Occupational settings

Societies concern with air quality has evolved from medieval times, when breathing smelting fumes was a major hazard, to where we are today (see Chapter 1). In modem society, a parallel effort has been under way to improve air quality in the outside or ambient air, which is the focus of this book, and in the industrial occupational setting in manufacturing and other traditional jobs. A combination of events is moving many countries to consider the quality of air in other locations where we live parts of our lives. Attention is now being refocused on "indoor" air quality. 

In occupational settings, exposure to endosulfan is mainly via the dermal and inhalation routes. Although workers involved in the manufacture and formulation of pesticide products containing endosulfan are potentially exposed to high concentrations of the compound, actual exposure is probably limited by the use of engineering controls and personal protection equipment. The highest documented dermal and inhalation exposures have been reported for agricultural workers involved in the spray... 

Little information is available on what happens when you are exposed to hydrogen sulfide by getting it on your skin, although care must be taken with the liquefied product to avoid frost bite. It is known that hydrogen sulfide will irritate your eyes if you are exposed to the gas. These types of exposures are more common in certain occupational settings. 

The Iodometric method has also been utilized in analyzing hydrogen sulfide in the air (EPA 1978). The method is based on the oxidation of hydrogen sulfide by absorption of the gas sample in an impinger containing a standardized solution of iodine and potassium iodide. This solution will also oxidize sulfur dioxide. The Iodometric method is suitable for occupational settings. The accuracy of the method is approximately 0.50 ppm hydrogen sulfide for a 30-L air sample (EPA 1978). 

Studies on workers in an occupational setting showed a dose-response relationship between the concentration of acrylonitrile of inspired air and the recovery of metabolites in the urine (Houthuijs et al. 1982 Sakurai et al. 1978). In a controlled study using human volunteers, urinary metabolite data suggested that the elimination of acrylonitrile followed first-order kinetics, with a half- life of seven to eight hours (Jakubowski et al. 1987). 

Exposure to arsine usually occurs in occupational settings that often involve concurrent exposures to other metal vapors and solvents. It is assumed that concurrent exposure with other chemicals, the toxicity of which targets the erythrocyte or renal function, would increase the severity of the response to arsine. 

Acrolein degrades quickly in soils and in plant tissues, regardless of mode of administration. Most terrestrial crop plants easily tolerate 25,000 pg acrolein/L of irrigation water, and some can tolerate 70,000 to 80,000 pg/L without adverse effects. Terrestrial plants were adversely affected at atmospheric concentrations of 500 pg acrolein/L air, but this concentration exceeds the recommended value of 110 pg/L (0.25 mg/m3) air for protection of human health in occupational settings. 

Thus, these orbitals can be used to represent exactly any property of the system in localized terms. The NAOs divide naturally into a leading high-occupancy set (the natural minimal basis ) and a residual low-occupancy set (the natural Rydberg basis ), where the occupancies of the latter orbitals are usually quite negligible for chemical purposes. Thus, even if the underlying variational basis set is of high dimensionality (6-311++G for the applications of this book), a perturbative analysis couched in NAO terms has the simplicity of an elementary minimal-basis treatment without appreciable loss of chemical accuracy. 

The National Institute of Occupational Safety and Health (NIOSH) and the Occupational Safety and Health Administration (OSHA) have established a limit of 0.1 mg endrin per cubic meter of air (0.1 mg/m3) averaged over an 8-hour day in an occupational setting for a 40-hour work week. In addition, NIOSH considers that a person could escape within 30 minutes from a concentration of 2,000 mg/m3 without respiratory protection and without experiencing any escape-impairing or irreversible health effects. 

Cyanide is used or produced in various occupational settings where activities include electroplating, some metal mining processes, metallurgy, metal cleaning, certain pesticide... 

Body Weight Effects. In an occupational setting, loss of appetite was reported in 58% and weight loss (approximately 8%) in 50% of workers exposed to 15 ppm hydrogen cyanide (14 ppm cyanide) for an unspecified duration in a silver-reclaiming facility (Blanc et al. 1985). 

Chronic dermal exposure of humans to cyanide can occur in occupational settings. However, the main route of exposure is considered to be inhalation and, therefore, the occupational exposure studies are discussed in Section 2.2.1. 

In a nested case-control study of cancers associated with chemical exposures in the wood industry, Kauppinen et al. (1986) found a significantly increased risk of respiratory system cancer associated with exposure to phenol and phenol in wood dust. As is often the case in occupational settings, these exposures were confounded by smoking and exposures to other materials like pesticides. The increased risk observed for exposure to phenol was almost 5-fold (odds ratio of 4.94), but showed no dose-related increase. This risk dropped to 4-fold with adjustments for smoking history, and to less than 3-fold (and non-significant) when workers exposed to both phenols and pesticides were excluded from the analysis. 

Several methods have been developed to estimate the exposure to such emissions. Most methods are based on either ambient air quality surveys or emission modeling. Exposure to other components of diesel emissions, such as PAHs, is also higher in occupational settings than it is in ambient environments. The principles of the techniques most often used in exhaust gas analysis include infrared (NDIR and FTIR), chemiluminescence, flame ionization detector (FID and fast FID), and paramagnetic methods. 

No neurological effects have been described in humans exposed in an occupational setting except for one report of nonspecific signs of headache and depression (Kochmann 1928). Neurologic signs were not reported in animals exposed by various routes and for intermediate and chronic durations. 

Fibrosis was first recognized in certain occupational settings. One of the well-known conditions of this type is silicosis, which is brought about by long-term, uncontrolled exposure to certain crystalline forms of silica (SiOi), and certain related substances called silicates. These minerals are widespread on earth, in fact most of the inorganic, non-aqueous earth consists of silica and silicates. Many of these minerals (e.g., quartz) have major industrial uses. It is important to emphasize that silica and silicates occur in both crystalline and non-crystalline... 

In Table 6.1 are listed some of the chemicals and occupational settings lARC has categorized as carcinogenic to humans - the data from... 

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