Aerosol toxicity

The current human estimates for nerve agent vapor and aerosol toxicity are based upon data from animal models. Rodents are popular animal models in that they are readily available, cheap, and convenient to handle. Additionally, there is a great amount of background data on rodents available in the literature for comparison to many biological endpoints. However, nonrodent models are preferred for studies of prophylactic and therapeutic efficacy associated with nerve agent exposure due to the protective buffering impact of relatively high blood carboxylesterase levels in... 

The aerosol toxicity of ricin has been documented in several laboratory animals, including rhesus (Wilhelmsen and Pitt, 1996) and African green monkeys, but it remains unclear which, if any, of these effectively model the human response to ricin. Is it necessary to conduct animal trials with medical countermeasures for ricin in an NHP aerosol model, or will other animal models suffice to predict the human response The unexpected appearance of VLS in human clinical trials underscores the difficulty in extrapolating from animal models. Data addressing these questions will be critical in devising practical and effective strategies for coping with ricin as a toxin weapon. 

Natusch des and Wallace JR (1974) Urban aerosol toxicity the influence of particle size. Science 186 695-699. 

T-2 is one of the more stable toxins, retaining its bioactivity even when heated to high temperatures. High concentrations of sodium hydroxide and sodium hypochlorite are required to detoxify it. Aerosol toxicities are generally too low to make this class of toxins useful to an aggressor as an MCBW as defined in Figure 30-1 however, unlike most toxins, these are dermally active. Clinical presentation includes nausea, vomiting, weakness, low blood pressure, and burns in exposed areas. 

The aerosol toxicity of even the most toxic trichothecene is low enough that the large-quantity production required (approximately 80 tonnes to expose a 10-km2 area with respirable aerosol) makes an inhalational threat unlikely on the battlefield. These toxins, therefore, might be dispersed as larger particles, probably visible in the air and on the ground and foliage. 

C. Manufactured by the action of HF on CCI4 using SbClj as a catalyst. Known commercially as Freon-12 or Arcton-12. Widely used as a refrigerant and aerosol propellant. It is much less toxic than carbon tetrachloride. 

Environmental Aspects. Airborne particulate matter (187) and aerosol (188) samples from around the world have been found to contain a variety of organic monocarboxyhc and dicarboxyhc acids, including adipic acid. Traces of the acid found ia southern California air were related both to automobile exhaust emission (189) and, iadirecfly, to cyclohexene as a secondary aerosol precursor (via ozonolysis) (190). Dibasic acids (eg, succinic acid) have been found even ia such unlikely sources as the Murchison meteorite (191). PubHc health standards for adipic acid contamination of reservoir waters were evaluated with respect to toxicity, odor, taste, transparency, foam, and other criteria (192). BiodegradabiUty of adipic acid solutions was also evaluated with respect to BOD/theoretical oxygen demand ratio, rate, lag time, and other factors (193). 

Lidocaine hydrochloride [73-78-9] (Xylocaine), is the most versatile local anesthetic agent because of its moderate potency and duration of action, rapid onset, topical activity, and low toxicity. Its main indications are for infiltration, peripheral nerve blocks, extradural anesthesia, and in spinal anesthesia where a duration of 30 to 60 min is desirable. Because of its vasodilator activity, addition of the vasoconstrictor, epinephrine, increases the duration of action of Hdocaine markedly. It is also available in ointment or aerosol preparations for a variety of topical appHcations. 

Ha2ard is the likelihood that the known toxicity of a material will be exhibited under specific conditions of use. It follows that the toxicity of a material, ie, its potential to produce injury, is but one of many considerations to be taken into account in assessment procedures with respect to defining ha2ard. The following are equally important factors that need to be considered physicochemical properties of the material use pattern of the material and characteristics of the environment where the material is handled source of exposure, normal and accidental control measures used to regulate exposure the duration, magnitude, and frequency of exposure route of exposure and physical nature of exposure conditions, eg, gas, aerosol, or Hquid population exposed and variabiUty in exposure conditions and experience with exposed human populations. 

Toxic chemical munitions have unique characteristics in comparison to other weapons systems, reaching personnel both widely dispersed and concentrated in fortifications, ie, gases and aerosols are not bound by corners. These materials can penetrate crevices reaching personnel physically protected from high explosives. In addition, toxic chemicals are minimum-destmction weapons as regards matHriel (5). 

The existing variety of means and methods of micro-element analysis is used worldwide for the determination of element contents in atmospheric aerosols when they ai e collected at aspiration filters, sediment and natural surfaces and biota objects where toxic substances migration can be observed. 

Toxic, flammable/explosive, reactive, unstable Liquid, solid (briquette, flake, powder), gas, vapour, ah-borne particulate (including mist, fume, froth, aerosol, dust)... 

The toxicity of a substance is its capacity to cause injury once inside the body. The main modes of entry into the body by chemicals in industry are inhalation, ingestion and absorption through the skin. Gases, vapours, mists, dusts, fumes and aerosols can be inhaled and they can also affect the skin, eyes and mucous membranes. Ingestion is rare although possible as a result of poor personal hygiene, subconscious hand-to-mouth contact, or accidents. The skin can be affected directly by contact with the chemicals, even when intact, but its permeability to certain substances also offers a route into the body. Chemicals accorded a skin notation in the list of Occupational Exposure Limits (see Table 5.12) are listed in Table 5.2. Exposure may also arise via skin lesions. 

LPG is considered to be non-toxic witli no chronic effects, but the vapour is slightly anaesthetic. In sufficiently high concentrations, resulting in oxygen deficiency, it will result in physical asphyxiation. The gases are colourless and odourless but an odorant or stenching agent (e.g. methyl mercaptan or dimethyl sulphide) is normally added to facilitate detection by smell down to approximately 0.4% by volume in air, i.e. one-fifth of the lower flammable limit. The odorant is not added for specific applications, e.g. cosmetic aerosol propellant. 

Preparations packed in aerosol dispensers shall be classified as flammable in accordance with Part III of this schedule. " Substances shall be classified as very toxic, toxic or harmful in accordance with the additional criteria set out in... 

Kaufman, J. W. (1999). The role of upper airway heat and water vapor exchange in hygroscopic aerosol deposition iii the human airway. In Toxicity Assessment Alternatives Methods, Issues, Opportunities (H. Salem and S.A. Katz, Eds.), pp. 63-70. Humana Press Inc., Totow a, NJ. 

The catalyst is formed by reaction of HF on SbClj. The Freons have a unique combination of properties which make them ideally suited for use as refrigerants and aerosol propellants. They have low bp, low viscosity, low surface tension and high density, and are non-toxic, non-flammable, odourless, chemically inert and thermally stable. The most commonly used is CF2CI2, bp, —29.8°. The market for Freons... 

The name dust , is used in a variety of ways, and with different meanings. These range from the material that accumulates on the earth s surface, such as on streets and in living and working environments, to the particulate material suspended in the atmosphere. In this paper I wish to consider these two materials in terms of their chemical composition, sources and relationship between them. The names used for the two materials will be surface dust and atmospheric dust . The word aerosol may also be used for atmospheric dust but it more properly applies to the finer particles of atmospheric dust and includes liquid aerosol (i). Botfi surface and atmospheric dusts are increasingly seen to be a hazard to human beings as they are a source of intake of toxic materials such as heavy metals. For this reason study is important of the composition and sources of the dusts. 

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