Estimation of occupational exposure to phenoxy acids (2,4-D and 2,4,5-T)

Occupational exposure to phenoxy acids (2,4-D and 2,4,5-T) has been studied in four men spraying 2% emulsion in kerosene from a tractor driven equipment. Air borne concentrations with stationary sampling point and from the individual breathing zone showed a mean 2,4-D and 2,4,5-T concentration of 0.1-0.2 mg/m3. Plasma and urine levels were followed during a week of exposed work and for 36 h after exposure. The highest levels of phenoxy acids were found in urine with a mean of 8 (2,4-D) and 4.5 (2,4,5-T) microgram/ml and ranging from 3-14 micrograms/ml for 2,4-D and from 1-11 micrograms/ml for 2,4,5-T in the afternoon after a day of exposure. The mean 24 h excretion in urine was 9 mg of 2,4-D and about 1 mg of 2,4,5-T. The elimination in urine was rapid. Uptake of phenoxy acids seems to be caused both by inhalation and dermal absorption. Improved hygienic conditions are suggested to decrease exposure. No symptoms indicating intoxication appeared. In control subjects with a low and indirect exposure no 2,4-D and 2,4,5-T could be detected in plasma or urine. Lowest detectable concentration in urine of 2,4-D and 2,4,5-T is 0.05 microgram/ml.