Urine excretion exposure

Following inhalation exposure to trichloroethylene in humans, the unmetabolized parent compound is exhaled, whereas its metabolites are primarily eliminated in the urine. Excretion of trichloroethylene in the bile apparently represents a minor pathway of elimination. Balance studies in humans have shown that following single or sequential daily exposures of 50-380 ppm trichloroethylene, 11% and 2% of the dose was eliminated unchanged and as trichloroethanol, respectively, in the lungs 58% was eliminated as urinary metabolites and approximately 30% was unaccounted for (Monster et al. 1976, 1979). Exhaled air contained notable concentrations of trichloroethylene 18 hours after exposure ended because of the relatively long half-life for elimination of trichloroethylene from the adipose tissue (i.e., 3.5-5 hours) compared to other tissues (Fernandez et al. 1977 Monster et al. 1979). 

Information on the excretion of americium after dermal exposure in humans or animals is extremely limited. Some qualitative information is available from an accidental exposure in which a worker received facial wounds from projectile debris and nitric acid during an explosion of a vessel containing 241 Am (McMurray 1983). The subject also inhaled 241Am released to the air as dust and nitric acid aerosols, which was evident from external chest measurements of internal radioactivity thus, excretion estimates reflect combined inhalation, dermal, and wound penetration exposures (Palmer et al. 1983). Measurements of cumulative fecal and urinary excretion of241 Am during the first years after the accident, and periodic measurements made from day 10 to 11 years post accident indicated a fecal urine excretion ratio of approximately 0.2-0.3, although the ratio was approximately 1 on day 3 post accident (Breitenstein and... 

Hammond SE, Lagerquist CR, Mann JR. 1968. Americium and plutonium urine excretion following acute inhalation exposure to high-fired oxides. Am Ind Hyg Assoc J 29(2) 169-172. 

The relationship between exposure and internal dose is known only for a few pyrethroids. Human volunteer studies have shown that, after a single oral administration, pyrethroids and the respective metabolites are excreted in urine within 24 hr and do not accumulate in the body. In field workers exposed to cypermetrin through the dermal route, urine excretion of the intact compound and its metabolites peaked 36 hr after exposure had ceased (WHO, 1989). 

White rats given a single dose of radiolabeled disulfoton intraperitoneally eliminated the metabolites phosphoric acid (4.1 %), DEP (61.2%), and DETP (24.8%) in urine as a percentage of excretory metabolites 10-12 hours after exposure (Bull 1965). Approximately 24 and 48 hours after exposure 14.1% and 28.6%, respectively, of the administered dose was excreted in the urine. Excretion rates for disulfoton and its metabolites were not determined. Mice eliminated 30--60% of the radiolabeled intraperitoneal dose of disulfoton in the urine and 2-3% in the feces within 96 hours of exposure (March et al. 1957). 

Animal studies indicate that the primary toxic effect of uranium exposure is on the kidney, with particular damage to the proximal tubules. Functionally, this may result in increased excretion of glucose and amino acids. Structurally the necrosis of tubular epithelium leads to formation of cellular casts in the urine. If exposure is insufficient to cause death from renal failure, the mbular lesion is reversible with epithelial regeneration. Although bone is the other major site of deposition, there is no evidence of toxic or radiocarcinogenic effects to bone or bone marrow from experimental studies. ... 

Total 2,4,5-T Excreted in Urine per Exposure in a Backpack Crew (adapted from Lavy, 15., 19.). ... 

Exposure assessment using alpha cellulose pads and DEP urine excretion were made on 8 workers applying ethion on a daily basis in two citrus groves in Orange County, Florida. The study format was divided into three phases ... 

Inhalation of PCE is followed by prolonged urinary excretion of metabolites, primarily TCA. At more than 10 mg/1 of urinary TCA, workers may show some signs of toxicity. The finding of both di- and trichloroacetic acids in human urine following exposure to PCE has led to the suggestion of an oxirane as the metabolic intermediate (ref. 67b). 

Erythroqde protoporphyrin concentrations are not a sensitive indicator of low-concentration Pb exposure but are definitive markers for Pb overdose an er)rthrocyte protoporphyrin concentration greater than 60(J.g/dL is a significant indicator of Pb exposure (see Chapter 32). Serum ALAD concentrations are also a useful indicator for medium to high concentrations of Pb exposure however, they do not correlate with low concentrations of Pb exposure. Serum Pb analysis is of very limited utility, because Pb concentrations are abnormal only for a short period of time after exposure. Normally the hair Pb content is lower than 5ug/g hair Pb concentration greater than 25 lg/g mdicates severe Pb exposure. Quantification of urine excretion rates either before or after chelation therapy has been used as an indicator of Pb exposure. However, blood Pb levels have the strongest correlation with toxicity. 

Male Sprague-Dawley rats received a low dose of [ H]-benzo[a]pyrene (suspended in 10% ethanol-soybean oil) daily for 3, 5, or 7 days (Yamazaki and Kakiuchi 1989). Highest radioactivity was excreted 2-8 days after first exposure. Polar and phenol metabolites represented approximately 60% and 20% of the radioactivity detected in urine, respectively. The conjugated from accounted for 80% of these urinary metabolites. Only small amounts of unmetabolized benzo[a]pyrene were detected in the urine. Excretion into the feces was not studied. 

Jongeneelen FJ, Leijdekkers C-M, Bos RP. et al. 1985. Excretion of 3-hydroxy-benzo(o)pyrene and mutagenicity in rat urine after exposure to benzo(a)pyrene. J Appl Toxicol 5 277-282. 

No studies were located regarding the excretion of wood creosote following inhalation exposure in humans or animals. Some studies were located that estimate excretion of individual PAHs or their metabolites in urine. Excretion of PAHs and their metabolites after inhalation exposure may be detected hours to days after exposure (Agency for Toxic Substances and Disease Registry 1995). 

Manganese is normally found in human tissue, blood, serum, and urine. Oral exposure to manganese can result in manganese increases in all tissues. The major route of manganese excretion is via the bile although some excretion does occur in urine, milk, and sweat (EPA 1993b). Tissue distribution of manganese usually reflects chronic exposure, not acute exposure. 

Usually, only spot urine specimens are available for trace element analysis. Because the concentration of many analytes is dependent on the rate of urine excretion, which varies to a great extent even in healthy people (Shephard et al., 1981 Young, 1979), some standardisation for urinary excretion rate has long been used in the assessment of exposure to toxic elements (Levine and Fahy, 1945 Molyneux, 1966 Elkins et ai., 1974). The most widely used approaches have been based on relative density, the concentration of creatinine in urine, and the length of the urine collection period, i.e. excretion rate. Araki and co-workers have extensively studied the correction of urine concentrations to a standard urinary flow rate of 1 mL/min in circumstance, where the water intake has been changed (Araki, 1980 Araki and Aono, 1989 Araki et al.. 1990). Although this approach cannot be applied in routine trace element analysis and is not necessarily representative of other situations where the renal treatment of trace elements and water varies, it provides a useful method to compare the behaviour of the excretion of different chemicals in the urine by the following equation ... 

A. Specific levels. Serum fluoride concentrations are not useful after acute exposure but may be used in evaluating chronic occupational exposure. Normal semm fluoride is less than 20 mcg/L, but varies considerably with dietary and environmental intake. In workers, preshift urine excretion of fluoride should not exceed 3 mg/g of creatinine. 

Official standards for As in urine following exposure to these compounds is lacking, other than one manufacturer s recommendation of 0.3 ppm. This standard appears to be based on a stu4y of urinary excretion of arsenic in 163 unexposed individuals, which showed a maximum excretion value of 0.85 mg As/day (10) the 0.3 ppm concentration was selected based on a 3-1 iter daily void of urine and is therefore quite conservative. In the Tarrant and Allard... 

Since analysis of our total urine excretion patterns reveals that workers routinely receive inadvertent exposure at times in addition to the application day, it is Imperative that total urine be collected if one is interested in obtaining quantitative measurements of the total absorbed dose. 

The average amount of urine excreted per day is 1.5 liters. Exposure to chlordimeform will occur five days per week, 10 weeks in a year, and for 10 years of a 70-year life span. Carcinogenic effect is determined by the total accumulated dose, i.e., (dose) x (time) tumor yield. 

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