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.

[Pesticide residues in feed-stuffs in Sweden (author's transl)]. / Pesticidrester i fodermedel i Sverige.

The occurrence of pesticide residues was studied in samples of feed-stuffs produced in Sweden or imported to Sweden during the years 1972--1976. In all, 278 samples representing 37 types of feed-stuffs (components, as well as finished feeds) and 18 countries were analyzed. Residues of chlorinated hydrocarbon pesticides and PCBs were looked for in 224 samples, mostly feed components. The analytical method used involved solvent extraction, florisil-column clean-up, thinlayer chromatographic separation and gas-chromatographic determination. Chlorinated hydrocarbons were found in several samples. DDT and its transformation products were detected in 66 samples (29.5%), lindane in 44 (19.5%), PCBs in 25 (11.2%), alpha-BHC in 22 (9.8%), beta-BHC in 11 (4.9%) and dieldrin in 9 (4.0%). The levels were usually low (Table I). The chloropesticides occurred most frequently and at the highest levels in feed-stuffs of animal origin and in imported oil-feeds. In 25 of the samples the contents of sigmaDDT exceeded the maximum limit accepted by the National (Swedish) Food Administration for grain and bran intended for human consumption (0.05 mg/kg, Talbe IV). The highest residue level of sigmaDDT (0.66 mg/kg) was encountered in a sample of fish meal. The PCB levels found did not exceed the temporary tolerance established by FDA (1973) for finished animal feeds (0.2 mg/kg). One hundred and seven samples were analyzed for phenoxy acid residues using a thin-layer chromatographic and gas-chromatographic technique. Phenoxy acids were detected in only 2 of 62 randomly selected feed samples (0.05 and 0.2 mg/kg, respectively). The residue limit established by the National Food Administration for 2,4-D and MCPA in grain and bran intended for human consumption is 0.1 mg/kg. Fortyfour samples of feeds were submitted because of suspected phenoxy acid contamination. In 12 of the samples phenoxy acid residues were found. The highest level (3.5 mg/kg, MCPA) was observed in a sample of accidentally contaminated molasses. Considering the apparently low level of contamination of Swedish grain with chloropesticides, PCBs and phenoxy acids and the dilution on compounding feed-stuffs of animal origin and oil-feeds, only very low pesticide residue levels can be expected in Swedish finished animal feeds.

Chlorinated phenoxyacetic acid derivatives and tetrachlorodibenzo-p-dioxin in foliage after application of 2,4,5-trichlorophenoxyacetic acid esters.

Six reforestation areas were sprayed with 2,4,5-T esters. Leaf samples from the areas were analyzed for the esters, tetrachlorodioxin, and dehalogenated phenoxyacetic acid esters. Tetrachlorodioxin was found in one leaf sample only, but the level found, relative to the amount of 2,4,5-T ester found, was lower than in the formulation material used in the study. The concentration of the dichlorophenoxyacetic acid esters present in several leaf samples was greater, relative to the 2,4,5-T ester, which indicated a photochemical breakdown of the 2,4,5-T in the environment.