Sampling
EPA received many questions about hazardous waste test methods. The questions and responses for this category are listed below.
On this page:
- What is the current holding time for samples collected in the EnCore sampler and analyzed using SW-846 Method 5035?
- How are representative sampling, confidence levels, and statistical analysis used to determine if a waste is hazardous?
- Which sampling method should a generator use to sample a waste for the purpose of hazardous waste identification?
- Where can I find wipe sampling methods in SW-846?
- Where can I find references regarding drum sampling?
- Where can I find information on sampling groundwater?
- Where can I find information on decontamination procedures for sampling equipment?
What is the current holding time for samples collected in the EnCore sampler and analyzed using SW-846 Method 5035?
The Office of Resource Conservation and Recovery's (ORCR) reviewed data from the manufacturer of the EnCore device. Those data suggested that samples could be held in the EnCore device for 48 hours without significant loss of volatile analytes. Subsequent data for freezing samples in the EnCore sampler also indicates a 48-hour limit without significant loss. As noted in Sec. 8.2.1.8 of Method 5035A, samples may be held for up to 48 hours before analysis, or before transfer to the glass vials used for the closed-system purge-and-trap device in the method. The overall holding time for the sample remains 14 days from collection to analysis. The same considerations apply to Methods 5021, 5032, and 8261 with respect to the EnCore sampler.
Other Category: Holding Time & Preservation
How are representative sampling, confidence levels, and statistical analysis used to determine if a waste is hazardous?
A generator can either test his or her waste or apply knowledge of the waste to determine whether the waste is hazardous. If a generator decides to test the waste, testing should be done in accordance with the test methods set forth in 40 CFR Part 261, Subpart C.
For the purposes of Subpart C, a representative sample can be obtained using any of the specified methods in Part 261, Appendix I. A representative sample means a sample of a universe or whole (e.g., waste pile, lagoon, groundwater) which can be expected to exhibit the average properties of the universe or whole.
Sampling is the physical collection of a representative portion of the universe or whole of a waste or waste treatment residual. For a sample to provide meaningful data, it is imperative that it reflect the average properties of the universe from which it was obtained, that its physical and chemical integrity be maintained, and that it be analyzed within a dedicated quality assurance program. You can choose to use sampling methods specified in the regulations in 40 CFR Part 261, Appendix I, or you may choose to petition EPA for equivalency testing and analytical methods. In particular, SW-846 has been developed by EPA to assist the regulated community in meeting analytical responsibilities under the RCRA program. Refer to the following documents for planning and implementing your strategies for representative sampling, and setting confidence levels for statistical analysis of data to determine if a waste is hazardous. See RCRA Waste Sampling Draft Technical Guidance Document (August 2002). Also see ASTM Manual 42 - RCRA Waste Management: Planning, Implementation, and Assessment of Sampling Activities.
Other Category: Hazardous Waste Characteristics
Which sampling method should a generator use to sample a waste for the purpose of hazardous waste identification?
There are a number of approaches for sampling a waste for the purpose of hazardous waste identification. Pursuant to §261.20(c), a representative sample must be obtained using any of the specified methods in 40 CFR Part 261, Appendix I. A representative sample is a sample of a universe or whole (e.g., waste pile, lagoon, groundwater) that can be expected to exhibit the average properties of the universe or whole (§260.10).
Additional guidance regarding representative sampling is available in the Memo, Cotsworth to Finazzo; February 11, 1998 (RCRA Online #14259)(PDF)(4 pp, 54.3 K, About PDF).
This and other documents are available in the RCRA Online Database.
In addition, the document Test Methods for Evaluating Solid Waste, Physical/Chemical Methods (SW-846) provides guidance concerning sampling plans and methods (Chapter 9 “Sampling Plan" and Chapter 10 “Sampling Methods").
See also RCRA Waste Sampling Draft Technical Guidance Documents (August 2002).
Where can I find wipe sampling methods in SW-846?
There are two instances where wipe sampling is addressed within SW-846, Method 3572 and Appendix A of Method 8290A. The two methods differ in their approach and applicability, method 8290A has a limited discussion of wipe sampling only in the context of laboratory safety concerns relative to dioxins and furans, the wipe sampling procedure in method 3572 is intended to assess surface contamination both inside and outside of the laboratory. However, EPA does not recommend that the procedures described in either of these methods be extended to other analytes or other situations.
Outside of SW-846, wipe sampling is specified as a means for determining compliance with certain cleanup and decontamination requirements in the TSCA PCB regulations (40 CFR 761). The method for conducting wipe sampling under the TSCA PCB regulations can be found at 40 CFR 761.123 under “standard wipe sample.” When the TSCA PCB regulations require wipe sampling as the method for determining compliance, the unit used is micrograms per 100 cm2.
While wipe sampling has been described in the open literature, one of the biggest problems is that it is very difficult to interpret the results. By its very nature, the analysis of whatever material is used to wipe a surface (often filter paper wet with a solvent) yields the mass of the analyte(s), for example nanograms of dioxin or micrograms of another analyte. However, there is no straightforward way in which to convert that mass into a concentration per unit area, nor any good way in which to compare results from different wipes, except to say that one wipe picked up more material than another. If the surfaces that are wiped have different characteristics, for example a smooth metal surface versus a rough concrete block, there is no way to judge the efficiency of the wiping process itself. Therefore, use caution in interpreting the results of wipe samples.
Other Category: 8000 Series
Where can I find references regarding drum sampling?
Several references are available on drum sampling. Chapter Nine of SW-846 (see page NINE-73) includes guidance on sampling drums and similar containers. The following EPA documents also include information on drum sampling:
USEPA. 1994. "Drum Sampling." Environmental Response Team SOP #2009, Revision #0.0. Edison, NJ (32 pp, 828.9 K, About PDF)
Also, the ASTM has published several guides that include information on drum sampling including:
ASTM D 5679-95a (2012). Standard Practice for Sampling Consolidated Solids in Drums or Similar Containers. West Conshohocken, PA.
ASTM D 5680-14 (2014) Standard Practice for Sampling Unconsolidated Solids in Drums or Similar Containers. West Conshohocken, PA.
ASTM D 5743-97 (2013). Standard Practice for Sampling Single or Multilayered Liquids, With or Without Solids, in Drums or Similar Containers. West Conshohocken, PA.
ASTM D 6063-11 (2011). Standard Guide for Sampling of Drums and Similar Containers by Field Personnel. West Conshohocken, PA.
ASTM D 6232-08 (2008). Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities. West Conshohocken, PA.
See also RCRA Waste Sampling Draft Technical Guidance Documents (August 2002).
Where can I find information on sampling groundwater?
Guidance on groundwater sampling can be found in EPA's "RCRA Groundwater Monitoring: Draft Technical Guidance" published by the Office of Resource Conservation and Recovery (ORCR), EPA/530/R-93/001, NTIS PB 93-139350. The document updates Chapter Eleven of SW-846.
Additional updated information on groundwater sampling can be found in "Low-Flow (Minimal Drawdown) Ground-Water Sampling Procedures" EPA/540/S-95/504 April 1996.
See also RCRA Waste Sampling Draft Technical Guidance Documents (August 2002).
Where can I find information on decontamination procedures for sampling equipment?
There are many references, but here are a few good ones for decontamination of waste sampling equipment:
USEPA. 2015. Laboratory Operations and Quality Assurance Manual. www2.epa.gov/sites/production/files/2015-06/documents/asb-loqam_0.pdf. Region 4, Science and Ecosystem Support Division. Athens, GA.
Please note that these references do not address chemical, biological, and radiological threat agents. Decontamination procedures for such agents are currently being developed. More information can be found on the EPA Homeland Security website.
For decontamination of groundwater sampling equipment, see:
USEPA. 1992. RCRA Ground-Water Monitoring: Draft Technical Guidance. EPA/530/R-93/001. Office of Resource Conservation and Recovery (ORCR). Washington, DC.
See also RCRA Waste Sampling Draft Technical Guidance Documents (August 2002).