Unknown exposure

Human toxicity data are limited to secondary citations. Because these citations provided no experimental details, they cannot be considered reliable. Deaths have occurred from aniline ingestion and skin absorption, but doses were unknown. Reviews of the older literature indicate that a concentration of 5 ppm was considered safe for daily exposures, concentrations of 7 to 53 ppm produced slight symptoms after several hours, a concentration of 40 to 53 ppm was tolerated for 6 h without distinct symptoms, a concentration of 130 ppm may be tolerated for 0.5 to 1 h without immediate or late sequalae, and 100 to 160 ppm was the maximum concentration that could be inhaled for 1 h without serious disturbance. In studies of accidents with unknown exposure concentrations, methemoglobin levels of up to 72% were measured. Recoveries occurred with a minimum of medical intervention following cessation of exposure. 

In the human studies described below, levels of organochlorine pesticides were measured in various tissues of adults at autopsy in stillborn infants and newborns at autopsy and in body fat, human milk, and serum. With the exception of one study (Stehr-Green et al. 1986), all of the studies are limited by the unknown exposure history of the individuals. 

Heptachlor and heptachlor epoxide were measured in 51 human milk samples at average concentrations of 0.0027 and 0.019 ppm, respectively, from women with unknown exposure histories (Jonsson et al. 1977). Heptachlor epoxide was found in 24% of the samples, and heptachlor in 6%. 

Infants and toddlers are exposed to higher levels (based on their greater dose to surface area [or body weight] ratio) of heptachlor epoxide in the diet (particularly from milk) than are adults. Higher exposure rates in indoor air may occur for at least 1 year in homes that have been treated for termites with heptachlor in the past. Although the most likely routes of exposure at hazardous waste sites are unknown, exposure may result from ingestion of contaminated soil near these sites particularly by children. Since both heptachlor and heptachlor epoxide volatilize from soil, inhalation exposure may also be important for persons living near hazardous waste sites. Exposure via... 

Itoh H, Yoshida K, Masunaga S (2007) Quantitative identification of unknown exposure pathways of phthalates based on measuring their metabolites in human urine. Environ Sci Technol 41 4542 547... 

Prophylaxis - Start in anticipation of contact or as soon as possible after exposure. Use daily for at least 10 days following a known exposure. The infectious period extends from shortly before onset of symptoms to up to 1 week after. Because amantadine does not appear to suppress antibody response, it can be used in conjunction with inactivated influenza A virus vaccine until protective antibody responses develop administerfor 2 to 4 weeks after vaccine has been given. When the vaccine is unavailable or contraindicated, give amantadine for the duration of known influenza A in the community because of repeated and unknown exposure. 

The discussion and studies cited previously generally reflect overall tissue distribution of total arsenic after acute exposure in the case of laboratory animals or unknown exposures in the case of humans. Advances in analytical technology in the last decade have facilitated the identification of tissue-specific patterns of metabolite distribution and accumulation in laboratory animals. Kenyon, Del Razo and Hughes (2005a) found that inorganic arsenic was the predominant form of arsenic in the liver and kidney up to two hours post administration of 10 or 100 p mol As kg-1 as inorganic As(V) to female mice, whereas... 

This chapter discusses CSDP monitoring of employee health status as it relates to the workplace. A responsible industrial operation involving hazardous substances must have an effective occupational and environmental health program to monitor workers for health effects that might result from unknown exposures to chemical or physical agents during normal operations or from accidental exposures during upset conditions. 

Treatment options are largely supportive. An assessment should first be made for airway patency and adequacy of breathing. Circulation may become affected as shock develops secondary to severe gastroenteritis. The following laboratory studies are recommended for all symptomatic patients computerized blood count, electrolytes, and coagulation studies (prothrobin time, activated partial thromboplastin time). In cases of uncertain or unknown exposure, there is an enzyme-linked immunosorption assay test available for the detection and verification of the presence of ricin... 

PERSONAL PROTECTION wear impervious protective clothing, including boots, chemical-resistant gloves, lab coat, sleeves, or encapsulating suits or coveralls wear splash-proof chemical safety goggles or face shields enclose operations and use local exhaust ventilation at site of chemical release appropriate respirators are needed in areas where the ambient concentration of this chemical exceeds the permissible exposure level wear self-contained breathing apparatus during operations that involve unknown exposures or IDLH conditions maintain eyewash baths and safety showers in work area. 

Chapter 7 Reporting and Recordkeeping L Previously Unknown Exposure... 

Color pigments do not represent a startling new technology with unknown potential and unknown exposure risks warranting extensive regulatory review and testing. 

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