Zinc oxide toxicity

Cadmium was discovered in 1817 by the German investigator Friedrich Stromeier. The name cadmium was taken from the ancient Greek word for zinc oxide. Toxic effects of cadmium in mammals were reported as early as 1858 by Sovet and 1867 by Marme. An extensive literature has now accumulated on the adverse effects of cadmium on viirious tissues in man and animals (see reviews by Friberg et al., Fassett, Fleischer et Samarawickrama ). 

Zinc is not considered to be toxic, but when freshly formed ZnO is inhaled a disorder known as the oxide shakes or zinc chills sometimes occurs. Where zinc oxide is encountered, recommendations include providing good ventilation to avoid concentration exceeding 5 mg/ms, (time-weighted over an 8-hour exposure, 40-hour work week). 

Polyisobutylene and isobutylene—isoprene copolymers are considered to have no chronic hazard associated with exposure under normal industrial use. Some grades can be used in chewing-gum base, and are regulated by the PDA in 21 CPR 172.615. Vulcanized products prepared from butyl mbber or halogenated butyl mbber contain small amounts of toxic materials as a result of the particular vulcanization chemistry. Although many vulcanizates are inert, eg, zinc oxide cured chlorobutyl is used extensively in pharmaceutical stoppers, specific recommendations should be sought from suppHers. 

Emissions from other nonferrous metal facilities are primarily metal fumes or metal oxides of extremely small diameter. Zinc oxide fumes vary from 0.03 to 0.3 jiim and are toxic. Lead and lead oxide fumes are extremely toxic and have been extensively studied. Arsenic, cadmium, bismuth, and other trace metals can be emitted from many metallurgical processes. 

Zinc and cadmium have an oxidation number of +2 in all their compounds. Zinc is an essential element for human health. It is present in many enzymes and plays a role in the expression of DNA and in growth. Zinc is toxic only in very-high amounts. However, cadmium is a deadly poison that disrupts metabolism by-substituting for other essential metals in the body such as zinc and calcium, leading to soft bones and to kidney and lung disorders. 

Another advantage cited for organic electronics is their perceived low environmental impact and high expected consumer safety. This assumption is generally based on the notion that plastics are easily recycled and are considered safe to humans and animals. However, the materials used are often completely new compositions with poorly understood health and safety attributes. The assumption that all plastics are completely safe for humans is inaccurate, as is exemplified by recent concerns about the toxicity of polyvinyl chloride (PVC).39 In contrast, most inorganic nanoparticle materials are already on the consumer market and have extensive historical data on their safety in a variety of applications. Some materials, such as zinc oxide, are even considered reasonably safe for ingestion and therefore are commonly used in food and cosmetics. However, the health effects and interactions of nanoparticles on the human body are still a topic of debate.40... 

Zinc phosphide — a rodenticide — is relatively toxic when compared to elemental zinc or zinc oxide most of the biocidal action is attributed to the phosphide fraction. Acute oral LD50s for zinc... 

A number of studies of the toxicity of zinc oxide/hexachloroethane smoke have been conducted (Brown et al. 1990 Karlsson et al. 1986 Marrs et al. 1983). These studies demonstrate that smoke exposure results in pulmonary inflammation and irritation. When male Porton Wistar rats were exposed to hexachloroethane/zinc oxide smoke for 60 minutes, the lungs showed pulmonary edema, alveolitis, and areas of macrophage infiltration 3 days later. At 14 days, there was interstitial fibrosis and macrophage infiltration. At 28 days, increased fibrosis and macrophage infiltration were noted. However, these same symptoms occurred when the animals inhaled zinc chloride there was no apparent synergism between the zinc chloride and residual hexachloroethane (Brown et al. 1990 Richard et al. 1989). This is consistent with the fact that smoke contains little hexachloroethane and the observation that acute exposure to 260 ppm hexachloroethane had no effects on the lungs of rats (Weeks et al. 1979). 

Marrs TC, Colgrave HF, Edginton JA, et al. 1988. The repeated dose toxicity of a zinc oxide/hexachloroethane smoke. Arch Toxicol 62 123-132. 

Zinc is an essential nutrient and is not regarded as toxic. However, the metal fumes, its oxide fumes, and chloride fumes can produce adverse inhalation effects. (See Zinc Oxide and Zinc Chloride, Toxicity) Ingestion of soluble salts can cause nausea. 

Sunscreens absorb ultraviolet radiation before it can be absorbed in the skin. They are recommended to protect the skin from the major toxicities of sun exposure sunburn and skin cancer. Most available agents primarily absorb UVB, although newer preparations also provide protection against UVA. Physical sunscreens (which are generally opaque, hke titanium dioxide and zinc oxide) block all ultraviolet radiation. 

Zinc peroxide is used as an accelerator in rubber-compounding, as a curing agent for synthetic elastomers, and as a deodorant for wounds and skin diseases. Zinc peroxide is a powerful ini taut to skm, eyes, and mucous membranes. The systemic toxicity is similar to that of zinc oxide, for which the LD o (rat, oral) is 7950 mg/kg. 

However, the exceptional size-specific behavior of nanomaterials in combination with their relatively large surface-to-volume ratio might result in potential risk for human health and the environment [26-28]. For example, fullerene (C60) particles suspended in water are characterized by antibacterial activity against Escherichia coli and Bacillus subtilis [29] and by cytotoxicity to human cell lines [30]. Single- and multiwalled carbon nanotubes (CWCNTs and MWCNTs) are toxic to human cells as well [31, 32]. Nano-sized silicon oxide (Si02), anatase (Ti02), and zinc oxide (ZnO) can induce pulmonary inflammation in rodents and humans [33-35],... 

Exposure to inorganic chemicals in the workplace has been traditionally evaluated using elemental analysis. However, in recent years some attention has been given to the toxic effects of specific compounds rather than elements, e.g., chromic acid ( ), nickel subsulfide Q), zinc oxide (4.), and sodium hydroxide (5.). It is therefore important that the occupational health chemist develop the capability to identify and quantitate chemical compounds. To this end, X-ray powder diffraction (XRD) is a unique tool for... 

Methods for Reducing Toxic Effects. Limited information is available on treatments to alleviate the symptoms of tetryl exposure. These include treatment of the dermatitis with calamine lotion and/or zinc oxide preparations, treatment of dermatitis and ocular irritation with aluminum acetate or boric acid compresses, and treatment of hypersensitivity-like symptoms (including severe dermatitis and asthma-like symptoms) with epinephrine or antihistamines (Bain and Thomson I 954 Bergman 1952 Cripps 1917 Eddy 1943 Ruxton 1917 Smith 1916 Troup 1946 Witkowski et al. 1942). The data on the pharmacokinetics of tetryl are also limited (Zambrano and Mandovano 1956). In order to develop mitigating agents, further studies are needed on its kinetics and mechanisms of action. 

Cadmium pigments have been manufactured by both a direct calcination process and a precipitation-calcination process. In the first instance, a mixture of cadmium carbonate and sulfur (and zinc oxide and selenium if the hue to be produced requires their addition) is calcined at 520-600°C for 1-2 h. This direct calcination process is complicated by the volatility of cadmium oxide and selenium, both of which are toxic and require special handling. In the precipitation process, an alkali sulfide solution is added to a solution of cadmium and (in the case of green-shade yellows) zinc salts or to a solution of cadmium and (in the case of deep oranges, reds, and maroon) selenium metal to precipitate the appropriate compound. The precipitate is washed, dried, and calcined at 600-700°C in an inert or reducing atmosphere to convert the precipitated cubic structure to a more stable wurtzite crystal. The calcination conditions control particle size, which ranges from 0.2 to 1.0pm. 

Toxicity and health effects Exposure to high concentrations of fumes of zinc compounds such as zinc chloride and zinc oxide causes poisoning among industrial workers. The symptoms include but are not limited to headache, blurred vision, low back pain, vomiting, fever, chills, muscle ache, dry throat, cough, weakness, exhaustion, metallic taste in the mouth, chest tightness, respiratory distress, and decreased pulmonary function. The clinical... 

Zinc oxide is an odorless, amorphous, white or yellowish-white powder. It is incompatible with chlorinated rubber, linseed oil, magnesium, hydrogen fluoride, aluminum + hexachloroethane, zinc chloride or phosphoric acid water should be avoided. On decomposition, toxic fumes are released from zinc oxide. °... 

Toxicity and health effects Exposure to zinc oxide causes adverse health effects to the lungs and the reproductive system in experimental animals. Inhalation of zinc oxide fumes by workers causes metal fume fever. ° ... 

Pohanish, R. P., ed. 2002. Zinc oxide. In Sittig s handbook of toxic and hazardous chemicals and carcinogens, 4th ed., vol. 2, 2358-2360. Norwich, NY Noyes Publications, William Andrew Publishing. 

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