Toxic compound, arsenic

Trimethyl arsine [593-88-4] C H As, has been identified as the toxic volatile arsenical, once known as "Gosio gas," produced by the reaction of certain molds that grow on wallpaper paste and react with inorganic arsenic compounds present in the paper. A number of microorganisms can methylate arsenic trioxide and other arsenic-containing compounds to yield trimethylarsine. These microorganisms include Scopulariopsis brevicaulis Candida humicola and Gliocladium roseum (72). 

BAL is the standard treatment for poisoning by arsenic compounds and will alleviate some effects from exposure to arsenic vesicants. It may also decrease the severity of skin and eye lesions if applied topically within minutes after decontamination is complete (i.e., within 2-5 minutes postexposure). Additional chelating agents for the treatment of systemic arsenic toxicity include meso-2,3-dimercaptosuccinic acid (DMSA) and 2,3-dimercapto-l-propanesulfonic acid (DMPS). 

Similarly, legislation has been, or will be, introduced to deal with the disposal of treated wood waste at the end of a product lifetime. No longer will it be acceptable to dispose of treated wood waste by dumping in landfill. Proper disposal will require the incineration of treated wood waste in appropriate facilities that have the necessary equipment to prevent stack emissions of toxic compounds. This requires expensive investment to build plant that can meet the relevant environmental requirements. Such methods probably represent the best option for the permanent removal of these potential pollutants. The ash generated in these plants may contain high concentrations of arsenic, which will then have to be disposed of as hazardous waste. 

Most of the compounds of arsenic are toxic when in contact with the skin, when inhaled, or when ingested. As with arsenics cousin phosphorus above it in group 15 of the periodic table, care must be taken when using arsenic. The compound arsenic trioxide (As O ), an excellent weed-killer, is also carcinogenic. Copper acetoarsenite, known as Paris green, is used to spray cotton for boll weevils. A poisonous dose of arsenic as small as 60 miUigrams can be detected within the body by using the Marsh test. 

Anaerobic metabolism occnrs nnder conditions in which the diffusion rate is insufficient to meet the microbial demand, and alternative electron acceptors are needed. The type of anaerobic microbial reaction controls the redox potential (Eh), the denitrification process, reduction of Mu and SO , and the transformation of selenium and arsenate. Keeney (1983) emphasized that denitrification is the most significant anaerobic reaction occurring in the subsurface. Denitrification may be defined as the process in which N-oxides serve as terminal electron acceptors for respiratory electron transport (Firestone 1982), because nitrification and NOj" reduction to produce gaseous N-oxides. hi this case, a reduced electron-donating substrate enhances the formation of more N-oxides through numerous elechocarriers. Anaerobic conditions also lead to the transformation of organic toxic compounds (e.g., DDT) in many cases, these transformations are more rapid than under aerobic conditions. 

Swedish law requires that major retailers make an assessment of potential health and environmental hazards when deciding on which products to stock and sell. As a guide to which chemicals should be avoided, KEMI has published a list of especially hazardous chemicals ( OBS-listan ). The hazard profiles of the KEMI-listed substances differ widely, from decidedly toxic compounds, like arsenic salts and benzene, to practically innocuous substances, such as metallic zinc and many zinc compounds. (Like any other chemical, including table salt, zinc and its compounds should, of course, not be dumped in rivers in large quantities, but they are perfectly safe in most other contexts.)... 

The important inorganic toxic compounds to be considered in the following pages are arsine, arsenic trichloride, white arsenic, arsenites and arsenates and arsenic sulphides. Metallic arsenic itself is not poisonous, and the intravenous injection of a colloidal solution of this substance has been found 8 to benefit greatly a case of bone sarcoma of the femur which did not respond to X-ray treatment. 

Jung, W., Knitzschke, G. and Gerlach, R. (1974) Zu den Schadstoffkomponenten Arsen, Antimon, Wismut, Tellur und Quecksilber im Kupferschiefer des Sudostharzvorlands (The toxic compounds in the Kupferschiefer of the southeastern Harz forelands arsenic, antimony, bismuth, tellurium, and mercury). Zeitschrift ftir Angewandte Geologie, 20(5), 205-11. 

In September 1966 The New York Times published a report that cacodylic acid, an organic arsenic containing compound, was also being used in Vietnam.49 Cacodylic acid was a defoliant that was also toxic to man. According to the Merck Index, cacodylic acid was a dimethylarsenic acid containing 54.29 per cent arsenic, and was extremely poisonous.50 Seventy grams would kill the average 150-lb man if administered subcutaneously. 

In spite of the limited amount of information available on the mechanism underlying the pharmacological and toxicological effects of organic arsenicals, the given data throw some light on the mode of action of these toxic compounds. 

Arsenic is considered to be an essential element but a lot of arsenic compounds are toxic [105]. Organic arsenic compounds are less toxic than inorganic ones. AsHs is the most toxic compound. The fatal dose is 250 mg/m at an exposure time of 30 minutes [106]. The lethal dose (LD50) for arsenic trioxide is 34.5 mg/kg, sodium arsenite 4.5 mg/kg, sodium arsenate 18 mg/kg, monomethylarsonic acid (50) 1800 mg/kg, dimethylarsinic acid (47) 1200 mg/kg, and trimethylarsine (51) 8000 mg/kg [107]. 

Research on anesthetic gases during the nineteenth century facilitated the development and use of poisonous war gases in the twentieth. This led to attempts to counteract the effects of chemical warfare agents and other toxic compounds, particularly arsenicals, introduced by Paul Ehrlich (1854-1915) for the treatment of syphilis. This resulted in the synthesis of the first specific chemical antidote, British anti-Lewisite (BAL), in 1945 by R.A. Peters, L.A. Stocken, and R.H.S. Thompson in Oxford. Studies on the mechanistic bases for toxicity were applied to the synthesis of effective insecticides. For example, during the 1940s, the Swiss chemist Paul Muller discovered a compound, now known as DDT, that poisons insects on contact. 

Phenylarsonic arsenicals are less toxic to mammals than the inorganic arsenicals. Phenylarsonic compounds are usually incorporated in swine (and poultry) feed for disease control and to improve weight gain. Examples of these compounds include arsenilic acid, 3-nitroarsenilic acid, and 4-nitroarsenilic acid. Organic arsenicals are also available as trivalent and... 

Like arsenic, antimony compounds were known in antiquity, but it was not until around 1450 that they were described by Johann Tholden. The name comes from two Greek words, anti ( against or not ) and monos, meaning single or solitary, so antimony is not alone. Antimony s chemical symbol comes from its Latin name, stibium. Nicolas Lemery (1645-1715) was the first person to scientifically study antimony and its compounds he published his work in 1707. Early use of antimony compounds was as a pigment in 1855, they were used as a component in safety matches. Modern uses include as a coloring for glass and as a trace element in electronics and plastics. Antimony is toxic, so it must be carefully used. 

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