WORLD HEALTH ORGANIZATION FOOD AND AGRICULTURE
ORGANIZATION
ORGANISATION MONDIALE DE LA SANTE ORGANISATION POUR L'ALIMENTATION
ET L'AGRICULTURE
VBC/DS/75.13
ORIGINAL: ENGLISH
DATA SHEETS ON PESTICIDES No. 13
1975
2,4,5-T
..........................
It must be noted that the issue of a Data Sheet for a
particular pesticide does not imply endorsement of the pesticide by
WHO or FAO for any particular use, or exclude its use for other
purposes not stated. While the information provided is believed to
be accurate according to data available at the time when the sheet
was compiled, neither WHO nor FAO are responsible for any errors or
omissions, or any consequences therefrom.
The issue of this document does Ce document ne constitue pas une
not constitute formal publication. Il ne doit faire
publication. It should not be l'objet d'aucun compte rendu ou
reviewed, abstracted or quoted résumé ni d'aucune citation sans
without the agreement of the l'autorisation de l'Organisation
Food and Agriculture des Nations Unies pour
Organization of the United l'Alimentation et l'Agriculture
Nations or of the World Health ou de l'Organisation Mondiale de
Organization. la Santé.
2,4,5-T
Part 1 - General information
CLASSIFICATION
Primary use: herbicide
Secondary uses: none
Chemical group: chlorinated phenoxy acid
Data sheet No. 13
Date issued: March 1975
1.1 COMMON NAME: 2,4,5-T
Identity: 2,4,5-trichlorophenoxyacetic acid
Under good manufacturing conditions, a typical production lot of the
technical material assayed about 95% 2,4,5-trichlorophenoxyacetic acid,
about 5% homologous and isomeric acids and less than 0.1 ppm of
2,3,4,7,8-tetrachlorodibenzo-p-dioxin (TCDD). This last impurity is
a highly toxic material whose toxic effects are highly species
dependent. Under poorly controlled manufacture it has been reported to
be present in one commercial sample of 2,4,5-T at a level of
approximately 27 ppm. Current production specifications limit TCDD
to 0.1 ppm.
Synonyms: none Local synonyms:
1.2 SYNOPSIS: A moderately toxic chlorinated phenoxy acid herbicide
which is rapidly excreted after ingestion.
1.3 SELECTED PROPERTIES
1.3.1 Physical characteristics: The pure acid is a white crystalline
solid with a melting point of 158°C.
1.3.2 Solubility: The pure acid is slightly soluble in water (278 ppm)
at 25°C and soluble (58.4%) in alcohol.
1.3.3 Stability: The technical acid is stable under normal conditions.
1.3.4 Vapour pressure: (volatility) No information. The volatility of
the pure acid can be expected to be low.
1.4 AGRICULTURAL, HORTICULTURAL AND FORESTRY
1.4.1 Common formulations
Various salts, amine salts and esters, the salts as aqueous
concentrates and esters as emulsifiable concentrates.
Often formulated in mixtures with 2,4-D. There are FAO specifications
for ester emulsifiable concentrates and amine salt aqueous solutions.
1.4.2 Susceptible pests
Woody plants and non-woody broadleaf plants. Little effect on
monocotyledonous species. Less effective than 2,4-D on some broadleaf,
but more effective on woody plants.
1.4.3 Use pattern
Selective control of weeds in cereal crops and lawns, nettles in
pasture and woody weeds in forestry, particularly with conifers. Mainly
used on non-edible crops. Types of treatment include foliage
treatment, basal bark treatment, stump treatment, frill treatment and
tree injection.
1.4.4 Unintended effects
Toxic to almost all broadleaf plants. Highly susceptible crops include
cotton, tomatoes, ornamentals, grapes and fruit trees. Danger of
contamination of irrigation ditches.
1.5 PUBLIC HEALTH PROGRAMMES
No known use.
1.6 HOUSEHOLD USE
Used in home gardens for broadleaf weed control in grass.
2, 4, 5-T
Part 2 - Toxicology and risks
Common name: 2,4,5-T
Data sheet No. 13
Date issued: March 1975
2.1 TOXICOLOGY - MAMMALS
2.1.1 Absorption route: Readily absorbed from the gastrointestinal
tract; also presumably absorbed if inhaled. Skin absorption is slight.
2.1.2 Mode of action: No information.
2.1.3 Excretion products
Single oral doses of (carboxy 14C) 2,4,5-T were administered to
groups of 3 male and 3 female adult Spague-Dowley rats and 2 male and 2
female adult beagle dogs.
The half-life values for the clearance of 14C activity from the
plasma of rats given doses of 5, 50, 100 or 200 mg/kg were 4.7,
4.2, 19.4 and 25.2 hours respectively. Urinary excretion of
unchanged 2,4,5-T accounted for most of the 14C activity eliminated
from the body of rats. A small amount of unidentified metabolite was
detected in the urine when rats were given 100 or 200 mg/kg but not 5
or 50 mg/kg. These results show that the distribution, metabolism and
excretion of 2,4,5-T are markedly altered when large doses are
administered. In dogs given 5 mg/kg, the half-life values for
clearance from the plasma and elimination from the body were 77.0 and
86.6 hours respectively. Appreciable excretion in the faeces was
noted and three unidentified metabolites were detected in urine of
dogs, indicating a considerable difference in metabolism of 2,4,5-T
by dogs and rats given the same dose.
2.1.4 Toxicity, single dose
Oral: LD50, rat 500 mg/kg
Dermal: No information
Most susceptible species: dog LD50 100 mg/kg
2.1.5 Toxicity, repeated doses
Oral: dogs survived a 90-day feeding test at 10 mg/kg for five days a
week; dogs died.
Inhalation: No information
Cumulation of compound: 2,4,5-T does not appear to accumulate in
mammalian tissues as judged by its rapid excretion.
Cumulation of effect: in the dog, the repeated daily dose necessary to
cause mortality is about one-fifth of the single dose, therefore, there
must be some accumulation of effect but the nature of this effect is
not known.
2.1.6 Dietary studies
Short-term: rats were fed diets adjusted so that they received 0, 3,
10, 30 or 100 mg/kg of 2,4,5-T daily for 90 days. Evidence of compound
related effects was minimal and limited to the animals given 30 and 100
mg/kg daily. Changes included depression in body-weight gain, slight
decrease in food intake and elevated serum alkaline phosphatase levels.
There were no effects at 3 or 10 mg/kg.
Long-term: No information
2.1.7 Supplementary studies of toxicity
Teratogenicity
Mouse: A significant increase in cleft palate and cystic kidney was
observed in the foetuses from pregnant mice which were given 46.4 or
113 mg/kg of 2,4,5-T (containing about 30 ppm of TCDD) orally on
gestation days 6 to 14 or 9 to 17 inclusive. A sample of 2.4,5-T
containing < O.1 ppm of TCDD was injected in dimethylsulfoxide solution
at a single dose level of 100 mg/kg on gestation days 6 to 15
inclusive. There was significant increase in incidence of cleft palate
and "kidney involvement". When a similar test was performed with
commercial 2,4,5-T containing about 0.5 ppm of TCDD there were no
adverse effects at 50 or 100 mg/kg but at 150 mg/kg there was increase
in the numbers of cleft palates and increased foetal mortality but no
"kidney involvement". Pure TCDD at doses of 1 or 3 µg/kg caused
"kidney involvement" in all tests but resulted in significant increases
in cleft palate and foetal mortality in some tests, not in others.
Rat: 2,4,5-T containing about 30 ppm of TCDD produced a significant
increase in foetal mortality and abnormal litters when administered
orally at 4.6 mg/kg on gestation days lo to 15 inclusive (the lowest
level tested). Cystic kidney appeared to be the major manifestation of
abnormality.
Increased foetal mortality but no terata resulted when 150 mg/kg of
TCDD free 2,4,5-T was administered orally to rats on days 13 and 14 of
gestation. In a separate study no teratogenic or embryotoxic effects
were observed when 2,4,5-T containing < 1 ppm of TCDD was administered
in levels up to 24 mg/kg on gestation days 6 to 15 inclusive. The no
effect level with respect to teratogenic effects in the rat from TCDD
alone when administered on gestation days 6 to 15 inclusive was 0.03
)ag/kg.
Rabbit: When 2,4,5-T containing < 1 ppm of TCDD was administered to
rabbits at a maximum dose level of 40 mg/kg on gestation days 6 to 18
inclusive there was no evidence of embryotoxic or teratogenic effects.
Hamster: Commercial samples of 2,4,5-T were foeticidal and
teratogenic in the hamster when administered orally on gestation days
6 to 10 inclusive, and the incidence of these effects The abnormalities
consisted chiefly of absence of eyelids increased with the content of
TCDD. and delayed head ossification.
Carcinogenicity
Mouse: There was no increase in tumour incidence in mice fed 60 ppm
(9.0 mg/kg/day) of 2,4,5-T for 18 months.
2.1.8 Modifications of toxicity
No information.
2.2 TOXICOLOGY - MAN
2.2.1 Dangerous doses
Single: No information. It has been stated that the oral dose
required to produce symptoms in man is probably 3-4 g.
Repeated: No information.
2.2.2 Observations of occupationally exposed workers
Extensive physical examinations revealed no differences between 130
employees engaged from 2 months to 3 years in the manufacture of 2,4,5-
T and a control group of 4600 men. When karyotyping was carried out on
52 exposed men, there was no indication that 2,4,5-T exposure had
affected the structural integrity or rearranged the genetic material of
the lymphocyte chromosomes. Sporadic outbreaks of severe acne have
been encountered in workers in chemical plants where 2,4,5-
trichlorophenol (a precursor in the manufacture of 2,4,5-T) is
manufactured or used. It is stated that one of the agents responsible
is TCDD.
In another study there was a moderately high incidence of urinary
porphyria, chloracne and hirsutism in workers employed in factories
manufacturing chlorinated phenols. A study of 73 male employees was
made in a 2,4,5-T factory. Chloracne was found in 13 (18%) of the
workers.
2.2.3 Observations of exposure of the general population
No substantiated information, although there have been allegations that
a rise in congenital abnormalities has been coincidental with use of
2,4,5-T. No dose relation has been demonstrated nor is the TCDD
content of the batches known.
2.2.4 Observations of volunteers
Five human male volunteers ingested a single dose of 5 mg/kg.
Concentrations of 2,4,5-T in plasma and its excretion were measured at
intervals after ingestion. The clearance of 2,4,5-T from the plasma as
well as its excretion from the body occurred via apparent first order
rate processes with half-lives of 23.60 and 23.06 hours respectively.
Essentially all of the 2,4,5-T was absorbed into the body and excreted
unchanged in the urine. In the body, 65% of the 2,4,5-T resided in the
plasma where 98.7% was bound reversibly to protein.
2.2.5 Reported mishaps
No information.
2.3 TOXICITY TO NON-MAMMALIAN SPECIES
2.2.1 Fish
Toxic to fish.
2.3.2 Birds
Low toxicity.
2.3.3 Other species
Toxicity to bees is low.
Toxicity to all species is increased if the level of TCDD impurity (see
Section 1.1) exceeds a few ppm.
2,4,5-T
Part 3 - For regulatory authorities
Common name: 2,4,5-T
Data sheet No. 13
Date issued: March 1975
RECOMMENDATIONS ON REGULATION OF COMPOUND
3.1 RECOMMENDED RESTRICTIONS ON AVAILABILITY
All formulations - (for definition of categories see introduction)
Liquids formulations over 25% category 4, neat solid formulations
category 4. All other formulations, category 5.
3.2 TRANSPORTATION AND STORAGE
All formulations
Should be transported or stored in clearly labelled impermeable
containers under lock and key and out of reach of children and away
from containers of food and drink.
3.3 HANDLING
All formulations
Protective clothing (see part 4) should be provided for those handling
the compound. Adequate washing facilities should be available close at
hand. Eating, drinking and smoking should be prohibited during
handling and before washing after handling.
3.4 DISPOSAL AND/OR DECONTAMINATION OF CONTAINER
If not decontaminated, container must either be burned or crushed and
buried below topsoil. Care must be taken to avoid subsequent
contamination of water sources. Container may be decontaminated (for
method, see paragraph 4.3 or part 4). Decontaminated containers should
not be used for food and drink.
3.5 SELECTION, TRAINING AND MEDICAL SUPERVISION OF WORKERS
All formulations
Pre-employment medical examination of workers desirable. Women in
their reproductive years and particularly pregnant women should be
excluded from contact.
3.6 ADDITIONAL REGULATIONS RECOMMENDED IF DISTRIBUTED BY AIRCRAFT
Pilot and loaders should have special training in application methods.
Flagmen, if used, should wear overalls and be located well away from
the dropping zone.
3.7 LABELLING
Minimum cautionary statement
"Keep well away from foodstuffs, animal feed and their containers."
3.8 RESIDUES IN FOOD
Residue levels have not been recommended by the Joint FAO/WHO meeting
on Pesticide Residues.
2, 4, 5-T
Part 4 - Prevention of poisoning in man and emergency aid
Common name: 2.4,5-T
Data sheet No. 13
Date issued: March 1975
4.1 PRECAUTIONS IN USE
4.1.1 General
2,4,5-T is a chlorinated phenoxy acid herbicide of moderate toxicity.
It is rapidly absorbed by the gastrointestinal tract and is also
presumably absorbed if inhaled, but skin absorption is slight. After it
is ingested it is rapidly excreted as soluble salts in the urine.
4.1.2 Manufacture and formulation
T.L.V.
(ACGIH) 10 mg/m3; (USSR).
Although volatility is low, vapour and dusts should be controlled
preferably by mechanical means. Protective equipment for the skin and
respiratory protection is usually necessary.
4.1.3 Mixers and applicators
When opening the container and when mixing, care should be taken to
avoid contact with the mouth and eyes. If necessary, a facial visor
should be worn. Mixing, if not mechanical, should always be carried
out with a paddle of appropriate length. The applicator should avoid
working in spray mist and avoid contact with the mouth. Splashes
should be washed immediately from the skin or eyes with large
quantities of water. Before eating, drinking or smoking, hands and
other exposed skin should be washed.
4.1.4 Other associated workers (including flagmen in aerial operations)
Persons exposed to 2,4,5-T and associated with its application should
observe the precautions described above in 4.1.3 under "mixers and
applicators".
4.1.5 Other populations likely to be affected
With good agricultural practice subject to 4.2 below, other populations
should not be exposed to hazardous amounts of 2,4,5-T.
4.2 ENTRY OF PERSON INTO TREATED AREAS
Pregnant women are advised not to enter sprayed areas.
4.3 DECONTAMINATION OF SPILLAGE AND CONTAINERS
Residues in containers should be emptied in a diluted form into a deep
pit taking care to avoid ground waters. The empty container may be
decontaminated by rinsing two or three times with water and scrubbing
the sides. An additional rinse should be carried out with 5% sodium
hydroxide solution which should remain in the container overnight.
Impermeable gauntlets should be worn during this work and a soakage pit
should be provided for the rinsings. Decontaminated containers should
not be used for food and drink. They should also never be used even
temporarily for transfer mixing or storage of other pesticides intended
for use on plants. Spillage of 2,4,5-T should be removed by washing
with 5% sodium hydroxide solution and then rinsing with large
quantities of water.
4.4 EMERGENCY AID
4.4.1 Early symptoms of poisoning
Information on the symptoms of 2,4,5-T poisoning is very limited. There
will probably be weakness and perhaps lethargy with anorexia and
diarrhoea. Muscle weakness may be present and may involve the muscles
of mastication and swallowing.
4.4.2 Treatment before person is seen by a physician if these symptoms
appear following exposure
If the pesticide has been ingested, vomiting should be induced.
2,4,5-T
Part 5 - For medical and laboratory personnel
Common name: 2,4,5-T
Data sheet No. 13
Date issued: March 1975
5.1 MEDICAL DIAGNOSIS AND TREATMENT OF CASES OF POISONING
5.1.1 General information
2,4,5-T is a phenoxy acetic acid herbicide of moderate toxicity. It is
rapidly absorbed by the gastrointestinal tract and is also presumably
absorbed if inhaled but skin absorption is slight. It is rapidly
excreted as soluble salts in the urine and does not persist in body
tissues.
5.1.2 Symptoms and signs
Information on the signs and symptoms of poisoning by 2,4,5-T are very
limited. There will probably be weakness and perhaps lethargy with
anorexia and diarrhoea. Muscle weakness may be present and may involve
the muscles of mastication and swallowing. More serious symptoms may
be ventricular fibrillation and/Or cardiac arrest and death. Following
prolonged exposure to 2,4,5-T, and its precursors, chlorvaine,
hirsutism and urinary porphyri have been reported.
5.1.3 Laboratory
The presence of 2,4,5-T or its salts in urine is indicative of
absorption, but sophisticated laboratory facilities are required.
5.1.4 Treatment
If 2,4,5-T has been ingested, unless the patient is vomiting, gastric
lavage should be performed with 2-3 litres of tap water. Other
treatment should be supportive.
5.1.5 Prognosis
Not known.
5.1.6 References of previously reported cases
No information. The description of symptoms is based on human
observations with related compounds (e.g. 2,4-D) and upon animal
studies performed with 2,4,5-T.
5.2 SURVEILLANCE TESTS
There are no practical surveillance tests.
5.3 LABORATORY METHODS
References are given only.
5.3.1 Detection and assay of compound
A microcoulometric gas-chromatographic method for determining 2,4,5-T
and its propylene glycol butyl ester after conversion to the methyl
ester, at levels down to 0.05 ppm in animal tissue, blood and urine is
given by Clark (1969). The method should be adaptable to other esters
and other substrates. Gas chromatography has been used to determine
2.4,5-T in water (Hindin, 1964) and apples (Edgerton & Lisk, 1963).
Other gas chromatography methods are given by Zweig & Sherma (1972).
Clean-up procedures are described by the US Food and Drug
Administration (1971).
5.3.2 Other tests in cases of poisoning
None.
REFERENCES
Clark, D. E. (1969) Determination of 2,4,5-trichlorophenoxyacetic acid
and its propylene glycol butyl ether esters in animal tissue,
blood and urine, Agric. Fd. Chem., 17, 1168
Edgerton, L. J. & Lisk, D. L. (1963) Determination of residues of
2,4,5-trichlorophenoxyacetic acid in apples by radioisotope and
gas chromatographic methods, Proc. Amer. Soc. Hort. Sci., 83,
120
Hindin, E., May, D.S. & Dunstan, G. H. (1964) Collection and analysis
of synthetic organic pesticides from surface and ground water,
Residue Reviews, 7, 130
US Food and Drug Administration (1971) Pesticide Analytical Manual,
Vol. I, Sections 221, 222
Zweig, G. & Sherma, J. (1972) In: Zweig, G., ed., Analytical Methods
for Pesticides, Plant Growth Regulators and Food Additives,
Vol. VI, Academic Press, New York and London, pp. 633, 702