The Texas Commission on Environmental Quality (TCEQ) has announced that, beginning January 1, 2016, the TCEQ Remediation Division will require the use of United States Environmental Protection Agency (EPA)SW-846 Method 5035A, as amended. The method is more commonly known as Closed-System Purge-and-Trap and Extraction for Volatile Organics in Soil and Waste Samples. This is a method commonly used for the collection and preparation of solid samples for analysis of volatile organic compounds (VOCs) using purge-and-trap technology.
TCEQ表示，2015年12月31日之后，TCEQ修复部门将拒绝据报道的VOC数据用于使用另一种方法在数据旨在遵守德克萨斯州行政代码（30TAC）第33章第334章的遵守情况第30章，335和350. TCEQ的修复部门所需的5035A所需的使用包括以下方案领域：自愿清理计划（VCP），纠正措施（CA）计划，石油储存罐（PST）计划，干洗修复程序（DCRP）和Superfund。
Solid samples intended for analysis by 5035A must be collected via appropriate procedures. The collection procedures include the use of a core sampler to sample aliquots that are then placed into three volatile organic analysis (VOA) vials. Two VOAs are pre-filled with distilled water; one of the VOAs is pre-filled with methanol for extraction purposes. Additionally, a bulk sample is collected to determine dry weight and for potential analysis in samples with exceptionally high levels of VOCs that are beyond the calibration curve of the methanol sample aliquot. Analytical methods corresponding to the mandated use of 5035A include SW-846 methods 8260 (detection by Gas Chromatography/Mass Spectrometry – often used for VOCs), 8021 (detection by Gas Chromatograph/Electrolytic Conductivity Detector – often used for benzene, toluene, ethyl benzene, and xylene), and 8011.
The TCEQ contends method 5035A is the most appropriate preparatory method for VOC analysis using methods 8260, 8021, and 8011. They also contend the policy was needed, as previously there was no policy on soil/solid sampling. They have also cited problems that arise from the use of bulk soil/solid sampling. TCEQ has required the use of 5035A for State-led Sites for a number of years. They contend that a body of evidence indicates using the traditional unpreserved bulk sample collection procedures to collect samples from soil/solids for VOC analysis can result in significant low bias due to the loss of VOCs during sampling, handling, transporting, and analysis activities.
Concerns of consultants and industry personnel arising from this mandate include the cost versus benefit of a core sampler and multiple sampling containers which are required for 5035A, as well as using a method that may include shipment of a hazardous material (methanol). Industry has also questioned the perceived issue that bulk sampling indicates a significant low bias when compared to 5035A sampling. The 5035A sampling protocol has been performed in controlled situations and by samplers who are skilled in the use of core sampling techniques, which is not the normal situation for most sampling. Additionally, Texas is one of the few U.S. States under 30 TAC 350 in which sample detection limits in excess of Protective Concentration Levels (PCLs) are considered an exceedance of the PCL, despite non-detectable sample results. Thus, under 5035A the analytical laboratory is much more likely to produce sample detection limits in excess of applicable PCLs, which result in further issues. Other cited concerns include a lack of conformity, as method 5035A is appropriate for VOC analysis, but not analysis of petroleum hydrocarbons using methods such as Texas Methods 1005 and 1006. As a result, collection and shipping of additional sample containers will now be required for analyses that, formerly, could be collected in the same containers.
Feel free to contactAndy Adamsfor additional information concerning 5035A.