Toxic strontium

Strontium is fairly reactive and therefore is rarely found in its pure form in the earth s crust. Examples of common strontium compounds include strontium carbonate, strontium chloride, strontium hydroxide, strontium nitrate, strontium oxide, and strontium titanate. The most toxic strontium compound is strontium chromate, which is used in the production of pigments and can cause cancer by the inhalation route. Strontium chromate is not included in the Levels of Significant Exposure (LSE) tables for strontium since the carcinogenic effects of the compound are a function of the concentration of hexavalent chromium, and strontium only contributes to solubility. The Toxicological Profile for Chromium (ATSDR 2000) should be consulted for additional information on the health effects of strontium chromate. 

Some elements found in body tissues have no apparent physiological role, but have not been shown to be toxic. Examples are mbidium, strontium, titanium, niobium, germanium, and lanthanum. Other elements are toxic when found in greater than trace amounts, and sometimes in trace amounts. These latter elements include arsenic, mercury, lead, cadmium, silver, zirconium, beryUium, and thallium. Numerous other elements are used in medicine in nonnutrient roles. These include lithium, bismuth, antimony, bromine, platinum, and gold (Eig. 1). The interactions of mineral nutrients with... 

Coatings, Paints, and Pigments. Various slightly soluble molybdates, such as those of zinc, calcium, and strontium, provide long-term corrosion control as undercoatings on ferrous metals (90—92). The mechanism of action presumably involves the slow release of molybdate ion, which forms an insoluble ferric molybdate protective layer. This layer is insoluble in neutral or basic solution. A primary impetus for the use of molybdenum, generally in place of chromium, is the lower toxicity of the molybdenum compound. 

Health and Safety Factors. The strontium ion has a low order of toxicity, and strontium compounds are remarkably free of toxic hazards. Chemically, strontium is similar to calcium, and strontium salts, like calcium salts, are not easily absorbed by the intestinal tract. Strontium carbonate has no commonly recognized hazardous properties. Strontium nitrate is regulated as an oxidizer that promotes rapid burning of combustible materials, and it should not be stored in areas of potential fire hazards. 

Strontium Chromate. Strontium chromate [7789-06-2] SrCrO, is made by precipitation of a water-soluble chromate solution using a strontium salt or of chromic acid using a strontium hydroxide solution. It has a specific gravity of 3.84 and is used as alow toxicity, yellow pigment and as an anticorrosive primer for zinc, magnesium, alurninum, and alloys used in aircraft manufacture (8) (see Corrosion and corrosion control). 

Without known nutritional function but toxic in excess Aluminum, arsenic, antimony, boron, bromine, cadmium, cesium, germanium, lead, mercury, silver, strontium... 

Some compounds, such as strontium chromate and strontium fluoride, are carcinogens and toxic if ingested. Strontium-90 is particularly dangerous because it is a radioactive bone-seeker that replaces the calcium in bone tissue. Radiation poisoning and death may occur in people exposed to excessive doses of Sr-90. Strontium-90, as well as some other radioisotopes that are produced by explosions of nuclear weapons and then transported atmospherically, may be inhaled by plants and animals many miles from the source of the detonation. This and other factors led to the ban on atmospheric testing of nuclear and thermonuclear weapons. 

Cochran KW et al Acute toxicity of zirconium, columbium, strontium, lanthanum, cesium, tantalum and yttrium. Arch Ind Hyg Occup Med 1 637-650, 1950... 

Bone. Although bone is a relatively inert tissue, it can accumulate such substances as tetracyclines, lead, strontium, and the antitumor agent cisplatin. These substances may accumulate in bone by absorption onto the bone crystal surface and eventually be incorporated into the crystal lattice. Tetracycline deposition during odontogenesis may lead to a permanent yellow-brown discoloration of teeth, dysplasia, and poor bone development. Lead can substitute for calcium in the bone crystal lattice, resulting in bone brittleness. Bone may become a reservoir for the slow release of toxic substances, such as lead and cisplatin. 

Strontium, Barium Strontium was discovered near, and named after, the small town of Strontian, Scotland, in 1787. There are no commercial uses for the pure metal, but the carbonate salt, SrC03, is used in the manufacture of glass for color TV picture tubes. Barium is found principally in the minerals witherite (BaC03) and barite (BaSC ), after which it is named. Though water-soluble salts of barium are extremely toxic, barium sulfate is so insoluble that it is used in medicine as a contrast medium for stomach and intestinal X rays. Like strontium, barium metal has no commercial uses, but various compounds are used in glass manufacture and in drilling oil wells. 

There are a few elements in these two groups that sometimes cause health problems because they are very similar to nearby elements. For instance, a toxic type of strontium can increase the risk of bone cancer and leukemia. Strontium, just one space below calcium in the table, is so similar to calcium that the body is sometimes fooled into absorbing it like calcium in bones and teeth. The similarities between elements can also be useful, as in the case of potassium chloride. People with high blood pressure and certain heart or kidney diseases need less sodium in their diets to stay healthy. Instead of sprinkling regular table salt or sodium chloride on their meals, they may use potassium chloride for a very similar salty taste. 

Most radioactive particles and vapours, once deposited, are held rather firmly on surfaces, but resuspension does occur. A radioactive particle may be blown off the surface, or, more probably, the fragment of soil or vegetation to which it is attached may become airborne. This occurs most readily where soils and vegetation are dry and friable. Most nuclear bomb tests and experimental dispersions of fissile material have taken place in arid regions, but there is also the possibility of resuspension from agricultural and urban land, as an aftermath of accidental dispersion. This is particularly relevant to plutonium and other actinide elements, which are very toxic, and are absorbed slowly from the lung, but are poorly absorbed from the digestive tract. Inhalation of resuspended activity may be the most important route of human uptake for actinide elements, whereas entry into food chains is critical for fission products such as strontium and caesium. 

Shubochkin LN, Pokhodzie YI. 1980. Toxic properties of strontium chromate. Gig Sanit 45 76-77. 

Although Mrs GG may not wish to take a bisphosphonate she may be persuaded to take calcium with or without vitamin D which is effective although less effective than a bisphosphonate. It is a cheaper and less toxic option. Other options such as teriparatide and strontium ranelate are more expensive and there is less experience in their use but they should be discussed with Mrs GG. 

R-phrases R45-22-43-50/53, S-phrases S53-45-60-61 Strontium chromate T Toxic (skull and cross bone)... 

DOT CLASSIFICATION 6.1 Label Poison SAFETY PROFILE Confirmed human carcinogen. A deadly poison. When heated to decomposition it emits toxic fumes of As. See also ARSENIC COMPOUNDS and STRONTIUM COMPOUNDS. 

DFG MAK DFG TRK 0.1 mg/mh Animal Carcinogen, Suspected Human Carcinogen NIOSH REL TWA 0.0001 mg(Cr(VI))/m3 SAFETY PROFILE Confirmed human carcinogen with experimental carcinogenic and tumorigenic data. Moderately toxic by ingestion. Mutation data reported. See also CHROMIUM COMPOUNDS and STRONTIUM COMPOUNDS. 

Natural attenuation encompasses processes that lead to reduction of the mass, toxicity, mobility, or volume of contaminants without human intervention. The US EPA has recently published guidelines for the use of MNA for a variety of contaminated sites (US EPA, 1997). For inorganic constiments, the most potentially important processes include dispersion and immobilization (reversible and irreversible sorption, co-precipi-tation, and precipitation) (Brady et al, 1998). Studies of remediation options at UMTRA sites (Jove-Colon et al, 2001) and the Hanford Site (Kelley et al, 2002) have addressed the viability of adopting an MNA approach for uranium and strontium, respectively. As discussed below, different approaches are required to establish the viabihty of MNA for these radioelements. 

Trace metal disturbances may be due to the uremia per se. Indeed, as the urinary excretion route is an important pathway of elimination of many trace elements, i.e. silicon, strontium, aluminum,... impairment of the kidney will be an important determinant of their accumulation, whilst in the presence of a reabsorptive defect a number of trace elements, especially those that are reabsorbed because of their essential role, be lost resulting in a deficient state. The presence of proteinuria may reasonably result in losses of protein bound elements. It has also been shown also that residual renal funchon may importantly alter the accumulation and hence toxic effects of aluminum [2]. In uremia translocation of a particular metal from one tissue to another may also occur. As an example, under normal circumstances the kidney is an important target organ for cadmium. In chronic renal failure however, possibly as a consequence of a reduction in binding proteins (e.g. metallothionein), the concentrahon of cadmium in this tissue decreases to extremely low levels which... 

One radioactive isotope of strontium, strontium-90, is of special interest. It is a toxic substance, which, at one time, was the cause of great concern because of its connection to atomic bomb testing. 

Most strontium compounds are regarded as harmless to plants and animals. A few, such as strontium chloride (SrCl2) and strontium iodide (Srl2), are somewhat toxic. 

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