Dusts inhalation exposure

Outdoor inhalation exposure is mainly due to traffic, energy production, heating, and natural factors such as pollen and mineral dusts. These outdoor sources of pollution also affect indoor air quality. The indoor concentration is typically 20-70% of the corresponding outdoor concentration. Occasionally the indoor concentrations of an external pollutant (especially radon) may even exceed the concentrations outdoors. ... 

MMT, monomethyltin DMT, dimethyltin MBT, monobutyltin DBT, dibutyltin TBT, tributyltin MOT, monooctyltin DOT, dioctyltin Exposure via house dust (which has been measured as containing organotins) was also considered it is likely that inhalation exposure indoors includes house dust, which picks up leached organotins from vinyl flooring. 

For each category of land or water body use, one may envision a simplified scenario. In each scenario, only those activities most likely to lead to toxic exposures are considered. For example, In the Industrial scenario, Indoor workers would not be exposed to levels of dust bearing high concentrations of soli contaminants outdoor workers who stir up dry soli with heavy machinery, however, could expect to Inhale contaminant-laden dust. A scenario could Involve more than one exposure pathway. Thus, the Industrial worker might drink water from a contaminated well, In addition to breathing contaminated dust these exposures might represent not only different pathways but different sources. 

The PPLVs applicable to industrial scenarios would possibly be water ingestion (as in the case of residential housing), and more likely dust inhalation. A conservative approach would be to use the equation applied to DNT for worker exposure to dust,... 

Ingot casting, 23 266 Ingot production, titanium, 24 857 Inhalation. See also Dust inhalation hydrogen fluoride, 14 17-18 influence on toxicity, 25 211 of PVC dust, 25 676-677 of sodium tetrasulfide, 22 875 studies of, 25 227t of sulfuric acid, 23 794 of toluene, 25 179t of VDC, 25 692-694 Inhalation anesthetics, 11 867-868 Inhalation exposure... 

Animals exposed vivo to cotton dust show similar results. In excised tissues, histamine methylating enzymes fall to zero during exposure, but rise following a rest from cotton dust inhalation. In flax dust exposed animals, histamine activity initially increases.In guinea pigs, enzyme levels fall upon exposure, then rise after removal from exposure. Further, while flax exposed animals show a fall in total lung histamine content, with cotton dust exposure there is an increase. It should, however, be borne in mind that histamine release is not necessarily correlated with total lung histamine (103). 

Acute-Duration Exposure. Information is not available on the health effects of 1,2-diphenylhydrazine resulting from inhalation exposure in humans or animals. Because 1,2-diphenylhydrazine is a solid with a low vapor pressure at ambient temperatures, it is highly unlikely that inhalation exposure to this chemical in the vapor state would occur (Chapter 5). However, the possibility of inhalation exposure to dusts of 1,2- diphenylhydrazine either free or adsorbed to soil is conceivable. Therefore, acute studies of inhalation exposure to dusts of 1,2- diphenylhydrazine could be designed to provide information on possible toxic effects and exposure levels that cause effects. No studies were located regarding acute oral exposure in humans. The only pertinent acute exposure toxicity studies of... 

No studies were located regarding lethal effects in humans or animals after inhalation exposure to 3,3 -diehlorobenzidine. No fatalities were observed in rats observed for 14 days following a 1-hour exposure to an unspecified concentration of 3,3 -diehlorobenzidine dihydroehloride dust (Gerarde and Gerarde 1974). No deaths were reported in male rats exposed to 23,700 mg/m 3,3 -diehlorobenzidine base (dust) for 2 hours per day for 7 days (Gerarde and Gerarde 1974). 

In summary, for the general population, the common routes of exposure to environmental compounds are ingestion, dermal contact and inhalation. Many PEAS are environmentally persistent but not lipophilic rather they have mixed lipophobic and hydrophobic properties. The exposure scenario is complex as PEAS have a large variety of applications. Gral exposure from materials other than food, inhalation and dermal contact may be important exposure routes for certain segments of the population. Dust inhalation could also be a possible source of exposure. However, the information on concentrations of PEAS in indoor dust is very limited and the bioavailability of the current compounds from dust is unknown. 

The general population can be exposed to chemical substances in indoor as well as in outdoor (ambient) air via inhalation of vapors, aerosols, and dusts in the air. The term inhalation exposure is defined as the concentration of a substance in inhaled air at the boundary of the body, and is expressed as an average concentration per unit time (e.g., mg/m per day). In order to estimate a daily dose of a substance from the exposure concentration of the substance in the air, the inhalation rate is used. According to US-EPA (1997), the average daily dose (ADD) can be estimated from the exposure concentration by using the following equation ... 

Respiratory Effects. No studies were located regarding respiratory effects in humans after inhalation exposure to 1,3,5-TNB. One retrospective study (Okubo and Shigeta 1982) of acute occupational exposure to 1,3-DNB dust particles was located. Six workers were removing crystallized 1,3-DNB from a tank and were protected with gauze masks and rubber gloves. Exposure occurred over a period of 6 days. By the end of the exposure period, some of the workers complained of slight dyspnea upon exertion. Inhalation was considered to be a primary route of exposure because a relatively small skin area (face and neck) was exposed. Limitations of this study include lack of information on the concentration of 1,3-DNB in the air, the amount of particulate 1,3-DNB deposited on workers skin, and the exact duration of exposure. 

Inhalation exposure to high levels of cadmium fumes or dust is intensely irritating to respiratory tissue. Particle size appears to be a more important determinant of toxicity than... 

The irritant effects are probably due primarily to its alkalinity, but dehydrating and thermal effects also may be contributing factors. Strong nasal irritation was observed from exposure to a mixture of dusts containing calcium oxide in the range of 25mg/m but levels of 9-lOmg/m produced no observable irritation. Inflammation of the respiratory tract, ulceration and perforation of the nasal septum, and pneumonia have been attributed to inhalation of calcium oxide dust severe irritation of the upper respiratory tract ordinarily causes persons to avoid serious inhalation exposure. ... 

In animal studies significant increases in the incidences of lung tumors have been observed in female rats after inhalation exposure. Repeated inhalation by monkeys caused deposition of the dust in the lungs with minimal or no fibrous tissue proliferation."... 

Diphenylhydrazine is a solid with a low vapor pressure at ambient temperature, which makes inhalation exposure of this substance in the vapor state unlikely. Exposure to dusts of 1,2-diphenylhydrazine is conceivable. ... 

Wagner JC et al An animal model for inhalation exposure to talc. In Lemen R, Dement JM (eds) Dusts and Disease, 389pp. Proceedings of the Conference on Occupational Exposure to Fibrous and Particulate Dust and Their Extension into the... 

After inhalation exposure, the primary route of excretion is in the feces following ciliary clearance from the lungs to the gastrointestinal tract (Wrenn et al. 1981). Fecal excretion may account for as much as 97% of total excretion (Fisher et al. 1983). Higher levels of thorium-230 were excreted in the feces by active crushermen (uranium mill workers exposed to uranium ore dust in the crusher building) compared to retired workers or controls (Fisher et al. 1983). Levels of thorium-230 in the urine were comparable to those of retired workers, and the levels in both were significantly greater than controls. 

Following inhalation exposure of humans to nickel particles, primarily as nickel oxides and nickel refinery dust, the respiratory system is the primary target. Effects noted included chronic bronchitis, emphysema, reduced vital capacity, and cancers of the lungs and nasal sinus. These effects occurred at... 

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