Urinary 2-methoxy acetic acid accumulation in response to 2-methoxy ethanol exposure.
Urinary 2-methoxy acetic acid reportedly has a long half-life (77.1 hr) in humans. The authors studied urinary 2-methoxy acetic acid in a group of 18 workers exposed to 2-methoxy ethanol from Monday to Saturday following a 7-d cease in production. The weekly time-weighted average exposure concentration of 2-methoxy ethanol was 4.5 ppm. The urinary 2-methoxy acetic acid of exposed workers was increased significantly, from 18.5 microg/ml (10.6 mg/gm creatinine) on Monday (prior to work) to 48.4 microg/ml (46.5 mg/gm creatinine) on Friday (after work), to 51.2 microg/ml (45.6 mg/gm creatinine) on Saturday after work. These levels occurred, despite that fact that the daily mean time-weighted average 2-methoxy ethanol exposures were very consistent and were close to the current Taiwan Permissible Exposure Limit of 5 ppm. These urinary 2-methoxy acetic acid levels were much higher than levels that occur with inhalation only, and they demonstrate that skin absorption is a significant contributor to 2-methoxy ethanol exposure. The high background concentrations of 2-methoxy acetic acid in the preshift urine samples following a 7-d production halt confirm that there is a long half-life of 2-methoxy acetic acid in humans. The determination of urinary 2-methoxy acetic acid is recommended for exposure assessment of 2-methoxy ethanol.
Shih
T S
TS
Institute of Occupational Safety and Health Council of Labor Affairs Taipei, Taiwan, Republic of China.
Liou
S H
SH
Chen
C Y
CY
Smith
T J
TJ
D000085:Acetates / Q000009:adverse effects* / Q000032:analysis* / Q000378:metabolism / Q000652:urine*; D001822:Body Burden; D003300:Copper; D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D008452:Maximum Allowable Concentration; D008657:Metabolic Clearance Rate; D008669:Metallurgy; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis*; D012869:Skin Absorption / Q000187:drug effects; D013997:Time Factors
D000085:Acetates; C048765:2-methoxy ethyl acetate; D003300:Copper; C013598:methoxyacetic acid