Section I - Iodine in the Soil
This page will detail some of the data that I have personally
generated as well as references that I have used to support the
mechanism I have proposed in my iodine paper. This will not be a
traditional bibliography but a discussion of the relevant data and the
portions of the related papers supporting my mechanism.
The Chilean Iodine Educational Bureau (1956)
Rock Type Iodine in parent material Iodine in soil derived from parent
ppm I2 ppm I2
Igneous Rocks (ALL) 0.26 4.67
Basic 0.25 5.09
Intermediate 0.26 4.17
Acid 0.27 3.06
Sedimentary Rocks (ALL) 0.78 1.93
Limestones 0.59 2.26
Sandstones 0.87 1.83
Shales and Argillites 1.09 1.11
Metamorphic Rocks (ALL) 0.81 2.66
In this same report the CIEB reported decreasing amounts of iodine with depth. Although my research
down to about eight feet is not deep enough to establish this, I did run a number of samples taken
from shot holes that I was told came from around 90 feet. Unfortunetly I have been unable to locate my
notes on this test but I do remember the iodine concentrations where well below the soils, in fact they
were near zero.
Section II - Iodine Compounds in the Soil
Many researchers have reported that little of the iodine in soil is water soluble.
Magomedova, Zyrin, Salmanov, (1970), IODINE IN THE SOIL AND ROCK OF MOUNTAINOUS
DAGESTAN, Agrokhim. No. 1 117-125
Reported 1%-12% of soil iodine was soluble.
Sinitskaya, (1969), IODINE CONTENT IN THE ZEYA-BUREYA PLAIN SOILS, Uch. Zap., Dal'nevost.
Gos. Univ. Khim. No. 27 72-88
Reported "small amounts" of soluble soil iodine.
Whitehead, (1978), STUDIES ON IODINE IN BRITISH SOILS, J. Soil Sci. 24 260-270
Reported 25% soluble soil iodine.
Below is my test of the solubility of soil iodine from various areas over a range of concentrations.
Each sample was run and rerun, soil was extracted for 24 hours with DI water and the residue was
analyzed.
Sample Location ppm I2 ppm I2 R H2O ext soil Average % extracted
Oklahoma 4.2 3.8 3.8 4.0 5
Oklahoma 2.6 2.5 2.5 2.6 4
Oklahoma 4.0 4.1 3.9 4.1 5
Oklahoma 4.6 4.2 4.1 4.4 7
Oklahoma 2.4 2.9 2.6 2.7 4
Oklahoma 1.6 1.6 1.6 1.6 0
Oklahoma 1.8 1.7 1.7 1.8 6
Oklahoma 1.7 1.8 1.7 1.8 6
Texas 1.5 1.8 1.8 1.7 -6
Texas 1.8 2.2 2.2 2.0 -10
Texas 2.8 3.2 3.2 3.0 -7
Texas 4.0 4.3 4.1 4.2 2
Texas 3.6 4.0 4.2 3.8 -11
Texas 5.1 5.1 5.4 5.1 -6
Texas 1.7 1.9 1.8 1.8 0
Texas 1.5 1.8 1.8 1.7 -6
Texas 2.1 1.9 1.9 2.0 5
Colorado 2.4 2.3 2.2 2.4 8
Colorado 2.5 2.4 2.3 2.5 8
Colorado 3.0 3.2 2.9 3.1 7
Colorado 3.4 3.2 3.2 3.3 3
Colorado 2.8 2.8 2.5 2.8 11
Colorado 3.3 3.3 3.0 3.3 9
Colorado 2.4 2.6 2.5 2.5 0
Montana 6.7 5.9 6.1 6.3 3
Montana 3.7 3.6 3.4 3.7 8
Montana 2.9 3.0 3.0 3.0 0
Montana 3.9 4.0 3.8 4.0 5
Montana 5.2 4.3 5.3 4.8 -10
Montana 3.2 3.1 2.8 3.2 12
Montana 2.7 2.7 2.5 2.7 7
Assuming the measured increases are due to analytical error the average extraction for the
remaining 24 samples ranges from 0 to 12% with an average of 5.2%. This agrees with the
researchers listed above. Clearly only a small portion of the iodine in soil is in a soluble form. All of
the simple ionic combinations of iodine with the most abundant anions are soluble, only an unusual or
complex ionic structure could explain this insoluble iodine. However, the more likely explanation is
covalently bonded organic-iodine compounds.
Raja, Babcock, (1961), ON THE SOIL CHEMISTRY OF RADIO-IODINE, Soil Sci. 91 1-5
Reported that a large fraction of iodine released into a soil was retained due to a "reaction" with
organic matter.
Vingradov (1959): Page 59
"As we have repeatedly noted, the organic material ties up the iodine in soils."
Keppler, Biester, Putschew, Silk, Scholer, Muller, (2003) Organoiodine formation durning
humification in peatlands: a key process in terrestrial iodine cycling. Environ. Chem. Lett.
"transformation of iodine from its inorganic form to organoiodine ... is a key process in the storage
of iodine ... Once bound in peat iodine remains stable for thousands of years."
Peat represents an extreme example of a reducing environment. The process of inorganic or
elemental iodine oxidizing hydrocarbons and being retained in areas of seepage, however, is the
same.
I conducted the following research to investigate the iodine compounds I measure in the soil. This
research project involved measuring soil iodine concentrations after exposing the soils to increasing
heat.
---------------------------Temperatures are degrees Centigrade-----------------------------
-------------------------------------Iodine, ppm I2----------------------------------------
Sample Location 0 200 250 300 350 400 450 500 550 600 1000
Nevada 2.0 1.8 1.8 1.9 1.9 1.9 1.8 1.8 1.4 1.3 1.6
Nevada 5.1 5.9 5.4 5.6 4.8 4.7 4.2 4.1 3.9 2.8 1.3
Ontario 5.9 5.8 4.1 3.6 2.7 0.9
Ontario 10.0 6.1 4.1 1.2
Ontario 13.6 3.3 2.2 1.2
Ontario 4.3 4.9 4.0 3.5 2.4 1.7
Ontario 13.6 4.5 4.3 3.6 2.8 1.9
Ontario 2.3 2.1 2.1 1.2 1.3 1.3 1.2 1.6
Ontario 3.0 2.9 2.8 2.3 2.1 2.1 1.6 1.4
Ontario 3.6 3.9 3.8 2.8 2.3 2.1 1.4 1.3 1.2
Ontario 2.0 1.9 1.6 1.6 1.4 1.3 1.6 1.3 1.6
Ontario 4.4 4.1 3.8 2.8 2.4 2.2 1.8 1.4 1.6
Texas 3.8 3.5 3.5 3.3 3.2 2.9 2.6 2.7 2.2 1.5 0.9
Texas 4.2 3.7 3.3 3.2 2.4 1.3
Texas 4.5 4.5 3.6 3.3 1.8 0.9
Texas 8.1 7.3 5.5 5.3 2.0 1.2
Texas 11.6 12.7 9.1 9.1 6.5 1.8 1.4 1.3
Colorado 4.1 4.2 4.3 4.3 4.6 4.2 4.2 4.1 3.3 2.2 1.4
Colorado 12.0 10.0 9.2 8.6 6.5 2.1
Colorado 10.0 7.8 7.2 6.6 3.0 1.6
Colorado 13.6 9.2 8.3 7.8 1.8
Colorado 3.1 2.4 2.5 2.2 2.0 1.3
Colorado 3.1 2.9 2.6 2.6 1.7 1.4
A number of interesting things can be derived from these data. The first is that a large percentage
of the original iodine in the high/anomalous samples is lost between 500 and 600 degrees C. A
subset of this observation is that the iodine from Ontario, which is mostly a natural gas region, is
more volatile, disassociating between 200 and 500 degrees C, than samples from Texas,
Colorado and Nevada which are from oil regions. The loss of iodine at these relatively low
temperatures is consistent with organic based iodine, additionally the range of temperatures over
which these loses occur, argues for a variety of compounds. However, all of the samples
regardless of their original iodine concentration, or region of origin, end with a high temperature
resistant iodine of around 1.5 ppm consistent with some sort of insoluble complex inorganic or
refractory material.
A high percentage of all the areas I have analyzed from North America to Argentina to Australia to
Turkey have all displayed "background" iodine concentrations between 1.5 and 2.5 ppm I2. Based
on the literature and my research I believe that iodine exists in the soil in two primary forms and one
minor form. An insoluble, "background" compound, an insoluble covalently bonded organic group
of compounds and a small amount of iodide or iodate salt. The second, organic form is the basis of
the massive empirical data base associating iodine enhancements with micro-seepage.
Section III - The Iodine Cycle and the Soil
The iodine cycle has been discussed in the literature with little explanation being given to why
iodine is distributed the way it is in the environment. The amount of iodine in the crust on average
is estimated at about 0.15 ppm I2. Most igneous rocks contain little or no iodine, sedimentary rock
is highly variable but is often less than 1 ppm I2 while the soils derived from highly variable
regolithic sources exhibit surprisingly consistent enhancements in iodine based mainly on their
location. In fact other than oil brines, iodine is more concentrated in soils than in any other
substance.
Iodine in the environment acts, in many ways, like oxygen. Because both elements wish to fill there
outer electron shells to achieve a noble gas configuration they are continually seeking electron
donors to combine with, to oxidize. Both form diatomic molecules that are mobile in the
atmosphere, although iodine is very near it's sublimation point at normal temperatures and could
not be a gas at low temperatures high in the atmosphere. One of the prime sources of electrons in
the environment are hydrocarbons. Unlike oxygen, which lacking an ignition source can not oxidize
saturated hydrocarbons, iodine can abstract a hydrogen, given just a relatively small amount of
energy, ultraviolet and visible frequencies being adequate, forming an iodohydrocarbon. Although
iodine can replace a primary hydrogen, it is far more likely to replace a secondary or even better a
tertiary hydrogen first available in a branched chain butane. Unsaturated hydrocarbons will be
replaced by iodine on contact, with the free radical step being unnecessary. Once iodine
incorporates into the hydrocarbon the new molecule is far less volatile and drops from the
atmosphere into the soil.
At normal temperatures the selectivity of this reaction will lean heavily towards secondary, tertiary
and unsaturated compounds and in fact according to:
Weininger & Stermitz (1984), ORGANIC CHEMISTRY, pp 143,
"Iodine (I2) does not react with methane to a measurable extent."
Possibly demonstrating the difficultly iodine has abstracting a primary hydrogen. Because ethane
also has only primary hydrogens the first substantial reaction with iodine likely would be propane.
This is fortunate, although an extremely dry gas deposit might not develop an iodine anomaly, most
of the gas deposits I have surveyed have produced substantial anomalies even though methane and
ethane are not contributing to the anomaly. Balanced against this is the elimination of problems due
to coal gas and biogenic methane.
This failure of iodine to react with methane was demonstrated by a survey over the Leyden gas
storage field just north of Golden, Colorado. Prior to the decommissioning of this old coal mine
used by public service to store gas, I collected samples along a road which crosses the old mine.
At the time 3 billion cu. ft. of methane was being stored at 170-250 psi as little as 600 feet below.
Distance (miles) 0 .2 .4 1.0 1.2 1.4 1.6 1.8 2.0
Iodine (ppm I2) 1.4 1.8 1.4 1.5 1.2 1.2 1.4 1.8 1.6
CASE 3.0 2.2 6.8 3.8 2.6 2.9 4.4 24.3 5.4
Gas Storage
None of the iodine values are anomalous for this area, although the CASE values are.
These general reactions are:
1/2 I2 + RCH3 (g) --------> RCH2I (s)
1/2 I2 + RCH2CH3 (g ) --------> RCHICH3 (s)
1/2 I2 + R2CHCH3 (g) -------> R2CICH3 (s)
1/2 I2 + RCH=CH2 (g) --------> RCHICH2I (s)
Light
Light
Light
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Much of the data on iodine in soils came originally from the study of goiter. One of the best sources is
from Vinogradov, (1959), THE GEOCHEMISTRY OF RARE AND DISPERSED CHEMICAL
ELEMENTS IN THE SOIL. 2nd ed. New York: Consultants Bureau.
Page 51 "Rocks formed from massive rocks as a result of weathering contain a large amount of
iodine and, finally, the soils formed on them contain still more."
Page 53 "The basic source of iodine in soils is iodine of the atmosphere."
" The ocean is the reservoir from which all of the iodine of the atmosphere
is drawn"
This cycle of iodine is well established with the ocean and the soils acting as the primary reservoirs for
iodine.
Page 57 "Soils are always richer in iodine than the rocks on which they developed, frequently by
a factor of 20-30."
The Chilean Iodine Education Bureau in 1956 produced the following table of their data.
GrayStone Exploration Labs, Inc
Iodine Data