Nickel

NICKEL (symbol Ni), a metal with an atomic weight of 58.69, atomic number 28, belongs together with cobalt and iron to Group VIII and the 4th row of Mendeleev's periodic system. Specific gravity is 8.8, melting point 1,452°. In its ordinary compounds, Nickel is divalent, but its derivatives are known in which its valence is 1 and 3. In nature, Nickel occurs in combination with arsenic (cupronickel), with arsenic and sulfur (nickel glance), in the form of the mineral pentlandite [Ni, Cu, Fe] S, and in the form of the complex silicate garnierite. Nickel ores are found in the USSR in the Urals. Pure Nickel metal is of a shining grayish-white color, little altered in air; weak acids do not act on it, but it dissolves in nitric acid. It is widely applied as a sheet metal, in the alloy of nickel with copper 1:1 (monel metal) and others (nickel silver, 'nickel'). Nickel salts possess a not strongly expressed antiseptic property: for example, its carbonate salt in a 0.16–0.17 molar solution (about 1.5%) kills Bact. coli, Bacillus pyocyaneus, and Vibrio cholerae in 60 minutes; nickel chloride acts somewhat more strongly on bacteria. Standing very close in its chemical nature to cobalt, Nickel is very similar to it also in its pharmacological properties: its salts are also absorbed with difficulty by the intestine, exerting a local irritating action on it, and in high concentration can cause gastroenteritis. In experimental poisoning of animals with Nickel salts, in addition to vomiting and diarrhea, there are observed as a result of the action of Nickel on the central nervous system an increase in respiration, trembling, convulsions, then general paralysis and cessation of respiration. The phenomena of excitement are more strongly expressed in chronic poisoning of animals. According to the experiments of Stuart, the lethal dose of nickel oxide upon subcutaneous administration is 7 mg for a cat, 9 mg for a rabbit, and 10 mg for a dog per 1 kg of animal weight. Absorbed Nickel is excreted from the organism through the digestive and renal channels, and the urine of animals poisoned with Nickel salts remains of normal color—a distinction from cobalt, which causes darkening of the urine. After the appearance of Nickel tableware for sale, many investigations were carried out to clarify the question whether cooking food in such tableware can cause symptoms of Nickel poisoning. The experiments of Rhode, Geerkens, and others, carried out on themselves, showed that even prolonged use of tableware made of pure Nickel for cooking food does not cause any pathological symptoms. The same was shown by experiments on animals: for example, a dog that received in total over 160 days together with its food 21.35 g of nickel sulfate, showed no signs of poisoning; in other experiments, per os to cats and dogs daily from 6 to 9 mg of Nickel salt was administered for 60 days and in them also no symptoms of poisoning were observed. On the basis of such data, all researchers consider that tableware made of pure Nickel without other harmful impurities cannot be a source of poisoning, since, using it, a person introduces at most 2 mg of Nickel per day into his body per 1 kg of his weight. However, some authors warn against prolonged storage of food, especially acidic food, in Nickel tableware, as it may retain a larger amount of Nickel salts. Preparations: Niccolum bromatum, Nickel bromide, crystals of green color (anhydrous-yellow color); soluble in water. - Niccolum sulfuricum, Nickel sulfate, dark green crystals or powder; soluble in 4 parts of water, insoluble in alcohol. At present, compounds of Nickel for therapeutic purposes are almost not applied. M. Likhachev. From the professional-hygienic point of view, the predominant significance belongs to nickel sulfate, NiSO₄, used in galvanoplastic workshops for nickel-plating metal articles. The process of nickel-plating consists of two phases: cleaning and degreasing of objects with the aid of kerosene, gasoline, alkalis (simple and Vienna lime, soda, potash, soap) and the actual nickel-plating, which in essence reduces to immersing suspended on a wire object in a 'nickel bath' with a solution of the double nickel-ammonium sulfate (NH₄)₂ S0₄ . Ni S0₄ . 6H₂0, in which they are subjected to the action of electrolysis. Among workers in nickel-plating workshops, a peculiar occupational skin disease is often observed, so-called 'nickel eczema', or, as the workers themselves call it, 'nickel itch' (Nickelkratze). This disease usually begins with burning and itching in the hands, then in the interdigital folds; on the hands and forearms a rash appears in the form of small red nodules, which often develop into moist purulent blisters. Sometimes, especially if the workers do not cease their work, this rash spreads to the shoulder, chest, face, and in individual cases also over the whole body. According to the testimony of most authors, this disease is primarily susceptible to weak individuals. The etiological role of Nickel in the occurrence of skin lesions in nickel-platers cannot be considered clarified. While some attribute a specific role in the origin of this disease to Nickel, others consider the skin lesions in nickel-platers to be the result of the combined effect on the skin of both Nickel solutions and irritating substances used for cleaning and degreasing, as well as the macerating effect of water. Koltsova, who examined 56 workers in nickel-plating workshops in Leningrad and found among them 23 patients with dermatitis and eczema, comes to the conclusion that dermatitis is caused mainly by degreasing substances, while eczemas are linked to the action of Nickel salts on previously degreased skin. Sanitary measures and personal prophylaxis in the work of nickel-platers: mechanization of degreasing, cleaning by electrolytic method, lubrication of hands and forearms with indifferent ointments before and after work, as well as during work breaks, removal of objects from the bath with tongs or hooks. Great preventive significance has medical selection with the prohibition of persons predisposed to skin diseases from this work. - It should be mentioned yet of another compound of Nickel, having professional-hygienic significance, namely nickel carbonyl, or tetracarbonyl-Nickel - Ni(CO)₄, a colorless liquid, easily evaporating at ordinary temperature; it is formed in gaseous form (Mond gas) during the extraction of metallic Nickel from ore with carbon monoxide at 80° (Mond's method). Inhalation of nickel carbonyl vapors causes poisoning, the main symptoms of which are expressed in vomiting, dilation of the pupils, difficult and rapid breathing, cyanosis. Several fatal cases of poisoning of workers have been described in England and the USA. Views on the pathogenesis also diverge here: some consider carbon monoxide to be the main cause of poisoning, while others, based on experimental data, attribute the toxic effect of Ni(CO)₄ mainly to Nickel. - First aid in poisoning with tetracarbonyl-nickel is the same as in poisoning with carbon monoxide (see).

II