Chapter 1 The Biosphere Chapter 2 The Anthroposphere Introduction Air Pollution Water Pollution Soil Plants Chapter 3 Soils and Soil Processes Introduction Weathering Processes Pedogenic Processes Chapter 4 Soil Constituents Introduction Trace Elements Minerals Organic Matter Organisms in Soils Chapter 5 Trace Elements in Plants Introduction Absorption Translocation Availability Essentiality and Deficiency Toxicity and Tolerance Speciation Interaction Chapter 6 Elements of Group 1 (Previously Group Ia) Introduction Lithium Rubidium Cesium Chapter 7 Elements of Group 2 (Previously Group IIa) Beryllium Strontium Barium Radium Chapter 8 Elements of Group 3 (Previously Group IIIb) Scandium Yttrium Lanthanides Actinides Chapter 9 Elements of Group 4 (Previously Group IVb) Titanium Zirconium Hafnium Chapter 10 Elements of Group 5 (Previously Group Vb) Vanadium Niobium Tantalum Chapter 11 Elements of Group 6 (Previously Group VIb) Chromium Molybdenum Tungsten Chapter 12 Elements of Group 7 (Previously Group VIIb) Manganese Technetium Rhenium Chapter 13 Elements of Group 8 (Previously Part of Group VIII) Iron Ruthenium Osmium Chapter 14 Elements of Group 9 (Previously Part of Group VIII) Cobalt Rhodium Iridium Chapter 15 Elements of Group 10 (Previously Part of Group VIII) Nickel Palladium Platinum Chapter 16 Elements of Group 11 (Previously Group Ib) Copper Silver Gold Chapter 17 Trace Elements of Group 12 (Previously of Group IIb) Zinc Cadmium Mercury Chapter 18 Elements of Group 13 (Previously Group IIIa) Boron Aluminum Gallium Indium Thallium Chapter 19 Elements of Group I4 (Previously Group IVa) Silicon Germanium Tin Lead Chapter 20 Elements of Group 15 (Previously Group Va) Arsenic Antimony Bismuth Chapter 21 Elements of Group 16 (Previously Group VIa) Selenium Tellurium Polonium Chapter 22 Elements of Group 17 (Previously Group VIIa) Fluorine Chlorine Bromine Iodine

Trace elements in soils and plants

Embryonic mortality and abnormalities of aquatic birds: apparent impacts of selenium from irrigation drainwater

The authors were asked by the Editors of ACS Chemical Biology to write an article titled “Why Nature Chose Selenium” for the occasion of the upcoming bicentennial of the discovery of selenium by the Swedish chemist Jons Jacob Berzelius in 1817 and styled after the famous work of Frank Westheimer on the biological chemistry of phosphate [Westheimer, F. H. (1987) Why Nature Chose Phosphates, Science 235, 1173–1178]. This work gives a history of the important discoveries of the biological processes that selenium participates in, and a point-by-point comparison of the chemistry of selenium with the atom it replaces in biology, sulfur. This analysis shows that redox chemistry is the largest chemical difference between the two chalcogens. This difference is very large for both one-electron and two-electron redox reactions. Much of this difference is due to the inability of selenium to form π bonds of all types. The outer valence electrons of selenium are also more loosely held than those of sulfur. As a result,...

Why Nature Chose Selenium

Background In a recent randomized intervention trial, the risk of prostate cancer for men receiving a daily supplement of 200 microg selenium was one third of that for men receiving placebo. By use of a nested case-control design within a prospective study, i.e., the Health Professionals Follow-Up Study, we investigated the association between risk of prostate cancer and prediagnostic level of selenium in toenails, a measure of long-term selenium intake. Methods In 1986, 51,529 male health professionals aged 40-75 years responded to a mailed questionnaire to form the prospective study. In 1987, 33,737 cohort members provided toenail clippings. In 1988, 1990, 1992, and 1994, follow-up questionnaires were mailed. From 1989 through 1994, 181 new cases of advanced prostate cancer were reported. Case and control subjects were matched by age, smoking status, and month of toenail return. Selenium levels were determined by neutron activation. All P values are two-sided. Results The selenium level in toenails varied substantially among men, with quintile medians ranging from 0.66 to 1.14 microg/g for control subjects. When matched case-control data were analyzed, higher selenium levels were associated with a reduced risk of advanced prostate cancer (odds ratio [OR] for comparison of highest to lowest quintile = 0.49; 95% confidence interval [CI] = 0.25-0.96; P for trend = .11). After additionally controlling for family history of prostate cancer, body mass index, calcium intake, lycopene intake, saturated fat intake, vasectomy, and geographical region, the OR was 0.35 (95% CI = 0.16-0.78; P for trend = .03). Conclusions Our results support earlier findings that higher selenium intakes may reduce the risk of prostate cancer. Further prospective studies and randomized trials of this relationship should be conducted.

/pdf/study-of-prediagnostic-selenium-level-in-toenails-and-the-75y3i4p6er.pdf

Study of Prediagnostic Selenium Level in Toenails and the Risk of Advanced Prostate Cancer

(1980). Toxicology of selenium: A review. Clinical Toxicology: Vol. 17, No. 2, pp. 171-230.

Toxicology of selenium: A review

Selenium-responsive diseases of livestock occur frequently
in the United States and have been responsible
for serious economic losses. White muscle disease
(WMD) of lambs and calves is perhaps the most common
of these disorders. The occurrence of WMD is
related to the geologic nature of the soil parent material
(19). There is also evidence that regional patterns of
occurrence of WMD are related to regional differences in
the Se concentration of feed crops (3).
In the U. S., there are also areas where Se toxicity
has been evident in livestock. These areas have been
studied extensively, and the distribution of geologic
formations that form soils capable of producing high-Se
plants has been established (14, 17, 21).
This report presents a map of the U. S. showing
areas where the Se content of plants is adequate to
protect animals from WMD, and areas where low levels
of Se in plants may lead to Se-responsive diseases in
animals, and describes how it was prepared. A similar
survey of plant Se levels has been reported from western
Australia (9).

/pdf/selenium-in-crops-in-the-united-states-in-relation-to-3nm86lldad.pdf

Selenium in Crops in the United States in Relation to Selenium-Responsive Diseases of Animals

Differences among Plant Species in Selenium Accumulation from Soils Low in Available Selenium1

A map illustrating the Se content of forage and hay crops in different sections of the Pacific Northwest was prepared, based on analyses of crop samples. The primary criterion used in mapping was to delineate areas where forage and hay crops generally contain insufficient Se to meet requirements of lambs and calves, and thus prevent white muscle disease (WMD) and other Seresponsive diseases. The minimal requirement may vary from 11.03 to 0.10 ppm Se in the diet, depending upon the diet level of vitamin E -and possibly other substances. Under normal livestock management practices, WMD is common when forages and hay contain less than 0.10 ppm Se and the incidence is greater at lower Se levels. The western half of Washington and Oregon and part of northern California comprise an extremely low Se area. The eastern half of Washington, northern Idaho, extreme western Montana, and the northeast corner of Oregon comprise a low Se area. Most of the remaining portion of the Northwest may be considered as variable in Se, with farm-to-farm variations common, but some small areas of adequate Se were found and mapped. Additional index words; white muscle disease, trace elements, animal nutrition, plant composition.

https://eprints.nwisrl.ars.usda.gov/4/1/113.pdf

W. H. Allaway

Papers

Selenium in Crops in the United States in Relation to Selenium-Responsive Diseases of Animals

Differences among Plant Species in Selenium Accumulation from Soils Low in Available Selenium1

Selenium Content of Forage and Hay Crops in the Pacific Northwest