Sulfur dioxide toxicity

Reactions of sulfite and bisulfite with biochemical compounds are shown in Table II. Sulfite has been used frequently as a reagent for cleaving disulfide bonds in proteins (6, 9). Such a reaction may participate in the scheme of sulfur dioxide toxicity. 

Smith, C. R. Studies of sulfur dioxide toxicity for two wine yeasts, personal commxmication. University of California, Davis, 1996. 

Lubricating Oil Extraction. Aromatics are removed from lubricating oils to improve viscosity and chemical stabihty (see Lubrication and lubricants). The solvents used are furfural, phenol, and Hquid sulfur dioxide. The latter two solvents are undesirable owing to concerns over toxicity and the environment and most newer plants are adopting furfural processes (see Furan derivatives). A useful comparison of the various processes is available (219). 

Toxic or malodorous pollutants can be removed from industrial gas streams by reaction with hydrogen peroxide (174,175). Many Hquid-phase methods have been patented for the removal of NO gases (138,142,174,176—178), sulfur dioxide, reduced sulfur compounds, amines (154,171,172), and phenols (169). Other effluent treatments include the reduction of biological oxygen demand (BOD) and COD, color, odor (142,179,180), and chlorine concentration. 

Health, Safety, and Environmental Factors. Sulfur dioxide has only a moderate acute toxicity (183). The lowest pubHshed human lethal concentration is 1000 ppm for 10 months. The lowest pubHshed human toxic concentration by inhalation is 3 ppm for 5 days or 12 ppm for 1 hour. The lowest pubHshed human lethal concentration is 3000 ppm for 5 months. In solution (as sulfurous acid), the lowest pubHshed toxic dose is 500 flg/kg causing gastrointestinal disturbances. Considerable data is available by other modes of exposure and to other species NIOSH standards are a time-weighted average of 2 ppm and a short-term exposure limit of 5 ppm (183). 

In removing excess free chlorine from municipal or industrial water and from wastewater, sodium sulfite competes with bisulfite or sulfur dioxide. Other commercial appHcations of sodium sulfite in wastewater treatment include the reduction of hexavalent chromium to the less toxic Cr " salts as well as the precipitation of silver and mercury. 

Health and Safety Factors. Sodium metabisulfite is nonflammable, but when strongly heated it releases sulfur dioxide. The oral acute toxicity is slight and the LD q (rat, oral) is 2 g/kg. Sodium bisulfite appears to be weakly mutagenic to some bacteria, ia rodent embryos, and ia a human lymphocyte test. There is iaadequate evidence for carciaogenicity (183,343). 

Those who analyzed these excess deaths (the number of deaths above the normal number for each calendar da ) believed that the level of sulfur dioxide was not near the toxic limit of 10 ppm necessary to affect healthy... 

Vapor Density (VD) — the mass per unit volume of a given vapor/gas relative to that of air. Thus, acetaldehyde with a vapor density of 1.5 is heavier than air and will accumulate in low spots, while acetylene with a vapor density of 0.9 is lighter than air and will rise and disperse. Heavy vapors present a particular hazard because of the way they accumulate if toxic they may poison workers if nontoxic they may displace air and cause suffocation by oxygen deficiency if flammable, once presented with an ignition source, they represent a fire or explosion hazard. Gases heavier than air include carbon dioxide, chlorine, hydrogen sulfide, and sulfur dioxide. 

The basis on which the TLVs are set may differ from substance to substance. For some, such as levels for silica dust, a guiding factor is protection against impairment of health. For others, it is the comfort level of the individual, such as freedom from irritation, nuisance, or other forms of stress for example, the TLV for sulfur dioxide is based on irritation and not on toxicity per se. The TLV list is reviewed annually resulting in some revisions in values and some additions to the list. 

Yourfacility receives toluene and naphthalene (both listed toxic chemicals) from an off-site location. You react the toluene with air to form benzoic acid and react the naphthalene with sulfuric acid, which forms phthalic acid and also produces sulfur dioxide fumes. Your facility processes toluene and naphthalene. Both are used as reactants to produce benzoic acid and phthalic acid, chemicals not on the section 313 list. 

Fire Hazards - Flash Point Flammable solid Flammable limits in Air (%) Not pertinent Fire Extinguishing Agents Sand and carbon dioxide Fire Extinguishing Agents Not to be Used Water fecial Hazards of Combustion Products Products of combustion include sulfur dioxide and phosphorus pentoxide, which are irritating, toxic and corrosive Behavior in Fire Not pertinent Ignition Temperature (deg. F) 527 (liquid) Electrical Hazard Not pertinent Burning Rate Not pertinem. 

Fire Hazards - Flash Poirrt Not flammable Flammable Limits in Air (%) Not flanunable Fire Extinguishing Agents Not pertinent Fire Extinguishing Agents Not To Be Used Not pertinent Special Hazards of Combustion Products Not pertinent Behavior in Fire Containers may rupture, releasing toxic and irritating sulfur dioxide Ignition Temperature Not flammable Electrical Hazard Not... 

Closed drain headers are normally provided for safe drainage of equipment containing severely toxic, corrosive, pollutant or high cost chemicals (e.g., phenol, sulfuric acid, monoethanolamine, sulfur dioxide, catacarb) where there is an appreciable inventory in a number of processing vessels in a plant. The header should be at least 50 mm in diameter, and should be tied into the major vessels and equipment with 25 mm minimum size connections (20 mm is considered adequate for pumps). The header may be routed to a gravity drain drum (with recovery to the process by pump or gas pressurization), or to a pumpout pump returning to the process, or in the case of sulfuric acid, to an acid blowdown drum. 

Chlororocarbon (CFG) refrigerants are inherently safer with respect to fire, explosion, and acute toxic hazards when compared to alternative refrigerants such as ammonia, propane, and sulfur dioxide. However, they are believed to cause long term environmental damage because of stratospheric ozone depletion. 

The interactions may be physicochemical without the participation of biological mechanisms for example, deep lung exposure to highly soluble irritative gases, such as sulfur dioxide, may become enhanced due to adsorption of the gas onto fine particles. Biological interactions may occur at all stages and body sites. For example, toxicity is increased when adverse effects are due to some reactive metabolic intermediate and exposure to another agent stimulates its metabolic activation (enzyme induction). 

Inhaled gaseous compounds are absorbed in all parts of the respiratory system whereas particle size determines how deep into the airways the parti cles will he transported in the airstrearn. Shortness of breath is a typical sign of a chemical exposure that has affected the lungs, and it may be evoked through iminunological mechanisms (e.g., formaldehyde, ethyleneoxide), or through toxic irritation (formaldehyde, isocyanates, sulfur dioxide, nitrogen dioxide, Frequently the mechanism depends on the concentration ol the com... 

Directs national efforts to meet air quality goals, particularly for smog, air toxics, carbon monoxide, lead, particulate matter (soot and dust), sulfur dioxide, and nitrogen dioxide. The office is responsible for more than half of the guidance documents, regulations, and regulatory activities required by the Clean Air Act Amendments of1990. 

SIPs are intended to prevent air pollution emergency episodes. The phms are directed toward preventing excessive buildup of air pollutants tliat me known to be harmful to the population and the enviroiunent when concentrations exceed certain limits. The compounds affected under the implementation plans are sulfur dioxide, particulate matter, ctirbon monoxide, nitrogen dioxide, and ozone. A contingency plan, which will outline the steps to be taken in tlie event tliat a particular pollutant concentration reaches tlie level at wliich it can be considered to be hannful, must be included in each implementation plan. The implementation plans are solely based on tlie continuous emission of tlie previously stated air pollutants. They do not mandate any actions to be taken in tlie event of an accidental toxic release. 

Sulfur dioxide is extremely stable to heat, even up to 3600°F. It docs not form flammable or cxplosi c mixtures witli air. It will, howe cr, react with water or steam to produce toxic and corrosive fumes.When the gas dissolves in water it forms a weak acid solution of sulfurous acid (H S03), which is corrosi C [Pg.274]

Use of some biomass feedstocks can increase potential environmental risks. Municipal solid waste can contain toxic materials that can produce dioxins and other poisons in the flue gas, and these should not be burned without special emission controls. Demolition wood can contain lead from paint, other heavy metals, creosote, and halides used in presen a-tive treatments. Sewage sludge has a high amount of sulfur, and sulfur dioxide emission can increase if sewage sludge is used as a feedstock. 

Reduction of cnviromncntal pollution requires lower energy use and new technology to decrease emission of gases such as sulfur dioxide and carbon dioxide, and to prevent toxic fluoride, heavy metal, and radioactive wastes from discharging into the environment. 

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