These requirements vary depending on the piece of equipment at the facility. Testing and statistical methods are specified in the regulations at §264.1063( c). The primary source of guidance is the regulations. See also the final rulemakings that promulgated the regulations:

June 21, 1990 (55 FR 25494)

June 13, 1997 (62 FR 32462) Appendix B 187 Table B 1. Summary of Waste Analysis Drivers for Major RCRA Regulatory Program Areas 40 CFR Citation and Description Applicable Standards Requirements for Demonstrating Attainment of or Compliance With the Standards Relevant USEPA Guidance Waste Analysis Drivers in Other RCRA Regulations (continued)

§266.112  Regulation of Residues A residue from the burning or processing of hazardous waste may be exempt from hazardous waste determination if the waste derived residue is either: substantially similar to normal residue or below specific health based levels for both metal and nonmetal constituents. Concentrations must be determined based on analysis of one or more samples obtained over a 24 hour period. Multiple samples may be analyzed and composite samples may be used provided the sampling period does not exceed 24 hours. If more than one sample is analyzed to represent the 24 hour period, the concentration shall be the arithmetic mean of the concentrations in the samples. The regulations under §266.112 have specific sampling and analysis requirements Part 266, Appendix IX Part 270  Subpart B  Permit Application, Hazardous Waste Permitting Provides the corresponding permit requirement to the general requirements (including the requirement for a waste analysis plan) under §270.14. There are also unit specific waste analysis,

monitoring, and sampling requirements incinerators (§ 270.19)

and boilers and industrial furnaces (§ 270.22). There are also specific requirements for dioxin listings handled in waste piles (§ 270.18)

and landfills (§ 270.21). The permittee must conduct appropriate sampling procedures,

and retain results of all monitoring.

All requirements are facility specific and are set forth in the permit and waste analysis plan. Test Methods for Evaluating Solid Waste, Physical/ Chemical Methods,

Updates I, II, IIA, IIB, III, and IIIA.

SW 846. (USEPA 1986a)

Waste Analysis at Facilities That Generate, Treat, Store, and Dispose of Hazardous Wastes, a Guidance Manual, EPA530 R 94

024 (USEPA 1994a)

Part 270  Subpart C  Conditions Applicable to All Permits Under §270.30, there are specific requirements for monitoring and recordkeeping. Section270.31 requires monitoring to be detailed in the permit. The permittee must conduct appropriate sampling procedures,

and retain results of all monitoring.

All requirements are facility specific and are set forth in the permit and waste analysis plan. Test Methods for Evaluating Solid Waste, Physical/ Chemical Methods,

Updates I, II, IIA, IIB, III, and IIIA.

SW 846. (USEPA 1986a)

Waste Analysis at Facilities That Generate, Treat, Store, and Dispose of Hazardous Wastes, a Guidance Manual, EPA530 R 94

024 (USEPA 1994a) Appendix B 188 Table B 1. Summary of Waste Analysis Drivers for Major RCRA Regulatory Program Areas 40 CFR Citation and Description Applicable Standards Requirements for Demonstrating Attainment of or Compliance With the Standards Relevant USEPA Guidance Waste Analysis Drivers in Other RCRA Regulations (continued)

Part 270  Subpart F  Special Forms of Permits Specifies sampling and monitoring requirements based on trial burns for incinerators (§ 270.62) and Boiler and Industrial Furnaces (§ 270.66). Waste analysis and sampling requirements are site specific and set forth in each facility's waste analysis plan required under 264.13. Test Methods for Evaluating Solid Waste, Physical/ Chemical Methods,

Updates I, II, IIA, IIB, III, and IIIA.

SW 846. (USEPA 1986a)

Waste Analysis at Facilities That Generate, Treat, Store, and Dispose of Hazardous Wastes, a Guidance Manual, EPA530 R 94

024 (USEPA 1994a)

Part 273  Universal Wastes Handlers and transporters of universal wastes must determine if any material resulting from a release is a hazardous waste.

(§ 273.17( b) for small quantity handlers, §273.37( b) for large quantity handlers, and §273.54 for transporters of universal wastes)

Also, if certain universal wastes are dismantled, such as batteries or thermostats, in certain cases the resulting materials must be characterized for hazardous waste purposes. (§§ 273.13( a)( 3) and (c)( 3)( i)) Sampling and analysis requirements are identical to hazardous waste identification requirements. Test Methods for Evaluating Solid Waste, Physical/ Chemical Methods,

Updates I, II, IIA, IIB, III, and IIIA.

SW 846. (USEPA 1986a)

Universal Waste Final Rule, 60 FR 25492; May 11, 1995 Final rule adding Flourescent Lamps, 64 FR 36465; July 6, 1999 Appendix B 189 Table B 1. Summary of Waste Analysis Drivers for Major RCRA Regulatory Program Areas 40 CFR Citation and Description Applicable Standards Requirements for Demonstrating Attainment of or Compliance With the Standards Relevant USEPA Guidance Waste Analysis Drivers in Other RCRA Regulations (continued)

Part 279  Standards for the Management of Used Oil Specifies sampling and analysis procedures for owners or operators of used oil processing and re

refining facilities. Under §279.55, owners or operators of used oil processing and re refining facilities must develop and follow a written analysis plan describing the procedures that will be used to comply with the analysis requirements of §279.53 and/ or §279.72. The plan must be kept at the facility. Sampling: Part 261, Appendix I Hazardous Waste Management System; Identification and Listing of Hazardous Waste; Recycled Used Oil Management Standards, 57 FR 41566, September 10, 1992 Part 279 Requirements: Used Oil Management Standards,

EPA530 H 98 001 190 This page intentionally left blank 191 APPENDIX C STRATEGIES FOR SAMPLING HETEROGENEOUS WASTES C. 1 Introduction "Heterogeneous wastes" include structures, demolition debris, waste construction materials, containers (e. g., drums, tanks, and paint cans), solid waste from laboratories and manufacturing processes, and post consumer wastes (e. g., electronics components, battery casings, and shredded automobiles) (USEPA and USDOE 1992). Heterogeneous wastes can pose challenges in the development and implementation of a sampling program due to the physical variety in size, shape, and composition of the material and the lack of tools and approaches for sampling heterogeneous waste. The application of conventional sampling approaches to heterogeneous waste is difficult and may not provide a representative sample.

To develop a sampling strategy for heterogeneous waste, it is first important to understand the scale, type, and magnitude of the heterogeneity. This appendix provides an overview of largescale heterogeneity and provides some strategies that can be used to obtain samples of heterogeneous wastes. See also Section 6.2.1 for a description of other types of heterogeneity including short range (small scale) heterogeneity (which includes distribution and constitution heterogeneity).

Additional guidance on sampling heterogeneous waste can be found in the following documents:

° Characterizing Heterogeneous Wastes: Methods and Recommendations (USEPA and USDOE 1992)

° Standard Guide for Sampling Strategies for Heterogeneous Waste (ASTM D 5956 96)

° Pierre Gy's Sampling Theory and Sampling Practice: Heterogeneity, Sampling Correctness, and Statistical Process Control. 2 nd ed. (Chapter 21) (Pitard 1993), and ° Geostatistical Error Management: Quantifying Uncertainty for Environmental Sampling and Mapping (Myers 1997).

C. 2 Types of Large Scale Heterogeneity The notion of heterogeneity is related to the scale of observation. An example given by Pitard (1993) and Myers (1997) is that of a pile of sand. From a distance of a few feet, a pile of sand appears to be uniform and homogeneous; however, at close range under magnification a pile of sand is heterogeneous. Substantial differences are found between the individual grains in their sizes, shapes, colors, densities, hardness, mineral composition, etc. For some materials, the differences between individual grains or items are not measurable or are not significant relative to the project objectives. In such a case, the degree of heterogeneity is so minor that for practical purposes the material can be considered homogeneous. The Standard Guide for Sampling Strategies for Heterogeneous Waste (ASTM D 5956 96) refers to this condition as Appendix C 192 "practical homogeneity," but recognizes that true homogeneity does not exist.

At a larger scale, such as an entire waste site, long range (or large scale) nonrandom heterogeneity is of interest. Large scale heterogeneity reflects local trends and plays an important role in deciding whether to use a geostatistical appraisal to identify spatial patterns at the site, to use stratified sampling design to estimate a parameter (such as the overall mean), or to define the boundaries of the sampling problem so that it comprises two or more decision units that are each internally relatively homogeneous.

Items, particles, or phases within a waste or site can be distributed in various ways to create distinctly different types of heterogeneity. These types of heterogeneity include:

° Random heterogeneity – occurs when dissimilar items are randomly distributed throughout the population.

° Non random heterogeneity – occurs when dissimilar items are nonrandomly distributed, resulting in the generation of strata. The term strata refers to subgroups of a population separated in space, in time, or by component from the remainder of the population. Strata are internally consistent with respect to a target constituent or a property of interest and are different from adjacent portions of the population.

The differences between items or particles that result in heterogeneity are due to differences in their composition or properties. One of these properties – particle size – deserves special consideration because significant differences in particle size are common and can complicate sampling due to the fundamental error. Fundamental error can be reduced only through particle size reduction or the collection of sufficiently large samples. (Section 6 describes the impacts that fundamental error and particle size can have on sampling error.)

Figure C 1 depicts populations exhibiting the three types of heterogeneity described in ASTM D 5956 96 Standard Guide for Sampling Strategies for Heterogeneous Waste: (1) homogeneous, (2) randomly heterogeneous, (3) and nonrandomly heterogeneous populations. The drum like populations portray different types of spatial distributions while the populations being discharged through the pipes represent different types of temporal distributions.

In the first scenario, very little spatial or temporal variation is found between the identical particles of the "homogeneous" population; however, in the second scenario, spatial and temporal variations are present due to the difference between the composition of the particles or items that make up the waste. ASTM D 5956 96 refers to this as a "randomly heterogeneous" population. In the third scenario, the overall composition of the particles or items remain the same as in the second scenario, but the two different components have segregated into distinct strata (e. g., due to gravity), with each strata being internally homogeneous. ASTM D 5956 96 refers to waste with this characteristic as "non randomly heterogeneous."

C. 3 Magnitude of Heterogeneity The magnitude of heterogeneity is the degree to which there are differences in the characteristic of interest between fragments, particles, or volumes within the population. The magnitude of heterogeneity can range from that of a population whose items are so similar that it is practically Appendix C 193 Figure C 1. Different types of spatial and temporal heterogeneity.

homogeneous to a population whose items are all dissimilar. Statistical measures of dispersion, the variance and standard deviation, are useful indicators of the degree of heterogeneity within a waste or waste site (assuming sampling error is not a significant contributor to the variance

an optimistic assumption).

If the waste exhibits nonrandom heterogeneity and a high magnitude of heterogeneity, then consider segregating (e. g., at the point of generation) and managing the waste as two or more separate decision units (if physically possible and allowed by regulations). This approach will require prior knowledge (for example, from a pilot study) of the portions of the waste that fall into each specified category (such as hazardous debris and nonhazardous debris).

C. 4 Sampling Designs for Heterogeneous Wastes The choice of a sampling design to characterize heterogeneous waste will depend upon the regulatory objective of the study (e. g., waste identification or classification, site characterization, etc.), the data quality objectives, the type and magnitude of the heterogeneity, and practical considerations such as access to all portions of the waste, safety, and the availability of equipment suitable for obtaining and preparing samples.

As described in Section 5 of this document, there are two general categories of sampling designs: probability sampling design and authoritative (nonprobability) sampling designs. Probability sampling refers to sampling designs in which all parts of the waste or media under study have a known probability of being included in the sample. This assumption may be difficult to support when sampling highly heterogeneous materials such as construction debris. Appendix C 194 All parts of a highly heterogeneous waste may not be accessible by conventional sampling tools, limiting the ability to introduce some form of randomness into the sampling design.

Random Heterogeneous Waste: For random heterogeneous waste, a probability sampling design such as simple random or systematic sampling can be used. At least one of two sample collection strategies, however, also should be used to improve the precision (reproducibility) of the sampling design: (1) take very large individual samples (to increase the sample support), or (2) take many increments to form each individual sample (i. e., use composite sampling). The concept of sample support is described in Section 6.2.3. Composite sampling is discussed in Section 5.3.

Non Random Heterogeneous Waste: For non random heterogeneous wastes, one of two strategies can be used to improve sampling: (1) If the objective is to estimate an overall population parameter (such as the mean), then stratified random sampling could be used. Stratified random sampling is discussed in detail in Section 5.2.2. (2) If the objective is to characterize each stratum separately (e. g., to classify the stratum as either a hazardous waste or a nonhazardous waste), then an appropriate approach is to separate or divert each stratum at its point of generation into discrete, nonoverlapping decision units and characterize and manage each decision unit separately (i. e., to avoid mixing or managing hazardous waste with nonhazardous waste).

If some form of stratified sampling is used, then one of three types of stratification must be considered. There are three types of stratification that can be used in sampling:

° stratification by space ° stratification by time ° stratification by component.

The choice of the type of stratification will depend on the type and magnitude of heterogeneity present in the population under consideration.

Figure C 2 depicts these different types of strata which are often generated by different processes or a significant variant of the same process. The different origins of the strata usually result in a different concentration or property distribution and different mean concentrations or average properties. While stratification over time or space is widely understood, stratification by component is less commonly employed. Some populations lack obvious spatial or temporal stratification yet display high levels of heterogeneity. If these populations contain easily identifiable components, such as bricks, gloves, pieces of wood or concrete, then it may be advantageous to consider the population as consisting of a number of component strata. An advantage of component stratification is that it can simplify the sampling and analytical process and allow a mechanism for making inferences to a highly stratified population. Component stratification shares many similarities with the gender or age stratification applied to demographic data by pollsters (i. e., the members of a given age bracket belonging to the same stratum regardless of where they reside). Component stratification is used by the mining industry to assay gold ore and other commodities where the analyte of interest is found in Appendix C 195 Figure C 2. Three different types of strata (from ASTM 5956 96)

discrete particles relative to a much greater mass of other materials.

Component stratification, although not commonly employed, is applicable to many waste streams, including the more difficult to characterize waste streams such as building debris. Additional guidance on stratification by component can be found in ASTM D 5956 96.

Table C 1 offers practical examples when wastes considered "non randomly heterogeneous" might be good candidates for stratification across space, time, or by component.

The stratification approach can result in a more precise estimate of the mean compared to simple random sampling. However, keep in mind that greater precision is likely to be realized only if a waste exhibits substantial nonrandom chemical heterogeneity and stratification efficiently "divides" the waste into strata that exhibit maximum between strata variability and minimum within strata variability. If that does not occur, stratified random sampling can produce results that are less precise than in the case of simple random sampling; therefore, it is reasonable to employ stratified sampling only if the distribution of chemical contaminants in a waste is sufficiently known to allow an intelligent identification of the strata and at least two or three samples can be collected in each stratum.

Note that failure to recognize separate strata might lead one to conclude incorrectly, via a statistical test, that the underlying population is lognormal or some other right skewed distribution. Appendix C 196 Table C 1. Examples of Three Types of Stratification Type of Stratification Example Scenario Stratification Across Space A risk based cleanup action requires a site owner to remove the top two feet of soil from a site. Prior to excavation, the waste hauler wants to know the average concentration of the constituent of concern in the soil to be removed. The top six inches of soil are known to be more highly contaminated than the remaining 18 inches of soil. Sampling of the soil might be carried out more efficiently by stratifying the soil into two subpopulations  the upper six inch portion and the lower 18 inch portion.

Stratification Across Time A waste discharge from a pipe varies across time. If the objective is to estimate the overall mean, then an appropriate sampling design might include stratification across time.

Stratification by Component Construction debris covered with lead based paint in the same structure with materials such as glass and unpainted wood could be sampled by components (lead based paint debris, glass, and unpainted wood). This strategy is known as "stratification by component" (from ASTM D 5956 96).

C. 5 Sampling Techniques for Heterogeneous Waste Due to practical constraints, conventional sampling approaches may not be suitable for use in sampling of heterogeneous wastes. For example, sampling of contaminated debris can pose significant challenges due to the high degree of heterogeneity encountered. Methods used to sample contaminated structures and debris have included the following:

° Coring and cutting pieces of debris followed by crushing and grinding of the matrix (either in the field or within the laboratory) so the laboratory can handle the sample in a manner similar to a soil sample (Koski, et al 1991)

° Drilling of the matrix (e. g., with a hand held drill) followed by collection of the cuttings for analysis. This technique may require 20 to 50 drill sites in a local area to obtain a sufficient volume for an individual field sample (Koski, et al 1991)

° Grinding an entire structure via a tub grinder followed by conventional sampling approaches (AFCEE 1995).

ASTM has published a guide for sampling debris for lead based paint (LBP) in ASTM E1908 97 Standard Guide for Sample Selection of Debris Waste from a Building Renovation or Lead Abatement Project for Toxicity Characteristic Leaching Procedure (TCLP) testing for Leachable Lead (Pb) .

Additional methods are described in Chapter Five, "Sample Acquisition," of Characterizing Heterogeneous Wastes: Methods and Recommendations (USEPA and USDOE 1992) and in Rupp (1990). 1 It is important to note that discussion of the "variance of the fundamental error" refers to the relative variance, which is the ratio of the sample variance over square of the sample mean ( ). The relative variance s x 2 2 is useful for comparing results from different experiments.

197 APPENDIX D A QUANTITATIVE APPROACH FOR CONTROLLING FUNDAMENTAL ERROR This appendix provides a basic approach for determining the particle size sample weight relationship sufficient to achieve the fundamental error level specified in the DQOs. The procedure is based on that described by Pitard (1989, 1993), Gy (1998), and others; however, a number of simplifying assumptions have been made for ease of use. The procedure described in this appendix is applicable to sampling of granular solid media (including soil) to be analyzed for nonvolatile constituents. It is not applicable to liquids, oily wastes, or debris.

The mathematical derivation of the equation for the fundamental error is complex and beyond the scope of this guidance. Readers interested in the full documentation of the theory and underlying mathematics are encouraged to review Gy (1982) and Pitard (1993). Several authors have developed example calculations for the variance of the fundamental sampling error for a "typical" contaminated soil to demonstrate its practical application. 1 Examples found in Mason (1992), and Myers (1997) may be particularly useful.

The equation for the variance of the fundamental error is extremely practical for optimization of sampling protocols (Pitard 1993). In a relatively simple "rule of thumb" form, the equation for the variance of the fundamental error ( ) is estimated by sFE 2 S d FE 2 3 1 2 =               f M a s LC   Equation D. 1 where = a dimensionless "shape" factor for the shape of particles in the material to be f sampled where cubic = 1.0, sphere = 0.523, flakes = 0.1, and needles = 1 to 10 = average density (gm/ cm 3 ) of the material   = the sample weight (or mass of sample) in grams Ms = proportion of the sample with a particle size less than or equal to the particle aLC size of interest = diameter of the largest fragment (or particle) in the waste, in centimeters. d Pitard's methodology suggests the particle size of interest should be set at 95 percent of the largest particle in the population (or "lot"), such that = 0.05. Equation D. 1 then reduces to aLC s d FE 2 3 18 = f Ma   Equation D. 2 Appendix D 198 The equation demonstrates that the variance of the fundamental error is directly proportional to the size of the largest particle and inversely proportional to the mass of the sample. To calculate the appropriate mass of the sample, Equation D. 2 easily can be rearranged as M f a =   () s d FE 2 3 18 Equation D. 3 Pitard (1989, 1993) proposed a "Quick Safety Rule" for use in environmental sampling using the following input assumptions for Equation D. 3:

= 0. 5 (dimensionless shape factor for a sphere) f = 2. 7 (density of a waste in gm/ cm 3 )   = (standard deviation of the fundamental error). sFE ± 5%

By putting these assumed factors into Equation D. 3, we get:

Ms = × 05 27 005 18 2 3 .. (. ) d Equation D. 4 Pitard (1993) rounds up, to yield the relationship Ms   10000 3 d Equation D. 5 Alternatively, if we are willing to accept , Equation D. 4 yields sFE = ± 16%

Ms   1000 3 d Equation D. 6 Equation D. 4 was used to develop Table D 1 showing the maximum particle size that is allowed for a given sample mass with the standard deviation of the fundamental error ( ) sFE prespecified at various levels (e. g., 5%, 10%, 16%, 20%, and 50%). A table such as this one can be used to estimate the optimal weight of field samples and the optimal weight of subsamples prepared within the laboratory. An alternative graphical method is presented by Pitard (1993) and Myers (1997).

An important feature of the fundamental error is that it does not "cancel out." On the contrary, the variance of the fundamental error adds together at each stage of subsampling. As pointed out by Myers (1997), the fundamental error can quickly accumulate and exceed 50%, 100%, 200%, or greater unless it is controlled through particle size reduction. The variance of the fundamental error, , calculated at each stage of subsampling and particle size reduction sFE 2 must be added together at the end to derive the total . sFE 2 Appendix D 199 Table D 1. Maximum Allowable Particle Size (cm) for a Given Sample Mass for Selected Standard Deviations of the Fundamental Error Sample Mass (g) Maximum Allowable Particle Size d (cm) SFE = 5% SFE = 10% SFE = 16%* SFE = 20% SFE = 50% 0.1 0. 02 0. 03 0. 05 0. 05 0. 10 1 0. 05 0. 07 0. 10 0. 12 0. 22 2 0. 06 0. 09 0. 13 0. 15 0. 27 3 0. 07 0. 11 0. 15 0. 17 0. 31 4 0. 07 0. 12 0. 16 0. 19 0. 35 5 0. 08 0. 13 0. 17 0. 20 0. 37 10 0.10 0.16 0.22 0.25 0.47 20 0.13 0.20 0.28 0.32 0.59 30 0.15 0.23 0.32 0.37 0.68 40 0.16 0.25 0.35 0.40 0.74 50 0.17 0.27 0.37 0.43 0.80 75 0.20 0.31 0.43 0.50 0.92 100 0.22 0.35 0.47 0.55 1.01 500 0.37 0.59 0.81 0.94 1.73 1000 0.47 0.74 1.02 1.18 2.17 5000 0.80 1.27 1.74 2.02 3.72 *A maximum standard deviation of the fundamental error of 16% has been recommended by Pitard (1993) and is included in this table as a point of reference only. Project specific fundamental error rates should be set in the DQO Process.

Two important assumptions underlie the use of Table D 1:

1. The table is valid only if each and all steps of the sampling and subsampling minimize other sampling error through use of careful and correct sampling procedures 2. The table is valid only for wastes or soils with a shape factor (f) and density ( )   similar to that used to derive the table; otherwise, waste specific tables or graphical methods (see Pitard 1993, Mason 1992, or Myers 1997) should be used.

Hypothetical Example Suppose we have a waste that is a particulate solid to be analyzed for total metals. The laboratory requires an analytical sample of only 1 gram. The DQO planning team wants to maintain the total standard deviation of the fundamental error ( ) within . The sample sFE ± 16% masses are determined at each stage of sampling and subsampling as follows:

Primary Stage: Based on prior inspection of the waste, it is known that 95 percent of the particles are 0.47 cm in diameter or less. Using Table D 1, we determine that a field sample of 1,000 grams (or 1 Kg) will generate a fundamental error not greater than . sFE ± 5% Appendix D 200 Secondary Stage: After shipment of the 1,000 gram sample to the laboratory, particle size reduction to about 0.23 cm (2.36 mm or a No. 8 sieve) is performed, and a 30 gram subsample is taken. This step generates a fundamental error of . sFE ± 10%

Final Stage: A 1 gram subsample is required for the analysis. Particle size reduction to 0.07 cm or less (e. g., a No. 30 sieve) is performed, and a 1 g subsample is taken. This step generates a fundamental error of . sFE ± 10%

The variance ( ) from each stage is then summed to determine the total variance of the sFE 2 fundamental error. As shown in Table D 2, the total standard deviation of the fundamental error is less than ±16 percent and the DQO is achieved.

Table D 2. Example Calculation of the Total Variance of the Fundamental Error Sampling and Subsampling Stage Mass (grams) d (cm) sFE sFE 2 Primary Stage 1000 0.47 .05 .0025 Secondary Stage 30 0.23 .10 .01 Final Stage 1 0. 07 .10 .01 Sum of the variances of the fundamental errors ( ) = 0.0225 sFE 2 sFE 2 Total standard deviation of the fundamental error ( ) (DQO = 16%) = 0.15 or 15% sFE sFE One final word of caution is provided regarding the use of the particle size reduction and subsampling routine outlined above. The approach can reduce bias and improve precision of analyses for total constituent analyses, but the particle size reduction steps may actually introduce bias when used in conjunction with some leaching tests. For example, the TCLP specifies a minimum sample mass of 100 grams (for nonvolatile extractions) and maximum particle size of 9.5 mm. While this combination would generate a of almost ±50 percent, sFE excessive particle size reduction below 9.5 mm to lower would increase the leachability of sFE the material during the test due to the increased surface area to volume ratio of smaller particles. Therefore, it is important to remember that particle size reduction to control fundamental error is beneficial when total constituent analyses are performed, but may introduce bias for some leaching tests. Furthermore, particle size reduction below 9.5 mm is not required by Method 1311 (TCLP) (except during Step 7.1.4, "Determination of Appropriate Extraction Fluid"). 201 APPENDIX E SAMPLING DEVICES The key features of recommended sampling devices are summarized in this appendix. For each sampling device, information is provided in a uniform format that includes a brief description of the device and its use, advantages and limitations of the device, and a figure to indicate the general design of the device. Each summary also identifies sources of other guidance on each device, particularly any relevant ASTM standards.

Much of the information in this appendix was drawn from ASTM standards (see also Appendix J for summaries of ASTM standards). In particular, much of the information came from ASTM D 6232, Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities.

Devices not listed in this appendix or described elsewhere in this chapter also may be appropriate for use in RCRArelated sampling. For example, other more innovative or less common technologies may allow you to meet your performance goals and may be appropriate for your sampling effort. Therefore, we encourage and recommend the selection and use of sampling equipment based on a performance based approach. In future revisions to this chapter, we will include new technologies, as appropriate.

This appendix is divided into subsections based on various categories of sampling technologies. The categories are based on those listed in ASTM D 6232. The equipment categories covered within this appendix are as follows:

E. 1 Pumps and Siphons E. 2 Dredges E. 3 Discrete Depth Samplers E. 4 Push Coring Devices E. 5 Rotating Coring Devices E. 6 Liquid Profile Devices E. 7 Surface Sampling Devices E. 1 Pumps and Siphons Pumps and siphons can be used to obtain samples of liquid wastes and ground water. For detailed guidance on the selection and use of pumps for sampling of ground water, see RCRA Ground Water Monitoring: Draft Technical Guidance (USEPA 1992c).

In this section, you will find summaries for the following pumps or siphons: Internet Resource Information on sampling devices can be found on the Internet at the Federal Remediation Technologies Roundtable site at http:// www. frtr. gov/. The Field Sampling and Analysis Technologies Matrix and accompanying Reference Guide are intended as an initial screening tool to provide users with an introduction to innovative site characterization technologies and to promote the use of potentially cost effective methods for onsite monitoring and measurement. Appendix E 202 Figure E 1. Automatic sampler E. 1.1 Automatic Sampler E. 1.2 Bladder Pump E. 1. 3 Peristaltic Pump E. 1.4 Centrifugal Submersible Pump E. 1.5 Displacement Pumps E. 1. 1 Automatic Sampler An automatic sampler (see Figure E 1) is a type of pumping device used to periodically collect samples. It is recommended for sampling surface water and point discharges. It can be used in waste water collection systems and treatment plants and in stream sampling investigations. An automatic sampler designed for collection of samples for volatile organic analyses is available.

An automatic sampler typically uses peristaltic pumps as the sampling mechanism. It can be programmed to obtain samples at specified intervals or to obtain a continuous sample. It also can be programmed to collect time composite or flow proportional samples.

Advantages ° Can provide either grab sample or composite samples over time.

° Operates unattended, and it can be programmed to sample variable volumes at variable times.

Limitations ° Requires power to operate (either AC or battery power).

° May be difficult to decontaminate.

° May not operate correctly when sampling liquid streams containing a high percentage of solids.

° Highly contaminated water or waste can degrade sampler components.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232. Appendix E 203 Figure E 2. Bladder pump E. 1.2 Bladder Pump The bladder pump is recommended for the sampling of surface water, ground water, and point discharges. It also can be used to sample other liquids in surface impoundments.

A bladder pump consists of a flexible membrane (bladder) enclosed by a rigid sample container and can be constructed of a variety of materials, such as neoprene, rubber, stainless steel, nitrile, etc. There are two types of bladder pumps  the squeeze type and the expanding type (see Figure E 2). The squeeze type has the bladder connected to the sample discharge line. The chamber between the bladder and the sampler body is connected to the gas line. The expanding type has the bladder connected to the gas line. In this type of bladder pump, the chamber between the bladder and the sampler body is connected to the sample discharge line.

During sampling, water enters the sampler through a check valve at the bottom of the device. Compressed air or gas is then injected into the sampler. This causes the bladder to expand or compress depending on the type of bladder pump. The inlet valve closes and the contents of the sampler are forced through the top check valve into the discharge line. The top check valve prevents water from re entering the sampler. By removing the pressure, the process is repeated to collect more sample. Automated sampling systems have been developed to control the time between pressurization cycles.

Advantages ° Is suitable for sampling liquids containing volatile compounds.

° Can collect samples up to a depth of 60 m (200 ft.) (ASTM D 6232).

Limitations ° Operation requires large volumes of compressed air or gas and a controller.

° Requires a power source.

° Can be heavy and difficult to operate.

° Decontamination can be difficult. Appendix E 204 Figure E 3. Peristaltic pump Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Guide for Sampling Groundwater Monitoring Wells, ASTM D 4448 E. 1. 3 Peristaltic Pump A peristaltic pump (Figure E 3) is a suction lift pump used at the surface to collect liquid from ground water monitoring wells or surface impoundments. It can be used for sampling surface water, ground water, point discharges, impounded liquids, and multi layer liquid wastes.

A peristaltic pump consists of a rotor with ball bearing rollers and it has a piece of flexible tubing threaded around the pump rotor and connected to two pieces of polytetrafluroethylene (PTFE) or other suitable tubing. One end of the tubing is placed in the sample. The other end is connected to a sample container. Silicone tubing is commonly used within the pumphead; however, for organic sampling purposes, medical grade silicone is recommended to avoid contamination of the sample (ASTM D 4448). Fluorocarbon resin tubing is also sometimes used for high hazard materials and for samples to be analyzed for organics (ASTM D 6063). The device can be modified to avoid contact of the sample with the flexible tubing. In such a case, the pump is connected to a clean glass container using a PTFE insert. A second PTFE tubing is used to connect the glass container to the sample source.

During operation, the rotor squeezes the flexible tubing, causing a vacuum to be applied to the inlet tubing. The sample material is drawn up the inlet tubing and discharged through the outlet end of the flexible tubing. In the modified peristaltic pump, the sample is emptied into the glass container without coming in contact with the flexible tubing. To sample liquids from drums, the peristaltic pump is first used to mix the sample. Both ends of the tubing are placed in the sample and the pump is turned on. Once the drum contents are mixed, the sample is collected as described above. To collect samples for organic volatile analyses, the PTFE tubing attached to the intake end of the pump is filled with the sample and then disconnected from the pump. The tube is then drained into the sample vials.

Advantages ° Can collect samples from multiple depths and small diameter wells.

° Easy to use and readily available. Appendix E 205 Figure E 4. Centrifugal submersible pump ° The pump itself does not need to be decontaminated. The tubing can be either decontaminated or replaced.

Limitations ° The drawing of a vacuum to lift the sample may cause the loss of volatile contaminants.

° Sampling depth cannot exceed about 7.6 m (25 ft.) (ASTM D 6232).

° Requires a power source.

° Flexible tubing may be incompatible with certain matrices.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Guide for Sampling of Drums and Similar Containers by Field Personnel, ASTM D 6063 ° Standard Guide for Sampling Groundwater Monitoring Wells, ASTM D 4448 E. 1.4 Centrifugal Submersible Pump The centrifugal submersible pump (Figure E 4) is a type of pump used for purging and sampling monitoring wells, sampling of waste water from impoundments, and sampling point discharges.

A centrifugal submersible pump uses a set of impellers, powered by an electric motor, to draw water up and through a discharge hose. Parts in contact with liquid may be made of PTFE and stainless steel. The pump discharge hose can be made of PTFE or other suitable material. The motor cavity is filled with either air or deionized or distilled water that may be replaced when necessary. Flow rates for centrifugal submersible pumps range from 100 mL per minute to 9 gallons per minute (ASTM D 6232).

During operation, water is drawn into the pump by a slight suction created by the rotation of the impellers. The impellers work against fixed stator plates and pressurize the water which is driven to the surface through the discharge hose. The speed at which the impellers are driven controls the pressure and, thus, the flow rate. Appendix E 206 Figure E 5. Displacement pump Advantages ° Can be constructed of materials (PTFE and stainless steel) that are chemically resistant.

° Can be used to pump liquids up to a 76 m (250 ft) head (ASTM D 6232).

° Flow rate is adjustable.

Limitations ° May be incompatible with liquids containing a high percentage of solids.

° May not be appropriate for collection of samples for volatile organics analysis. Loss of volatiles can occur as a result of motor heating and sample pressurization.

° Requires an electric power source; e. g., either a 12 v (DC) or a 110/ 220 v (AC) converter (ASTM D 6232).

° May require a winch or reel system for portable use.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 E. 1.5 Displacement Pumps The displacement pump (Figure E 5) is a type of pump used for the sampling of surface water, ground water, point discharges and other liquids (e. g., in impoundments).

A displacement pump forces a discrete column of water to the surface via a mechanical lift. During sampling, water enters the sampler through the check valve at the bottom of the device. It is commonly constructed of PVC, stainless steel, or both. It also can be made of PTFE to reduce the risk of contamination when collecting samples with trace levels of organic compounds. Two common types of displacement pumps include the air/ gas and piston displacement pumps.

The air/ gas displacement pump uses compressed gas and it operates by applying positive Appendix E 207 pressure to the gas line. This causes the inlet check valve to close and the discharge line check valve to open, forcing water up the discharge line to the surface. Removal of the gas pressure causes the top valve to close and the bottom valve to open. Water enters the sampler and the process is repeated.

The piston displacement pump uses an actuating rod powered from the surface or from an air or electric actuator. The mechanically operated plunger delivers the sample to the surface at the same time the chamber fills. It has a flap valve on the piston and an inlet check valve at the bottom of the sampler.

Advantages ° Can be constructed of PTFE to reduce the risk of contamination caused by materials of construction when collecting samples for trace levels of organics.

Limitations ° May be difficult to decontaminate.

° Displacement pumps require large volumes of air or gas and a power source.

° Loss of dissolved gases or sample contamination from the driving gas may occur during sampling.

° Displacement pumps may be heavy.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Guide for Sampling Groundwater Monitoring Wells, ASTM D 4448 E. 2 Dredges Dredges include equipment that is often used to collect bottom material (e. g., sediments) from beneath a layer of stationary or moving liquid. A variety of dredges are available including the Ekman bottom grab sampler and the Ponar dredge. The Ponar dredge is described below.

E. 2.1 Ponar Dredge The ponar dredge is recommended for sampling sediment. It has paired jaws that penetrate the substrate and close to retain the sample. The sample volume range is 0.5 to 3.0 liters (ASTM D 6232). Appendix E 208 Figure E 6. Ponar dredge The Ponar dredge is lowered slowly with controlled speed so that the dredge will properly land and avoid blowout of the surface layer to be sampled. The weight of the dredge causes it to penetrate the substrate surface. The slack in tension unlocks the open jaws and allows the dredge to close as it is raised. The dredge is raised slowly to minimize disturbance and sample washout as the dredge is retrieved through the liquid column. The collected sample is emptied into a suitable container. Auxiliary weight may be added to the dredge to increase penetration.

Advantages ° Reusable ° Can obtain samples of most types of stationary sediments ranging from silt to granular material ° Available in a range of sizes and weights ° Some models may be available in either stainless steel or brass.

Limitations ° Not capable of collecting undisturbed samples ° May be difficult to decontaminate (depending upon the dredge's design and characteristics of the sampled material)

° Cannot collect a representative lift or repeatedly sample to the same depth and position ° Can be heavy and require a winch or portable crane to lift; however, a smaller version, the petit Ponar, is available and can be operated by a hand line (ASTM D 4342).

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Practice for Collecting of Benthic Macroinvertebrates with Ponar Grab Sampler, ASTM D 4342 ° Standard Guide for Selecting Grab Sampling Devices for Collecting Benthic Macroinvertebrates, ASTM D 4387 Appendix E 209 Figure E 7. Bacon bomb ° "Sediment Sampling" (USEPA 1994e)

E. 3 Discrete Depth Samplers Discrete depth samplers include equipment that can collect samples at a specific depth. Such samplers are sometimes used to collect samples from layered liquids in tanks or surface impoundments. You will find summaries for the following discrete depth samplers in this section:

E. 3.1 Bacon Bomb E. 3.2 Kemmerer Sampler E. 3.3 Syringe Sampler E. 3.4 Lidded Sludge/ Water Sampler E. 3.5 Discrete Level Sampler Besides the samplers listed below, a self purging, discrete depth sampler is available for sampling ground water monitoring wells. It fills when stopped at the desired depth and eliminates the need for well purging. It samples directly into a 40 mL glass VOA sample vial contained within the sampler; therefore, the loss of volatile organic compounds is minimized.

E. 3.1 Bacon Bomb A bacon bomb (Figure E 7) is a type of discrete level sampler that provides a sample from a specific depth in a stationary body of water or waste. A bacon bomb is recommended for sampling surface water and is usually used to collect samples from a lake or pond. It can also be used to collect liquid waste samples from large tanks or lagoons. It originally was designed to collect oil samples. The sample volume range is from 0.1 to 0.5 liters (100 to 500 mL) (ASTM D 6232).

A bacon bomb has a cylindrical body sometimes constructed of stainless steel, but it is sometimes made of chrome plated brass and bronze. It is lowered into material by a primary support line and has an internal tapered plunger that acts as a valve to admit the sample. A secondary line attached to the top of the plunger opens and closes the plunger valve. The top cover has a locking mechanism to keep the plunger closed after sampling. The bacon bomb remains closed until triggered to collect the sample. Sample collection is triggered by raising the plunger line and allowing the sampler to fill. The device is then closed by releasing the plunger line. It is returned to the surface by raising the primary support line, and the sample is transferred directly to a container. Appendix E 210 Figure E 8. Kemmerer sampler Advantages ° Collects a discrete depth sample; it is not opened until the desired depth.

° Easy to use, without physical requirement limitations.

Limitations ° May be difficult to decontaminate due to design or construction materials.

° Maximum sample capacity is only 500 mL.

° Materials of construction may not be compatible with parameters of concern.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° "Tank Sampling" (USEPA 1994c)

E. 3.2 Kemmerer Sampler A kemmerer sampler (Figure E 8) is a type of discrete level sampler that provides a sample from a specific depth. Recommended for sampling surface water, it is usually used to collect samples from a lake or pond. It can also be used to collect liquid waste samples from large tanks or lagoons. The sample volume range is from 1 to 2 liters (ASTM D 6232).

The sampler comprises a stainless steel or brass cylinder with rubber stoppers for the ends, but all PFTE construction also is available. The ends are left open while being lowered in a vertical position, allowing free passage of water or liquid through the cylinder. When the device is at the designated depth, a messenger is sent down a rope to close the stoppers at each end. The cylinder is then raised and the sample is removed through a valve to fill sample containers.

Advantages ° Can collect a discrete depth sample. Appendix E 211 Figure E 9. Syringe sampler ° Provides correct delimitation and extraction of sample (Pitard 1989)

° Easy to use ° All PTFE construction is available.

Limitations ° May be difficult to decontaminate due to construction or materials.

° The sampler is exposed to the medium at other depths while being lowered to a sampling point at the desired depth.

° Materials of construction may not be compatible with parameters of concern.

Other Guidance:

° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 E. 3.3 Syringe Sampler A syringe sampler (Figure E 9) is a discrete depth sampler used to sample liquids. With the optional coring tip, it can be used as a coring device to sample highly viscous liquids, sludges, and tarlike substances. It is used to collect samples from drums, tanks, and surface impoundments, and it can also draw samples when only a small amount remains at the bottom of a tank or drum. The sample volume range is 0.2 to 0.5 liters (ASTM D 6232).

A syringe sampler generally is constructed of a piston assembly that comprises a T handle, safety locking nut, control rod, piston body assembly, sampling tube assembly, and two tips for the lower end (a closeable valve and a coring tip). When used as a syringe, the sampler is slowly lowered to the sampling point and the Thandle is gradually raised to collect the sample. Once the desired sample is obtained, the lock nut is tightened to secure the piston rod and the bottom valve is closed by pressing down on the sampler against the side or bottom of the container. When used as a coring device, the sampler is slowly pushed down into the material. Once the desired sample is obtained, the lock nut is tightened to secure the piston rod and the sampler is removed from the media. The sample material is extruded into the sample container by opening the bottom valve (if fitted), loosening the lock nut, and pushing the piston down. Appendix E 212 Figure E 10. Lidded sludge/ water sampler Advantages ° The syringe sampler is easy to use and decontaminate.

° The syringe sampler can sample at discrete depths, including the bottom of a container.

Limitations ° The syringe sampler can be used to depths of about 1.8 meters only (ASTM D 6232).

° Material to be sampled must be viscous enough to remain in the device when the coring tip is used; the valve tip is not recommended for viscous materials (ASTM D 6063).

Other Guidance ° Standard Guide for Sampling Single or Multilayered Liquids, ASTM D 5743 ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Guide for Sampling of Drums and Similar Containers by Field Personnel, ASTM D 6063 E. 3.4 Lidded Sludge/ Water Sampler A lidded sludge/ water sampler (Figure E 10) is a type of discrete depth device that provides a sample from a specific depth. It is used to collect sludges or waste fluids from tanks, tank trucks, and ponds. It can sample liquids, multi layer liquid wastes, and mixed phase solid/ liquid wastes. The typical sample volume is 1.0 liter (ASTM D 6232).

A lidded sludge/ water sampler comprises a removable glass jar, sometimes fitted with a cutter for sampling materials containing more than 40 percent solids (ASTM D 6232), that is mounted on a stainless steel device.

The sampler is lowered into the material to be sampled and opened at the desired depth. The top handle is rotated to upright the jar and open and close the lid. Then, the device is carefully retrieved from the material. The jar is removed from the sampler by lifting it from the holder, and Appendix E 213 Figure E 11. Discrete level sampler the jar serves as a sample container so there is no need to transfer the sample.

Advantages ° The jar in the sampling device also serves as a sample container reducing the risk of cross contamination.

° Bottles and lids are unique to each sample, therefore, decontamination of an intermediate transfer container is not required.

Limitations ° Heavy and limited to one bottle size ° Thick sludge is difficult to sample (ASTM D 6232).

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 E. 3.5 Discrete Level Sampler A discrete level sampler (Figure E 11) is a dismountable cylindrical sampler fitted with a manually operated valve( s). It is recommended for sampling surface water, ground water, point discharges, liquids, and multi layer liquids and is used for sampling drums, tanks, containers, wells, and surface impoundments. The typical sample volume range is 0.2 to 0.5 liters (ASTM D 6232).

A discrete level sampler is made from PTFE and stainless steel and is designed to be reusable. It comprises a tube fitted with manually operated valve or valves, which are operated by a control assembly attached to the upper end of the sampler. This assembly consists of a rigid tube and rod or a flexible tube and inner cable. The standard level sampler has a manually operated upper valve and a lower spring retained bottom dump valve. The dual valve model may be emptied by opening the valves manually or with a metering device attached to the lower end of the sampler (not shown). Appendix E 214 To collect a sample, the discrete level sampler is lowered into the sample material to the desired sampling depth. The valve or valves are opened manually to collect the sample and closed before retrieving the sampler. The standard model is emptied by pressing the dump valve against the side of the sample container. The dual valve sampler is emptied by opening the valves manually. Alternatively, the collected sample may be taken to the laboratory in the sampler body by replacing the valves with solid PTFE end caps.

Advantages ° Relatively easy to decontaminate and reuse ° May be used to sample liquids in most environmental situations.

° Can be remotely operated in hazardous environments.

° Sample representativeness is not affected by liquids above the sampling point.

° The sampling body can be used for sample storage and transport.

Limitations ° Limited to sample chamber capacities of 240 475 mL (ASTM D 6232).

° May be incompatible with liquids containing a high percentage of solids.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 E. 4 Push Coring Devices Push coring devices include equipment that use a pushing action to collect a vertical column of a solid sample. You will find summaries for the following push coring devices in this section:

E. 4.1 Penetrating Probe Sampler E. 4.2 Split Barrel Sampler E. 4.3 Concentric Tube Thief E. 4.4 Trier E. 4.5 Thin Walled Tube E. 4.6 Coring Type Sampler (with Valve) E. 4.7 Miniature Core Sampler E. 4.8 Modified Syringe Sampler Appendix E 215 Figure E 12. Probe sampler E. 4.1 Penetrating Probe Sampler The penetrating probe sampler (Figure E 12) is a push coring device and, therefore, provides a core sample. The probe sampler is recommended for sampling soil and other solids. The sample volume range is 0.2 to 2.0 liters (ASTM D 6232).

The probe sampler typically consists of single or multiple threaded steel tubes, a threaded top cap, and a detachable steel tip. The steel tubes are approximately 1 inch or less in diameter. Specialized attachments may be used for various matrices. Some probes are equipped with adjustable screens or retractable inner rods to sample soil vapor or ground water.

Advantages ° Easy to decontaminate and is reusable.

° Can provide samples for onsite analysis (ASTM D 6232).

° Versatile and may sample 15 to 20 locations a day for any combination of matrices (ASTM D 6232).

° Can reduce quantity of investigative derived wastes.

Limitations ° May be heavy and bulky depending on the size used.

° Limited by composition of subsurface materials and accessibility to deeper depth materials.

° May be inappropriate for sampling materials that require mechanical strength to penetrate.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 Appendix E 216 Figure E 13. Split barrel sampler E. 4.2 Split Barrel Sampler A split barrel sampler (Figure E 13) is a push coring device often used with a drill rig to collect deep subsurface samples. The device is recommended for soil sampling, but can be used to sample other solids. The materials to be sampled should be moist enough to remain in the sampler. The sample volume range is 0.5 to 30.0 liters (ASTM D 6232).

The sampler consists of a length of steel tubing split longitudinally and equipped with a drive shoe, made of steel, and a drive head. The drive shoe is detachable and should be replaced when dented or distorted. The samplers are available in a variety of diameters and lengths. The split barrel is typically 18 to 30 inches in length with an inside diameter of 1.5 to 2.5 inches (ASTM D 4700, ASTM D 1586). The split barrel sampler can be used to collect relatively undisturbed soil samples at considerable depths.

The split barrel sampler may be driven manually, but is usually driven with a drill rig drive weight assembly or hydraulically pushed using rig hydraulics. The sampler is placed on the surface of the material to be sampled, then pushed downward while being twisted slightly. Because pushing by hand may be difficult, a drop hammer typically is attached to a drill rig used to finish inserting the sampler. When the desired depth is reached the sampler is twisted again to break the core; then, the sampler is pulled straight up and out of the material. The sample may be removed from the barrel or the liner may be capped off for analysis. Barrels may be extended to 5 inches in diameter (ASTM D 6232). Liners often are used when sampling for volatile organic compounds or other trace constituents of interest. With a liner, the sample can be removed with a minimum amount of disturbance. Liners must be compatible with the matrix and compounds of interest; plastic liners may be inappropriate if analyzing for organics.

Advantages ° Reusable, easily decontaminated, and easy to use.

° Provides a relatively undisturbed sample, therefore, can minimize the loss of volatile organic compounds.

Limitations ° Requires a drill or direct push rig for deep samples.

° Made of steel and may penetrate underground objects such as a pipe or drum. Appendix E 217 Figure E 14. Concentric tube thief ° Only accommodates samples that contain particles smaller than the opening of the drive shoe (ASTM D 4700).

Other Guidance:

° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Guide for Soil Sampling from the Vadose Zone, ASTM D 4700 ° Standard Test Method for Penetration Test and Split Barrel Sampling of Soils, ASTM D 1586 E. 4.3 Concentric Tube Thief The concentric tube thief (also known as a grain sampler) (Figure E 14) is a push coring device that the user directly pushes into the material to be sampled. It can be used to sample powdered or granular solids and wastes in piles or in bags, drums, or similar containers. The concentric tube thieves are generally 61 to 100 cm (24 to 40 inches) long by 1.27 to 2.54 cm (½ to 1 inch) in diameter (USEPA 1994i). The sample volume range is 0.5 to 1.0 liters (ASTM D 6232).

The concentric tube thief consists of two slotted telescoping tubes, which are constructed of stainless steel, brass, or other material. The outer tube has a conical pointed tip on one end which allows the thief to penetrate the material being sampled. The thief is opened and closed by rotating the inner tube, and it is inserted into the material while in the closed position. Once inserted, the inner tube is rotated into the open position and the device is wiggled to allow the material to enter the open slots. The thief then is closed and withdrawn.

Advantages ° Is a good direct push sampler for dry unconsolidated materials.

° Easy to use. Appendix E 218 Figure E 15. Trier Limitations ° May be difficult to decontaminate, depending on the matrix ° Not recommended for sampling of moist or sticky materials.

° Does not collect samples containing all particle sizes if the diameter of the largest solid particle is greater than one third of the slot width (ASTM D 6232). Most useful when the solids are no greater than 0.6 cm (1/ 4 inch) in diameter (USEPA 1994i).

° Depth of sample is limited by the length of the thief.

° Not recommended for use when volatiles are of interest. Collects a somewhat disturbed sample, which may cause loss of some volatiles.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° "Waste Pile Sampling" (USEPA 1994d)

E. 4.4 Trier A trier (Figure E 15) is a push coring device that resembles an elongated scoop and is used to sample moist or sticky solids with a particle diameter less than one half the diameter of the tube portion. The trier can be used to sample soils and similar fine grained cohesive materials. The typical sample volume range is 0.1 to 0.5 liters (ASTM D 6232).

A trier comprises a handle connected to a tube cut in half lengthwise, with a sharpened tip that allows it to cut into the material. Triers are made of stainless steel, PTFE coated metal, or plastic. One should be selected who materials of construction are compatible with the sampled material.

A trier, typically 61 to 100 cm long and 1.27 to 2.54 cm in diameter, is used as a vertical coring device when a relatively complete and cylindrical sample can be extracted.

The trier is pushed into the material to be sampled and turned one or two times to cut a Appendix E 219 core. The rotation is stopped with the open face pointing upward. The core is then carefully removed from the hole, preventing overburden material from becoming a part of the sample. The sample is inspected for irregularities (e. g., pebbles) or breakage. If breakage occurred and if the core does not satisfy minimum length requirements, discard it and extract another from an immediately adjacent location (ASTM D 5451). The sample is emptied into the appropriate container for analysis.

Advantages ° A good direct push sampler for moist or sticky materials.

° Lightweight, easy to use, and easy to decontaminate for reuse.

Limitations ° Limited to sample particle sizes within the diameter of the inserted tube and will not collect particles greater than the slot width.

° Not recommended for sampling of dry unconsolidated materials. (A concentric tube thief is good for such materials.)

° Only for surface sampling, and the depth of sample is limited by the length of the trier.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Practice for Sampling Using a Trier Sampler, ASTM D 5451 ° Sampling of Drums and Similar Containers by Field Personnel, ASTM D 6063 ° Standard Practice for Sampling Unconsolidated Solids in Drums or Similar Containers, ASTM D 5680 E. 4.5 Thin Walled Tube A thin walled tube (Figure E 16) is a type of push coring device recommended for sampling cohesive, unconsolidated solids – particularly soil. It is not recommended for gravel or rocky soil. The sample volume range is 0.5 to 5.0 liters (ASTM D 6232).

The tube generally is constructed of carbon stainless steel, but can be manufactured from other metals (ASTM D 4700). It is commonly 30 inches long and is readily available in 2, 3, and 5 inch outside diameters (ASTM D 4700). The tube is attached with set screws to a length of a solid or tubular rod, and the upper end of the rod, or sampler head, is threaded to accept a handle or extension rod. Typically, the length of the tube depends on the desired sampling depth. Its advancing end is beveled and has a cutting edge with a smaller diameter than the Appendix E 220 Figure E 16. Thin walled tube tube inside diameter. The tube can be used in conjunction with drills – from hand held to full sized rigs.

The end of the sampler is pushed directly into the media using a downward force on the handle. It can be pushed downward by hand, with a jack like system, or with a hydraulic piston. Once the desired depth is reached, the tube is twisted to break the continuity of the tip and is pulled from the media. The sample material is extruded into the sample container by forcing a rod through the tube. A paring device has been developed to remove the outer layer during extrusion (ASTM D 4700). Plastic and PFTE sealing caps for use after sampling are available for the 2, 3, and 5 inch tubes.

Advantages ° Readily available, inexpensive, and easy to use.

° Reusable and can be decontaminated.

° Obtains a relatively undisturbed sample.

Limitations ° Some thin walled tubes are large and heavy.

° The material to be sampled must be of a physical consistency (cohesive sold material) to be cored and retrieved within the tube. It cannot be used to sample gravel or rocky soils.

° Some volatile loss is possible when the sample is removed from the tube.

° The most disturbed portion in contact with the tube may be considered unrepresentative. Shorter tubes provide less disturbed samples than longer tubes.

° Materials with particles larger than one third of the inner diameter of the tube should not be sampled with a thin walled tube. Appendix E 221 Figure E 17. Coring type sampler (with valve) Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Guide for Core Sampling of Submerged, Unconsolidated Sediments, ASTM D 4823 ° Standard Practice for Thin Walled Type Geotechnical Sampling of Soils, ASTM D 1587 ° Standard Guide for Soil Sampling from the Vadose Zone, ASTM D 4700 E. 4.6 Coring Type Sampler (with Valve)

A coring type sampler with valve (Figure E 17) is a type of push coring device recommended for wet soil, and can also be used to sample unconsolidated solid waste, mixed phase solid/ liquid waste, and free flowing powders. The coring device may be used in drums and small containers as well as tanks, lagoons, and waste impoundments. The sample volume range is 0.2 to 1.5 liters (ASTM D 6232).

The coring type sampler with valve is a stainless steel cylindrical sampler with a coring tip, top cap, an extension with a cross handle, and a non return valve at the lower end behind a coring or augering tip. The valve is a retaining device to hold the sample in place as the coring device is removed. Samples are normally collected in an optional liner. It is operated by attaching a handle or an extension with a handle to the top of the coring device. The corer is lowered to the surface, pushed into the material being sampled and removed. The top cap is removed and the contents emptied into a sample container. Alternatively, the liner can be removed (with the sampled material retained inside) and capped on both ends for shipment to a laboratory.

Advantages ° Reusable and is easily decontaminated.

° Provides a relatively undisturbed sample if not extruded.

° Can be hand operated and does not require significant physical strength. Appendix E 222 Figure E 18. Miniature core sample (Encore™ sampler) Limitations ° Can not be used in gravel, large particle sediments, or sludges.

° When sampling for volatile organic compounds, it must be used with a liner and capped to minimize the loss of volatiles.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Guide for Core Sampling Submerged, Unconsolidated Sediments, ASTM D 4823 E. 4.7 Miniature Core Sampler The miniature core sampler (Figure E 18) can be used to collect soil and waste samples for volatile organics analysis. These include devices such as the Purge and Trap Soil Sampler™, the EnCore™ sampler, or a cut plastic syringe (see Section 6.0 of SW 846 Method 5035). A miniature core sampler is a single use push coring sampling device that also can be used as an air tight sample storage and shipping container. It collects a small contained subsample and is particularly useful for the sampling and analysis of volatile organic compounds.

It is recommended for sampling soil, from the ground or the side of a trench, and may be used for sampling sediment and unconsolidated solid wastes. It cannot be used for sampling cemented material, consolidated material, or material having fragments coarse enough to interfere with proper coring. The EnCore™ sampler can be used to collect subsamples from soil cores and has a sample volume range of 0.01 to 0.05 liters (ASTM D 6232).

The device is available from the manufacturer in two sizes for collection of 5 and 25 gram samples (assuming a soil density of 1.7 g/ cm 3 ). The size is chosen based on the sample size required by the analytical procedure.

SW 846 Method 5035, "Closed System Purge and Trap and Extraction for Volatile Organics in Soil and Waste Samples," recommends that samples not be stored in the device longer than 48 hours prior to sample preparation for analysis. The manufacturer's instructions for sample extrusion should be followed carefully. Appendix E 223 Advantages ° Maintains sample structure in a device that also can be used to store and transport the sample directly to the laboratory.

° Recommended for collecting samples for the analysis of volatile compounds. It collects a relatively undisturbed sample that is contained prior to analysis to minimize the loss of volatile compounds.

° Usually is compatible with the chemicals and physical characteristics of the sampled media.

° No significant physical limitations for its use.

° Cross contamination should not be a concern if the miniature core sampler is certified clean by the manufacturer and employed as a single use device.

Limitations ° Cannot be used to sample gravel or rocky soils.

° Instructions must be followed carefully for proper use to avoid trapping air with the sample and to ensure that the sample does not compromise the seals.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Practice for Using the Disposable EnCore™ Sampler for Sampling and Storing Soil for Volatile Organic Analysis, ASTM D 6418 ° Standard Guide for Sampling Waste and Soils for Volatile Organic Compounds, ASTM D 4547 Appendix E 224 Figure E 19. Modified syringe sampler E. 4.8 Modified Syringe Sampler A modified syringe sampler (Figure E 19) is a push coring sampling device constructed by the user by modifying a plastic, single use, medical syringe. It can be used to provide a small, subsample of soil, sediments, and unconsolidated solid wastes. It is sometimes used to sub sample a larger core of soil. It is not recommended for sampling cemented material, consolidated material, or material having fragments coarse enough to interfere with proper coring. Unlike the EnCore™ sampler, it should not be used to store and ship a sample to the laboratory. Instead, the sample should be extruded into another container. Although the modified syringe sampler does not provide as contained a sample as the EnCore™ sampler, it can be used for sampling volatile compounds, as long as sample extrusion into another container is quickly and carefully executed. The modified syringe sample has a volume range of 0.01 to 0.05 liters (ASTM D 6232).

A modified syringe sampler is constructed by cutting off the lower end of the syringe attachment for the needle. The rubber cap is removed from the plunger, and the plunger is pushed in until it is flush with the cut end. For greater ease in pushing into the solid matrix, the front edge sometimes can be sharpened (ASTM D 4547). The syringe sampler is then pushed into the media to collect the sample, which then may be placed in a glass VOA vial for storage and transport to the laboratory. The sample is immediately extruded into the vial by gently pushing the plunger. The volume of material collected should not cause excessive stress on the device during intrusion into the material, or be so large that the sample falls apart easily during extrusion.

Advantages ° Obtains a relatively undisturbed profile sample.

° Can be used for the collection of samples for the analysis of volatile compounds as long as sample extrusion is quickly and carefully executed.

° No significant physical limitations for its use.

° Low cost, single use device. Appendix E 225 Figure E 20. Bucket auger Limitations ° Cannot be used to sample gravel or rocky soils.

° Material of construction may be incompatible with highly contaminated media.

° Care is required to ensure that the device is clean before use.

° The device cannot be used to store and transport a sample.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Guide for Sampling Waste and Soils for Volatile Organic Compounds, ASTM D 4547 E. 5 Rotating Coring Devices Rotating coring devices include equipment that obtains vertical columns of a solid sample through a rotating action. Some of these devices (such as augers) also can be used for just boring a hole for sample collection at a certain depth using another piece of equipment. You will find summaries for the following rotating coring devices in this section:

E. 5.1 Bucket Auger E. 5.2 Rotating Coring Device E. 5.1 Bucket Auger The bucket auger (Figure E 20) is a handoperated rotating coring device generally used to sample soil, sediment, or unconsolidated solid waste. It can be used to obtain samples from drums, storage containers, and waste piles. The sample volume range is 0.2 to 1.0 liters (ASTM D 6232).

The cutting head of the auger bucket is pushed and twisted by hand with a downward force into the ground and removed as the bucket is filled. The empty auger is returned to the hole and the procedure is repeated. The sequence is continued until the required depth is reached. The same bucket may be used to advance the hole if the vertical sample is a composite of all intervals; however, discrete grab Appendix E 226 samples should be collected in separate clean auger buckets. The top several inches of material should be removed from the bucket to minimize chances of cross contamination of the sample from fall in material from the upper portions of the hole.

Note that hand augering may be difficult in tight clays or cemented sands. At depths approaching 20 feet (6 m), the tension of hand auger extension rods may make operation of the auger too difficult. Powered methods are recommended if deeper samples are required (ASTM D 6232).

Advantages ° Reusable and easy to decontaminate.

° Easy to use and relatively quick for shallow subsurface samples.

° Allows the use of various auger heads to sample a wide variety of soil conditions (USEPA 1993c).

° Provides a large volume of sample in a short time.

Limitations ° Depth of sampling is limited to about 20 feet (6 m) below the surface.

° Not suitable for obtaining undisturbed samples.

° Requires considerable strength to operate and is labor intensive.

° Not ideal for sampling soils for volatile organic compounds.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Practice for Soil Investigation and Sampling by Auger Borings, ASTM D 1452 ° Standard Guide for Soil Sampling from the Vadose Zone, ASTM D 4700 ° Standard Practice for Sampling Unconsolidated Waste From Trucks, ASTM D 5658 ° Standard Guide for Sampling of Drums and Similar Containers by Field Personnel, ASTM D 6063 ° "Waste Pile Sampling" (USEPA 1994d) Appendix E 227 Figure E 21. Rotating coring device ° "Sediment Sampling" (USEPA 1994e)

E. 5.2 Rotating Coring Device The rotating coring device (Figure E 21) collects vertical columns of a solid sample through a rotating action and can be used in sampling consolidated solid waste, soil, and sediment. The sample volume range is 0.5 to 1.0 liters (ASTM D 6232).

The rotating coring device consists of a diamond or carbide tipped open steel cylinder attached to an electric drill. The coring device may be operated with the drill hand held or with the drill mounted on a stand. When on a portable stand, fulldepth core samples can be obtained. The barrel length is usually 1 to 1.5 feet long and the barrel diameter ranges from 2 to 6 inches (ASTM D 6232 and ASTM D 5679). The rotating coring device may be used for surface or depth samples.

The rotating coring device is placed vertical to the surface of the media to be sampled, then turned on before contact with the surface. Uniform and continuous pressure is supplied to the device until the specified depth is reached. The coring device is then withdrawn and the sample is placed into a container for analysis, or the tube itself may be capped and sent to the laboratory. Capping the tube is preferred when sampling for volatile organic compounds. The rotating tube must be cooled and lubricated with water between samples.

Advantages ° Easy to decontaminate.

° Reusable.

° Can obtain a solid core sample.

Limitations ° Requires a battery or other source of power.

° Requires a supply of water, used for cooling the rotating tube.

° Not easy to operate. Appendix E 228 Figure E 22. COLIWASA Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Practice for Sampling Consolidated Solids in Drums or Similar Containers, ASTM D 5679 ° "Drum Sampling" (USEPA 1994b)

° "Sediment Sampling" (USEPA 1994e)

E. 6 Liquid Profile Devices Liquid profile devices include equipment that can collect a vertical column of a liquid, sludge, or slurry sample. You will find summaries for the following liquid profile devices in this section:

E. 6.1 Composite Liquid Waste Sampler (COLIWASA) E. 6. 2 Drum Thief E. 6.3 Valved Drum Sampler E. 6.4 Plunger Type Sampler E. 6.5 Settleable Solids Profiler (Sludge Judge)

E. 6.1 COLIWASA (Composite Liquid Waste Sampler)

The COLIWASA (Figure E 22) is a type of liquid profile sampling device used to obtain a vertical column of sampled material. A COLIWASA is recommended for sampling liquids, multi layer liquid wastes, and mixed phase solid/ liquid wastes and is commonly used to sample containerized liquids, such as tanks and drums. It also may be used for sampling open bodies of stagnant liquids. The sample volume range is 0.5 to 3 liters (ASTM D 6232).

A COLIWASA can be constructed of polyvinyl chloride (PVC), glass, metal, PTFE or any other material compatible with the sample being collected. In general, a COLIWASA comprises a tube with a tapered end and an inner rod that has some type of stopper on the end. The design can be modified or adapted to meet the needs of the sampler. One configuration comprises a piston valve attached by an inner rod to a locking Appendix E 229 mechanism at the other end. Designs are available for specific sampling situations (i. e., drums, tanks). COLIWASAs specifically designed for sampling liquids, viscous materials, and heavy sludges are also available. COLIWASAs come in a variety of diameters (0. 5 to 2 inches) and lengths (4 to 20 feet) (ASTM D 6232).

COLIWASAs are available commercially with different types of stoppers and locking mechanisms, but all have the same operating principle. To draw a sample, the COLIWASA is slowly lowered into the sample at a right angle with the surface of the material. (If the COLIWASA sampler is lowered too fast, the level of material inside and outside the sampler may not be the same, causing incorrect proportions in the sample. In addition, the layers of multi layered materials may be disturbed.) The sampler is opened at both ends as it is lowered to allow the material to flow through it. When the device reaches the desired sampling depth, the sampler is closed by the stopper mechanism and both tubes are removed from the material. The sampled material is then transferred to a sample container by opening the COLIWASA. A COLIWASA can be reused following proper decontamination (reusable point sampler) or disposed after use (single use COLIWASA). The reusable point sampler is used in the same way as the single use COLIWASA; however, it can also sample at a specific point in the liquid column.

Advantages ° Provides correct delimitation and extraction of waste (Pitard 1989).

° Easy to use.

° Inexpensive.

° Reusable.

° Single use models are available.

Limitations ° May break if made of glass and used in consolidated matrices.

° Decontamination may be difficult.

° The stopper may not allow collection of material in the bottom of a drum.

° High viscosity fluids are difficult to sample.

Other Guidance ° Standard Practice for Sampling with a Composite Liquid Waste Sampler (COLIWASA), ASTM D 5495 ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 Appendix E 230 Figure E 23. Drum thief ° Standard Guide for Sampling Drums and Similar Containers by Field Personnel, ASTM D 6063 ° Standard Practice for Sampling Single or Multilayered Liquids, With or Without Solids, in Drums or Similar Containers, ASTM D 5743 ° "Drum Sampling" (USEPA 1994b)

° "Tank Sampling" (USEPA 1994c)

E. 6.2 Drum Thief A drum thief (Figure E 23) is an open ended tube and liquid profile sampling device that provides a vertical column of the sampled material. It is recommended for sampling liquids, multi layer liquid wastes, and mixed phase solid/ liquid wastes and can be used to sample liquids in drums or similar containers. The typical sample volume range is 0.1 to 0.5 liters (ASTM D 6232).

Drum thieves can be made of glass, stainless steel, or any other suitable material. Drum thieves are typically 6 mm to 16 mm inside diameter and 48 inches long (USEPA 1994c). To sample liquids with low surface tension, a narrow bailer works best. In most cases, tubes with a 1 centimeter inside diameter work best. Wider tubes can be used to sample sludges.

The drum thief is lowered vertically into the material to be sampled, inserted slowly to allow the level of material inside and outside the tube to be approximately the same. This avoids incorrect proportions in the sample. The upper end is then sealed with the thumb or a rubber stopper to hold the sample in the tube as it is removed from the container. The thief is emptied by removing the thumb or stopper.

Advantages ° Easy to use and inexpensive.

° Available in reusable and single use models.

Limitations ° Sampling depth is limited to the length of the sampler.

° May not collect material in the bottom of a drum. The depth of unsampled material depends on the density, surface tension, and viscosity of the material being sampled. Appendix E 231 Figure E 24. Valved drum sampler ° Highly viscous materials are difficult to sample.

° May be difficult to retain sample in the tube when sampling liquids of high specific gravity.

° If made of glass, may break if used in consolidated matrices. In addition, chips and cracks in a glass drum thief may cause an imperfect seal.

° Decontamination is difficult.

° When sampling a drum, repeated use of the drum thief to obtain an adequate volume of sample may disturb the drum contents.

° Drum size tubes have a small volume and sometimes require repeated use to obtain a sample. Two or more people may be required to use larger sizes.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Guide for Sampling of Drums and Similar Containers by Field Personnel, ASTM D 6063 ° Standard Practice for Sampling Single or Multilayered Liquids, With or Without Solids, in Drums or Similar Containers, ASTM D 5743 ° "Drum Sampling" (USEPA 1994b)

° "Tank Sampling" (USEPA 1994c)

E. 6.3 Valved Drum Sampler A valved drum sampler (Figure E 24) is a liquid profile device often used to sample liquids in drums or tanks and provides a vertical column of the sampled material. A valved drum sampler is recommended for sampling liquids, multi layered liquid wastes, and mixed phase solid/ liquid wastes. The typical sample volume range is 0.3 to 1.6 liters (ASTM D 6232).

The sampler can be constructed from PTFE for reuse or polypropylene for single use and comprises a tube fitted with a top plug and a bottom valve. A sliding indicator ring allows specific levels or fluids interfaces to be identified.

The valved drum sampler is open at both ends during Appendix E 232 Figure E 25. Plunger type sampler sample collection and lowered vertically into the material to be sampled. The sampler is inserted slowly to allow the level of material inside and outside the tube to equalize. Once the desired amount of sample is collected, the top plug and the bottom valve are closed. The top plug is closed manually and the bottom valve is closed by pressing against the side or bottom of the container. The sample is poured from the top of the sampler into a suitable container.

Advantages ° Easy to use, inexpensive, and unbreakable.

° Obtains samples to depths of about 8 feet (2. 4 m) (ASTM D 6232).

° Reusable if made from PTFE (single use if made from polypropylene) (ASTM D 6232).

Limitations ° Somewhat difficult to decontaminate ° The bottom valve may prevent collection of the bottom 1.25 cm of material (ASTM D 6232).

° High viscosity fluids are difficult to sample.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 E. 6.4 Plunger Type Sampler The plunger type sampler (Figure E 25) is a liquid profile sampling device used to collect a vertical column of liquid and is recommended for the sampling of single and multilayered liquids or mixtures of liquids and solids. The plunger type sampler can be used to collect samples from drums, surface impoundments, and tanks. Sample volume is at least 0.2 liters and ultimately depends on the size of the sample container (ASTM D 6232).

A plunger type sampler comprises a sample tube, sample line or rod, head section, and plunger and is made of HDPE, PTFE, or glass. A sample jar is connected to the head section. The sample tube is lowered into the liquid to the desired depth. The plunger is engaged into the tube to secure the sample within the tube and the cord or rod is raised to transfer the sample directly into the Appendix E 233 Figure E 26. Settleable solids profiler sampling bottle or jar. The plunger can be pushed back down the sampling tube to reset the sampler.

Advantages ° Easy to use.

° Provides a sealed collection system.

° Relatively inexpensive and available in various lengths.

Limitations ° Care is needed when using a glass sampling tube.

° Decontamination may be difficult, particularly when a glass sampling tube is used.

Other Guidance:

° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Practice for Sampling Single or Multilayered Liquids, With or Without Solids, in Drums or Similar Containers, ASTM D 5743 E. 6.5 Settleable Solids Profiler (Sludge Judge)

The settleable solids profiler (Figure E 26), also known as the sludge judge, primarily is used to measure or sample settleable (suspended) solids found in sewage treatment plants, waste settling ponds and impoundments containing waste. It also can be used to sample drums and tanks. It has a sample volume range of 1.3 to 4.0 liters (ASTM D 6232).

The sludge judge is made from clear PVC and has 1 foot depth markings on its 5 foot long body sections. It has a check valve on the lower section and a cord on the upper section and is assembled using the threaded connections of the sections to the length needed for the sampling event. The sampler is lowered into the media to allow it to fill. A tug on the cord sets the check valve and it is removed from the sampled material. The level of settleable solids can be measured using the markings. It is emptied by pressing in the protruding pin on the lower end. Appendix E 234 Figure E 27. Bailer Advantages ° Allows measurement of the liquid/ settleable solids columns of any length.

° Easy to assemble and use.

° Unbreakable in normal use and reusable.

Limitations ° Suitable for sampling noncaustic liquids only.

° May be difficult to sample high viscosity materials.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 E. 7 Surface Sampling Devices Surface sampling devices include equipment that by design are limited to sample collection at the surface of material or can sample material of limited depth or width only. You will find summaries for the following surface sampling devices in this section:

E. 7.1 Bailer E. 7.2 Dipper E. 7.3 Liquid Grab Sampler E. 7.4 Swing Jar Sampler E. 7.5 Spoons, Scoops, Trowels, and Shovels E. 7.1 Bailer Bailers (Figure E 27) are designed for obtaining samples of ground water; however, they also can be used to obtain samples of liquids and multi layered liquid wastes from tanks and surface impoundments. Bailers are not suitable for sampling sludges. The sample volume range is 0.5 to 2 liters (ASTM D 6232).

A bailer is a hollow tube with a check valve at the base (open bailer) or valves at both ends (point source bailer). A bailer can be threaded in the middle so that extension tubes can be added to increase the sampling volume. It can be constructed of stainless steel, PVC, PTFE, or any other Appendix E 235 suitable material and is available in numerous sizes for use in a variety of well sizes. The bailer is attached to a line and gradually lowered into the sample. As the bailer is lowered, the bottom check valve allows water to flow through the tube. The bailer is then slowly raised to the surface. The weight of the water closes the bottom check valve. A point source bailer allows sampling at a specific depth. The check valve at the top of the tube limits water or particles from entering the bailer as it is retrieved.

The bailer is emptied either by pouring from the top or by a bottom emptying device. When using a top emptying bailer, the bailer should be tipped slightly to allow a slow discharge into the sample container to minimize aeration. A bottom emptying model has controlled flow valves, which is good for collecting samples for volatile organic analysis since agitation of the sample is minimal.

Advantages ° Easy to use, inexpensive, and does not require an external power source.

° Can be constructed of almost any material that is compatible with the parameters of interest.

° Relatively easy to decontaminate between samples. Single use models are available.

° Bottom emptying bailers with control valves can be used to obtain samples for volatile compound analysis.

Limitations ° Not designed to obtain samples from specific depths below liquid surface (unless it is a point source bailer).

° If using a top emptying bailer, the sample may become aerated if care is not taken during transfer to the sample container.

° May disturb the sample in a water column if it is lowered too rapidly.

° High suspended solids' content or freezing temperatures can impact operation of check valves.

° One of the least preferred devices for obtaining samples of ground water for low concentration analyses due to their imprecision and agitation of the sample (see USEPA 1992a and Puls and Barcelona 1996).

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Guide for Sampling Groundwater Monitoring Wells, ASTM D 4448 Appendix E 236 Figure E 28. Dipper ° "Tank Sampling" (USEPA 1994c)

E. 7.2 Dipper A dipper (Figure E 28) is a type of surface sampling device used to sample surface samples from drums, surface impoundments, tanks, pipes, and point source discharges. Sampling points are shallow (10 inches) and taken at, or just below, the surface. The typical sample volume range is 0.5 to 1.0 liters (ASTM D 6232).

A dipper comprises a glass, metal, or plastic beaker clamped to the end of a two or three piece telescoping aluminum or fiberglass pole, which serves as a handle. A dipper may vary in the number of assembled pieces. Some dippers have an adjustable clamp attached to the end of a piece of metal tubing. The tubing forms the handle; the clamp secures the beaker. Another type of dipper is a stainless steel scoop clamped to a movable bracket that is attached to a piece of rigid tube. The scoop may face either toward or away from the person collecting the sample, and the angle of the scoop to the pipe is adjustable. The dipper, when attached to a rigid tube, can reach easily 10 to 13 feet (3 to 4 m) away from the person collecting the samples (ASTM D 6232).

The dipper is used by submerging the beaker end into the material slowly (to minimize surface disturbance). It should be on its side so that the liquid runs into the container without swirling or bubbling. The beaker is filled and rotated up, then brought slowly to the surface. Dippers and their beakers should be compatible with the sampled material.

Advantages ° Inexpensive.

° Easy to construct and adapt to the sampling scenario by modifying the length of the tubing or the type of container.

Limitations ° Not appropriate for sampling subsurface layers or to characterize discrete layers of stratified liquids.

° Can only be used to collect surface samples. Appendix E 237 Figure E 29. Liquid grab sampler Other Guidance ° Standard Practice for Sampling with a Dipper or Pond Sampler, ASTM D 5358 ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Practice for Sampling Wastes from Pipes and Other Point Discharges, ASTM D 5013 E. 7. 3 Liquid Grab Sampler A liquid grab sampler (Figure E 29) is a surface sampling device designed to collect samplers at a specific shallow depth beneath the liquid surface. It can be used to collect samples of liquids or slurries from surface impoundments, tanks, and drums. Its sample volume range is from 0.5 to 1.0 liters (ASTM D 6232).

The liquid grab sampler is usually made from polypropylene or PTFE with an aluminum or stainless steel handle and stainless steel fittings. The sampling jar is usually made of glass, although plastic jars are available. The jar is threaded into the sampler head assembly, then lowered by the sampler to the desired sampling position beneath the liquid surface. The valve is then opened by pulling up on a finger ring to fill the jar. The valve is closed before retrieving the sample.

Advantages ° Easy to use.

° The sample jar can be capped and used for transport to the laboratory, thus minimizing the loss of volatile organic compounds.

° The closed sampler prevents contaminants in upper layers from compromising the sample.

Limitations ° Care is required to prevent breakage of glass sample jar.

° Materials of construction need to be compatible with the sampled media. Appendix E 238 Figure E 30. Swing jar sampler ° Cannot be used to collect deep samples.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 E. 7.4 Swing Sampler (Swing Jar Sampler)

The swing jar sampler (Figure E 30) is a surface sampler that may be used to sample liquids, powders, or small solids at distances of up to 12 feet (3. 5 m). It can be used to sample many different types of units, including drums, surface impoundments, tanks, pipe/ point source discharges, sampling ports, and storage bins. It has a sample volume range of 0.5 to 1.0 liters.

The swing jar sampler is normally used with high density polyethylene sample jars and has an extendable aluminum handle with a pivot at the juncture of the handle and the jar holder. The jar is held in the holder with an adjustable clamp. The pivot allows samples to be collected at different angles.

Advantages ° Easy to use.

° Easily adaptable to samples with jars of different sizes and materials, which can be used to facilitate compatibility with the material to be sampled.

° Can be pivoted to collect samples at different angles.

° Can sample from a wide variety of locations and units.

Limitations ° Cannot collect discrete depth samples.

° Care is required to prevent breakage when using a glass sample jar.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 Appendix E 239 Figure E 31. Scoops E. 7.5 Spoons, Scoops, Trowels, and Shovels Spoons, scoops, trowels, or shovels are types of surface sampling devices used to sample sludge, soil, powder, or solid wastes. The typical sample volume range is 0.1 to 0.6 liters for scoops or trowels and 1.0 to 5.0 Liters for shovels (ASTM D 6232). The typical sample volume for a spoon is 10 to 100 grams (USEPA 1993c).

Spoons, available in stainless steel or PTFE (reusable) or in plastic (disposable), easily sample small volumes of liquid or other waste from the ground or a container.

Scoop samplers provide best results when the material is uniform and may be the only sampler possible for materials containing fragments or chunks. The scoop size should be suitable for the size and quantity of the collected material. Scoops and trowels come in a variety of sizes and materials, although unpainted stainless steel is preferred (ASTM D 6232). Scoops may be attached to an extension, similar to the dipper, in order to reach a particular area. Scoops and trowels are used by digging and rotating the sampler. The scoop is used to remove a sample and transfer it into a sample container.

Shovels, usually made from stainless steel or suitable plastic materials, are typically used to collect surface samples or to remove overburden material so that a scoop may remove a sample.

Advantages ° A correctly designed scoop or spatula (i. e., with a flat bottom and vertical sides) is one of the preferred devices for sampling a one dimensional mass of granular solids (see also Sections <IP_ADDRESS> and <IP_ADDRESS>).

° Spoons, scoops, trowels, and shovels are reusable, easy to decontaminate, and do not require significant physical strength to use.

° Spoons and scoops are inexpensive and readily available.

° Spoons and scoops are easily transportable and often disposable  hence, their use can reduce sampling time.

° Shovels are rugged and can be used to sample hard materials. Appendix E 240 Limitations ° Spoons, scoops, trowels, and shovels are limited to shallow and surface sampling.

° Shovels may be awkward to handle and cannot be used to easily fill small sample containers.

° Sampling with a spoon, scoop, trowel, or shovel may cause loss of volatile organic compounds through disturbance of the media.

° Spoons, scoops, trowels, and shovels of incorrect design (e. g., with rounded bottoms) can introduce bias by preferentially selecting certain particle sizes.

Other Guidance ° Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities, ASTM D 6232 ° Standard Practice for Sampling with a Scoop, ASTM D 5633 ° "Waste Pile Sampling" (USEPA 1994d)

° "Sediment Sampling" (USEPA 1994e). 241 APPENDIX F STATISTICAL METHODS This appendix provides guidance on the statistical analysis of waste testing and environmental monitoring data. You should select the statistical test during the Data Quality Assessment (DQA) phase after you review the data quality objectives, the sampling design, and the characteristics of the data set. See guidance provided in Section 8.

The statistical methods in this appendix are appropriate for use in evaluating sample analysis results when comparing constituent concentrations in a waste or environmental medium to a fixed standard. Users of this guidance may have other objectives such as comparing two populations, detecting trends, or characterizing the spatial pattern of contamination. If so, review other guidance or seek assistance from a professional environmental statistician.

Note that not all RCRA standards require the waste handler to use sampling, analysis, and statistical tests to measure compliance. However, if sampling and analysis is used by the waste handler to measure compliance with a RCRA standard, then statistical methods may be used to help quantify uncertainty associated with the decisions made using the data – even where there is no regulatory obligation to do so (see also Sections 2 and 3).

This appendix is divided into subsections that describe the following statistical methods:

F. 1 Testing Distributional Assumptions F. 1.1 Overview and Recommendations F. 1.2 Shapiro Wilk Test for Normality ( ) n   50 F. 2 Confidence Limits for the Mean F. 2.1 Confidence Limits for the Mean of a Normal Distribution F. 2.2 Confidence Limits for a Normal Mean When Composite Sampling Is Used F. 2.3 Confidence Limits for a Lognormal Mean F. 2.4 Confidence Limits for the Mean of a Non normal or Unknown Distribution F. 3 Tests for a Proportion or a Percentile F. 3.1 Parametric Upper Confidence Limits for an Upper Percentile F. 3.2 Using a Simple Exceedance Rule Method for Determining Compliance With A Fixed Standard F. 4 Treatment of Nondetects F. 4.1 Recommendations F. 4.2 Cohen's Adjustment Table F 1 provides a summary of frequently used statistical equations. See Appendix G for statistical tables used with these methods. Additional Guidance on the Statistical Analysis of Waste Testing and Environmental Monitoring Data USEPA. 2000d. Guidance For Data Quality Assessment, EPA QA/ G 9, (QA00 version). EPA/ 600/ R 96/ 084. Office of Research and Development, Washington, D. C. Appendix F 242 Table F 1. Summary of Basic Statistical Terminology Applicable to Sampling Plans for Solid Waste Terminology Symbol Mathematical Equation Equation No.

Variable (e. g., barium or endrin)   x Individual measurement of xi  variable

Simple Random Sampling and Systematic Random Sampling Mean of measurements generated from the samples (sample mean) x x n xi i n = =   1 1 where n = number of sample measurements. 1 Variance of sample s 2 s n x x i i n 2 2 1 1 1 =     =   () 2 Standard deviation of sample s s s = 2 3 Standard error (also standard deviation of the mean) sx s s n x = 4 Approximate number of samples to estimate the mean (financial constraints not considered) (See Section 5.4.1) n n z zsz = + +   () 1 1  2 2 2 1  2 2        where the " " values are obtained from the last z row of Table G 1 in Appendix G. 8 Approximate number of samples to test a proportion against a fixed standard (See Section 5.5.1). n n z GR GR z AL AL =   +                     1 1  2 2 1 1    () ()

  15 Number of samples to test a proportion when the decision rule specifies zero nonconforming samples (See Section 5.5.2). n n p = log( ) log( )   where equals the proportion of the waste or p media exceeded by the largest sample 16 Appendix F 243 Table F 1. (Continued)

Terminology Symbol Mathematical Equation Equation No.

Stratified Random Sampling (Proportional Allocation)

Arithmetic mean of the measurements generated from the samples obtained from each stratum hth xh x n x h h hi i nh = =   1 1 where = number of sample measurements nh obtained from each stratum. hth

Variance of measurements generated from the samples obtained from each stratum hth sh 2 s n x x h h hi h i nh 2 2 1 1 1 =     =   ()

The weighting factor assigned to each hth stratum when stratified random sampling is used Wh

Overall sample mean using stratified random sampling x st x Wx st h h h L = =   1 9 Standard error of the mean for a stratified random sample sxst s W s n x h h L h h st = =   2 1 2 10 Total number of samples to collect from a solid waste to estimate the mean using stratified random sampling (proportional allocation) n [ ] n t t W s df df h h h L = +     =   1 1 2 2 2 1    ,,

  11 Degrees of freedom associated with the t quantile in Table G 1, Appendix G, when stratified random sampling is used df df W s W s nW h h h L h h h h L =               = =     2 1 2 2 4 1 1 12 Appendix F 244 F. 1 Testing Distributional Assumptions F. 1.1 Overview and Recommendations The assumption of normality is very important as it is the basis for many statistical tests. A normal distribution is a reasonable model of the behavior of certain random phenomena and often can be used to approximate other probability distributions. In addition, the Central Limit Theorem and other limit theorems state that as the sample size gets large, some of the sample summary statistics (such as the sample mean) behave as if they are normally distributed variables. As a result, a common assumption associated with parametric tests or statistical models is that the errors associated with data or a model follow a normal distribution.

While assumption of a normal distribution is convenient for statistical testing purposes, it is not always appropriate. Sometimes data are highly skewed. In environmental applications, it is not unusual to encounter data that exhibit a lognormal distribution in which the natural logarithms of the data exhibit a normal distribution. Statistical tests can be used to verify the assumption of normality or lognormality, but the conclusion of lognormality should not be based on the outcome of a statistical test alone. There are several physical phenomena that can cause the underlying distribution to appear lognormal when in fact it is not. For example, Singh, et al. (1997) note that the presence of a relatively small highly contaminated area in an otherwise uncontaminated area can cause sampling results to indicate a lognormal distribution. In such a situation, it may be more appropriate to treat the areas as two separate decision units or use a stratified sampling design. In other cases, sampling bias may cause a population to appear lognormal. For example, analytical results could be skewed if highly concentrated portions of the waste are over or under represented by the sampling procedure.

There are many methods available for verifying the assumption of normality ranging from simple to complex. This guidance recommends use of the Shapiro Wilk test for normality. Use of the test is appropriate when the number of samples (n) is 50 or less. For n greater than 50, an alternative test for normality should be used. One alternative presented in EPA's QA/ G 9 guidance (USEPA 2000d) and the DataQUEST software (USEPA 1997b) is Filliben's Statistic (Filliben 1975). Refer to EPA's QA/ G 9 (USEPA 2000d) guidance or EPA's statistical guidance for ground water monitoring data (USEPA 1989b and 1992b) for other graphical and statistical goodness of fit tests.

F. 1.2 Shapiro Wilk Test for Normality ( ) n   50 Purpose and Background This section provides the method for performing the Shapiro Wilk test for normality. The test is easily performed using statistical software such as EPA's DataQUEST freeware (USEPA 1997b); however, the test also can be performed manually, as described here.

The Shapiro Wilk test is recommended as a superior method for testing normality of the data. It is based on the premise that if the data are normally distributed, the ordered values should be highly correlated with corresponding quantiles (z scores) taken from a normal distribution (Shapiro and Wilk 1965). In particular, the Shapiro Wilk test gives substantial weight to evidence of non normality in the tails of a distribution, where the robustness of statistical tests based on the normality assumption is most severely affected. Appendix F 245 The Shapiro Wilk test statistic (W) will tend to be large when a probability plot of the data indicates a nearly straight line. Only when the plotted data show significant bends or curves will the test statistic be small. The Shapiro Wilk test is considered to be one of the very best tests of normality available (Miller 1986, Madansky 1988).

Procedure Step 1. Order the data from least to greatest, labeling the observations as for xi . Using the notation , let the order statistic from any data set i n = 1... x j () jth represent the smallest value. jth Step 2. Compute the differences for each . Then determine x x n i i ()()   +   1 i n = 1...

as the greatest integer less than or equal to . k (/) n 2 Step 3. Use Table G 4 in Appendix G to determine the Shapiro Wilk coefficients, , an i   + 1 for . Note that while these coefficients depend only on the sample size i n = 1... ( ), the order of the coefficients must be preserved when used in step 4 below. n The coefficients can be determined for any sample size from n = 3 up to n = 50.

Step 4. Compute the quantity given by the following formula: b b bax x i ninii i k i k = =     +   + = =     1 1 1 1 () ()() Equation F. 1 Note that the values are simply intermediate quantities represented by the bi terms in the sum of the right hand expression in the above equation.

Step 5. Calculate the standard deviation (s) of the data set. Then compute the Shapiro Wilk test statistic using the following formula:

W b s n =               1 2 Equation F. 2 Step 6. Given the significance level ( ) of the test (for example, 0.01 or 0.05),   determine the critical point of the Shapiro Wilk test with n observations using Table G 5 in Appendix G. Compare the Shapiro Wilk statistic (W) against the critical point ( ). If the test statistic exceeds the critical point, accept normality wc as a reasonable model for the underlying population; however, if , reject W wc < the null hypothesis of normality at the level and decide that another   distributional model would provide a better fit.

An example calculation of the Shapiro Wilk test for normality is presented in Box F. 1. Appendix F 246 Box F. 1. Example Calculation of the Shapiro Wilk Test for Normality Use the Shapiro Wilk test for normality to determine whether the following data set, representing the total concentration of nickel in a solid waste, follows a normal distribution: 58.8, 19, 39, 3.1, 1, 81.5, 151, 942, 262, 331, 27, 85.6, 56, 14, 21.4, 10, 8.7, 64.4, 578, and 637.

Solution Step 1. Order the data from smallest to largest and list, as in Table F 2. Also list the data in reverse order alongside the first column.

Step 2. Compute the differences in column 4 of the table by subtracting column 2 x x n i i ()()   +   1 from column 3. Because the total number of samples is , the largest integer less than n = 20 or equal to is . (/) n 2 k = 10 Step 3. Look up the coefficients from Table G 4 in Appendix G and list in column 4. an i   + 1 Step 4. Multiply the differences in column 4 by the coefficients in column 5 and add the first k products ( ) to get quantity , using Equation F. 1. bi bi b = .4734( 941.0)+. 3211( 633.9) + .0140( 2. 8)       = 932 88 .

Step 5. Compute the standard deviation of the sample, = 259.72, then use Equation F. 2 to calculate s the Shapiro Wilk test statistic:

W =             = 932 88 259 72 19 0 679 2 . . .

Step 6. Use Table G 5 in Appendix G to determine the .01 level critical point for the Shapiro Wilk test when = 20. This gives = 0.868. Then, compare the observed value of = 0.679 to n wc W the 1 percent critical point. Since < 0.868, the sample shows significant evidence of non W normality by the Shapiro Wilk test. The data should be transformed using natural logs and rechecked using the Shapiro Wilk test before proceeding with further statistical analysis. Appendix F 247 Table F 2. Example Calculation of the Shapiro Wilk Test (see example in Box F. 1)

i x i () x n i ()   + 1 x x n i i ()()   +   1 an i   + 1 bi 1 1 942 941 0.4734 445.47 2 3. 1 637 634 0.3211 203.55 3 8. 7 578 569 0.2565 146.03 4 10 331 321 0.2085 66.93 5 14 262 248 0.1686 41.81 6 19 151 132 0.1334 17.61 7 21.4 85.6 64.2 0. 1013 6.5 8 27 81.5 54.5 0. 0711 3.87 9 39 64.4 25.4 0. 0422 1.07 10 56 58.8 2. 8 0.0140 0.04 11 58.8 56 –2.8 b = 932.88 12 64.4 39 –25.4 13 81.5 27 –54.5 14 85.6 21.4 –64.2 15 151 19 –132.0 16 262 14 –248.0 17 331 10 –321.0 18 578 8.7 –569.3 19 637 3.1 –633.9 20 942 1 –941.0 F. 2 Confidence Limits for the Mean When a fixed standard or limit is meant to represent an average or mean concentration level, attainment of the standard can be measured using a confidence limit on the mean. A confidence limit is then compared with the fixed compliance limit. Under the null hypothesis that the mean concentration in the waste exceeds the standard unless proven otherwise, statistically significant evidence of compliance with the standard is shown if and only if the entire confidence interval lies below the standard. By implication, the key test then involves comparing the upper confidence limit (UCL) to the standard. In other words, the entire confidence interval must lie below the standard for the waste to be compliant with the standard. If the UCL exceeds the regulatory limit, on the other hand, we cannot conclude the mean concentration is below the standard.

F. 2.1 Confidence Limits for the Mean of a Normal Distribution Requirements and Assumptions Confidence intervals for the mean of a normal distribution should be constructed only if the data pass a test of approximate normality or at least are reasonably symmetric. It is strongly recommended that a confidence interval not be constructed with less than four measurements, though the actual number of samples should be determined as part of the planning process. The reason for this is two fold: (1) the formula for a normal based confidence interval on the Appendix F 248 mean involves calculation of the sample standard deviation (s), which is used as an estimate of the underlying population standard deviation (this estimate may not be particularly accurate when the sample size is smaller than four), and (2) the confidence interval formula also involves a Student's t quantile based on n  1 degrees of freedom, where n equals the number of samples used in the calculation (see Table G 1 in Appendix G). When n is quite small, the tquantile will be relatively large, leading to a much wider confidence interval than would be expected with a larger n. For example, at a 90 percent confidence level, the appropriate tquantile would be t = 3.078 for n = 2, t = 1.638 for n = 4, and t = 1.415 for n = 8.

Procedure Step 1. Check the n sample concentrations for normality. If the normal model is acceptable, calculate the mean ( ) and standard deviation (s) of the data set. If x the lognormal model provides a better fit, see Section F. 2.3.

Step 2. Given the desired level of confidence, ( ), calculate the upper confidence 1      limit as follows:

UCL x t s n df = +   1   , Equation F. 3 where is obtained from a Student's t table (Table G 1) with the t df 1      ,

appropriate degrees of freedom. If simple random or systematic sampling is used, then . df n =   1 If stratified random sampling is used, calculate the UCL as follows:

UCL x t s st st df xst = +   1   , Equation F. 4 where is the overall mean from Equation 8, the is obtained from Equation xst df 11, and the standard error ( ) is obtained from Equation 9 (see also Table F sxst 1 for these equations).

Step 3. Compare the UCL calculated in Step 2 to the fixed standard. If the UCL is less than the standard, then you can conclude, with 100( )% confidence, that 1      the mean concentration of the constituent of concern is less than the standard. If, however, the upper confidence bound is greater than the standard, then there is not sufficient evidence that the mean is less than the standard.

An example calculation of the UCL on the mean is provided in Box F. 2. Appendix F 249 F. 2.2 Confidence Limits for a Normal Mean When Composite Sampling Is Used If a composite sampling strategy has been employed to obtain a more precise estimate of the mean, confidence limits can be calculated from the analytical results using the same procedure outlined above in Section F. 2.1, except that n represents the number of composite samples and s represents the standard deviation of the n composite samples.

F. 2.3 Confidence Limits for a Lognormal Mean If the results of a test for normality indicate the data set may have a lognormal distribution, and a confidence limit on the mean is desired, then a special approach is required. It is not correct to simply transform the data to the log scale, calculate a normal based mean and confidence interval on the logged data, and transform the results back to the original scale. It is a common mistake to do so. Invariably, a transformation bias will be introduced and the approach will underestimate the mean and UCL. In fact, the procedure just described actually produces a confidence interval around the median of a lognormal population rather than the higher valued mean.

To calculate a UCL on the mean for data that exhibit a lognormal distribution, this guidance recommends use of a procedure developed by Land (1971, 1975); however, as noted below, Land's procedure should be used with caution because it relies heavily on the lognormal assumption, and if that assumption is not true, the results may be substantially biased.

Requirements and Assumptions Confidence intervals for the mean of a lognormal distribution should be constructed only if the data pass a test of approximate normality on the log scale. While many environmental Box F. 2. Example Calculation of the UCL for a Normal Mean A generator obtains ten samples of waste to demonstrate that the waste qualifies for the comparable fuels exclusion under 40 CFR 261.38. The samples are obtained using a simple random sampling design. Analysis of the samples for lead generated the following results: 16, 17.5, 21, 22, 23, 24, 24.5, 27, 31, and 38 ppm. The regulation requires comparison of a 95% UCL on the mean to the specification level. The specification level is 31 ppm.

Solution Step 1. Using the Shapiro Wilk test, we confirmed that the normal model is acceptable. The mean is calculated as 24.4 ppm and the standard deviation as 6.44 ppm.

Step 2. The RCRA regulations at 40 CFR 261.38( c)( 8)( iii)( A) require that the determination be made with a level of confidence, 100( )%, of 95 percent. We turn to Table G 1 (Appendix G) and find the Student's t 1     value is 1.833 for degrees of freedom. The UCL is calculated as follows: n   = 1 9 UCL = + =   24 4 1833 644 10 281 28 .. . .

Step 3. We compare the limit calculated in step 2 to the fixed standard. Because the UCL (28 ppm) is less than the regulatory level (31 ppm), we can conclude with at least 95 percent confidence that the mean concentration of the constituent in the waste is less than 31 ppm. Appendix F 250 populations tend to follow the lognormal distribution, it is usually wisest to first test the data for normality on the original scale. If such a test fails, the data can then be transformed to the logscale and retested.

Cautionary Note: Even if a data set passes a test for normality on the log scale, do not proceed with calculation of the confidence limits using Land's procedure until you have considered the following:

° The skewness of the data set may be due to biased sampling, mixed distributions of multiple populations, or outliers, and not necessarily due to lognormally distributed data (see Singh, et al. 1997). Review the sampling approach, the physical characteristics of the waste or media, and recheck any unusually high values before computing the confidence limits. Where there is spatial clustering of sample data, declustering and distribution weighting techniques (Myers 1997) may also be appropriate.

° If the number of samples (n) is small, the confidence interval obtained by Land's procedure could be remarkably wide. Singh, et al. (1997) have recommended that Land's procedure not be used for cases in which the number of samples is less than 30. They argue that in many cases the resulting UCL will be an order of magnitude larger than the maximum observed data value. Even higher values for the UCL could be generated if the coefficient of variation (CV or the standard deviation divided by the mean) is greater than 1.

If the lognormal distribution is the best fit, and the number of samples (n) is small, then Land's method (provided below) can still be used, though a "penalty" will be paid for the small sample size. If the number of samples is small and the distribution is skewed to the right, one of the following alternative approaches should be considered: (1) Simply treat the data set as if the parent distribution were normal and use the parametric Student t method to calculate confidence limits using the untransformed (original scale) data (as described in Section F. 2.1). If, however, this normal theory approach is used with highly skewed data, the actual confidence level achieved by the test will be less than that desired (Porter, et al. 1997); (2) UCLs on the mean could be constructed using procedures such as the "bootstrap" or the "jackknife," as recommended by Singh, et al. (1997) (see Section F. 2.4).

The approach for Land's "H statistic" method is given below:

Procedure Step 1. Test the data for normality on the log scale. After determining that the lognormal distribution is a good fit, transform the data via logarithms (the natural log is used) and denote the transformed measurements by . yi Step 2. Compute the sample mean and the standard deviation ( ) from the log scale sy measurements.

Step 3. Obtain Land's bias correction factor( s) ( ) from Table G 6 in Appendix G, H1      where the correct factor depends on the sample size (n), the log scale sample Appendix F 1 For a more extensive tabulation of Land's factors, see Land (1975) or Tables A10 through A13 in Gilbert (1987).

251 standard deviation ( ), and the desired confidence level ( ). 1 sy 1      Step 4. Plug all these factors into the equations given below for the UCL.

UCL y s s H n y y 1 2 1 5 1     = + +                   exp . Equation F. 5 Step 5. Compare the UCL against the fixed standard. If the UCL is less than the standard, then you can conclude with 100( )% confidence that the mean 1    concentration of the constituent of concern is less than the standard. If, however, the upper confidence bound is greater than the standard, then there is not sufficient evidence that the mean is less than the standard.

An example calculation of the UCL on a lognormal mean is given in Box F. 3.

Box F. 3: Example Calculation of the UCL on a Lognormal Mean This example is modified after an example provided in Supplemental Guidance to RAGS: Calculating the Concentration Term (USEPA 1992a).

The concentration of lead (total in mg/ Kg) in 31 soil samples obtained using a simple random sampling design are: 1, 3, 13, 14, 18, 20, 21, 36, 37, 41, 42, 45, 48, 59, 60, 110, 110, 111, 111, 136, 137, 140, 141, 160, 161, 200, 201, 230, 400, 1300, and 1400. Using these data, calculate a 90% UCL on the mean.

Solution Step 1. Using the Shapiro Wilk test, the natural logarithms of the data set are shown to exhibit a normal distribution. The data are then transformed to natural logs.

Step 2. The mean of logged data is . The standard deviation is . y = 4 397 . sy = 1509 .

Step 3. The bias correction factor ( ) is obtained from Table G 6 for and a confidence H1 2 282   =   . n = 31 level of 90 percent .

Step 4. Plug the factors into the equation for the upper (UCL) confidence limit.

UCL1 2 4 222 05 1509 1509 2 282 31 1 5989 399   = + +               = =   exp . . ( . ) .(.)

exp( . ) mg / kg Step 5. The 90 percent UCL on the mean is 399 mg/ kg. Appendix F 252 F. 2.4 Confidence Limits for the Mean of a Non normal or Unknown Distribution If the assumption of a normal or lognormal distribution cannot be justified, then you may construct a UCL on the mean using one of several alternative methods described in this section.

Bootstrap or Jackknife Methods: Bootstrap and jackknife procedures, as discussed by Efron (1981) and Miller (1974), typically are nonparametric statistical techniques which can be used to reduce the bias of point estimates and construct approximate confidence intervals for parameters such as the population mean. These procedures require no assumptions regarding the statistical distribution (e. g., normal or lognormal) for the underlying population.

Using a computer, the bootstrap method randomly samples n values with replacement from the original set of n random observations. For each bootstrap sample, the mean (or some other statistic) is calculated. This process of "resampling" is repeated hundreds or perhaps thousands of times and the multiple estimates of the mean are used to define the confidence limits on the mean. The jackknife approximates the bootstrap. Rather than resampling randomly from the entire sample like the bootstrap does, the jackknife takes the entire sample except for one value, and then calculates the statistic of interest. It repeats the process, each time leaving out a different value, and each time recalculating the test statistic.

Both the bootstrap and the jackknife methods require a great deal of computer power, and, historically have not been widely adopted by environmental statisticians (Singh, et al. 1997). However, with advances in computer power and availability of software, computationally intensive statistical procedures have become more practical and accessible. Users of this guidance interested in applying a "resampling" method such as the bootstrap or jackknife should check the capabilities of available software packages and consult with a professional statistician on the correct use and application of the procedures.

Nonparametric Confidence Limits: If the data are not assumed to follow a particular distribution, then it may not be possible to calculate a UCL on the mean using normal theory techniques. If, however, the data are non normal but approximately symmetric, a nonparametric UCL on the median (or the 50 th percentile) may serve as a reasonable alternative to calculation of a parametric UCL on the mean. One severe limitation of this approach is that it involves changing the parameter of interest (as determined in the DQO Process) from the mean to the median, potentially biasing the result if the distribution of the data is not symmetric. Accordingly, the procedure should be used with caution.