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SW-846 Update VI Announcements

EPA is releasing Update VI to the SW-846 compendium of methods in four phases. Since all of the Update VI methods are intended  to be used as guidance, the streamlined method publication process will be used.

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Phase I: Method 1340 - In Vitro Bioaccessibility Assay for Lead in Soil, Completed Nov. 2017

Method 1340 defines the proper analytical procedure for the validated in vitro bioaccessibility (IVBA) assay for lead in soil under 50,000 mg/kg in concentration. At this time, this method has only been validated for lead-contaminated soil under field conditions and not for other matrices (e.g., water, air, amended soils, dust, food, etc.). Knowledge of lead bioavailability is important because the amount of lead that actually enters the blood and body tissues from an ingested medium can vary due to many field, chemical and physical conditions of the exposure. This method uses a leaching procedure in a rotary extractor to extract lead from soil at a known temperature and time of exposure. The supernatant liquid is separated from the sample by filtration and can be analyzed for lead by an appropriate analytical method (e.g., Method 6010 or Method 6020).

The public comment period for this method closed on May 1, 2017. Although submissions will no longer be accepted, the EPA Docket for this method can be viewed by searching for ID# EPA-HQ-OLEM-2017-0122. EPA has responded to all public comments in the Method 1340 Response to Comments document. No changes to the method were made based on the public comments received, and the final method was added to the SW-846 compendium on November 28, 2017.

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Phase II: Methods 8260D and 8270E - Volatile and Semivolatile Organic Compounds by Gas Chromatography/Mass Spectrometry (GC/MS)

Methods 8260D and 8270E are used to determine volatile (VOCs) and semivolatile organic compounds (SVOCs) in a variety of matrices by gas chromatography with a mass spectrometer detector (GC/MS). A MS, interfaced to the GC, allows identification of target analytes by comparing mass spectra and retention times with those known standards.  Quantitation is accomplished by comparing the response of a major (quantitation) ion relative to an internal standard using an appropriate calibration curve. Method revisions include the option of hydrogen as a carrier gas, use of advanced measurement techniques, (e.g. selected ion monitoring, chemical ionization, and tandem mass spectrometry) and updated language for lower limit of quantitation and method blanks. In addition, tuning requirements were updated to harmonize with other EPA program methods.

VOCs are introduced into the GC by one of several listed preparation methods (i.e. purge & trap, direct injection, or various form of distillation). SVOCs are applicable to most neutral, acidic, and basic organic compounds that are soluble in methylene chloride and are capable of being eluted, without derivatization, as sharp peaks from a GC capillary column. SVOCs are extracted from various matrices by one of several listed preparation methods which are matrix dependent. Extracts are generally injected into a heated port on the GC and flash vaporized into the capillary column, which is temperature-programmed to separate the analytes.

Since the addition of Method 8260C to the SW-846 validated methods collected in 2006, GC/MS technologies have advanced substantially and new measurement issues have emerged. Due to the significance of the changes, EPA assigned a new suffix to the 2017 revision of the method, 8260D. Concurrent to the addition of Method 8260D to the SW-846 validated methods, Method 8260C was removed from the validated methods collection and placed in the EPA Archive. Method 8260C was never incorporated into the SW-846 compendium because EPA never solicited public comment on the method.

The public comment period for these methods closed on June 28, 2017. Although submissions will no longer be accepted, the EPA Docket can be viewed by searching for ID# EPA-HQ-OLEM-2017-0133. EPA is now reviewing all comments, and will publish a Response to Comments document along with the final versions of the methods.

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Phase III: LEAF Methods and Guidance

The Leaching Environmental Assessment Framework (LEAF) is a leaching evaluation system, which consists of four leaching methods, data management tools, and scenario assessment approaches designed to work individually or to be integrated to provide a description of the release of inorganic constituents of potential concern (COPCs) for a wide range of solid materials. The LEAF methods have been designed to consider the effect of key environmental conditions and waste properties on leaching. The LEAF "How-To" Guide describes how the LEAF method results can be used to develop screening level assessments of constituent release or to develop more accurate estimates of release in specific use or disposal scenarios.

LEAF Methods and "How-To" Guide

Method 1313 is designed to evaluate the partitioning of constituents between liquid and solid phases at or near equilibrium conditions over a wide range of pH values. The method consists of 9-10 parallel batch extractions of solid material at various target pH values. 

Method 1314 is a percolation column test designed to evaluate constituent releases from solid materials as a function of cumulative liquid-to-solid ratio. The method consists of a column packed with granular material with moderate compaction. Eluent is pumped up through the column to minimize air entrainment and preferential flow.

Method 1315 is a semi-dynamic tank leaching procedure used to determine the rate of mass transport from either monolithic materials (e.g., concrete materials, bricks, tiles) or compacted granular materials (e.g., soils, sediments, fly ash) as a function of time using deionized water as the leaching solution. The method consists of leaching a sample in a bath with periodic renewal of the leaching solution at specified cumulative leaching times.

Method 1316 is an equilibrium-based leaching test intended to provide eluate solutions over a range of liquid-to-solid ratios. This method consists of five parallel batch extractions of a particle-size-reduced solid material in reagent water over a range of liquid-to-solid ratios. At the end of the contact interval, the liquid and solid phases are separated for constituent analysis.

The purpose of the LEAF "How-To" Guide is to provide an understanding of the Leaching Environmental Assessment Framework to facilitate its broader use in environmental assessment. The guide provides background on the LEAF methods, how to perform the methods, and how to understand the method results. It also provides guidance on the application of LEAF to assess leaching potential of COPCs from solid waste materials for beneficial use, disposal, treatment, and remediation applications. In addition, the guide addresses frequently asked questions about the four LEAF methods, data management and reporting using freely-available software, and potential applications of the LEAF approach.

Frequent Questions

EPA has developed answers to frequently asked questions about the LEAF Methods and "How-To" Guide.

Public Comment Period

The public comment period for the LEAF methods and "How-To" Guide closed on January 31, 2018. Although submissions will no longer be accepted, the EPA Docket can be viewed by searching for ID# EPA-HQ-OLEM-2017-0210. EPA is now reviewing all comments, and will publish a Response to Comments document along with the final versions of the methods.

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Phase IV: Method 3050C - Acid Digestion of Sediments, Sludges, and Soils

Method 3050C is a very strong acid digestion that will dissolve and liberate to solution for analysis almost all elements that could become “environmentally available.” By design, elements bound in silicate structures are not normally dissolved by this procedure, as they are not usually mobile in the environment. Changes to the method will include an appendix on incremental sampling procedures.

EPA anticipates  releasing Method 3050C for public comment in late 2018.

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