Arsine

ARSINE (AsH₃), a colorless gas with a specific gravity of 2.72. It usually possesses a garlic odor (although in some cases, especially when the concentration of AsH₃ in the air is significant, this odor may be absent). AsH₃ is a very unstable compound, destroyed by high temperature, electric spark, etc. In industry, AsH₃ is almost not applied; nevertheless, as an industrial poison, it plays an important role, since it occurs as a byproduct in many productions. AsH₃ is formed everywhere where hydrogen is released from arsenic-containing metals and acids. Very many metals (iron, zinc, lead, tin, antimony, etc.) contain arsenic, and "technical" inorganic acids also contain it, mainly sulfuric and hydrochloric (sulfuric acid - 0.0045-0.14%, hydrochloric acid - 0.0014-0.691%). Diluted acids act especially strongly on metals, and therefore the danger of AsH₃ release is greater when they are used. Hydrogen, however obtained (even electrolytically), almost always contains at least negligible amounts of AsH₃. Cases of AsH₃ poisoning occur mainly in various branches of the chemical and metalworking industries. Of 116 cases, the information about which was collected by Heffter in 1918, 14 occurred in laboratories, 64 at various chemical and metalworking enterprises, 22 in aeronautics (hydrogen production), and 16 in the production of children's balloons. Cases of poisoning are described in battery rooms, on submarines, etc. AsH₃ enters the organism through the respiratory tract; it is excreted in the form of arsenic with urine, feces, and through the skin. The toxicity of AsH₃ is extremely great; according to Dubitzki, it exceeds the toxicity of CO by 10-20 times. Poisoning caused by AsH₃ (almost exclusively acute) always has a serious character and gives a high percentage of mortality. For AsH₃ poisoning, a certain "latent period" (9-24 hours) between the moment of inhalation and the appearance of the first symptoms is characteristic. The disease begins with nausea, severe headache, marked weakness, and abdominal pain; then follows repeated vomiting (dark masses due to the presence of a large amount of bile), cyanosis, which then turns into jaundice, the discharge of bloody urine, and in severe cases - retention of urine, inflammation of the kidneys, uremia, and enlargement of the liver and spleen. The main cause of the pathological symptoms is the changes developing in the blood. In the latter, AsH₃ causes the destruction of erythrocytes and a decrease in hemoglobin content, and these changes develop very quickly and in an extremely severe form: hemoglobin falls to 50-30% or less, the number of erythrocytes falls to 1.5-2.5 million, and cases were observed when their number fell to 700-800 thousand (Joachimoglu, Gel'man). In the following days, this drop increases further. The number of leukocytes is increased (15-30 thousand and more). The severe condition after AsH₃ poisoning lasts for several days, during which the symptoms of poisoning may increase, and death occurs with signs of anuria and paralysis of the central nervous system, or else a slow improvement begins with an outcome in complete recovery. The mechanism of the action of AsH₃ on the blood has not yet been fully elucidated. Toxic doses for humans vary (according to different authors) over a wide range: from hundredths to tens and hundreds of mg. In this case, one has to take into account the different sensitivity of different individuals, various methods for determining AsH₃ in the air, and almost complete absence of observations in production; there are only data from the USSR by Schneider (for zinc chloride production) and Aranovsky (for a metalworking plant pickling); they found amounts from 0.014 to 0.0054 mg per 1 liter of air, and these authors do not mention poisoning among the workers. A concentration considered non-dangerous by some authors can be 0.035 mg per 1 liter of air. The most complete summaries of published cases of AsH₃ poisoning are by Glaister (in 1908 - 118 cases with 37 fatal outcomes), Heffter (in 1918 - 116 cases with 33 fatal outcomes), and Kelyn (in 1920 - 131 cases with 36 fatal outcomes). In the USSR, in recent years, cases of mass poisoning have occurred: 12 workers at a zinc plant (1 death), 8 artisans making children's balloons (2 deaths), 11 students of a factory school (AsH₃ was released in a neighboring battery room). Several methods for determining AsH₃ in the air have been proposed: Hebert and Heim developed a method based on the reaction between AsH₃ and corrosive sublimate (yellow coloring); Dubitzki used volumetric methods with solutions of calcium chloride, silver nitrate, and potassium iodide; Selivanov (Institute of Labor Protection) proposed a linear colorimetric method based on the interaction of arsenic with corrosive sublimate and iodine (the test paper is colored to different lengths depending on the concentration of AsH₃ in the air). Prevention: the use of acids not containing arsenic (e.g., H₂S0₄ obtained by the contact method); rational local and general ventilation; training of workers; placing cages with small birds in workshops: the latter are very sensitive to such concentrations of AsH₃ which do not yet act on humans, etc. Wentzki (1906) proposed a method for neutralizing hydrogen: the latter is passed immediately after production through cylinders containing 2 parts of bleaching powder and 1 part of moist sand, then - to retain chlorine - through slaked lime. On legislative labor protection - see Arsenic. Treatment for AsH₃ poisoning: inhalation of O₂ (helps little; it must be performed for several days); assistance with kidney function (enemas); injection of NaCl, Ringer's solution. Otherwise, symptomatic treatment.