navbar.gif (6338 bytes)

2 Evaluation Criteria

2.2 Sample Access and Collection Tools

Technologies listed in the Sample Access and Collection Tools Matrix have been divided into three categories:

  1. Access Tools which enable field staff to access media.
  2. Collection Tools that allow staff to physically remove samples.
  3. Extraction Tools that bridge the process between sample collection and sample analysis.

The Access Tools category is divided into the following seven subcategories (a descriptive summary for each technology listed under Access Tools is contained in Section 3 of the Reference Guide):

1. Drilling Methods - Unconsolidated Materials identifies six power-driven methods for drilling in clays, sands, silts, and gravel. Drilling is used for the collection of solids samples or cores for lithologic (physical character and composition of unconsolidated deposits or rocks) logging and chemical analysis; lithologic and hydrogeologic characterization using borehole geophysical logging; and installation of piezometers or monitoring wells. When evaluating the alternatives listed, the user should make selections based on the following factors: (1) suitability for the type of geologic materials at a site; (2) potential effects on sample integrity (influence by drilling fluids and potential for cross contamination between aquifers); and (3) availability and cost.

2. Drilling Methods - Consolidated Materials describes three techniques used for drilling in heavier materials and at greater depths. Users should base their evaluations on the same factors. For each drilling method listed, users are instructed to follow proper safety protocols. In addition, slower drilling rates improve contamination control and limit public and worker exposure to contaminants. For this reason, drilling in contaminated areas using any method should be slowed to allow for greater control of the hazardous material being extracted from the hole.

3. Drive Methods utilize a hydraulic device to penetrate the ground typically resulting in reduced levels of investigation derived waste and minimizing migration of contaminants from shallower to deeper levels.

4. Sampling Installations for Portable Samplers identifies four permanent well installation methods used for the portable samplers covered in Sections 4.3, 4.4, and 4.5.

5. Portable In-Situ Ground Water Samplers are used for ground water monitoring.

6. Fixed In-Situ Samplers cover three permanent installation methods that are placed directly into a borehole.

7. Destructive Sampling Methods generally are utilized during the drilling process.

The Collection Tools category is divided into the following seven subcategories (a descriptive summary for each technology listed under Collection Tools is contained in Section 4 of the Reference Guide):

  1. Hand-Held Methods are generally selected based on the following criteria: (1) whether an undisturbed core is required, (2) soil conditions at the site, and (3) desired sample size and depth.
  2. Power-Driven Soil Samplers are usually operated in conjunction with a drill rig.
  3. Portable Positive Displacement Pumps are placed below the static water level of the well and pump the sample to the surface.
  4. Other Portable Ground Water Sampling Pumps covers three other pump types used for sampling ground water.
  5. Portable Grab Samplers covers three manually operated methods for collecting ground water samples.
  6. Extractive Collection Methods covers two methods used for soil water extraction from the vadose zone and the use of biological indicators.
  7. Gas/Air Collection Methods covers two methods for collecting soil-gas samples and one method for collecting ambient air samples.

Extraction Tools (a descriptive summary for each technology listed under Extraction Tools is contained in Section 5 of the Reference Guide) are used to extract or prepare a sample in order for it to be analyzed by the methods listed on the Sample Analysis Tools Matrix. For example, gas chromatography requires samples to be in a gas phase. This is often achieved through thermal desorption for soil samples.

For the purpose of comparison, each technology in the Access Tools, Collection Tools, and Extraction Methods categories has been broken down into seven evaluation criteria:

  1. Media
  2. Maximum Depth
  3. Production Rate
  4. Investigative Derived Waste Volume
  5. Technology Status
  6. Certification/Validation
  7. Relative Cost per Sample

The evaluation criteria for each technology are summarized in the Sample Access and Collection Tools Matrix. Ratings for each criteria were derived through two Expert Work Group meetings and a final government review. Many of the ratings are based on subjective evaluations for the purpose of comparison within specific categories. For example, the media rating provided for the hollow-stem auger should only be compared against other methods listed under Access Tools. If additional technical information or clarification surrounding a specific rating is available, it is provided in the Reference Guide.

The following is a description of each column on the Sample Access and Collection Tools Matrix:

Technique/Instrumentation: Most commonly used field techniques, as identified in Subsurface Characterization and Monitoring Techniques (EPA 625-R-93-003), are identified on the Matrix in italics. Usage levels are only approximations, and actual usage may vary from region to region.
Reference Guide Page #: Page number for applicable technique or instrument in Reference Guide. The Reference Guide provides a preliminary description identifying the primary use of a method within the site characterization process and technical information on the components and operational procedures of the method
Analytes: Analytes which can be accessed, collected, or extracted are identified. Section 2.4 of the Reference Guide provides a listing of individual contaminants contained in each group. It should be noted that technologies identified as appropriate for a specific analyte group are not necessarily effective for all contaminants listed within that group.
Media:
n Minimum Impact.
l Moderate Impact.
D Maximum Impact.
Rating provided is a subjective evaluation of the extent of the disturbance created at a site when a sample is taken. The lower the impact a technology has on a site, the more representative the sample produced. The project DQOs should identify the sample representativeness required. The following five media types were rated:
  1. Soil - natural aggregate of mineral grains with or without organic materials yhat can be separated by mechanical means. Soil sampling can be classified into two primary types: surface and subsurface.
  2. Sediment - material that is submerged/saturated or suspended in any surface water body.
  3. Ground Water - water found beneath the earth's surface that fills pores between such materials as sand, soil, or gravel.
  4. Surface Water - water naturally open to the atmosphere such as rivers, lakes, reservoirs, streams, and seas.
  5. Gas/Air - pollutants generally fall into two main groups: (1) those emitted directly from identifiable sources, and (2) those produced in the air by interaction between two or more primary pollutants, or by reaction with normal atmospheric constituents, with or without photoactivation. Soil gas includes gaseous elements and compounds in the small spaces between particles of the earth and soil.

The Reference Guide identifies applicable media-specific capabilities and equipment requirements. Specific media limitations are listed in the Reference Guide under “Limitations.”

Maximum Depth:
n 100 feet plus.
l Up tp 100 feet.
D Up to 25 feet.
A depth range has been developed for each method listed. When applicable, the Reference Guide identifies specific depth limitations and specific equipment requirements. Users should be aware that the cost of a technology generally increases when greater depth is required. In addition, different media conditions and characteristics can influence the ability of a technology to reach a specific depth.
Production Rate:
n Sample is available quickly.
l Sample is available in a short amount of time.
D Sample is available after an extended wait.
Rating provided is a subjective evaluation based on the average production time from the beginning of the sampling event until the sample is available for analysis preparation. Rating is a relative comparison within the specific category (see Relative Cost for an example).
Investigation Derived Waste Volume:
n Small volume of waste.
l Medium volume of waste.
D Large volume of waste.
Rating provided is a subjective evaluation based on the volume of waste generated to obtain a sample. Collecting, labeling, storing, and disposing of investigation derived waste (IDW) should be addressed when developing a sampling project. In addition, procedures should be implemented to determine if IDW is hazardous. Rating is a relative comparison within the specific category (see Relative Cost for an example).
Technology Status:
III Commercially available and routinely used field technology.
II Commercially available technology with moderate field experience.
I Commercially available technology with limited field experience.
Technology status was developed based on information from Subsurface Characterization and Monitoring Techniques (EPA 625-R-93-003), EPA's Vendor FACTS, and specific vendor contacts.
Certification/Verification:
Yes Technology has participated in CalEPA certification and/or Consortium for Site Characterization Technology verification program.
No Technology has not participated in CalEPA certification and/or Consortium for Site Characterization Technology verification program.
The California Environmental Protection Agency's (CalEPA) award-winning certification program is a voluntary program that provides participating technology developers, manufacturers, and vendors an independent, recognized third-party evaluation of the performance of new and mature environmental technologies. Developers and manufacturers define quantitative performance claims for their technologies and provide supporting documentation; CalEPA reviews that information and, where necessary, conducts additional testing to verify the claims. The technologies, equipment, and products that are proven to work as claimed receive official state certification. The certification program is voluntary and self-supporting. Companies participating in the program pay the costs of evaluating and certifying their technologies.

The goal of the Consortium for Site Characterization Technology (CSCT) is to increase the use of new characterization and monitoring technologies at cleanup sites. To attain this goal, the Consortium will: (1) identify, demonstrate, evaluate, verify, and transfer information about innovative and alternative monitoring, measurement, and site characterization technologies to developers, users, and regulators; and (2) define and demonstrate a process for verifying the performance of innovative site characterization technologies. By developing this process, the Consortium will facilitate independent testing and demonstrations that can generate the data necessary to evaluate and verify performance.

In addition, the Reference Guide will identify applicable SW-846 Sample Preparation, Cleanup, and Determinative Methods; American Standard for Testing and Materials (ASTM) standards; U.S. Department of Energy (DOE) compendium recommendations; and Army Corps Design Manual Methods.

Relative Cost per Sample:
n Least expensive.
l Mid-range expense.
D Most expensive.
Because of the number of factors that affect cost, a subjective scale was developed. The current relative cost per sample is a comparison within technology subsections (3.1, 3.2, etc.). For example, relative cost per sample for technologies in section 3.1 Drilling Methods - Unconsolidated Formations can't be compared with the relative cost for technologies in section 3.2 Drilling Methods - Consolidated Formations. Assumption is that a contractor was hired to provide the analysis or technique at an "average" site that does not have extraordinary features or conditions. When available, one time capital, operation, and maintenance costs are included in the Reference Guide.

In addition, the Reference Guide contains the following sections:

Limitations: Limitations such as geologic/atmospheric conditions, lack of consistent sample volume, total sample volume produced, media/Matrix limitations, temperature operating range, mobility, durability, and availability are listed in the Reference Guide as applicable.
ASTM Standards: Applicable ASTM standards are listed. A complete list of ASTM Standards applicable to environmental investigations can be found in the following:

ASTM 1996. Standard Guide to Site Characterization for Environmental Purposes with Emphasis on Soil, Rock, the Vadose Zone and Ground Water. ASTM D 5730 - 96.
EPA Guidance: Applicable EPA guidance documents are listed.
Previous Page Sample Access/Collection Matrix Sample Analysis Matrix Home Areas of Interest Next Page