[GreenYes] SW methods not chemically validated

[<randsney@no.address>]

The SW methods are validated using a statistical method, not a chemical analytical extraction method to prove quantification. In no way can statistical methods prove extraction efficiencies or validity of extractions. Statistical methods cannot provide a material balance, account for total residues, bound/adsorbed residues in soil or fat, or prove extraction. The method cannot discern if soil does not contain residues or if it has been cleansed during and after cleanup.



What do you think of this?

 

Dr. Ron 

 

----- Original Message ----- 

From: EHSG MICE 

To: 

Cc: EHSG MICE 

Sent: Monday, October 02, 2006 12:43 PM

Subject: RE: Need answers on SW extraction procedures/methods

 

Dear Ronald,

 

Thank you for your follow-up inquiry.

 

The majority of SW-846 methods are validated and peer reviewed using the statistical validation model from the American Organization of Analytical Chemists (AOAC) or some variation of this model which is an official validation approach for analytical methods.  The AOAC approach is a statistically rigorous, peer-reviewed procedure approved by IUPAC for evaluating new methods.  Additionally, the AOAC procedure is more cost-effective when compared with other statistical validation approaches relative to the number of required matrices and replicates.  An outline of the AOAC validation study requirements is presented below:

 

  

Table 2. AOAC Method Validation Requirements

      Minimum No. of Labs
     Minimum No. of Test Matrices
     Miminum No. of Spike Levels per Matrix for Determining Method Performance Characteristics
     
      Repeatabilitya
     Reproducibilitya
     Accuracy
     
      5b
     5
     2c
     1
     1
     

 

aSee Table 6 for definition.

b8 laboratories are normally required.  However in cases involving expensive equipment or specialized laboratories, this requirement may be reduced to 5.

cRepeatability data may be obtained from analysis of the following in order of preference:

 

·         Youden pairs (= 5% difference in concentration)

·         Blind duplicates

·         Known duplicates.

 

Table 6. Summary Statistical Evaluation of Interlaboratory Validation Data

      Method Performance Parameter
     Definition
     Final Method Application
     
      Bias
     Difference between the analysis result and the "true" or assigned concentration value
     Control limits for:

      ·         MS recovery of med- to high-range samples

      ·         Laboratory control sample recovery

      Laboratory control sample recoveryLaboratory control sample recove
     
      Repeatability
     Single operator precision
     Control limits for duplicate variation
     
      Reproducibility
     Interlaboratory precision
     Expected variation across laboratories
     
      Laboratory Quantitation Limit
     The lowest concentration level of analyte which can be measured with suitable precision and accuracy
     ·         LLOQs

      ·         MS recovery control limits for low-range samples
     
      Linearity
     The ability of a test method to obtain measurement results which are directly proportional to the actual concentration of analyte within a given concentration range
     Method scope and calibration range
     
      Range
     The concentration interval for which a test method has been demonstrated to have suitable precision and accuracy
     Method scope and calibration range
     
      Robustness
     The ability of a test method to obtain measurement results having suitable precision and accuracy when applied to the analysis of sample matrices intended for its use
     Method Scope:

      ·         Matrix applicability

      ·         Conductivity background
     

 

Regarding your comentary to the following statement:  "Furthermore, most extraction and analytical protocols assume that the detected concentration represents the total for a given compound, so it would be uncommon to perform a material balance with the non-extracted concentration since this is an unknown value."  We can assure you this pertains to RCRA related analyses for the EPA OSW and was not intended to pertain to those analytical requirements under FIFRA.  As you are probably aware, the EPA Office of Pesticides utlizes the FDA's Pesticde Anaytical Manual (PAM) for methodologhy that would be applicable for enforcing tolerances established by EPA for amounts of pesticide residues that may legally remain on food (including animal feed).  Since the MICE service is primarily dedicated to responding to questions related to the SW-846 methods manul, we cannot provide any direct comments on the PAM methods validation and approval process.

 

We hope this additional information is helpful!

 

 

----- DISCLAIMER ----- 

The MICE Service is operated by Science Applications International Corporation (SAIC) under contract to the USEPA Office of Solid Waste. All MICE Service staff are contractors. As such, they do not create or interpret USEPA policies. The role of the MICE service is to provide answers and take comments regarding the OSW methods manual known as "Test Methods for Evaluating Solid Waste: Physical/Chemical Methods (SW-846)."

 

  

 

-----Original Message-----
From: Sent: Saturday, September 30, 2006 5:14 PM
To: EHSG MICE
Cc: 
Subject: Re: Need answers on SW extraction procedures/methods

You state, 'Also note that the compound lists that are included with each SW-846 method are merely those that are recommended with performance data that were generated during the method validation process. ", could you email me this validation method?

 

You state, "Furthermore, most extraction and analytical protocols assume that the detected concentration represents the total for a given compound, so it would be uncommon to perform a material balance with the non-extracted concentration since this is an unknown value.", wrong. It is required for pesticide registration under FIFRA.  I wrote and started the data requirements in USDA under PR Notice 70-15 and in the USEPA  40CFR § 158:290.

 

Ron 

 

----- Original Message ----- 

From: EHSG MICE 

To: 'randsney@no.address' 

Cc: EHSG MICE 

Sent: Friday, September 29, 2006 3:06 PM

Subject: RE: Need answers on SW extraction procedures/methods

 

Dear Ronald,

 

Thank you for your inquiry.

 

Since you have not defined what specific compounds that would be included in your term "residues,"  we cannot fully respond to your questions.  We can note that SW-846 extraction and determinative methods are effective for the efficient recovery and determination for a wide variety of RCRA target analytes from numerous sample matrices that would include the two you have mentioned; an organic matter contaminated soil and animal / fish or plant tissue.  Also note that the compound lists that are included with each SW-846 method are merely those that are recommended with performance data that were generated during the method validation process.  However, users are not limited to only the method-listed compounds, since acceptable performance is all that is required to demonstrate the appropriateness for the given sample preparation and quantitation technology.  Other than the performance data provided either in the back or noted in the individual references of many of the SW-846 methods, there are no additional sources of performance data EPA would possess for distribution.  Due to the wide variety of sample matrices that may be covered under the RCRA program, it would simply be impractical for EPA to be the repository of all performance data generated during the use of SW-846 methods.  Ultimately, this becomes the method users responsibility in order to support the reported analytical data for the intended use.  We do know that on many occasions, the method performance data are published in any number of scientific journals.  We would therefore suggest performing a literature search for something that may be applicable for your application.

 

Typically, SW-846 methods are applied to the determination of RCRA regulated constituents which could either be the parent or some degradate.  However, unless the laboratory is instructed to do so and the determinative instrumentation is calibrated for the desired target analytes, it is not a common practice to quantitate every conceivable degradate of the parent compound.  Furthermore, most extraction and analytical protocols assume that the detected concentration represents the total for a given compound, so it would be uncommon to perform a material balance with the non-extracted concentration since this is an unknown value.  The exception would be metals speciation analyses where one could compare the speciated concentrations to the total metal concentration.  

 

We hope this information is helpful!

 

---------------------------------------------------------------------------------- 

NEWS!! NEWS!! NEWS!! 

OSW on April 17, 2006, re-posted Method 8270D - Semivolatile Organic Compounds by Gas Chromatography/Mass Spectrometry (GC/MS).  This is an advance copy of Method 8270D as it will appear when published in Update IV later this year. All public and Workgroup comments have been addressed.  In addition, OSW on July 14, 2005, posted Method 3200 - Mercury Species Fractionation and Quantification by Microwave-assisted Extraction, Selective Solvent Extraction and/or Solid Phase Extraction.  OSW also recently made available Method 9015 - Metal Cyanide Complexes by Anion Exchange Chromatography and UV Detection on November 15, 2004, and released Method 5035A - Closed-System Purge-and-Trap and Extraction for Volatile Organics in Soil and Waste Samples on July 26, 2002. Go to:

http://www.epa.gov/sw-846/new-meth.htm 

to download a copy of these methods. 

The Methods Information Communication Exchange (MICE) Service 

E-mail address: mice@no.address 

Phone: 703-676-4690 (leave a message) Fax: 703-318-4646 

MICE Web Site: http://www.epa.gov/sw-846/mice.htm 

MICE FAQs: http://www.epa.gov/sw-846/faqs.htm 

SW-846 methods can be downloaded from the web at: 

http://www.epa.gov/sw-846/sw846.htm 

----- DISCLAIMER ----- 

The MICE Service is operated by Science Applications International Corporation (SAIC) under contract to the USEPA Office of Solid Waste. All MICE Service staff are contractors. As such, they do not create or interpret USEPA policies. The role of the MICE service is to provide answers and take comments regarding the OSW methods manual known as "Test Methods for Evaluating Solid Waste: Physical/Chemical Methods (SW-846)."

         

-----Original Message-----
From: 
Sent: Friday, September 22, 2006 3:03 PM
To: mice@no.address
Cc: 
Subject: Need answers on SW extraction procedures/methods

 

September 22, 2006

 

To: USEPA, mice@no.address

 

Cc: 

 

From: Ron, PhD

 

Subject: Need answers on SW extraction procedures/methods

 

I have three questions that I would like for you to provide separate answers on. A simple yes, no or we don’t know will be adequate. 

 

1.     Do the SW extraction procedures/methods extract residues bound in the organic matter of soil?

 

2.     Do the SW extraction procedures/methods extract residues bound in fat in animals?

 

3.     Do the SW extraction procedures/methods provide a material balance for residues in each of the following matrices soil, plants and animals, that is total residues of parent, degradates, and bound (non-extractable residues) residues?

 

If you answered yes to any of my questions please provide some data.

 

Regards,

 

Dr. Ron 

 

 


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