Exposure integration

Mushak P, Davis JM, Crocetti AF, et al. 1989. Prenatal and postnatal effects of low-level lead exposure Integrated summary of a report to the U.S. Congress on childhood lead poisoning. Environ Res 50 11-36. 

Chronic Oral Exposure. Integrated Risk Information System (IRIS). Online file. http //www.epa.gov/iris/ (Accessed July 22, 1998). ERA (U.S. Environmental Protection Agency). 1992. Maladiion Reference Dose for Chronic Oral Exposure. Integrated Risk Information System (IRIS). Online file, http //www.epa.gov/iris/ (Accessed July 22,1998). 

Chemica.1 Properties. The FEP resin is inert to most chemicals and solvents, even at elevated temperatures and pressures. However, it reacts with fluorine, molten alkah metal, and molten sodium hydroxide. Acids or bases are not absorbed at 200°C and exposures of one year. The absorption of organic solvents is less than 1% at elevated temperatures and long exposure times. Absorption of chemicals or solvents has no effect on the chemical integrity of the FEP molecule and is a reversible physical process. 

Specifications and Packaging. Aluminum chloride s catalytic activity depends on its purity and particle size. Moisture contamination is an important concern and exposure to humid air must be prevented to preserve product integrity. Moisture contamination can be deterrnined by a sample s nonvolatile material content. After subliming, the material remaining is principally nonvolatile aluminum oxide. Water contamination leads to a higher content of nonvolatile material. 

Risk characterization is defined as the integration of the data and analysis of the above three components to determine the likelihood that humans wiU. experience any of the various forms of toxicity associated with a substance. When the exposure data are not available, hypothetical risk is characterized by the integration of hazard identification and dose—response evaluation data. 

Skin. The skin may become contaminated accidentally or, in some cases, materials may be deHberately appHed. Skin is a principal route of exposure in the industrial environment. Local effects that are produced include acute or chronic inflammation, allergic reactions, and neoplasia. The skin may also act as a significant route for the absorption of systemicaHy toxic materials. Eactors influencing the amount of material absorbed include the site of contamination, integrity of the skin, temperature, formulation of the material, and physicochemical characteristics, including charge, molecular weight, and hydrophilic and lipophilic characteristics. Determinants of percutaneous absorption and toxicity have been reviewed (32—35,42,43,46—49). 

The threshold limit value—time integrated average, TLV—TWA, of chlorine dioxide is 0.1 ppm, and the threshold limit value—short-term exposure limit, STEL, is 0.3 ppm or 0.9 mg /m of air concentration (87,88). Chlorine dioxide is a severe respiratory and eye irritant. Symptoms of exposure by inhalation include eye and throat irritation, headache, nausea, nasal discharge, coughing, wheezing, bronchitis, and delayed onset of pulmonary edema. Delayed deaths occurred in animals after exposure to 150—200 ppm for less than one hour. Rats repeatedly exposed to 10 ppm died after 10 to 13 days of exposure. Exposure of a worker to 19 ppm for an unspecified time was fatal. The ingested systemic effects of low concentration chlorine dioxide solutions are similar to that of chlorite. 

Fully automatic processing was introduced in 1972 with the SX-70 camera, which ejected each integral picture unit automatically, passing it between motorized processing rollers and out of the camera immediately after exposure (12,13). Kodak instant cameras, introduced in 1976 and now discontinued, included both motorized and hand-cranked models. Fuji instant cameras for integral films are motorized. 

Polaroid Integral Films. In 1972 the SX-70 automatic camera and integral film system were introduced (12,13). The SX-70 film provided images that required no timing and no peeling apart. Each film unit was ejected through processing rollers immediately after exposure. The entire development process took place within the film unit under ambient conditions. 

The relative susceptibHity of several commercial aHoys is presented in Table 8. The index used is a relative rating based on integrating performance in various environments. These environments include the harsh condition of exposure to moist ammonia, Hght-to-moderate industrial atmospheres, marine atmosphere, and an accelerated test in Mattsson s solution. The latter testing is described in ASTM G30 and G37 (35,36) and is intended to simulate industrial atmospheres. The index is linear. A rating of 1000 relates to the most susceptible and zero designates immunity to stress corrosion. 

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