### Karla Faught - Re: OTM-28 Analysis

Hi Ron We're recommending for your consideration as part o f the response to comments for this CFR proposal th e following method change:



### 6.3.9 Sonication device. The device must have a nominal sonication freque ncy of 25 to 40 kHz and be approximately 4 to 6 inches deep to accommodate the sample extract or tube.

This may help respond to questions about sonicator specifications. Most modern sonicators operate at 40 kHz although you can still order one at 25 kHz.

Ray

>>> <Myers.Ron@epamail.epa.gov> 1/7/2010 2:26 PM >> > Paul: I have re-read OTM-28 and there is no requirement t o measure the pH of the samples until the aqueous p ortion is rehydrated and then neutralized with 0.1 N NaOH (para 11.2.2.4).

Paragraph 11.2.1 and subsequent subparagraphs cover the sonication of the filters. We can not recomme nd any specific sonicator. But any sonicator that the vesel you have placed the filter would be complete ly imersed to the water line would be acceptable. The goal is to dislodge all the particulate from the filter an d get it into

solution.

_________________________________ Ron Myers U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policy and Programs Division Monitoring Policy Group, D243-05

RTP NC 27711

Tel. 919.541.5407

Fax 919.541.1039 E-mail myers.ron@epa.gov

-----"Taverna, Paul" <paul.taverna@aecom.com> wrote : -----

To: Ron Myers/RTP/USEPA/US@EPA From: "Taverna, Paul" <paul.taverna@aecom.com> Date: 01/07/2010 11:12AM cc: "Moll, David" <David.Moll@aecom.com>, "Tringale , Frank" <frank.tringale@aecom.com> Subject: OTM-28 Analysis From: Ray Merrill

To: Myers.Ron@epamail.epa.gov

Date: 1/7/2010 3:00 PM
Subject: Re: OTM-28 Analysis

CC: Greene, Danny; Merrill, Ray 

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...Ron,

I manage in the AECOM gravimetric laboratory in Har vard MA and we are in the process of equipping our laboratory to perform the OTM-28 test method. I wo rk with Dave Moll at AECOM and he suggested asking you some questions I have about the analysis. I would greatly appreciate any help or advice you could giv e me for the following questions;

1. Do we need to test the PH level of the sampl es in the lab if the PH levels are measured in the field during recovery? I did not see in the method where this s tep was required to be done in the lab.

2. Do we need to use the sonicator bath on each sample? The sonic bath is listed in the equipment , but I am unclear as to where in the process to use the sonic bath. Also, can you recommend what type of sonica tor (i.e. brand and size) would be appropriate for this test method?

Thanks for any help you can provide.

Paul

Paul Taverna Project Specialist

AECOM Environment D: (978)589-3200 x3523 C: (978)758-2542 paul.taverna@aecom.com

AECOM 2 Technology Park Drive Westford, MA 01886 T: (978)589-3000 F: (978)589-3312

www.aecom.com Please note: My e-mail has changed to [paul.taverna @aecom.com]. Please update your address books accordingly.

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