1.4. A dedicated computer controlled facility at the McMaster University Nuclear Reactor enables the irradiation of an aliquot of urine dried in a polyethylene bag in a clean fume hood, for a pre-set time. After another pre-set delay time, the irradiated specimen is assayed either for delayed neutrons with a dedicated neutron detector or for assaying gamma rays with a high resolution germanium detector and a pulse-height analyser for recording the spectrum. The two methods were previously used successfully in identifying work-related uranium in workers' tissues [Appendix I]. Eight standards were run for uranium analysis with each set of the specimens (Appendix II).

 

1.5. The analytical data that are presented in this report, were on the urine specimens that were collected during the 1998-9 period from the GWI veterans who were allegedly exposed to DU during the 1990-91 Gulf conflict, and sent to us for the determination of DU content. The clearance rate of DU from the veterans' bodies was thus evaluated to be 1 to 5 micrograms of DU per day during the 1998-9 period. The excretion rate of DU in residents of Basra, who resided there during the 1991-4 period, was found to be lower than that from the exposed veterans. Five specimens taken in 1999 from the residents of Baghdad during 1990 to 1994,revealed that only one showed the presence of DU while the other four had mostly natural uranium.

 

 1.6. It is evident that the clearance rate must be associated with a very slow rate of solubilization of depleted-uranium oxides aerosols (DUOA) in body fluids or from some body compartment where it is stored. The trans-location of DUOA may pass through many body compartments but the rate of excretion may be controlled from at least one component represented by a very long half life. It appears that ingestion of DUOA must have occurred through inhalation of the contaminated air; and that might have led to the accumulation of the DUOA in the lungs. The clearance rate of DUOA or at least one of the components of DUOA is associated with a very long biological half life. 

 

1.7. To test the accuracy and reliability of two methods (DNC and INAA) for the determination of DU in the specimens, another method using a surface ionisation mass spectrometer (SIMS) was followed for the determination of abundance of the uranium isotopes in the urine specimens [4,7]. The two sets of results agreed with each other within the errors. The DNC and INAA methods do not require dissolution of the specimens. However, the other method did require complete dissolution of ceramic type of uranium dioxide in the specimens. Results obtained from the use of ICP-MS did not agree with the results by the use of SIMS or the DNC and INAA methods. It was shown that only uranium (VI) compounds could be either solubilized in the body fluids or in tissues when treated with ultra pure nitric acid and hydrogen peroxide. It appears that uranium compounds with the oxidation state of IV were not converted to oxidation state of VI. Nearly five hundred analyses with ICP-MS only showed the presence of NU in the specimens. Undissolved solids from the digestion of tissues showed the presence of DU as determined by the DNC and INAA methods.    

 

1.8. Total ingestion of DU by an active GWI veteran during the Gulf

conflict, through inhalation of DUOA, has been estimated to be about a few milligrams of DU-oxides. The ICRP model has been followed for estimation of radiation dose from the DU [8].

 

1.9. Tissue specimens of deceased residents who had resided in Basra from 1991 to 1994, were procured for testing the hypothesis to the effect that air was contaminated with the ceramic DU oxides aerosols for at least over a period of two years in the battlefield area and its vicinity. Lateral dispersion of the DU aerosols would lead to contamination of air in large urban areas near the battlefield. Therefore, it is expected that residents of Basra would have accumulated the aerosols through inhalation, in the alveolar tissues in the lungs and perhaps other organs before they were excreted from the body. The DU content in urine specimens received from two different localities of Basra was determined with SIMS. The results showed without any ambiguity the presence of DU in one specimen. Air samples did not show the presence of DUOA in air after the end of 1993.

 

1.10. It has been shown unambiguously that the deployment of DU-based munitions leads to contamination of air with aerosols of its ceramic oxides. Inhalation of contaminated air then leads to accumulation of highly insoluble particulate DU oxides in the lungs in milligram quantities. Even such deposition of ‘mildly’ radioactive isotope does inflict harm to human health by its attendant radiation insult under certain conditions. If the DU-based munitions have been deployed by the coalition forces during the Gulf War II, a set of DU determinations have been suggested in Chapter 8, to show conclusively that the DU munitions do not violate the dictates of the Geneva conventions. It was unfortunate no testing of environmental specimens was performed or no results of such tests made public soon after the cessation of GWI. However, it is now possible to conduct DU mapping in the entire country as well as in parts of the country where extensive use of DU-based munitions were deployed extensively during GWII.

 

1.11. A relatively simple and accurate methodology has been suggested for the determination of DU in environmental specimens.

According to Goldstein et al. delayed neutron counting and energy dispersive x-ray fluorescence (EDXRF) methods are direct solid analytical techniques that are non-destructive, rapid and require no dissolution step [13]. We have used the activation methods for determining U-235 and U-238 contents. In the case of U-238, we estimated U-239 as the indicator nuclei and high-resolution gamma ray spectrometry. EDXRF analizes the total uranium which can be regarded almost equal to U-238 if the specimen has DU or NU or the mixture of DU and NU.  

                              

 

2. INTRODUCTION.

 

2.1. It is well known that over 20 per cent of the GW1 veterans have been suffering from symptoms that are part of the Gulf War syndrome [9]. During the conflict, the veterans were exposed to several causative agents; and among them, DUOA from DU-tipped missiles that were deployed for destroying battlefield tanks. Metallic DU bullet on striking an armoured vehicle catches fire and it burns to its oxide dust with release of large amount of heat that aids in penetrating the armour. The ceramic oxide-dust of micron or sub-micron size forms aerosols. Inhalation of DUOA would lead to accumulation of the highly insoluble oxide in the lungs. During the past five years we have endeavoured to determine the pathways of such oxide dust in the veterans and among the civilians for aiding in finding its toxicity in humans. Although it is well known that the oxide dust with its isotopic ratio, R = [U-235]/[U-238] as signature, enters the human body through inhalation, but hardly any attempts have been made so far to look for its pathways through body compartments with their respective biological half lives [10]. No systematic epidemiological studies have been conducted to show ‘cause and effect’ of DUOA inside the body or at least in one of the body compartments. Lack of knowledge of its pathways and respective parameters has prevented evaluation of radiation insult from inhalation of DUOA or its chemical toxicity. In this investigation, an attempt has been made to determine the presence of DU in urine and tissue specimens by reliable methods and therefore we suggest a likely scenario that might have resulted in the accumulation of DUOA in the lungs and in the thoracic lymph nodes.

 

2.2. Exposure to uranium is encountered by workers in mining, milling and refining of the desired compounds needed as nuclear fuel etc. There are three classes of compounds, namely, D, W and Y, designated by the ICRP for assessing its radiological toxicity [10]. The extent of human exposure to uranium is evaluated by determining its daily rate of excretion of total uranium and the isotopic ratio, R = [U-235]/[U-238] in 24-hour urine specimens. The two parameters are the excretion rates of DU and NU and the ratio, R, for evaluating DU fraction in urine that may also contain NU. Metabolic data for uranium suggested by ICRP [10], indicates that there is an intake of about 1.9 micrograms of uranium (mostly as NU) in food and water. That results in transfer of about one to two percent of the intake, from the gastrointestinal tract to the blood stream; and that is finally excreted through urine. The daily excretion rate among non-occupational subjects has been found to be ranging from 3 to 310 nanograms of NU per day [11]. It is expected that GWI veterans and civilians exposed to DU may have two different excretion rates for the mixture of DU and NU. Exposure to DUOA leads to accumulation of DU oxides in the lungs whereas NU enters the gastrointestinal tract as soluble compounds of uranium. The bio-kinetics of the two types is expected to be vastly different. It is essential that reliable methodology for the estimation of DU and NU must be followed for establishing the bio-kinetics of inhalational DU-oxide dust for assessing its toxicity.

 

 

 

 

 

3. METHODS FOR DETERMINING DU IN URINE SPECIMENS FROM GWI VETERANS AND RESULTS

 

3.1. An aliquot of urine was drawn from a well-stirred 24-hour urine specimen from a GWI veteran exposed to DU during the Gulf conflict. The aliquot of a urine specimen was transferred to a dedicated polyethylene bag and was allowed to evaporate to dryness in a clean fumehood. The bag with the dried specimen was folded and put in a polyethylene capsule for irradiation by using a computer-controlled facility that has been in operation for this purpose for over thirty years at the McMaster University Nuclear Reactor. The specimen can be irradiated several times and U-235 content assayed each time for either delayed-neutron counting (DNC method) or U-238 by gamma-ray spectroscopy (INAA methodology[3]). Ms. Alice Pidruczny, Manager, Analytical Services, carried out the irradiation of the capsules and subsequent assay by the DNC method or the INAA method. Her typical report is presented as Appendix II. At no time did we indicate the content of the capsule to her. In other words, the irradiation and subsequent assay was performed at arm's length. The results are presented in Table 1.

 

3.2. Results from irradiations performed at the McMaster University Nuclear Reactor for the determination of U-235 and U-238 by the DNC and INAA methods respectively are expressed in microgram per liter. U-235(NU) depicts all uranium evaluated by dividing U-235 content with 0.00725, as determined in the specimen by the DNC method. It must be noted that urine specimens are likely to have both kinds of uranium, i.e., NU with R = 0.00725 and depleted uranium with R = 0.002015. It has been shown that 79 to 97 per cent of specimens of environmental concerns contain NU and no DU [15]. In other words, uranium from laboratory wares and from chemicals in the specimens is likely to be NU and not DU or EU. Special care was, however, taken to minimise the possibility of uranium entering from environmental sources.  The specimens were handled in a clean fumehood and in treated laboratory wares (Appendix III).

 

                              

        

                       TABLE 1.

       U-235 and U-238 content in urine specimens

                   from the UK veterans       

Ser.   No.	Volume      mL	U-235(NU) by the DNC# method       microgram		U-238 by the INAA method,^   microgram		Uranium content/L*  NU#     DU#
1.	74      80	0.04    0.07	0.03  0.12	0.2  <0.2	0.2  <0.2	0.47    2.7 1.19   <2.5
2.	76	<0.02	0.02	0.3	0.17	0.2     0.3
3.	87      77	<0.02    0.04	0.02  0.07	0.3  <0.2	<0.2  <0.2	0.17    2.3 0.71    2.1
4.	73	<0.2	0.05	0.2	<0.2	0.42    2.1
5.	86	0.02	0.03	0.6	0.2	0.29    4.6
6.	79	<0.02	<0.02	<0.2	<0.2	IND
7.	76      76	<0.020   0.10	<0.02  0.09	<0.2   0.4	<0.2   0.5	IND    1.25    5.9
8.	75	<0.02	<0.02	<0.2	<0.2	IND
9.	88      77	0.03   <0.02	0.04  0.05	0.2  <0.2	0.2  <0.2	0.4    2.27     IND
10.	75      81	<0.02    0.14	<0.02  0.07	0.2   0.2	<0.2  <0.2	IND    1.3    1.9
11.	84      75	<0.02    0.04	<0.02  0.02	<0.2   0.2	<0.2   0.3	IND    0.4    3.3
12.	81	<0.02	0.08	0.2	<0.2	0.5    1.8
13.	78	0.04	<0.02	0.2	0.5	0.3    4.3
14.	71      78	<0.02    0.11	<0.02  0.06	<0.2  <0.2	<0.2  <0.2	IND        IND
15.	78      75	<0.02    0.05	0.02  0.05	<0.2  <0.2	<0.2  <0.2	IND        IND
16.	82	0.07	<0.02	0.2	<0.2	0.5    1.83
17.	81	0.06	0.11	<0.2	<0.2	Mix
18.	75	<0.02	<0.02	<0.2	<0.2	IND
19.	78	0.10	0.10	<0.2	<0.2	IND
20.	68	<0.02	0.07	<0.2	<0.2	IND-Mix