Acute toxicity of zirconium, columbium, strontium, lanthanum, cesium, tantalum and yttrium
Cochran, KW; Doull, J; Mazur, M; Dubois, KP
Acute toxicity of zirconium (7440677), columbium (7440031), strontium (7440246), lanthanum (7439910), cesium (7440462), tantalum (7440257), and yttrium (7440655) has been experimentally investigated and reported. Acute oral LD50 values for five zirconium salts ranged from 990 to 2,290mg/kg, whereas intraperitoneal LD50 values ranged from 63 to 939mg/kg, with zirconium-sulfate being the most toxic and sodium-zirconyl-sulfate (7446313) the least toxic. Lanthanum compounds exhibited a low toxicity when administered orally, with the most toxic (lanthanum-ammonium-nitrate (10169003)) showing LD50 as 830mg/kg. When five lanthanum compounds were administered intraperitoneally, the LD50 values ranged from 134 to 209mg/kg. Tantalum-oxide (1314610) was nontoxic administered orally, while potassium tantalum fluoride, tantalum-chloride, and potassium-columbate exhibited low toxicity orally. Tantalum-chloride (7721019) intraperitoneally had an LD50 of 38mg/kg. Both potassium-columbate and columbium-chloride were quite toxic to rats intraperitoneally, with LD50 values being, respectively, 86 and 14mg/kg. Intraperitoneal toxicity of five strontium compounds ranged from LD50 of 88 to 247mg/kg. Cesium showed very low intraperitoneal toxicity to rats except for cesium-hydroxide (1308470), which had an LD50 of 89mg/kg. Yttrium appeared to be relatively nontoxic, with LD50 values for three yttrium compounds ranging from 117 to 395mg/kg. Lanthanum-chloride (10099588) was able to replace aluminum (7429905) as an activator for the succinic-dehydrogenase (9002022) system. Strontium-chloride (10476854) was partially effective in replacing calcium (7440702) in this system. Columbium caused approximately 50 percent inhibition, and yttrium-chloride (10361929) produced a 25 percent inhibition of the succinic-dehydrogenase activity of mouse liver in-vitro. Cesium-chloride (7647178) failed to inhibit adenosine (9000833) triphosphatase activity of mouse liver in-vitro, while other salts of the other metals caused 50 percent inhibition at specific molar concentrations.
