Australian soils are deficient in Selenium?

According to vitamins & supplements companies Australian soils are deficient in Selenium:

“On a world scale in reference to the availability of minerals, Australian soils are widely regarded as being selenium deficient. Plants take up metallic minerals from the soil, converting these minerals into colloidal mineral complexes.” http://novoorganics.com/index.php?pr=infoselenium

“Selenium has antioxidant activity and Australian soil has low levels of this trace mineral.” http://www.gcsau.org/resources/complementary_med.asp

It is so serious that Australian soils to be blamed for causing asthma:

“Deficiencies in the soil in Australia and New Zealand may explain the countries high incidence of asthma.” http://www.yourhealth.com.au/index.php?page=/nutrients/view-content.php?id=152

The reason for its apparently low content is due to our farming practices, and being an old continent and has the oldest soils:

“This is probably due to the selenium deficiency in some Australian soils, the nature of those soils e.g. acidic and some modern farming practices.” http://www.selena.com.au/whatisselenium.html

“Over farming and inorganic fertilizers are responsible for worldwide soil mineral depletion, and this means that many of us are not getting anywhere near the amounts of selenium (amongst other nutrients) required for good health. In New Zealand and parts of Australia and the United States, soils are so low in selenium that many of us are at risk of serious selenium deficiency, with the associated health problems.” http://www.femhealth.com/selenium.html

“Disastrous mismanagement of our soil and intensive farming methods have created such poor food quality that high dose supplements are not a luxury but the bread and butter of robust good health.” http://www.orkneyorganicmeat.co.uk/special%20reports.htm

“Australia, for example, being the oldest continent, has depleted and leached soils.  Selenium is present in most of our soils at much lower proportions than it is in North America.  If it is not in the soils, It is not going to get into the crops nor into the flesh of the animals that eat those crops.  Australian soils are also poor in some of the more significant minerals - we rely on imported phosphatic fertilizers for example.” http://www.evfit.com/soil.htm

“Australia has some of the world's oldest soils. They lack organic matter and are often highly acidic. Excessive use of the land to grow crops and prolonged use of inorganic fertilisers can further acidify soils and degrade the land.”

Extensive use of pesticide degrades a plant's ability to take nutrients from the soil. For example copper, mercury, and cadmium in super phosphates compete with zinc and selenium uptake. http://www.btoxicfree.com/nutrient%20deficiencies.htm

The message is Australian soils are so poor that we have to take supplements. But where do they get this information? How do they know the content is low and apparently Australian soil is the oldest?

Simply out of the air and not from any scientific literature. The first study of the forms of Selenium in soil is by Hal Geering (Geering et al. 1968) during his MSc in Cornell. The availability and form of Selenium in soil depends on pH and redox potentials.  The source of Selenium in soil is mostly from atmospheric deposition (Deckers and Steinnes, 2004). Selenium seems to originate from the sea from where it comes into the atmosphere as (CH₃)₂Se produced by bacteria. A second source of Se in the soil is atmospheric pollution. Selenium concentration in igneous rock s very small on average 0.09 ppm (Reuter, 1975). Sedimentary rock, especially shales contain abundant of Se, on average 0.6 ppm.

The status of Selenium in Australian soil is reviewed in Judson and Reuter (1999). 

Selenium has no significant role in the nutrition for plants but its deficiency in livestock (and human) can cause a well known white muscle disease.  Meanwhile a high concentration of Se can also occur and cause toxicity. Since selenium deficiency is mainly affecting animals in grazing, and can be detected particularly livestock, the most practical way to monitor Se condition is analyzing the Se concentration in blood, rather than in soil itself.

In Australia, areas that are identified with Selenium deficiency (in livestock) are mainly soils derived from basaltic and granitic parent materials (igneous rather than sedimentary rocks) in humid, high rainfall areas (Price, 2006). There is a wide variation of Se concentration in Australian soils. Areas of deficiency were reported in:

- NSW: the Central and Southern Tablelands (Hart, 1985); the Northern Tablelands (Langlands et al., 1981) and some areas in the coast.

- Queensland: South-eastern and coastal areas (Judson and Reuter, 1999)

- Western Australia: South-western areas (Gardiner and Gorman 1963)

- South Australia: South-eastern areas (Reuter, 1975)

- Pockets of high rainfall in Victoria & Tasmania (Judson and Reuter, 1999).

Langlands et al. (1981) presented a nice analysis between Se blood levels and soil types and environmental variables in NSW.

Meanwhile Se toxicity is reported in some areas in Queensland. In Northwestern Queensland in Australia, soils with high level of Se are associated with limestone shale. Vegetation grown on soils receiving the run-off from these limestones produced acute toxicities in livestock (Knott et al., 1958).

The concentration in blood plasma is the commonly indicator of Se status in human. Lyons et al.  (2004) analysed blood samples from donors to the Red Cross in Adelaide from 1977 to 2002. The whole blood and plasma selenium concentrations were above those reported for most other countries and in most previous Australian studies.

Although there are some areas reported with Se deficiency, there is no general trend that Australian soil is deficient in Selenium. Deficiency is related to the parent material and leaching, not due to being and old climate and our farming practices.

At least the blue pages confirmed with it: http://bluepages.anu.edu.au/treatments/what_works/lifestyle_alternative/selenium

Areas with Se deficiency have been corrected with Se fertilizers (Whelan et al., 1994). Mineral fertilisers have been used in Finland and New Zealand at a rate of 6 g Se per ton fertiliser. As a consequence, it is estimated that Se uptake by man has increased 5-fold in the target area (Deckers and Steinnes, 2004).

References

Deckers, J., Steinnes, E., 2004. State of the art on soil-related geo-medical issues in the world. Advances in Agronomy 84, 1-35.

Gardiner, M. R., Gorman. R.C., 1963. Further observations on plant selenium levels in Western Australia. Australian Journal of Experimental Agriculture and Animal Husbandry 3, 284-9.

Geering, H.R., Gary, E.E., Jones, L.H.P., Allaway, W.H., 1969. Solubility and redox criteria for the possible forms of selenium in soils. Soil Science Society of America Proceedings 32, 35–40.

Judson, G.J., Reuter, D.J., 1999. Selenium. In ‘Soil analysis: an interpretation manual’. (Eds KI Peverill, LA Sparrow, DJ Reuter) pp. 325–329. CSIRO Publishing, Melbourne.

Knott, S.G., McCray, C.W.R., 1959. Two naturally occurring outbreaks of selenosis in Queensland. Aust. Vet. J. 35, 161–165.

Langlands, J.P., Bowles, J.E.,  Smith, A.J., Donald, G.E., 1981. Selenium concentration in the blood of ruminants grazing in Northern New South Wales. II Relationship with geological, pedological and other variables. Australian Journal of Agriculture Research 32, 523-33

Lyons, GH., Judson, GJ, Stangoulis, JCR,  Palmer, LT, Jones, JA, Graham, RD. 2004. Trends in selenium status of South Australians. Medical Journal of Australia 180, 383-386

Reuter, D.J., 1975. Selenium in Soils and Plants. Agricultural Record. 2, 44-55.

Whelan, B.R., Peter, D.W., Barrow, N.J. 1994. Selenium Fertilizers for Pastures Grazed by Sheep. I. Selenium. Concentrations in Whole Blood and Plasma. Australian Journal of Agriculture Research 45, 863-875.