Elements crustal abundance

Elements Crustal Abundance Mean in Oregon Rock Types Western Surface Soils Total Recoverable uses Mean DEO Max ... 

Iodine is concentrated in humans by the thyroid gland to form the iodo-amino acid thyroxine, which is essential to normal health and development. Iodine is a rather rare element (crustal abundance 0.00003 weight %, cf. Table 1.1), so the thyroid gland has become very efficient at scavenging iodide ion. As iodine is deficient in the diet in some locations, a small amount of iodide ion is routinely added to commercial table salt ( iodized salt ). 

Abundance The abundance of a chemical element measures how relatively common (ot tare) the element is, or how much of the element is present in a given environment by comparison to all other elements. Crustal abundance of an element is the estimate of the average concentration of that element in the continental ciust... 

However, most of the available metal-based eatalysts for ROP and a-olefin polymerisation suffer from inherent toxicity, low abundance, high price and are listed as endangered elements, which is in contradiction with their application in green and sustainable procedures for polymer synthesis. In line with sustainable catalyst development, titanium is nontoxic (no known biological role), readily accessible and an abundant element (crustal abundance of 4136 ppm with the lowest supply risk searcity factor is about 2.5/8.5) making this element one of the most attraetive metals for use in sustainable polymerisation catalysis. 

In the geosphere, strontium is ranked fifteenth in the order of the elemental crustal abundance at 450 ppm. Its presence is greater than that of carbon or chlorine, and slightly less than that of sulfur or fluorine. Of the trace elements, it is ranked fifth [7). Strontium is mainly found in Scotland and the United States, where calcareous rocks with natural apatites containing up to 73000 ppm of strontium are located [8]. 

Phosphorus is the tenth most abundant element on Earth with an average crustal abundance of 0.1% and may be found in a wide variety of mineral phases. There are approximately 300 naturally occurring minerals in which PO4 is a required structural component. Phosphate may also be present as a trace component in many minerals either by the substitution of small quantities of POt into the crystal structure or by the adsorption of P04 onto the mineral surface (Nriagu and Moore, 1984 Slansky, 1986). 

Uranium is not a very rare element. It is widely disseminated in nature with estimates of its average abundance in the Earth s crust varying from 2 to 4 ppm, close to that of molybdenum, tungsten, arsenic, and beryllium, but richer than such metals as bismuth, cadmium, mercury, and silver its crustal abundance is 2.7 ppm. The economically usable tenor of uranium ore deposits is about 0.2%, and hence the concentration factor needed to form economic ore deposits is about 750. In contrast, the enrichment factors needed to form usable ore deposits of common metals such as lead and chromium are as high as 3125 and 1750, respectively. 

Multi-Element Analytical Scheme The 76 elements analyzed include 39 elements originally analyzed in the RGNR Projects, and 37 new elements. The analytical scheme is based largely on ICPMS, ICPAES and XRF, supplemented with other techniques (Table 1). The lower levels of detection of all elements are less than their crustal abundances (Table 2). 

Schematic depth ocean profiles for elements. This figure is based on a classification of elements according to their oceanic profiles given by Whitfield and Turner (1987). Uptake of some of the elements, especially the recycled ones, occurs somewhat analogously as that of nutrients. There are some elements such as Cd that are non-essential but may be taken up (perhaps because they mimick essential elements) the same way as nutrients. The concentration ranges given show significant overlap, since the concentrations of the elements also depend on crustal abundance.

Relationship between the trace elemental composition of phytoplankton, continental crust and seawater. Phytoplankton and crustal abundances are normalized to phosphorus (ppm trace metal ppm P). Seawater trace elements abundances are normalized to phosphate (ppb trace metal ppb P as phosphate). Source-. From Quigg, A., et al. (2003). Nature 425, 291-294. 

Figure 1. Enrichment factors with respect to crustal abundances (39) for elements attached to urban aerosols from (9) Washington, D.C. (16), (O) Tucson, AZ f40j, (y,) St. Louis, MO (based on data from Loo et al. (41)),(A) Charleston, WV (42), (Ls) Portland, OR (21), and fB) Boston, MA (3,43). See Table IV, Footnote a...

Iron was chosen as the reference element because its major source is likely to be soil and it is measured with good accuracy and precision by FIXE. Crustal abundances were taken from Mason (21). Enrichment factors greater than 1 indicate an enrichment of that element relative to crustal abundances values less than 1 indicate a depletion. The results of this calculation are shown in Table 4. For this calculation it was assumed that ammonium and nitrate accounted for all aerosol nitrogen. It is seen that Si and Ca are near their crustal abundance, indicating a probable soil dust source. The low EF for Al is probably due to a systematic error in the Al measurement rather than a true depletion. Potassium, although present in small concentrations, is slightly enriched relative to crust. The other fine aerosol species, C, N, S, and Pb are enriched by factors of thousands over their natural crustal abundance, indicating that they are not due to wind-blown dust. 

The results presented a variety of evidence for the identity of Ca sources near our rural sampling site. The distribution of mean crustal element concentrations as a function of wind direction in summer and fall, from the streaker data, suggest a combination of road and soil sources. This agrees with a comparison of crustal abundances in aerosols and source materials. The comparison showed that most of the elements examined had abundances in the aerosol that often fell between those characteristic of roads and soil. This was not the case for Si, but Si may be expected to be less abundant in aerosol samples than in bulk surficial materials because of the preponderance of quartz (Si02) in the larger particles. 

When the data for vanadium, nickel, cobalt, copper, and iron in petroleum of the Western Interior Region (15) shown below are divided by the average crustal abundance of these elements, the relation, V>Ni>Co>Cu>Fe is... 

As reported by Olmez and Gordon (University of Maryland), the concentration pattern of rare earth elements on fine airborne particles (less than 2.5 micrometers in diameter) is distorted from the crustal abundance pattern in areas influenced by emissions from oil-fired plants and refineries. The ratio of lanthanum (La) to samarium (Sm) is often greater than 20 (crustal ratio is less than 6). The unusual pattern apparently results from tlie distribution of rare earths in zeolite catalysts used in refining oil. Oil industry emissions have been found to perturb the rare earth pattern even in very remote locations, such as the Mauna Loa Observatory in Hawaii. 

Cs are more depleted in western coals. Silicon is also depleted in coal, probably because of the presence of clay minerals. Most lithophile elements (i.e., those normally associated with the earth s crust) have EF values near one, but it is interesting that the rare earth elements show slightly, but consistently higher enrichments in eastern coal. The apparent depletion of Ta is probably not real, but an artifact resulting from Wedepohl s use of too large a crustal abundance for it (14). 

Table 1-1. Elements with a crustal abundance >0.1% (data from Emsley, 1989).

Chapter 8 discusses aspects of the geochemistry of the first series transition elements, most of which are trace elements in the Earth s Crust (that is, their crustal abundances are below 1,000 ppm). 

Properties of the terrestrial planets that are central to this chapter are summarized in table 10.1 and information about element abundances is contained in Appendix 1. The crustal abundance data for the Earth indicate the presence of relatively high concentrations of Fe, and to a lesser extent Ti, compared to other first-series transition elements. However, the terrestrial abundance of Fe... 

Most previous CMBs, e.g., (10), were performed on whole-filter data sets, for which about half of the mass is from coarse particles. In that case, many elements arise mainly from crustal dust, making them easy to fit. By contrast, the fine fraction contains little crustal material and many elements are highly enriched (relative to crustal abundances) because of passage through combustion processes. Because of the sensitivity of enrichments to details of the combustion sources and their pollution-control devices, these elements are difficult to fit. 

The major part of elements are enriched in manganese nodules due to adsorption processes on hydroxides. The limited number of analyse does not allow the conclusion in which phase these elements are concentrated. Table 1 shows factors of enrichment of a number of elements in nodules, compared with the crustal abundance of these elements. 

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