The Texas Commission on Environmental Quality (TCEQ) announced last month that its Remediation Division will require that solid samples for volatile organic compound (VOC) analysis must be collected and prepared using US EPA SW-846 Method 5035A procedures as of January 1, 2016.
After December 31, 2015, the TCEQ Remediation Division will no longer accept VOC analytical data reported for solid samples using a method other than Method 5035 when the data are intended to demonstrate compliance with the rules in 30 Texas Administrative Code Chapters 334, 335, or 350.
Senior chemists at Environmental Standards, Inc. have been providing training on Method 5035 to sample collection teams since 1998 and have conducted hundreds of field and laboratory audits throughout the country focusing on acceptable execution of Method 5035.
Below are only some of the sample collection and analytical considerations and best practices collected by Environmental Standards throughout the years:
- Collecting a representative sample is the most critical aspect of the acceptable execution of Method 5035. Past collection techniques (bulk jars and brass sleeves) allowed a larger solid sample to be collected by the field. Now representative subsampling is the entire responsibility of the field crews as only a 5 gram sample is contained in each VOC vial (or core sampler) and submitted for analysis. Therefore, field sampling plans must be very specific as to what material is specifically collected to VOCs.
- Collection of loose, light, or large particle size samples can cause problems when using coring or transfer devices.
- Collecting substantially more or less sample mass than 5 gram can cause problems.
- Addition of labels or tape to pre-tared vials will result in inaccurate sample weights to be determined prior to analysis skewing reported results.
- Positive VOC results greater than low level direct analysis calibration by 5035/8260 may not be detected in methanol analysis due to the inherent dilution caused by the methanol medium level collection method.
- Loss of methanol is possible.
- High sample weights can lead to methanol not covering the sample causing insufficient extraction of volatile organics and prevent removal of methanol from vials for analysis.
- Collection of percent moisture sample aliquot is critical unless other sample fractions are collected for use in determining dry weight correction factor.
- Holding time requirements: Method 5035 only allows 48 hours to have samples analyzed or to be frozen to extend holding times. Samples must be shipped on a daily basis.
- Data Quality Objectives: Understanding laboratory LODs/LOQs, samples masses and the aspects of moisture correction.
- Field use of balances for samples – options, purpose, and accuracy.
If you have operations and site responsibility in Texas, beginning on January 1, 2016, solid samples for VOC analysis must be collected and prepared using the Method 5035A procedures.