[ RadSafe ] Uranium and genotoxicity

[Dan W McCarn]

Dan W. McCarn, Geologist; 3118 Pebble Lake Drive; Sugar Land, TX 77479; USA 
HotGreenChile at gmail.com    mccarn at unileoben.ac.at    UConcentrate at gmail.com

Dear Group:

James asked me a few questions:

<< What is your opinion on whether (U-238)O2-Y is more dangerous than (U-238)O3-D, as the ICRP and NRC assert, or does the bioavailability of the uranyl ion make equivalent activities of (U-238)O3 more of an ingestion and inhalation hazard?>> 
 
I am neither physician, biochemist or epidemiologist. Why should my lay opinion count for anything regarding that?  Why should yours?

<< Does that imply that mathematical models require a firm foundation in empirical observation from weathering of the oxides to human bioavailability on the specific terrain in question?>>

You are jumping several fences at the same time.  No, deriving data just for a leaching coefficient, or transfer coefficients to plants, etc. would be very time-consuming and expensive.  Lab assessment would require a long-term column experiment, for instance. ICRP only offers rather conservative guidelines.  

Usually you are left with field data and reconstructed water use and quality records.  You can "back into" soil concentrations by understanding source concentration and amount of water applied over the years and get an estimate of the Leaching Coefficient.  One example is a mining company in Wyoming that used drinking water quality process water to irrigate large acreages of alfalfa in order to dispose of the water (beneficial use).  The slight concentration of selenium (below drinking water quality standards) concentrated in the soils over 20 years requiring them to "clean-up" the alfalfa property because of soil contamination.  If a farmer had done the same thing, there would be no consequences.  There is no EIS process for farming.

<<In the mean time, would you please have a look at this article and please tell me your opinion of it?>> 
 
My opinion is, had they been a little more honest, they should have described the overall distribution of uranium, not just the "contaminated" water.  The use of the word "contaminated" directly implies an anthropogene cause.  The gullible reader is left to believe that all waters are "contaminated", probably by the mining activity. In this region where uranium deposits and occurrences are common, "natural" levels of uranium are high, or very low, depending on the redox condition of the water and proximity to mineralization.  Some of these high values may be associated with tailings or mining, but I would have to look at the pre-mining baseline to know if "mining" was the culprit.  I suspect that most of the high values are "natural" outliers associated with pre-existing U mineralization.  If that is any indication of the quality of the rest of their paper, then I would have my doubts.

Quote
"The U levels found in contaminated water sources ranged from 33.3 to 1,131 μg/L, with the highest concentration being 38 times the safe drinking water level (U.S. EPA 2004)."  
UNQUOTE

I'm sure that in the EPA report, there were a half dozen paragraphs describing the spatial distribution, cumulative distribution, etc. and mentioning the large number of samples below the MDL.  The fact that they chose the only one to "validate" their case reminds me strongly of "Cherry Picking".  Just like the recently falsified report from the medical university in Vienna about cell phones, are they presenting a "politically correct" version of their research?

James, please note that they only reported "contaminated" sources and not "all" sources. If they had presented all the data about uranium distribution, there would have been many values below the Method Detection Limit (MDL).  But this is consistent with the fact that the uranium concentration is naturally high in the area spatially associated with uranium mineralization and redox zone, very low in the reduced portion, and moderate to low in the oxidized portion. Remember that these are active, ore-forming processes.  On the (chemically) reducing side, I seriously doubt that you could find a sample of water above the MDL.  I had many hits over 30 ug/L in the San Luis Valley because I was looking for indications of my predicted uranium feature, and my sampling target was focused to detect exactly that.  I also had many "misses" below the MDL because I was in the reduced zone not 100 m from the roll front, not in the redox zone or on the oxidized zone.  USGS's sampling program in the San Luis Valley (SLV) only had 1 well in my target area (they used a random design), so they only had 1 "high" hit in the SLV (which they were baffled by), but then they were not looking for uranium, and certainly did not know how to look for uranium.

Just an observation: "U’s effect on the reproductive system was examined in early studies with rats fed high doses of 2% uranyl nitrate (UN). U exposure caused significant weight loss in dams, fewer litters, and fewer pups per litter (Maynard and Hodge 1949). When female rats were returned to chow diet without UN, they regained the lost body weight, but a reduction in the number of litters and pups per litter persisted, suggesting that the ovaries had been permanently damaged (Maynard and Hodge 1949)."

I had a court case as an expert witness (never went to trial) in NW Georgia in the early 90s involving a chicken hatchery, the use of NaOH-based cleaners, a septic-tank-leach field, and 1-2% arsenopyrite mineralized in a fractured Paleozoic limestone.  The high pH of the effluent dumped into the leach field hydrolyzed the arsenic out of the arsenopyrite in the fractures.  The concentration in the spring-fed pond in a neighboring horse farm 100 m away was 0.5% arsenic in the horses' drinking water (pH=12).  Every foal died, and the mares were all in poor condition, many of them suffering from chronic colic.  I won my case at the deposition stage.  The dose makes the poison.  I'm surprised that the above reference to a 2% UN solution (Maynard and Hodge 1949) did not do as much damage as a 0.5% arsenic solution for horses.  As I recall, arsenic also is teratogenic, carcinogenic, mutagenic and a heavy metal poison and has an interesting distribution because of the worldwide metalogenic association to gold.  Gold mining may actually be more hazardous than uranium mining because of the increased mobilization of arsenic from tailings. You should Google "Nevada gold arsenic"

............................

To recap what James has said: 
      - 25,000 km^2 of area in Iraq

Fathallah's (2007) assertion: 
      - Uranium uptake in agricultural products and drinking water from airborne redistribution of uranium.

Quoting Fathallah (2007)
"The fine uranium dust has been spread by the wind from the war zone to the surrounding region, including Basrah, and it is by now pushing down the soil by the effect of rain to reach the water table, which is used for drinking & irrigating the vegetables for human consumption 34."
Unquote

My Assumptions:
      - About 7.5 Tonnes of airborne releases of U in Iraq
      - In Iraq, 10% to 25% (more likely 10%) of total area used for agriculture
      - Assume uniform distribution of airborne U over 25,000 km^2
      - Irrigated area: between 2,500 sq.km (0.75 Tonnes U) to 6,250 sq.km (1.85 Tonnes U)
	- 100% dissolution as uranyl ion complexed as carbonate at neutral pH.
      - Migration of U into soil zone; no longer available as runoff.
      - Surface waters are typically very low in dissolved uranium.

San Luis Valley (SLV):
      - 1,796.13 Sq.Km irrigated cropland
      - About 7.5 Tonnes U per annum deposited on agricultural soils
      - Range: 5 - 10 Tonnes / annum
      - 1 million acre-feet per year (1.3 x 10^12 L)
      - 2 million tonnes produced crops; 1 million tonnes of potatoes.

Numbers:
Area - Source Term   Iraq Agr.25%  Iraq Agr.10%  SLV - Low  SLV-Mid   SLV - High
Area sq.km               6250          2500         1,796     1,796      1,796
Tonnes U                 1.875         0.75           5        7.5         10
Tonnes U / Sq. Km       0.00030      0.00030       0.00278   0.0042      0.0056
Multiplier for SLV Source Term                       9.3       13.9       18.6

Conclusion:
	- SLV has about 14 times the amount of uranium deposited per annum per unit area as Iraq theater.
	- SLV ranges from 9.3 to 18.6 times the amount U per unit area as Iraq, on an annual basis;
	- Over 10 years, this will be 90 to 180 times the amount of uranium in the SLV;
      - SLV has been in active production for 100 years;
      - No reported problems.

What is your point, James?

Dan ii


-----Original Message-----
From: jsalsman at gmail.com [mailto:jsalsman at gmail.com] On Behalf Of James Salsman
Sent: Saturday, June 07, 2008 1:25 AM
To: Dan W McCarn; radsafelist
Subject: Re: [ RadSafe ] Uranium and genotoxicity

Dan,

Thank you for your message.

What is your opinion on whether (U-238)O2-Y is more dangerous than
(U-238)O3-D, as the ICRP and NRC assert, or does the bioavailability
of the uranyl ion make equivalent activities of (U-238)O3 more of an
ingestion and inhalation hazard?

> James is persistent; I just wish that he would listen.
> My presentation of moles per liter of PHREEQC
> equilibrium concentrations has been previously presented.

I wish you would listen, too.  When will you use the 25,000 km^2 area
in which depleted uranium munitions were used instead of "a third of
Iraq," which is several times larger?

Furthermore, have you taken into account that potable water in that
region is taken from rainwater runoff?

>... Also consider that groundwater may also have
> a number of other trace metals and materials,
> e.g. major anions & cations (Na, Ca, Cl, SO4,
> HCO3, CO3) trace metals (selenium, molybdenum,
> etc. that may concentrate in the soil zone over time.
> It all depends on the "Leaching Coefficient", how
> quickly or slowly specific analytes move through
> the soil column.

Does that imply that mathematical models require a firm foundation in
empirical observation from weathering of the oxides to human
bioavalability on the specific terain in question?

> The fact is that the uranium does not concentrate
> significantly in desert soils with the possible
> exception of caliche- or gypcretes-forming soils....

I will have to look those up.

In the mean time, would you please have a look at this article and
please tell me your opinion of it?
  http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2137136

James Salsman