Polk Co. Florida, Mosaic and GASP! Radiation!!!

For anyone who hasn’t already seen the news, a Mosaic Phosphate fertilizer plant in Florida, in Polk County, had a 40 ft diameter sink hole open up and swallow one of their “phosphogypsum stacks” I.e. a waste product pond full of gypsum byproduct from phosphate rock processing went down a natural sinkhole and back into the earth, and since Florida is a honeycomb of Karst rocks, into the groundwater. That Karst structure with dissolving rocks is, BTW, why they get sinkholes… Now you might ask just what the rock is that is dissolving, but I’ll leave that for another day. Though a bit of clue comes from the phosphate mine being right next to the drained ‘pond’ / stack, and that they mine phosphate rocks from between carbonate strata…

OK, this concerns me. Polk County was basically where I lived, fished, hung out, etc. most when in Florida. Fishing is good in the various ponds left behind by phosphate mining. I drank that ground water, and will again. So what is this “radiation” that’s gotten into the ground water and just how much ought I panic? That’s the question.

Oh, and a bit of chemistry. They dig up a Calcium Phosphate natural rock, crush it, add sulphuric acid, and get out phosphoric acid (used for fertilizers and in prior times laundry soap, though now that use is largely forbidden due to it also fertilizing wherever the city put your waste water and causing algae to be very happy…) This leaves Calcium Sulphate, that is also known as Gypsum. The white chalky stuff the drywall in pretty much all our homes is made from. Unfortunately, there is way more of it made than needed for wall board, and the natural gypsum has lower natural radiation levels, so this “phosphogypsum” mostly just piles up on it’s way to becoming a new gypsum rock deposit. Or eroding to return to the ocean from which it came when Florida was underwater a few tens of thousands of years ago.

My First Thought

My first thought was WTF is radiation doing at a fertilizer plant? Are they talking about K40? Bananas are radioactive due to the potassium 40 in them. I am radioactive for the same reason. So are you.

Well, it was only partly that. Partly too was that the phosphate rock they mine has some Radium, Uranium, and Thorium in it. Not really a surprise as sea water has those in it, and so do the sands from the mountains that make the monzanite sands of The Carolinas, Georgia, and down to the Florida coast. Nice sources of “rare earths” and Thorium. The decay products of U and Th also make basements without good ventilation a not-very-good-idea over much of that area too.

So ok, there’s U, Th, Ra and the breakdown product Rn Radon kicking around the place, and some of it ends up in the gypsum… somehow. Is it enough to be a worry? I go digging… but not in the phosphate mine…

Comes From, Goes To, Sizes

Things I always want to know about “stuff” and “data”:
Where’s the ‘comesouta” and the “goesinta” and how big is the flow?

All bolding, unless otherwise noted, done by me.

This article is about a plant in India, so we can assume the worst, with zero EPA oversight and few environmental standards. The Mosaic plant ought to be much better.


Natural radioactivity assessment of a phosphate fertilizer plant area

S.K. Sahu, P.Y. Ajmal, R.C. Bhangare, M. Tiwari, G.G. Pandit,

Environmental Monitoring and Assessment Section, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India

Received 17 October 2013, Revised 1 January 2014, Accepted 2 January 2014, Available online 22 January 2014

Open Access funded by The Egyptian Society of Radiation Sciences and Applications
Under a Creative Commons license


Rock phosphate ore processing and disposal of phosphogypsum contribute to enhanced levels of natural radionuclides in the environment. The concentration of naturally occurring radionuclides in soil, rock phosphate and phosphogypsum samples collected around a phosphate fertilizer plant were determined. Also the external background gamma levels were surveyed.238U, 232Th, 226Ra and 40K activities in soil samples were 21–674 Bq/kg, 11–44 Bq/kg, 22–683 Bq/kg and 51–295 Bq/kg respectively. The external background gamma radiation levels in the plant premises were ranging from 48 to 133 nGy/h.

Rock phosphate; Phosphogypsum; TENORM; Radium equivalent activity

1. Introduction

Phosphate rocks of sedimentary origin contain Uranium (238U), Thorium (232Th) and its decay products in addition to phosphate minerals (Roesseler, 1990). Considerable variations are found in the chemical composition of rock phosphate from different mining areas. In general, sedimentary phosphate rocks, or phosphorites, originated in a marine environment, are characterized by activity concentrations of uranium much higher than those of volcanic and biological rocks. Reported values of 238U in rock phosphate range from 1.0 to 5.7 Bq/g (Barisic et al., 1992, Guimond and Hardin, 1989 and Heijde et al., 1988). These phosphates are largely used for the production of phosphoric acid, fertilizers and hence phosphate fertilizer industries are considered to be a potential source of natural radionuclide contamination. Their radioactivity leading to health problems from radiation at the level of the industrial processes which involves mining and transportation of phosphate ores and production of fertilizers. At the usage level, when fertilizers dispersed into the geo and biospheres, have a potential to transfer to living beings. Leaching of the minerals and wastes is another potential source of radioactivity dissemination which may contribute to enhanced exposure of workers, public and the environment to these radionuclides.

Phosphogypsum is a waste by-product from the processing of phosphate rock by the ‘‘wet acid method’’ of fertilizer production, which currently accounts for over 90% of phosphoric acid production.
The wet process is economic but generates a large amount of phosphogypsum (5 tons of phosphogypsum per ton of phosphoric acid produced)
3. Results and discussion

The levels of naturally occurring radionuclides (238U, 226Ra, 232Th and 40K) in soil samples are given in Table 1. The 238U activity in soil samples varied from 21.5 to 674.5 Bq/kg and that of 226Ra was ranging from 22.8 to 683.7 Bq/kg. At location 7 (gypsum pond) 226Ra values were found to be considerably higher than 238U, which is consistent with the nature of elemental distribution during chemical processes resulting in the generation of phosphoric acid. During acid attack of rock phosphate to produce phosphoric acid, majority of uranium along with thorium get partitioned with phosphoric acid while the radium, which follows calcium chemistry, finds its way with phosphogypsum (Poole, Allington, Baxter, & Young, 1995). The levels of 238U and 226Ra in soils at the two locations (location 4 and 7) were about 10–30 times higher than the rest of the plant locations and the average Indian soil levels of 20 Bq/kg. The open storage of such high radioactivity material could affect the surrounding in various pathways like emanation of 222Rn, atmospheric transport, leaching, dissolution and transport to aquatic environment (Bolivar et al., 1995). Activity concentration of all the nuclides except for 40K, were found to be maximum at location 4, at the Rock Silo, where phosphate rock is stored in large quantities. This is due to the fact that raw materials containing phosphorus show low activity concentrations of 40K but have significant activity concentrations of radionuclides belonging to 238U chain (Serena, Patrizia, & Luigi, 2005).

Gee… the majority of the radioactivity at a plant is in the rock INPUT to the process. The U and Th tend to end up with the phosphoric acid product, while the radium ends up in the gypsum. OK, so avoid the rock pile… which came out of the ground… where the ground water is percolating…

The article goes on with a fairly detailed and painful mapping of where there is how much of what. All nice to know, and yes, the gypsum pond is also hotter than ‘background’ at the natural surface, but not by all that much, and less than the natural input rock in the rock pile.


Radiation and Phosphogypsum

• Both natural gypsum and phosphogypsum contain radioactivity, but phosphogypsum contains more.

• In the manufacture of phosphoric acid, the acid is filtered through cloth to remove solids. The radium is filtered out with the solids. The solid portion is known as phosphogypsum.

Phosphogypsum produced in North Florida contains roughly 5 – 10 picocuries per gram (pCi/g) of radium while phosphogypsum from Central Florida contains about 20 – 35 pCi/g radium.

• The U.S. EPA prohibits the use of phosphogypsum. An exception is made for phosphogypsum with an average concentration less than 10 pCi/g radium which can be used as an agricultural amendment. EPA’s ban was based on a single scenario which assumed that the by-product was used in road building or as an agricultural amendment and 100 years later a house was built on the farm field or the abandoned road and the homeowner lived in the house 70 years, staying in the house 18 hours a day. Under this scenario the homeowner’s risk of radon-related health concerns only slightly exceeded the EPA’s acceptable limits.

• Phosphogypsum is primarily calcium sulfate, and plants need the sulfur it contains. Since much of the North Florida phosphogypsum is below the EPA restriction level, it can be used as a crop amendment, but for no other use.

• The Central Florida phosphogypsum is restricted to storage on land in large piles called “stacks.”

The overall radioactivity in the stacked phosphogypsum is actually less than what was in the original phosphate ore that was taken out of the ground.

OK, so this gypsum ‘stack’ (which is in Central Florida) is about 2 x 3 times the level that can be used to grow food… and if you are a prisoner in a home built on top of it, kept there for all but 6 hours a day, and live to 70 years old, you might, might be able to find some health impact base on EPA paranoid levels of concern.

The “stuff” is less radioactive than the rocks dug out of the ground under the plant, and through which the present ground water percolates.

It “moves with calcium” so will tend to bind into the rocks just like all the other calcium (which is likely why it was in the rocks to begin with).

IF it gets diluted by a factor of 2 or 3 as it runs into the huge ground water flows under Florida, it gets back to that “ok to put on food” level.

Somehow I’m not seeing much of a problem.

Though I’m pretty sure there will be panic all over central Florida, the EPA will be grandstanding and looking for ways to shut down phosphate production in the USA, the news will be endlessly Panties-In-A-Bunch about RADIATION!!!! in the groundwater of Florida, and a gazillion dollars of lawsuits will be filed.

Oh, and note that the quantity found in the soils and rocks in the first study were from 20 Bq/kg in clean soil up to a few hundred Bq/kg in ‘dirty’ places. Gee, that must be a lot..


China set standards on granite countertop materials, banning the export of
lower radiation level granites. They grade granite countertop material into four
grades : A, B, C, and below C. Only grade A can be used inside a home.
Grades B, C, and below C are allowed to be exported or used outside of homes
in China.

Finland 300 Ra bq/kg th 200 bq/kg 40K 3000
Latvia Residential interior use or Ra + Th 170 bq/kg 40K 1500 bq/kg
Industrial or exterior use residential ra + Th 250 bq/kg 40 K 2000 bq/kg
Industrial exterior or road use ra + Th 300 bq/kg 40 K 2500 bq/kg

Germany radium 226 levels below 300 Bq/Kg
Luxembourg Th less that 250 Bq/kg radon less than 350 bq/kg
Czech republic action level 150 -200 bq/kg for buildings occupied 1000 hrs or
more advisory level is 80 to 120.
Sweden says less than 200 Bq per cubic meter and gamma 0.5 uSv/h building
materials must be considered in the amount.
Nordic countries radium 300 thorium 200 40K 3000
Israel .5msv radium 150 thorium 185 40 K 3500

Oh… about as much in your granite counter top…

Never Mind…

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About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
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26 Responses to Polk Co. Florida, Mosaic and GASP! Radiation!!!

  1. agesilaus says:

    Gee we were almost neighbors I grew up and went to HS in DeSoto Cty. I spent my career dealing with environmental chemistry at a municipal owned power system. To remain nameless. At the coal fired plant flyash is produced and most of the radioactive species (Ra-226, Pb-210 ect) end up in the flyash. A coal fired power plant produces a small mountain of flyash over the years of operation. The plant operators want to get that material off site and do their best to find anyone who will take it. And in large part that turns out to be cement manufacturers who can mix flyash into their product thus making ‘hot’ concrete as the result. It’s also used to make concrete blocks and in road construction.

    The Feds are blocked from regulating flyash by Congressional fiat. We were never required to analyzed the flyash or to check it for radioactivity. We did analyze ground water well samples from locations around the flyash landfill. We occasionally got slightly high readings for Radium but on resampling the value always dropped below the regulatory limit. I did a few times over the years slip a flyash sample into the sample stream and after getting one at 3000 piC/L I stopped doing that. What a flap that generated, heh.

    So what is the morale of this story? The power industry lobbyists are much better than the phosphate industry. That Roessler who wrote that paper is probably Dr Roessler from UF in Gainesville. Probably retired by now.

    When I was in Arcadia one of those mines in Polk county had a dike failure and dumped several million gallons of that waste into the Peace river. The river turned chalk white for over a week and the particles clogging the fish gills killed most of them in the river. At the time (late 1960’s) this got the mine a fine of less than a thousand dollars. Not what would happen these days, unless of course the EPA is the one who polluted the river.

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  3. Larry Ledwick says:

    We can thank the left for demonizing something which is ubiquitous and harmless at the levels normally encountered, and the school system for not teaching any useful information about the units of radioactivity, absorbed dose and dose rate etc. (hint they are different) and biological effect of radiation.
    Memo for the uneducated, just because it has a big number does not mean it is bad.


    And since folks refuse to use multiple units in papers and you have to constantly interconvert radiation units to get to one you are familiar with, here is a calculator I like because you can pick both the input and output units of your choice.


    I quit working in radiation protection just about the time they made the conversion from the traditional units of Curie, Rem and Rad to becquerel, grays and Sieverts etc. I have not worked with the newer units enough to make the conversions in my head.

  4. agesilaus says:

    Yeah me too. I was a health physics tech (ELT) and a reactor operator in the Navy and we used rem for dose units. Along with Roentgens and rads. Every time I see Bq my mind freezes up heh.

  5. John F. Hultquist says:

    If you look here: https://en.wikipedia.org/wiki/Allegheny_Plateau
    There is a map showing the extent of the Allegheny Plateau. About centered in this region is where I grew up. This is an area of tilted sedimentary rocks with coal, oil, natural gas, and various other things that we knew nothing about.
    Our house and many others had dug basements with uncovered floors. Apparently, prior to 1984 there was no knowledge that such a thing was not a good idea. Link below. I moved away in 1965.


  6. Larry Ledwick says:


    That is the 10 billion dollar question, if you believe the health department (you know the folks that killed several million people by banning DDT due to unnecessary malaria deaths). It is a big problem. If you don’t believe in the linear dose/exposure dogma not so much. There is some indication it is really only a significant risk to someone who spends a lot of time in the basement and has other risk factors like smoking. Normal life style factors make a big difference. Do you use a swamp cooler in the summer which force ventilates the house, keeping it slightly above ambient air pressure? Then very low risk in summer. Do you use radiant heating where the house is all closed up, or forced air furnace that pumps air through out the house.

    It only accumulates to high levels when you have porous floors and walls to the basement (bare dirt, cinder block etc.) AND you have stagnant air and a closed up room/basement or ventilation which pulls a slight vacuum on the house (like an attic exhaust fan).

    It has a relatively low half life (ie decays quickly) see the half lives of the isotopes in the properties chart on this page. The longest isotope has a half life of 3.8 days so for all practical purposes 7x that period and it goes away. If the air in your house (basement) turns over rapidly compared to the half life of this isotope it can’t accumulate to significant levels.

    The mitigation steps are to reduce porosity of the walls and floor to slow the diffusion into the space and to set up some forced ventilation that keeps the air from stagnating and dilutes the air with fresh outside air on a regular basis. The decay daughter products are mostly also short lived, except for Po 210 which as demonstrated by the Russians is not something you want in your system. If you are a smoker that will help capture and hold the Po210 in your lungs due to it attaching to the smoke and the poor cleaning of smoking damaged lungs.


    Quite frankly for most people and their life style it is not a big risk if they are active and have normal turnover of air in their house. If they are the sort of people who seal up the house and spend all their time in a Barcalounger in the basement watching TV and smoking it might be a risk. Especially if you have compromised lungs (emphysema etc.) Compared to other real risks like falling off a ladder, getting killed in a car accident, falling in the bath tub not a big deal in my view.

  7. gallopingcamel says:

    High levels of gamma radiation or high global temperature are deadly. Increasing the average temperature by 50 degrees Centigrade would kill all life on Earth with the exception of some hardy microbes. Likewise an acute dose of 5 Sieverts will kill 50% of humans affected and a dose of 100 Sieverts would likely kill everything that moves…….even cockroaches.

    Low temperatures are more deadly. A reduction of 50 degrees Centigrade would create an “Iceball Earth” with no land flora or fauna.

    Low levels of gamma radiation on the other hand may be beneficial. While radiation workers in the USA are limited to 20 milli-Sieverts per annum the people who live in Ramsar, Iran receive 13 times that dose:

    Radiation that does not kill you makes you stronger. There are many studies that support this idea. Here are two of them:

    Click to access Sakamoto-2012_ANSconf-June23.pdf

    Please note that I served on the Duke University Radiation Safety Committee for many years.

  8. Richard Ilfeld says:

    I am a former Mosaic employee. IT Sr. Programmer on the blue collar side in the former Gardinier plant. Maybe the radiation from the gyp stacks at the plant has destroyed my mind.. Mosaic hate is Not about science. There is a network of ‘public advocates’ in Mosaic territory with a long wish list of civic projects, from fire stations to coastal remediation projects. Each time something happens, the usual suspects emerge from their caves, with the usual arguments & fear-mongering. These events terminate naturally with a settlement that crosses a few items off the list as a few do-gooder priorities are extracted from a company fully used of being embattled.
    I have a picture album somewhere of over a hundred signs celebrating Mosaic’s “public spirited environmental projects”. All coerced, priorities set by leftists.

    Mosaic wasn’t a perfect employer, or the worlds cleanest miner…. but the fear-mongers were pretty disgusting. I once volunteered for a bay island cleanup, but when I arrived with a Mosaic shirt on, was told they didn’t need ‘my kind’…..by one of the “organizers”. A work unit supervisor caught me on the way out and pleaded with me to stay – it seems they were short of transport and the fully fueled boat I had volunteered and was towing might be useful. I said something about people who want to stop the production of fertilizer but decried the starving people around the world and high prices in the supermarket. The super rolled his eyes and pointed out that the political types weren’t actually going out on the cleanup. Turned out he was a company guy from Lake Wales.

    Yes I stayed. It’s a wonder I didn’t throw the kids in their leftist slogan T-shirts overboard. After all the shirt reveals the person.

    Work for a company like Mosaic will convince one of the inherent nastiness and smug superiority of the “caring left”. No idea how the world works, & corporate America is a piggy bank for their desires. Same idiocy on the local as the national level.

    In today’s parlance, we were deplorable.

  9. gallopingcamel says:

    @Richard Ifield,
    Your story is a good example of what happens when Leftists are allowed to run anything. In short order they create a minature version of Venezuela.

  10. gallopingcamel says:

    @Larry Ledwick,
    Radon is not a problem as long as the exposure is of short duration because the gas is rapidly purged from your bloodstream through respiration.

    However chronic exposure to Radon as in working in a mine or living in a poorly ventilated basement with high levels of Radon is a significant health risk as some of the Radon will decay into Polonium which has a long biological half life.

  11. Gail Combs says:

    “…However chronic exposure to Radon as in working in a mine or living in a poorly ventilated basement with high levels of Radon is a significant health risk …”

    GEE, I lived in a house with a basement. Part of that basement was dirt a big a$$ piece of granite ledge. My bedroom was in that basement…..

    Granddad died at 59, Uncle at 56, Mom at 62. I have out lived all of them by at least a 1/2 decade.

    I am not going to find it with Google, But IIRC studies have shown that some radiation will increase the human life span.

    The whole flap about radiation in basements was caused by Petr Beckmann constantly telling the panties in a twist useful idiots that the radiation exposure in their houses was higher than from a nuclear plant. The information was starting to get traction so it had to be killed with another lie.

  12. David says:

    It seems too easy to predict what the response will be here, yet some of you seem knowledgeable. What are your thoughts on eating vegetables grown in soil with 1) that phosphoric acid 2) rock phosphate 3) granite dust? Thanks.

  13. p.g.sharrow says:

    It would appear to me to be far too small an amount to be of concern. Of course I have spent most of my 70 years growing food in ground that was of volcanic origin. Sunlight is much more hazardous than the soil emitted radiation…pg

  14. E.M.Smith says:

    No worries on eating food… much food is grown in soils with decayed granite and hotter rocks in in. Note the last part of the posting per granite. Notice the huge numbers for potassium. .. Odds are the potassium in your body is a bigger dose than the phosephate…

    Further, I do not remember ever seeing a report of food crops bioaccumululating radium, thorium, or uranium. (There are some weeds used for bioremediating contaminated soils though. Wild buckwheat is one, so buckwheat might? A small dig here…)

    Finally, I had a front tooth capped in about 1970. It was finally replaced about 2010. The enamel on it was slightly yellow to match my other tea stained teeth…using Uranium… I asked the dentist and he said “yes, it is a little radioactive, but not much”. Later paranoia got it and uranium yellow enamel plates essentially banned (you can collect the plates, but not use them). Yet I’m fine (despite 40 years of food and soda washed over uranium) and people used uranium plates for centuries… at much higher concentrations than in phosphate rock.

    BTW, a banana registers on radiation meters due to the potassium 40… yet we still eat bananas. A KCl salt shaker can be used as a geiger counter test standard, but I have one in the kitchen and both the spouse and I use it daily… heck, you are radioactive…


    The phosephate product gets the radium, so Th and U not relevant.

    The original phosphate rock comes from bird crap… concentrated, yes, but that radiation has been through animals already…

    Granite is ubiquitous. The sand and clay in valleys comes from eroding mountains made of… granite. You already eat food grown in granite dust… As did the birds that crapped… though some of them ate fish that ate plants and bioaccumulated it more…

    So no worries and eat happy 8-0)

    Oh, and oxygen does more damage to your cells than natural radiation levels, yet we don’t stop breathing…. though have a lot of antioxidants in pathways… so our cells don’t die.

  15. Gail Combs says:

    Phosphoric acid
    Phosphoric acid is used in dentistry and orthodontics as an etching solution, to clean and roughen the surfaces of teeth where dental appliances or fillings will be placed. In addition, phosphoric acid is a constituent in bone and teeth, and plays a role in many metabolic processes.

    Rock phosphate

    Rock phosphate, or phosphorite, is mined from clay deposits that contain phosphorus and is used to make organic phosphate fertilizers that many gardeners utilize. In the past, rock phosphate was used alone as a fertilizer, but due to a lack in supply, as well as low concentration, most applied fertilizer is processed.


    The Appalachian moun­tains were formed over 480 mil­lion years ago. At one time they were as tall or taller than the Rockies. All that eroded rock now forms the east coast of the USA. I now live on the piedmont of the Appalachians. There is a large quarry mining granite near me. (I just got a pickup truck load of crusher run to fill the holes in my driveway.)

    Since I have lived on the east coast full of granite and clay, the veggies I eat ARE from soil containing all three of these materials. As a matter of fact companies in Florida and North Carolina produced about 85% of the marketable phosphate rock mined in the United States.

    Note people here research a topic before spouting off. We try not to let propagandists jerk our chains.

  16. James Kramer says:

    If you mean guano aka bat crap instead of bird crap then that was actually for nitrates. Chile and, I think, Bolivia fought a war over it and Bolivia lost and now is landlocked. Haber–Bosch developed a method to make nitrates out of atmospheric nitrogen and thus caused WWI to last so long.

    As for Food, I haven’t heard of plants bioconcentrating radium or uranium. As you point out the K-40 in bananas exceeds any other food born dose. A Cat Scan will give you a huge amount of radiation comparatively. One scan exceeded the dose I got in six years in the Navy and we were the first people to enter the reactor compartment when the plant shutdown. Try talking about the radiation dose with the X-ray tech and they will talk all around it but never will be specific.

  17. Gail Combs says:

    If I recall bird is also very high in nitrates as is pig, sheep and goat. The problem is it gets washed out above ground. Store pig or goat or sheep or chicken manure in a closed dry shed for a couple of years and you will end up with strips of. white nitrate crystallized out. (BTDT)

  18. E.M.Smith says:

    Well, James, I have to thank you. I’d talked from an old memory of one topic about sea islands. You got me to check, and phosphate rock comes from several sources. Straight sea precipitation, fish teeth and bones, and more. Oh, and from guano (which can be bat, bird, or even seals.)


    Guano (via Spanish, ultimately from the Quechua wanu) is the accumulated excrement of seabirds, seals, or cave-dwelling bats.[1] As a manure, guano is a highly effective fertilizer due to its exceptionally high content of nitrogen, phosphate and potassium: nutrients essential for plant growth.

    Seal guano? Who knew…


    bold mine

    Types of phosphorite deposition

    Phosphate nodules: These are spherical concentrations that are randomly distributed along the floor of continental shelves. Most phosphorite grains are sand size although particles greater than 2 mm may be present. These larger grains, referred to as nodules, can range up to several tens of centimeters in size.

    Bioclastic phosphates or bone beds: Bone beds are bedded phosphate deposits that contain concentrations of small skeletal particles and coprolites.
    Some also contain invertebrate fossils like brachiopods and become more enriched in P2O5 after diagentic processes have occurred. Bioclastic phosphates can also be cemented by phosphate minerals.

    Phosphatization: Phosphatization is a type of rare diagenetic processes. It occurs when fluids that are rich in phosphate are leached from guano.
    These are then concentrated and reprecipitated in limestone. Phosphatized fossils or fragments of original phosphatic shells are important components within some these deposits.

    Tectonic and oceanographic settings of marine phosphorites

    Epeiric sea phosphorites: Epeiric sea phosphorites are within marine shelf environments. These are in a broad and shallow cratonic setting. This is where granular phosphorites, phosphorite hardgrounds, and nodules occur.

    Continental margin phosphorites: Convergent, passive, upwelling, non-upwelling. This environment accumulates phosphorites in the form of hardgrounds, nodules and granular beds. These accumulate by carbonate fluorapatite percipitaion during early diagenesis in the upper few tens of centimeters of sediment. There are two different environmental conditions in which phosphorites are produced within continental margins. Continental margins can consist of organic rich sedimentation, strong coastal upwelling, and pronounced low oxygen zones. They can also form in conditions such as oxygen rich bottom waters and organic poor sediments.

    Seamount phosphorites: These are phosphorites that occur in seamounts, guyots, or flat topped seamounts, seamount ridges. These phosphorites are produced in association with iron and magnesium bearing crusts. In this setting the productivity of phosphorus is recycled within an iron oxidation reduction phosphorus cycle. This cycle can also form glauconite which is normally associated with modern and ancient phosphorites.

    Insular phosphorites: Insular phosphorites are located in carbonate islands, plateaus, coral island consisting of a reef surrounding a lagoon or, atoll lagoon, marine lakes. The phosphorite here originates from guano. Replacement of deep sea sediments precipitates, that has been formed in place on the ocean floor.

    Lots of it still comes from animal origin, but lots doesn’t. There is more bird guano than bat guano as bat roosts & caves are more rare. Seal guano? No idea how much of that exists…

    Nor any idea how much fossil guano or poo (coprolites) there are.

    Well, enough of this shit… :-) So it comes from many animal poos, bones, teeth, or the ocean they live in.

    Still not worried about the U Th or Ra levels post critter or sea. But at least now I know my shit!

  19. Gail Combs says:

    E.M. It is always important to know your shit esp. if you garden.

    Horse manure is the only manure safe to put on a garden fresh. All the others are too strong and will burn the plants.

  20. E.M.Smith says:

    Rabbit pellets worked fine for me, then again, the quantity is small. ..

    Allowed to accumulate, get peed on a lot, and age under the pens could generate a stronger layer… but never had a burn problem…. then again I knew to be careful and usually watered it in avoiding high concentration extracts from just a little water…

  21. David says:

    Potassium isn’t much of an issue as the body self-regulates quantity, and it won’t change much. I use KCL too. The line about not seeing in the literature that vegetables take up radium, thorium, uranium is important. I don’t know the literature, which is part of the reason I ask, but I do believe vegetables near fukushima and chernobyl had elevated levels of iodine and cesium, for whatever that’s worth. As for the many examples of natural radiation, it’s all true, but that doesn’t mean it’s good. It’s not exactly, “I know a smoker who lived to 100” type evidence, but not too far off either. We all live with certain levels of risk in our environments; that doesn’t mean we want to elevate it. Don’t mean to argue with you, just my way of trying to tease out the truth.

  22. E.M.Smith says:


    The point on potassium isn’t body excess, it is ubiquity and K40 radiation. You bath you in lots of radiation from the K40 in you. A granite counter has and order of magnitude more radiation from the K40 in it, than the Th. It is a hugh souce from your counter top of granite when compared to the carrot on your plate grown with fertilizer.

    Essentialy, mentioning it is a nonnumeric way of saying: phosphate rock 300 from U, granite 3000 from K40. (Actual risk level 30,000 to 300,000…), or similar, whitout getting caught up in being a units wonk and converting Bq to Curies to Sv to REM to…

    The smoker analogy is flawed in that a smoker increases from, say, 300 to 3000,000,000 of carcinogen while breaking their lung cleaning system (ciliary death), the radiation add from phosphate fertilizing is more like adding 0.003 to 3,000 while improving your health and repair response. Net it is either entirely irrelevant or more likely beneficial. (There is a large body of case reports of low level radiation stimulating repair processes and leading to fewer cancers and longer lives.)

    Put another way, your radiation exposure will be increased more (as a hypothetical example), by moving from the 3rd floir to the top floor of a skyscraper, or flying to Disneyland once a year (cosmic ray radiation increases with altitude. Airline pilots get lots more than the average guy… above 40,000 ft. it starts to be an issue in lifetime burden, maybe).

    If you don’t want to deal with the math or the biochem, the one word answer is “irrelevant”. There just isn’t any risk change from phosphate fertilizers. Swimming in the ocean will expose you to more U.

  23. E.M.Smith says:

    Oh, and life needs Iodine, so plants accumulate it. Th is useless, so gets thrown out (really, lacks an active transporter to absorbe it). Cesium is chemically similar to a metal we need (K and Na in the periodic chart https://en.m.wikipedia.org/wiki/Periodic_table#/media/File%3A14LaAc_periodic_table_IIb.jpg ) so can substitute in some reactions and transporters. It is also highly soluable. U and Th generally not, and unused in the bodies biochem, so don’t get soaked up. Like I said, my U tooth enamel was inert and no threat despite being in my mouth for 40 years.

    For biochem, each atom is handled differently, though some slop up / down a column of the chart exists, so you can’t just say a column one element is absorbed so a column 3 actinide will. Just doesn’t work that way. (Thankfully… or we would all be dead already…there are lots of natueal things in the environment that would kill us if our bodies let them in…)

  24. Larry Ledwick says:

    I think the missing factor in most media coverage of radiation is a sense of proportion. Normal background radiation in my area of Colorado is about 1.18 Rad/year, and typical geiger counter numbers here in Denver will be around 60-80 counts/minute gamma which is approximately 0.05-0.06 mr/hr. The allowed annual occupational absorbed does by the EPA is a total effective dose equivalent of 5 rems (0.05 Sv) per year.

    The point being just because you can detect it, does not mean it is even remotely dangerous. The detection limit of radiation is so staggeringly small compared to normal daily exposure rates that people have no comprehension of their normal radiation exposure, and people freak out over perfectly normal and harmless radiation levels.

    As an analogy, a person with no tan (early spring) or hypersensitivity to the sun can typically tolerate about 10-30 minutes of full noon time sun exposure without getting any sun burn. That light level is millions of times more intense than the level of light that the dark adapted eye can detect.

    A geiger counter is like a fully dark adapted eye, in its ability to detect low level gamma radiation (or with proper probe beta radiation and sometimes high energy alpha radiation), yet the threshold for detectable biological effects are literally 10’s of millions times higher.

    Statistically you cannot even detect biological damage on a large population until you get to radiation absorbed doses near 100 rads acute dose. (ie the equivalent of 90 years of Colorado background radiation received in a compressed period of just a few minutes or hours). The LD50/30 dose is near 450 rad acute dose (9000 years normal background as an acute dose) where 50% of the exposed population would be expected to die in 30 days.

    We routinely did radiation monitoring training with Co60 and Cs137 gamma sources that achieved dose rates of 2 mr/hr (2000 – 2500 counts per minute) when you were within a few feet of them, which is 40x normal background radiation in Colorado and about 50-60x normal background radiation at sea level.

    To properly measure body burden of radioactive materials they need to put people inside a specially shielded full body counter to keep out the normal background radiation which totally swamps the body burden of potassium 40 and other biologically accumulated isotopes (strontium 90 etc)

    Click to access 3445602689160.pdf

  25. James Kramer says:

    There is also the debate about what level of radiation is actually harmful. The regs are written by the ‘no safe minimum dose’ crowd (LNT: Linear No-Threshold). The other group (radiation hormesis) tho seems to be pulling ahead from what I’ve noticed in the press. That is the ‘there is a minimum safe dose’ group and that dose is around the 100 to 150 REM acute dose. Three Mile Island and Chernobyl both failed to show any measurable increase in morbidity with low, sub 100-150 REM doses. The LNT group came by their theory some experiments in 1927 on fruit flies give a high acute dose. They took that point on a graph and just drew a straight line from there to the origin to calculate their limits.

    It seems like someone would have done some low dose lifetime experiments on mice or rats by now.

  26. Gail Combs says:

    James Kramer,
    The US government did radiation experiments on American citizens in the 1960s -70s. My Mom was burnt to crispy critter by Strong Memorial Hospital. It was blamed on a ‘malfunction’ Her Doctor finally killed her with his ‘experiments’ despite my trying to prevent it.


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