIBRATION AND QUALITY CONTROL:

8. Prepare at least six working standards fresh daily to cover the range 50 to 2000 μg CN - per

sample by diluting aliquots of 1000 μg/mL calibration stock solution with 0.1 N KOH (e.g., 0.05

to 2.0 mL calibration stock solution diluted to 25 mL).

9. Analyze the working standards according to steps 11 and 12 together with the samples and

blanks.

10. Prepare a calibration graph on semilog paper by plotting cyanide ion concentration on the

logarithmic axis and mV on the linear axis.

MEASUREMENT:

11. Transfer the solution to be measured to a 50-mL beaker. Immerse the cyanide ion electrode

and reference electrode in the sample and start the magnetic stirrer.

12. With the magnetic stirrer on, allow the potential reading to stabilize. Record the mV reading.

NOTE 1: Potential readings are a function of temperature. Measure samples and working

standards at the same temperature (± 2 °C).

NOTE 2: The cyanide electrode will malfunction if chloride, iodide and bromide ions, which form

insoluble silver salts, are present in sufficient quantity. Several metal ions are also

known to complex with cyanide such as cadmium, zinc, silver, nickel, cuprous iron and

mercury. Consult the electrode instruction manual for the procedure to use when such

ions are present.

CALCULATIONS:

13. Read the mass, μg, of cyanide ion present in the sample filter (W f), sample bubbler (W b),

average media blank filter (B f) and media blank bubblers (B b) from the calibration graph.

14. Calculate the concentration (mg/m 3) of particulate cyanide, C p, and hydrogen cyanide, C HCN, in

the air volume sampled, V (L):

where 1.04 is the stoichiometric conversion factor from CN - to HCN.

NOTE: Particulate cyanides will be collected on the filter. In humid atmospheres, however, it

has been observed that during the collection of particulate cyanide, HCN is gradually

liberated [2]; therefore, particulate cyanide interference is not completely removed.

EVALUATION OF METHOD:

HCN: Method S288 was issued on September 2, 1977 [4]. Test atmospheres of HCN were generated

by calibrated flow from a compressed mixture of HCN in nitrogen [3,8]. The range of HCN

concentrations in air was 5 to 21 mg/m 3 for 12-L air samples. Eighteen HCN samples collected at 0.2

L/min for 60 min indicated overall precision of 6.2%, with a 96.7% recovery. An eight-day storage

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
CYANIDES, aerosol and gas: METHOD 7904, Issue 2, dated 15 August 1994 - Page 4 of 4

stability study involving six samples at the OSHA standard concentration level indicated a 92.4%

average recovery for the one-day old samples and a 92.6% for eight-day old samples. A collection

efficiency study at twice the OSHA standard level, which included backup bubblers, indicated that an

average of 99.8% of HCN was collected in the first bubbler. The HCN air generated concentrations

were independently confirmed by a titration method [3].

KCN: Method S250 was issued on January 30, 1976 [5]. A set of six weighed KCN samples in the

range of 1.8 to 2.5 mg KCN per filter indicated a 97% recovery and a 3.8% measurement precision [2]. 

Spiking with aqueous or basic solutions of KCN proved unsuccessful (low recovery) because of the

cyanide instability in the presence of water and CO 2. Test atmospheres of KCN were generated by

atomization of an aqueous solution (162 g/L) of KCN into a dry airstream. Eighteen KCN samples

collected in 0.1 N NaOH at 1.5 L/min for 60 min indicated overall precision, Sˆ

rT, of 0.103. Collection was

accomplished with cellulose ester membrane filters followed with backup bubblers. The collection

efficiency at twice the OSHA level was 100.0% on the filters. Cyanide salts are known to decompose in

moist air with liberation of HCN. This instability was determined with two sets of six samples at the one

and two times the OSHA level. Each of the samples which were twice the OSHA level were connected

with two backup bubblers. Both sets indicated a loss of 16.5%.

REFERENCES:

[1] Perkins, J.B., D.G. Tharr, J. Palassis, D.B. Fannin, and P.M. Eller, Case Studies: Reduction of

Blank Values in the Determination of Particulate Cyanides. Appl. Occup. Environ. Hyg. 5:836-837

(1990).

[2] Documentation of the NIOSH Validation Tests, S250, U.S. Department of Health, Education, and

Welfare, Publ. (NIOSH) 77-185 (1977).

[3] Backup Data Report for Hydrogen Cyanide, S288, available as "Ten NIOSH Analytical Methods, Set

5," Order No. BP 287-499 from NTIS, Springfield, VA 22161.

[4] NIOSH Manual of Analytical Methods, 2nd. ed., V. 4, S288, U.S. Department of Health, Education,

and Welfare, Publ. (NIOSH) 78-175 (1978).

[5] Ibid, V. 3, S250, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 77-157-C

(1977).

[6] Ibid, V. 1, P&CAM 116, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH)

77-157-A (1977).

[7] Criteria for a Recommended Standard...Occupational Exposure to Hydrogen Cyanide and Cyanide

Salts, 5-9, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 77-108 (1976).

[8] NIOSH Research Report-Development and Validation of Methods for Sampling and Analysis of

Workplace Toxic Substances, U.S. Department of Health and Human Services, Publ. (NIOSH)

80-133 (1980).

METHOD REVISED BY:

J. Palassis, NIOSH/DTMD; S250 and S288 originally validated under NIOSH Contracts CDC-99-74-45

and 210-76-0123, respectively.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
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