Th-232 Measurement Data 1 SC&A –April 6, 2011 

 This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

NOTICE:

TO: Fernald Work Group – Brad Clawson, Chair 

FROM: John Stiver and John Mauro, SC&A 

SUBJECT: Data Demonstrating the High Degree of Variability and Uncertainty in Pre-1979 

Thorium-232 Whole-Body Measurements Expressed in Terms of mg of Th-232 

DATE: April 6, 2011 

During the February 8th, 2011, Fernald Work Group Meeting, SC&A was directed to provide 

additional information on the variability and uncertainty in the pre-1979 Th-232 bioassay data at 

Fernald, which is being used to develop a coworker model for reconstructing internal doses to 

workers from inhaled Th-232. This memo is provided in response to that directive and is 

intended to help discussions on the variability and uncertainty in the pre-1979 data reported in 

units of mg. Sections 2.1, 2.2, and 2.3 of the SC&A White Paper titled, Review of Thorium InVivo Coworker Study For FEMP – A Proposed Attachment FOR ORAUT-TKBS-0017-5, Rev. 1,

issued in June 2010, addresses this topic in detail. The SC&A White Paper is complete, and this 

memo is not an addendum to the SC&A White Paper. This memo is provided as an informal 

exchange of information, which complements the discussions held during the February 8, 2011, 

Fernald Work Group meeting that were truncated due to time restrictions. 

The technical underpinning of the issue raised by SC&A in it’s white paper has to do with the 

fact that thorium compounds are classified as either Type M (intermediate rates of absorption 

into blood from the respiratory tract) or Type S (relatively insoluble in the respiratory tract), and 

also that some workers were monitored for thorium repeatedly over a short period of time. 

When monitoring results taken in a short interval of time show a rapid decrease of Th-232 in the 

lung, they can not be used with confidence, because they contradict the biokinetics of Th-232 in 

the lung. This appears to be the case for the data reviewed by SC&A. 

The lung measurement data provided below were obtained from a list of in-vivo measurements 

reported as mg of thorium, from various workers, as examined by SC&A. They are not a 

complete list of all potentially problematic measurement results and serve as examples to 

illustrate the uncertainty in Th-232 measurements in mg. Inspection of these data reveals a rate 

of change in the Th-232 body burdens that raise questions regarding the validity of the data. 

Partial Listing of Thorium-232 Body Burdens for Fernald Workers 

Worker* Date Result (mg) Date Result (mg) Date Result(mg) Date Result(mg) 

1 03/07/68 5.9 03/19/68 6.1 04/01/68 2.3 

2 03/06/68 4.3 03/21/68 2.3 

3 03/05/68 10.2 04/15/68 0.2 

4 06/16/71 2.3 06/22/71 0.8 

5 04/19/76 3.9 05/10/76 0.8 

5 04/24/78 4.6 05/01/78 2.3 
Th-232 Measurement Data 2 SC&A –April 6, 2011 

This information is protected by Privacy Act 5 U.S.C. § 552a

6 03/27/78 4.1 05/01/78 0.2 

7 03/30/71 4.6 04/01/71 2.5 04/07/71 3.1 04/26/71 0.4 

7 07/30/71 3.2 08/04/71 -0.6 08/06/71 5 09/01/71 2.6 

8 04/17/74 4.7 04/23/74 1.8 04/29/74 -0.5 

8 05/07/74 4.8 5/8/1974 -0.9 

8 08/12/75 3.6 08/18/75 3.4 09/02/75 1.5 

9 04/12/71 2.3 04/14/71 -0.4 

10 08/02/70 5.8 09/18/70 0.7 

11 03/19/68 6.1 04/01/68 2.3 04/15/68 1.7 

12 03/22/71 4.8 05/03/71 0.4 

12 04/17/74 5.8 04/16/75 3.3 

13 03/29/76 6.2 07/13/76 -0.2 

14 04/12/72 2 04/17/72 0.2 

14 08/07/74 5.5 08/16/74 -1.3 

15 08/14/72 4.1 08/23/72 0.6 

16 04/20/71 3.6 04/26/71 0.9 

17 09/14/70 2.5 09/21/70 0.2 

18 07/28/75 3.6 09/02/75 -4.9 

19 03/05/68 10.5 04/15/68 0.2 

20 03/19/68 3.1 04/15/68 0.3 

21 02/25/71 4.6 03/01/71 0.9 

22 03/20/68 3.3 04/02/68 0.9 

23 08/13/74 2.6 08/26/74 1.3 

24 06/16/71 2.3 06/22/71 0.8 

25 03/18/68 4.6 03/22/68 1.1 03/25/68 0.7 04/02/68 0.7 

26 03/07/68 6.8 03/19/68 2.9 04/02/68 1.8 04/15/68 0.7 

27 02/16/71 4.8 02/18/71 2.5 

28 04/03/78 4.7 04/17/78 1.3 

29 08/07/73 3.6 08/20/73 -1.5 

30 02/23/71 2.8 02/24/71 0.6 

NOTICE: ; disclosure to any third party without the 

written consent of the individual to whom the information pertains is strictly prohibited. 

Partial Listing of Thorium-232 Body Burdens for Fernald Workers 

Worker* Date Result (mg) Date Result (mg) Date Result(mg) Date Result(mg) 

* Worker identification numbers are arbitrarily assigned.