Exposure Biomonitoring

Dose-biomonitoring (exposure) - exposure Effects-biomonitoring (response) ... 

Presently available methods to diagnose and biomonitor exposure to anticholinesterases, e.g., nerve agents, rely mostly on measurement of residual enzyme activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in blood. More specific methods involve analysis of the intact poison or its degradation products in blood and/or urine. These approaches have serious drawbacks. Measurement of cholinesterase inhibition in blood does not identify the anticholinesterase and does not provide reliable evidence for exposure at inhibition levels less than 20 %. The intact poison and its degradation products can only be measured shortly after exposure. Moreover, the degradation products of pesticides may enter the body as such upon ingestion of food products containing these products. 

Ostennan-Golkar, S.M., Bond, J. A., Ward, J.B., Jr Legator, M.S. (1993) Use of haemoglobin adducts for biomonitoring exposure to 1,3-butadiene. In Sorsa, M., Pcltonen, K., Vainio, H. Henuninki, K., eds, Butadiene and Styrene Assessment of Health Hazards (lARC Scientific Publications No. 127), Lyon, lARC, pp. 127-134... 

Centers for Disease Control and Prevention—National Health and Nutrition Examination Surveys (NHANES) National Reports on Human Exposure to Environmental Chemicals Provides continuing assessment of U.S. population s exposure to environmental chemicals using biomonitoring data from NHANES. First National Report on Human Exposure to Environmental Chemicals (First Report) was issued in March 2001. Second Report, released in January 2003, presents biomonitoring exposure data on 116 environmental chemicals for noninstitutionalized, civilian U.S. population in 1999-2000. Third report was released in July 2005 and includes data on 148 chemicals (CDC 2005). 

Calafat, A.M., and R.H. McKee. In press. Integrating biomonitoring exposure data into the risk assessment process Phthalates (diethyl phthalate and di[2-ethylhexyl] phthalate) as a case study. Environ. Health Perspect. [online]. Available http //ehp.niehs.nih.gov/docs/ 2006/9059/abstract.html [accessed Aug. 21, 2006]. 

Leonard A, Bernard A. 1993. Biomonitoring exposure to metal compounds with carcinogenic properties. Environ Health Perspect 101(3) 127-133. 

Marked, B., Oehlmann, J., Roth, M 1997b. General aspects of heavy metal monitoring by plants and animals. In Subramanian, K.S., Iyengar, G.V. (Eds.), Environmental Biomonitoring - Exposure Assessment and Specimen Banking. ACS Symp Ser 654, American Chemical Society, Washington, DC, pp. 18-29. 

Industrial Health and Hygiene Biomonitoring Exposure Analysis... 

Calafat, A.M. McKee, R.H. Integrating biomonitoring exposure data into the risk assessment process Phthalates... 

Collectively, the data from Table 7 and Figures 1 through 3 lead to the conclusion that concurrent biomonitoring and passive dosimetry techniques can be achieved and are not divergent worker exposure assessment methods. The correlation between exposure levels measured by these methods is quite good. 

Assessments of risks associated with the use of chlorpyrifos insecticide products for workers have been made. The assessments are based on the results of field studies conducted in citrus groves, a Christmas tree farm, cauliflower and tomato fields, and greenhouses that utilized both passive dosimetry and biomonitoring techniques to determine exposure. The biomonitoring results likely provide the best estimate of absorbed dose of chlorpyrifos, and these have been compared to the acute and chronic no observed effect levels (NOELs) for chlorpyrifos. Standard margin-of-exposure (MOE) calculations using the geometric mean of the data are performed however, probability (Student s f-test) and distributional (Monte Carlo simulation) analyses are deemed to provide more realistic evaluations of exposure and risk to the exposed population. 

The results from the several studies that have been conducted to measure exposures associated with the use of chlorpyrifos are summarized in Tables 1 and 2. Table 1 summarizes results from mixer-loader and applicator studies reported by Honeycutt et al.1 Listed for each work description are the number of replicates, the arithmetic mean, and the geometric mean for the replicates from both the passive dosimetry measurements and the biomonitoring tech-... 

Table 3 Estimated Margins of Exposure for Chlorpyrifos from Biomonitoring Data Using Geometric Means (Single-Point Approach)3...

Human dose comparisons utilizing biomonitoring and passive monitoring of an exposure environment following surface treatment with an insecticide... 

Pesticide exposure assessment Jazzercize activities to determine extreme case indoor exposure potential and in-use biomonitoring... 

Potential dermal exposure (PDE) was the sum of the amount of chlorpyrifos retained by the dosimeter (socks, gloves, and union suit) during the 20-min exposure period. Absorbed daily dose (ADD) was the sum of chlorpyrifos equivalents measured in urine for days 2,3, and 4. Home-use biomonitoring data are expressed as chlorpyrifos equivalents per day, as exposure continued throughout the test period. 

Both skin-exposed volunteers and those wearing WBDs were biomonitored for urinary clearance of trichloropyridinol. An unexpected finding was that before exposure (day 0) each 24-hr urine specimen contained measurable... 

Table 2 Summary of Human Chlorpyrifos Exposures Estimated Using Whole-Body Dosimeters and Biomonitoring...

Table 3 Estimates of Human Exposure Derived from Whole-Body Dosimetry, Biomonitoring, and Routine Use of Pesticide Fogger...

Krieger, R.I., Bernard, C.E., Dinoff, T.M., Fell, L., Osimitz, T. G., Ross, J.I., and Thongsinthusak, T. (2000) Biomonitoring and whole body cotton dosimetry to estimate potential human dermal exposure to semivolatile chemicals, /. Exposure Anal. Environ. Epidemiol., 10 50-57. 

If a further refinement of the determination of exposure is necessary, an exposure study using the product of concern and conducted under conditions of real practice might be required. The exposure study may include passive dosimetry or biomonitoring, depending on the properties of the active substance and the data on metabolism and toxicokinetics in mammals. 

With respect to worker safety and re-entry studies, reference substances are necessary to assay the test substance (and, if applicable, any control substance) and determine its stability and for the analyses of specimens collected in the study. Specimens may include plant material (dislodgeable residues), adsorbent media (inhalation), or clothing/dosimeter materials collected during a worker safety study to assess exposure. If biomonitoring is involved, blood and/or urine specimens may be analyzed against reference substances of known purity. 

Schuhmacher M, Patemain JL, Domingo JL, et al. 1997. An assessment of some biomonitors indicative of occupational exposure to lead. Trace Elements and Electrolytes 14(3) 145-149. 

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