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SW-846 Method 5035 Fact Sheet

Closed-System Purge-and-Trap and Extraction for Volatile Organics in Soil and Waste Samples

1. What is SW-846 Method 5035?

The United States Environmental Protection Agency's (U.S. EPA) "Test Methods for Evaluating Solid Waste" describes procedures to be used in collecting and preserving samples of waste, soil, sediments, and groundwater. Method 5035, referred to as the "Closed-System Purge-and-Trap and Extraction for Volatile Organics in Soil and Waste Samples," was included in SW-846 as part of Final Update III. This update was published in the Federal Registeron June 13, 1997.

SW-846 Method 5035 identifies procedures to collect soil samples for volatile organic compound (VOC) analysis. The procedures are outlined in the method's Subsection 4.5 (Field Sampling Equipment), Section 5.0 (Reagents), and Section 6.0 (Sample Collection, Preservation, and Handling). The soil samples must be preserved with one of two preservatives prior to analysis, either in the field at the time of collection or in the laboratory within 48 hours of collection. A sodium bisulfate preservative is added to soils anticipated to contain VOCs at concentrations less than 200 parts per billion (ppb), while a methanol preservative is used for those soils anticipated to contain VOCs at concentrations greater than 200 ppb. If the soil samples are to be preserved in the laboratory, the samples must be collected in a Purge-and-Trap Soil Sampler, an EnCore sampler, or a similar type device and must then be delivered to the lab for preservation within 48 hours of sample collection.

2. Why did U.S. EPA change the method of VOC soil sampling?

Method 5035 more accurately identifies the types and concentrations of VOCs in soils than the previously used method, which was susceptible to errors due to evaporative losses of volatiles and microbial degradation prior to sample analysis.

3. Is SW-846 Method 5035 incorporated into Illinois regulations?

Yes. On June 4, 1998, the Illinois Pollution Control Board adopted amendments to 35 Illinois Administrative Code (35 Ill. Adm. Code) 742: Tiered Approach to Corrective Action Objectives (TACO). As part of the changes to TACO, SW-846 was incorporated by reference to include Update III, which contained Method 5035.

Newer Test Method 5035A, which, in part, allows for sample preservation by freezing, is also included in SW-846.

4. What remedial programs use Method 5035?

Generally, all Illinois EPA remedial programs using TACO recognize the importance of Method 5035, including:

Resource Conservation and Recovery Act (RCRA) Program: SW-846 Method 5035 is required and currently being implemented. Following the procedures listed in Attachment A of the closure guidance will meet the requirements of Method 5035.

Leaking Underground Storage Tank (Leaking UST) Program: Sites that reported a release on or after June 4, 1998, and before June 24, 2002, and are classified as high priority; sites for which the owner or operator elected to conduct corrective action pursuant to 35 Ill. Adm. Code 732.300(b), 732.400(b), or 732.400(c); and sites that reported a release on or after June 24, 2002, must use SW-846 Method 5035 for VOC soil sampling. For samples collected prior to the leaking UST site being classified as high priority, the Illinois EPA recommends the use of SW-846 Method 5035. If the leaking UST release was reported before June 4, 1998, the owner or operator may use either SW-846 Method 5035 or Method 5030 when soil sampling for VOCs.

Voluntary Site Remediation Program: The use of SW-846 Method 5035 provides a more reliable and valid result than previous methods; consequently, the use of this new method is strongly encouraged.

5. Will I need new sampling equipment?

The necessary soil sampling equipment is identified in Subsection 4.5 of SW-846 Method 5035 and includes: Purge-and-Trap Soil Sampler, EnCore sampler, disposable plastic syringes, portable balance, and balance weights.

6. What labs can analyze my soil samples? What analytical methods must my lab use?

The soil samples can be sent to an accredited laboratory capable of performing complete VOC analysis using SW-846 methods and able to follow the procedures identified in Method 5035. Method 5035 may be used in conjunction with any appropriate gas chromatographic procedure including, but not limited to, Methods 8015, 8021, and 8260.

7. What happens if the detection limits are above the remediation objectives established in 35 Ill. Adm. Code 742 (TACO)?

The Illinois EPA recognizes problems may be encountered when preserving soil samples using sodium bisulfate (i.e., certain soils may react vigorously with the acid). In these cases, the methanol preservation technique must be substituted. Since the methanol preservation method is accurate only for soils with VOC contamination greater than 200 ppb, the analysis of these soil samples will often not provide evidence that the remediation objectives established in TACO have been met. The site owner may need to request alternative remediation objectives under a TACO-Tier 3 scenario.

Please note: The Illinois EPA will require verification from the laboratory that performed the analysis indicating the soil did react with sodium bisulfate and only the methanol preservation method could be used.

8. Will the Illinois EPA re-visit sites that were closed using the previous VOC methods/procedures?

The Illinois EPA will not investigate sites closed (i.e., No Further Remediation Letter, 4(y) letter, etc.) using the previous method for VOC sampling and analysis unless additional contaminants are identified that pose a threat to human health or the environment.

9. If I have questions, who can I contact at the Illinois EPA?

The following Illinois EPA representatives are available to answer program-specific questions concerning SW-846 Method 5035:

Leaking UST Program -Contact your assigned Project Manager or Greg Dunn at 217-524-3300

RCRA Program - Rob Watson (217) 524-3300

Voluntary Site Remediation Program - Contact your assigned Project Manager or Greg Dunn at 217-524-3300.

A paper copy of SW-846 Method 5035 can be obtained through the U.S. Government Printing Office at (202) 512-1800 or NTIS at (703) 487-4650.

This fact sheet is for general information only and is not intended to replace, interpret, or modify laws, rules, or regulations.