Ingestion potential sites

In the occupational setting, inhalation is the most important route of entry of chemical agents into the body, followed by contact with skin and subsequent cutaneous absorption. Although the gastrointestinal tract is a potential site of absorption, the ingestion of significant amounts of chemicals is rare in the occupational setting. 

Which of the following organs or tissues is a potential site for drug accumulation of lead that has been ingested ... 

Three main constraints tend to decrease the rate of product formation through nucleus growth. These are coalesence of nuclei, ingestion of sites potentially capable of generating nuclei, and crystal boundaries, and are explained below. 

Six of the eleven sites evaluated (Sites A, B, F, G, I, and K) identified generie remediation hazards in their SSAHPs but did not address the hazards assoeiated with site- and operation-speeifie tasks. For example, the SSAHP for Site B broadly deseribed hazards sueh as the potential for inhalation, ingestion, eontaet, and absorption of eontaminants or heavy equipment and general eonstruetion hazards. The plan did not deseribe speeifie hazards (i.e., levels of speeifie ehemieal eontaminants, the hazards related to the use of speeifie types of equipment) assoeiated with speeifie workplaee aetivities and their related eontrol measures. These general analyses do not provide employees with suflheient information to enable them to work safely, nor do they enable the employer... 

During reaction, the number of potential nuclei-forming sites present at time t, Ni(t), progressively diminishes from the initial value N0, at t = 0, as N(t) of them form existing nuclei and N2(t) are eliminated by ingestion (i.e. converted to phantom nuclei). Now... 

Exposure of the general population to higher concentrations of methyl parathion may result from contact with, or ingestion of, contaminated hazardous waste site media, principally soils and water. No information was found in the available literature regarding the size of the human population potentially exposed to methyl parathion through contact with contaminated waste site media. 

Klienfeld and Tabershaw 1954 Prout et al. 1985 Stephens 1945 Stevens et al. 1992 Templin et al. 1993 Withey et al. 1983), or dermal (Bogen et al. 1992 Jakobson et al. 1982 McCormick and Abdul-Rahman 1991 Sato and Nakajima 1978 Steward and Dodd 1964 Tsuruta 1978) exposure. All these routes of exposure may be of concern to humans because of the potential for trichloroethylene to contaminate the air, drinking water, food, and soil. More information on the absorption of trichloroethylene following ingestion of contaminated soil and plants grown in contaminated soil near hazardous waste sites are needed to determine bioavailability of the compound in these media. 

Exposures of Children. Children will be exposed to americium in the same manner as adults in the general population (i. e., ingestion of food and water and inhalation of air). Americium is potentially found at hazardous waste sites at elevated levels. Since children may have oral exposure to soil through hand-to-mouth activity, bioavailability studies of americium in soil via the oral route may be useful to assess the risk of this type of exposure. 

Different rules apply to individuals at the site of an attack. They must be concerned about potential radiation exposure, inhalation of airborne contaminants, contamination on skin and clothing, and incidental ingestion of contaminated substances. For individuals at the site of an attack, the following time factor rules apply ... 

The fact that endrin is no longer produced or used in the United States greatly reduces the potential for human exposure. Future levels of endrin, endrin aldehyde, and endrin ketone in environmental media are expected to be low. The most significant route of exposure is most likely ingestion of imported foods contaminated with endrin however, there may also be some localized risks from exposures near waste disposal sites or from groundwater contaminated with endrin. 

The Mann et al. (1985) study is limited in that too few animals were used, organs other than the liver were not adequately evaluated, and only males were studied. Although an adequate acute-duration oral study would be useful to corroborate or refute the thyroid effects seen in the Mann et al. (1985) study, this does not represent a data need, since an acute oral MRL has been derived. Ingestion of contaminated drinking water is expected to be the predominant route of exposure for individuals living in the vicinity of hazardous waste sites. However, acute-duration inhalation and dermal studies in animals are needed to assess the potential toxicity of di- -octylphthalate following exposure via these routes because there are insufficient pharmacokinetic data available to support the extrapolation of data obtained after oral administration to other routes of exposure. 

Monitoring data on 2,3-benzofuran in environmental media are scarce. Potential human exposure to 2,3-benzofuran may occur by ingestion of foods treated with coumarone-indene resin however, migration of 2,3-benzofuran from this resin has not been confirmed. Occupational exposure to 2,3-benzofuran may occur in several energy-related industries, and individuals living in the vicinity of hazardous waste sites at which this compound has been detected may also be exposed. The EPA has identified 1,177 NPL sites. 2,3-Benzofuran has been found at 5 of the sites evaluated for the presence of this chemical (View 1989). However, it is not known how many of the 1,177 NPL sites have been evaluated for 2,3-benzofuran. As more sites are evaluated by the EPA, the number may change. The frequency of the sites in the United States at which... 

Populations with potentially high exposure include those occupationally exposed to isophorone (e.g., screen print workers, some adhesives formulators and users, some coatings manufacturing and use workers). Individuals living near hazardous waste sites may be exposed to isophorone dermally, but probably not by inhalation. These individuals also may be exposed to isophorone by ingestion if they drink water from contaminated wells located down gradient from the site. 

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