Significance and Use
5.1 PFAS are widely used in various industrial and commercial products; they are persistent, bio-accumulative, and ubiquitous in the environment. PFAS have been reported to exhibit developmental toxicity, hepatotoxicity, immunotoxicity, and hormone disturbance. PFAS have been detected in soils, sludges, surface, and drinking waters. This is a quick, easy, and robust method to quantitatively determine these compounds at trace levels in soil/biosolid matrices.
5.2 This test method has been validated using four ASTM reference soils (CH-1, ML-1, CL-1, and SP-1). ASTM reference soil CH-1 is Fat Clay (CH)—Vicksburg Buckshot Clay; ASTM reference soil ML-1 is silt (ML)—Vicksburg silt; ASTM reference soil CL-1 is lean clay (CL)—Annapolis clay; and ASTM reference soil SP-1 is sand (SP)—Frederick sand and four biosolids (Missouri, California, Idaho, and Georgia). Refer to the Precision and Bias (Section ).
1.1 This test method covers the determination of per- and polyfluoroalkyl substances (PFAS) in soil/biosolid matrices by solvent extraction, filtering, separation using liquid chromatography (LC), and detection with tandem mass spectrometry (MS/MS). These analytes are extracted from soil/biosolids with basic water and methanol then qualitatively and quantitatively determined by this test method. Quantitation is by selected reaction monitoring (SRM), sometimes referred to as multiple reaction monitoring (MRM).
1.2 The reporting limit (RL) and reporting range (see ) for the target analytes are listed in Table 1. The reporting limit is calculated from the concentration of the Level 1 calibration standard as shown in Table 5 for the PFAS after taking into account a 2 g sample weight and a final extract volume of 10 mL, 50 % water/50 % MeOH with 0.1 % acetic acid. The final extract volume is assumed to be 10 mL because 10 mL of 50 % water/50 % MeOH with 0.1 % acetic acid was added to each soil sample and only the liquid layer after extraction is filtered, leaving the solid and any residual solvent behind. Sporadic PFAS hits due to PFAS contamination in consumables/collection tools used during sample collection and preparation is possible while executing this standard and must be monitored. All samples should be taken at a minimum as duplicates in order to compare the precision between the two prepared samples to help ensure the concentration/positive result is reliable.
Note 1: This standard only includes the determination of the analytes listed in Table 1 and is only applicable to soil and biosolid matrices; any added compost or soil additives may contain PFAS that may be bound and not able to be determined by this method. Analysis of packaging materials and polymeric PFAS moieties are not amenable to this standard.
Note 2: Injection volume variations and sensitivity of the instrument used will change the reporting limit and ranges.
1.2.1 Recognizing continual advancements in the sensitivity of instrumentation, advancements in column chromatography, and other processes not recognized here, the reporting limit may be lowered assuming the minimum performance requirements of this test method at the lower concentrations are met.
1.2.2 Depending on data usage, you may modify this test method but limit to modifications that improve performance while still meeting or exceeding the method quality acceptance criteria. Modifications to the solvents, ratio of solvent to sample, or shortening the chromatographic run simply to save time are not allowed. Use Practice or similar statistical tests to confirm that modifications produce equivalent results on non-interfering samples. In addition, use Guide or equivalent statistics to revalidate the modified test.
1.2.3 Analyte detections under the reporting limit are estimated concentrations. If results are to be reported below the RL using this standard and following the method detection limit procedure in 40 CFR Part 136 Appendix B, data shall be qualified estimated and extra caution must be taken to evaluate and identify false positives.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.