Eurofins Environment Testing LEAF Methods supporting PFAS

Understanding LEAF for PFAS Analysis

The LEAF protocol, developed by the EPA, provides a systematic framework for evaluating how constituents leach from solid materials under various environmental conditions. When applied to PFAS analysis, this approach becomes particularly complex due to the unique chemical properties of these persistent compounds.

EPA SW-846 LEAF Methods Summary

Method 1313 : pH Dependence Test

Liquid-Solid Partitioning as a Function of Extract pH for Constituents in Solid Materials using a Parallel Batch Extraction Procedure

This method evaluates leaching behavior as a function of pH. Given that PFAS leaching can be pH-dependent—particularly for precursors that may transform under different conditions—this method provides valuable information about how changing environmental conditions affect PFAS mobilization.

Method 1314 : Column Percolation Test

Liquid-Solid Partitioning as a Function of Liquid-Solid Ratio for Constituents in Solid Materials using an Up-Flow Percolation Column Procedure

This approach simulates liquid percolation through a fixed bed of granular material, providing insights into PFAS migration through soil or waste materials when exposed to infiltrating water. The column percolation method offers an excellent representation of field conditions, particularly for contaminated soils or industrial waste containing PFAS.

Method 1315 : Mass Transfer Rate Test

Mass Transfer Rates of Constituents in Monolithic or Compacted Granular Materials using a Semi-dynamic Tank Leaching Procedure

This method evaluates constituent release under diffusion-controlled conditions, making it particularly valuable for assessing long-term PFAS leaching from materials such as concrete, soil, or sediment where PFAS has been absorbed. The method simulates real-world conditions where rainfall or groundwater gradually extracts PFAS from contaminated media over extended periods, enabling evaluation of both short-term and long-term release rates.

Method 1316 : Natural pH Batch Test

Liquid-Solid Partitioning as a Function of Liquid-Solid Ratio for Constituents in Solid Materials using a Parallel Batch Extraction Procedure

This method evaluates liquid-solid partitioning of constituents as a function of the liquid-to-solid ratio. For PFAS, this approach helps determine distribution coefficients, which are essential for understanding transport behavior and fate in environmental systems.

Optimal LEAF Approach for PFAS

Based on current scientific understanding, Method 1314 (Column Percolation) typically provides the most environmentally relevant data for PFAS scenarios because it best simulates natural water infiltration processes, accounts for time dependent PFAS release, identifies breakthrough curves that help predict transport behavior, and allows collection of sequential fractions that reveal changes in PFAS speciation or concentration over time.

However, comprehensive characterization often requires a multi-method approach: begin with Method 1313 to understand pH effects on PFAS leaching, follow with Method 1314 to assess transport behavior, and complement with Method 1316 for understanding partitioning behavior.

Critical Modifications for PFAS Analysis

When applying LEAF protocols to PFAS, several important modifications must be considered.

• All materials must be PFAS-free, avoiding Teflon, PTFE, and certain plastics.
• While deionized water is typically used as the leaching solution, site-specific groundwater chemistry may be more appropriate for realistic PFAS leaching assessment.

• Analysis methods include Modified Method 537 and EPA 1633 for targeted PFAS analysis of leachate.

• Quality assurance and quality control measures must include field and equipment blanks to prevent PFAS contamination from sampling equipment.

Framework Considerations

The framework for PFAS continues to evolve rapidly. While the LEAF methods are not written to include PFAS, the data generated can inform site-specific risk assessments and remediation planning.

Contact us to discuss our method modifications and how they can support your project requirements.