Cyanides health effects

Carson, B.L., H.V.Ellis, B.L.Herndon, E.M.Horn, and L.H.Baker. 1981. Hydrogen Cyanide Health Effects. EPA-460/3-81-026, U.S. EPA, Office of Mobile Source Air pollution Control, Ann Arbor, MI. 

Silver compounds having anions that are inherently toxic, eg, silver arsenate and silver cyanide, can cause adverse health effects. The reported rat oral LD values for silver nitrate, silver arsenate [13510-44-6] and silver cyanide are 500—800 (29), 200—400 (29), and 123 mg/kg (30), respectively. Silver compounds or complexes ia which the silver ion is not biologically available, eg, silver sulfide and silver thiosulfate complexes, are considered to be without adverse health effects and essentially nontoxic. 

The mechanism of hydrogen sulfide toxicity is in part similar to that of cyanide. Like cyanide, hydrogen sulfide can inhibit the enzyme cytochrome oxidase resulting in tissue hypoxia. Specific health effects are discussed in greater detail below. 

There is a test that can detect acrylonitrile in blood. In addition, the major breakdown products of acrylonitrile by the body (termed metabolites) can be measured in urine. Some breakdown products that can be measured are specific to acrylonitrile. However, one breakdown product of the body (cyanide) that is commonly measured is not specific to acrylonitrile exposure, and the results can be affected by cigarette smoking. Because special equipment is needed, these tests cannot be performed routinely in your doctor s office. There is not enough information at present to use the results of such tests to predict the nature or severity of any health effects that may result from exposure to acrylonitrile. Further information on how acrylonitrile can be measured in exposed humans is presented in Chapters 2 and 6. 

Studies using radioactivity-labeled acrylonitrile indicate that acrylonitrile or its metabolites form covalent adducts with cellular macromolecules in most tissues. Studies to develop chemical or immunological methods for measuring these adducts would be especially valuable in detecting and perhaps even quantifying human exposure to acrylonitrile. Adverse health effects demonstrated following exposure to acrylonitrile, particularly acute exposures, were characteristic of cyanide toxicity. Because these effects are also indicative of exposure to many other toxicants, additional methods are needed for more specific biomarkers of effects of acrylonitrile exposure. 

Estimates of exposure levels posing minimal risk to humans (Minimal Risk Levels or MRLs) have been made for cyanide. An MRL is defined as an estimate of daily human exposure to a substance that is likely to be without an appreciable risk of adverse effects (noncarcinogenic) over a specified duration of exposure. MRLs are derived when reliable and sufficient data exist to identify the target organ(s) of effect or the most sensitive health effect(s) for a specific duration within a given route of exposure. MRLs are based on noncancerous health effects only and do not consider carcinogenic effects. MRLs can be derived for acute, intermediate, and chronic duration exposures for inhalation and oral routes. Appropriate methodology does not exist to develop MRLs for dermal exposure. 

This section provides information regarding known health effects of cyanide exposure. Exposure to hydrogen cyanide (HCN) gas is most common by inhalation. In the discussion below, inhalation exposures are expressed as ppm hydrogen cyanide. Exposure to cyanide can also occur by inhalation of cyanogen gas, a dimer of cyanide. However, cyanogen breaks down in aqueous solution into cyanide ion (CN1) and OCN" ions (Cotton and Wilkinson 1980). The rate of the breakdown depends on pH and is... 

No studies were located regarding the following health effects in humans or animals after inhalation exposure to cyanide ... 

Section 104(i)(5) of CERCLA, as amended, directs the Administrator of ATSDR (in consultation with the Administrator of EPA and agencies and programs of the Public Health Service) to assess whether adequate information on the health effects of cyanide is available. Where adequate information is not available, ATSDR, in conjunction with the National Toxicology Program (NTP), is required to assure the initiation of a program of research designed to determine the health effects (and techniques for developing methods to determine such health effects) of cyanide. 

Figure 2-6. Existing Information on Health Effects of Cyanide... 

Reliable monitoring data for the levels of cyanide and thiocyanate in contaminated media at hazardous waste sites are needed so that the information obtained on levels of cyanide and thiocyanate in the environment can be used in combination with the known body burdens of cyanide and thiocyanate to assess the potential risk of adverse health effects in populations living in the vicinity of hazardous waste sites. Also, there is a need for data relating to exposure levels of cassava eaters in the United States. 

EPA. 1984a. Health effects assessment for cyanide. EPA/540/1-86-011. Response prepared by the Office of Health and Environmental Assessment Environmental Criteria and Assessment Office for the Office of Solid Waste and Emergency Response. 

EPA. 1990a. Summary review of health effects associated with hydrogen cyanide Health issue assessment. Research Triangle Park, NC Environmental Criteria and Assessment Office, Office of Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, EPA 600/8-90/002F. 

Towill LE, Drury JS, Whitfield BL, et al. 1978. Reviews of the environmental effects of pollutants. V. Cyanide. EPA Health Effects Research Laboratory, Office of Research and Development, Cincinnati, OH. NTIS PB28-9920. 

On the basis of its review of human and experimental animal health-effects and related data, the subcommittee concludes that the Navy s proposed SEAL 2 of 4.5 ppm for hydrogen cyanide is too conservative. The subcommittee recommends a SEAL 2 of 15 ppm. The recommended SEAL 2 is also based on the El Ghawabi et al. (1975) study, which is discussed under the derivation of SEAL 1. It is supported by studies in monkeys that show some central nervous system effects (e.g., changes in brain wave activity and reduced auditory cortical evoked potential) occur after a 30-min exposure at a concentration of 60 ppm (Purser et al. 1984). The subcommittee concludes that exposures of submariners to hydrogen cyanide at a concentration of 15 ppm for only 1 d is not likely to produce any irreversible health effects. 

The subcommittee recommends that additional research be conducted on the health effects of mixtures of the irritant gases—ammonia, chlorine, hydrogen chloride, hydrogen sulfide, nitrogen dioxide, sulfur dioxide. The subcommittee also recommends additional studies be conducted on the combined effects of hydrogen cyanide, carbon monoxide, and hydrogen sulfide. 

While there is no documented evidence of health effects caused by exposure to cyanide in drinking-water in normal circumstances, potentially high concentrations from spills must be managed to prevent these concentrations penetrating drinking-water supplies. 

Alarie, Y., Ferguson, J.S., Stock, M.F., Weyel, D.A., Schaper, M. (1987). Sensory and pulmonary irritation of methyl isocyanate and pulmonary irritation and possible cyanide-like effects of methyl isocyanate in guinea pigs. Environ. Health Perspect. 72 159-67. 

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