In similar studies in which rats or rabbits were exposed by the dermal route, Buslovich (1963) reported myotonia and death in rats given unspecified doses of 2,4-D amine salt or 2,4-D butyl ester, but no peripheral neuropathy, while Vinokurova (1960) found 130 - 180 mg of a 50% aqueous emulsion of 2,4-D octyl ester/kg body weight to have "no systemic effect" on rabbits.
(1979) found an impaired iodine uptake by the thyroid, and decreased thyroxine, thyroxine clearance, and thyroxine iodine values in workers packaging 2,4-D sodium salt.
Concentration of 2,4-D Solution
ECOLOGICAL EFFECTS FROM FIELD APPLICATION Appraisal No direct toxic effects, acute or long-term, of 2,4-D applications under field conditions on any animals species have been observed thus far. There are, inevitably, indirect effects resulting from the intended selective herbicidal properties of the compound.
Uptake and fate of 2,4-D in the body
Thefirst is the calculated effect of the non-hydrolysed ester and thesecond, entered as `total 2,4-D', is the observed effect of the mixtureof ester and free acid produced by hydrolysis during the course of theexperiment.
Physical and chemical properties of 2,4-D
However, the importance of solvents, surfactants, and other ingredients of the herbicides in the uptake of 2,4-D via the dermal route still needs to be defined.
Composition of technical 2,4-D materials
The 2,4-D excretion in urine is delayed and more prolonged after dermal application than after intraveneous or oral administration (Feldmann & Maibach, 1974; Sauerhoff et al., 1977), and complete elimination may take about one week (Levy et al., 1982; Leng et al., 1982).
Analysis of technical and formulated 2,4-D products
Alabaster (1969) examined several formulations of 2,4-D in twospecies of fish, and found that pelleted herbicide, either as clay-based or resin-based pellets, was the least toxic to fish of any of theformulations tested.
ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION OF 2,4-D
Animals The uptake of 2,4-D from the gut of rats, mice, guinea-pigs, cattle, pigs, and sheep appears to be similar in both rapidity and extent to that observed in human beings (Mitchell et al., 1946; Lisk et al., 1963; Bache et al., 1964a; Erne, 1966a,b; Milhaud et al., 1970; Shafik et al., 1971; Buslovich et al., 1973; Fedorova & Belova, 1974; Clark et al., 1975; Senczuk & Pogorzelska, 1975, 1981; Van Peteghem & Heyndrickx, 1975).
Degradation of 2,4-D in the soil
Human beings Only 5.8% of a dilute solution of 14C-labelled 2,4-D in acetone applied at a dose of 4 µg a.i./cm2 to the ventral forearm of adults was excreted in the urine compared with 100% of a small intravenous dose (Feldmann & Maibach, 1974) (Table 14).