WORLD HEALTH ORGANIZATION FOOD AND AGRICULTURE
ORGANIZATION
ORGANISATION MONDIALE DE LA SANTE ORGANISATION POUR L'ALIMENTATION
ET L'AGRICULTURE
WHO/VBC/DS/87.78
ORIGINAL: ENGLISH
Distr.: LIMITED
DATA SHEETS ON PESTICIDES No. 78
PROPACHLOR
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.
CLASSIFICATION:
Primary Use: Herbicide
Secondary Use:
Chemical Group: Acetanilide
1.0 GENERAL INFORMATION
1.1 COMMON NAME
Propachlor (BSI, ISO and WSSA)
1.1.1 Identity
IUPAC: 2-chloro-N-isopropylacetanilide
CAS: 2-chloro-N-(1-methylethyl)-N-phenylacetamide
CAS Reg. No.: 1918-16-7
Molecular formula: C11H14ClNO
Molecular weight: 211.7
Structural formula:
1.1.2 Synonyms
BextonR; Bexton 4LR; Kartex AR; NiticidR; propachlore;
RamrodR; SatecidR; CP 31393.
1.2 SYNOPSIS
Propachlor is a pre-emergence herbicide used against annual
grasses and certain broad-leaved weeds. Soil persistance can range
from 28 to 42 days post-spraying. Propachlor is slightly toxic and
the technical product is listed in WHO Hazard Class III.
1.3 SELECTED PROPERTIES
1.3.1 Physical characteristics
Propachlor is a light tan or white crystalline solid. It has a
melting point of 67-76°C, a boiling point of 110°C at 0.03 mmHg and
a density of 1.13 g/ml at 25°C.
1.3.2 Solubility
Its water solubility is 700 mg/l at 20°C; readily soluble in
most organic solvents except aliphatic hydrocarbons.
1.3.3 Stability
Indefinitely stable, not sensitive to light; resistant to
photo-decomposition.
1.3.4 Vapour pressure
2.3 x 10-4 mmHg at 25°C.
1.4 AGRICULTURE, HORTICULTURE AND FORESTRY
1.4.1 Common formulations
These include a wettable powder (650 g a.i./kg) and granules
(200 g a.i./kg).
1.4.2 Pests controlled
Annual grasses and certain broad-leaved weeds.
1.4.3 Use pattern
Used on maize, cotton, soyabeans, sugarcane, sorghum, sugar
beets and vegetable crops at 3.5-5.0 kg a.i./ha.
1.4.4 Unintended effects
No information available.
1.5 PUBLIC HEALTH USE
No recommended use.
1.6 HOUSEHOLD USE
No recommended use.
2.0 TOXICOLOGY AND RISKS
2.1 TOXICOLOGY - MAMMALS
2.1.1 Absorption
Propachlor may be absorbed through the gastrointestinal tract;
through the intact skin; or by inhalation of dust or spray mist.
2.1.2 Mode of action
Propachlor has been reported to cause dystrophic changes in
liver and kidneys of rats, mice and rabbits at oral doses of 100-
1800 mg/kg, accompanied by decreased enzyme activities.
2.1.3 Excretion products
Propachlor is metabolized via the mercapturic acid pathway.
Eleven urinary metabolites, six of which are 2-
methylsulfonylacetanalides have been isolated. The major fecal
metabolite is identified as the cysteine conjugate. Rats given 14C
propachlor orally excreted 98.6% of dose in the urine and feces
within 48 hours.
2.1.4 Toxicity, single dose
Oral LD50:
Rat 710 mg/kg b.w.
Mouse 290 mg/kg b.w.
Rabbit 710 mg/kg b.w.
Following oral and percutaneous administration of propachlor,
increased bromosulphalein retention was seen. The liver demonstrated
leukocyte infiltration in peripherolobular zones and focal necrosis.
Dermal LD50:
Rabbit 380 mg/kg b.w. (10.4% suspension in water)
Propachlor causes severe dermatitis, ulceration and necrosis of
the skin in rabbits and mice.
Inhalation LC50:
Rats 3580 mg/m3 (60% w.p.
Inhalation of w.p. dust for four hours caused inflammation of
tracheal mucosa, 25% mortality, and haemorrhagic secretions in lungs
and bronchi. Effective threshold concentration was 136-456 mg/m3.
Eye irritation: Minimum concentration of 0.01% 6.5g/kg w.p.
in rats caused conjunctivitis.
2.1.5 Toxicity, repeated doses
No information available.
2.1.6 Dietary studies
Short term: Ninety-day rat and dog studies showed no
observable effects at 1.3, 13.3 and 133.3 mg/kg bw/day except for a
9% reduction in weight gain in rats at ]33.3 mg/kg bw/day.
Four and six month studies in white rats with 1/20, 1/100 and
1/200 of the LD50 inhibited spermatopoiesis at the phase of
spermatid formation and caused histomorphologic changes in the
spermaopoietic epithelium.
Long term: No information available.
2.1.7 Supplementary studies of toxicity
Carcinogenicity: No information available.
Teratogenicity: No information available.
Reproduction: See section 2.1.6.
Mutagenicity: No induction of recessive lethality was
observed in Dropsophila. Propachlor at 10 mg/kg b.w. caused
increased aberrant metaphases (3 x control level) in mouse bone
marrow cells.
2.1.8 Modification of toxicity
No information available.
2.2 TOXICOLOGY - MAN
2.2.1 Absorption
Propachlor may be absorbed through the gastrointestinal tract,
through the intact skin or by inhalation of dust or spray mist
2.2.2 Dangerous doses
Single: Toxicity rating 2 (Gosselin), probably oral lethal
dose (man) 5-15 g/kg b.w.
Repeated: No information available.
2.2.3 Observations on occupationally exposed workers
Exposure to propachlor for eight days caused erythematopapular
contact eczema on hands and forearms of workers.
2.2.4 Observations on exposure of the general population
No information available.
2.2.5 Observations on volunteers
No information available.
2.2.6 Reported mishaps
No information available.
2.3 TOXICITY - NON-MAMMALIAN SPECIES
2.3.1 Fish
Fathead minnows 96 hr TLM 0.49 rag/1
Bluegill fingerlings 96 hr TLM 1.30 mg/1
2.3.2 Birds
Oral LD50 pheasants 735 mg/kg b.w.
Oral LC50 mallard ducks 5000 mg/1
bobwhite quail 5000 mg/1
2.3.3 Other species
No information available.
3.0 FOR REGULATORY AUTHORITIES - RECOMMENDATION ON REGULATION OF
COMPOUND
3.1 RECOMMENDED RESTRICTIONS ON AVAILABILITY
(For definition of categories see Introduction to data sheets)
All solid formulations over 38%, category 3
All other solid formulations, category 4
3.2 TRANSPORT AND STORAGE
Formulations in all categories: Should be transported in
clearly labelled, rigid and leakproof containers out of reach of
children, away from food and drink. Storage should be under lock and
key and secure from access by children and other unauthorized
persons.
3.3 HANDLING
Formulations in all categories: Protective clothing to shield
skin and eyes should be used by all handling the compound. Adequate
washing facilities should be available at all times during handling
and they should be close to the site of handling. Eating, drinking
and smoking should be prohibited during handling and before washing
hands and face.
3.4 DISPOSAL AND/OR DECONTAMINATION OF CONTAINERS
All formulations: Containers may be decontaminated (for
method see paragraph 4.3 of Part 4). Decontaminated containers
should not be used for food and drink. Containers that are not
decontaminated should be burned or should be crushed and buried well
below topsoil. Care must be taken to avoid subsequent contamination
of water sources.
3.5 SELECTION, TRAINING AND MEDICAL SUPERVISION OF WORKERS
Formulations in all categories: Special account should be
taken of the worker's ability to comprehend and follow instructions.
Training of workers in techniques to avoid contact is essential.
Pre-employment and periodic medical examinations are not required.
3.6 ADDITIONAL REGULATIONS RECOMMENDED IF DISTRIBUTED BY AIRCRAFT
All formulations: Pilots and loaders should have special
training in application methods
3.7 LABELLING
Formulations in categories 3 and 4, minimum cautionary
statement:
CAUTION - POISON
(skull and cross bones insignia)
This formulation contains propachlor which is a skin and eye
irritant, a dermal sensitizer and it may be poisonous if swallowed.
Keep the material out of reach of children and well away from
foodstuffs, animal feed and food containers.
3.8 RESIDUES IN FOOD
Maximum residue limits have been recommended by the Joint
FAO/WHO Meeting on Pesticide Residues.
4.0 PREVENTION OF POISONING IN MAN AND EMERGENCY AID
4.1 PRECAUTIONS IN USE
4.1.1 General
Propachlor is an acetanilide compound, a chlorinated tertiary
amide of slight toxicity to mammals. It is a skin and eye irritant,
a dermal sensitizer, and probably inhibits various enzymes at the
cellular level. It may be absorbed by inhalation of dust or spray
mist; through the gastrointestinal tract; and, through the intact
skin.
4.1.2 Manufacture and formulation - T.L.V.
No information. Closed systems and forced ventilation may be
required to reduce as much as possible the exposure of workers to
the chemical.
4.1.3 Mixers and applicators
When opening the container and when mixing, protective
impermeable boots, clean overalls, safety glasses, and gloves 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. Care is needed when equipment is being
washed after use. All protective clothing should be washed
immediately after use, including the insides of gloves. Splashes
must 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 the compound and associated with its
applications should wear protective clothing and observe the
precautions described above in 4.1.3 under "Mixers and applicators".
4.1.5 Other populations likely to be affected
With good application practice subject to 4.2 below, other
populations should not be exposed to hazardous amounts of
propachlor.
4.2 ENTRY OF PERSONS INTO TREATED AREAS
Unprotected persons should be kept out of treated areas until
the compound is dry
4.3 SAFE DISPOSAL OF CONTAINERS AND SPILLAGE
Residues in containers should be emptied in a diluted form into
a deep pit taking care to avoid contamination of ground water. The
empty container may be decontaminated by rinsing two or three times
with water and scrubbing the sides. Impermeable gauntlets should be
worn during this work and a soakage pit should be provided for the
rinsings. Refill container with water and allow to stand 24 hours.
Repeat twice. Obliterate label. Spillage of propachlor and its
formulations 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
Symptoms of poisoning include irritation and inflammation of
the skin, eyes, and mucous membranes. Other effects are unknown.
4.4.2 Treatment before a person is seen by a physician, if these
symptoms appear following exposure
The person should stop work immediately, remove contaminated
clothing and wash the affected skin with water and soap, if
available, and flush the area with large quantities of water. Take
to a physician. If swallowed call a physician and transport to
nearest hospital immediately.
5.0 FOR MEDICAL AND LABORATORY PERSONNEL
5.1 MEDICAL DIAGNOSIS AND TREATMENT IN CASES OF POISONING
5.1.1 General information
Propachlor is an acetanilide of moderate toxicity. It is
absorbed from the gastrointestinal tract, by inhalation and through
the intact skin. The mode of action is probably by inhibition of
various hepatic enzymes at the cellular level. This chlorinated
tertiary amide is a skin and eye irritant as well as a derma]
sensitizer.
5.1.2 Symptoms and signs
Except for dermatitis, no clinical or laboratory signs of
toxicity to man are known. Propachlor can be irritating to the skin
and eyes as well as a derma] sensitizer.
5.1.3 Laboratory
No information available.
5.1.4 Treatment
If the pesticide has been ingested, unless the patient is
vomiting, rapid gastric lavage should be performed with water,
followed by activated charcoal and a mild laxative. For skin
contact, the skin should be washed with soap and water. If the
compound has entered the eyes they should be washed with isotonic
saline or water. There is no specific antidote for propachlor
poisoning.
5.1.5 Prognosis
If the acute toxic effect is survived, recovery will be
uneventful.
5.1.6 References of previously reported cases
There have been no published reports of propachlor poisoning.
5.2 SURVEILLANCE TESTS
None indicated
5.3 LABORATORY METHODS
5.3.1 Detection and assay of compound
Caverley, D. J. and Denney, R. C. (1978), Analyst (London)
103 (1225), 368
Worley, J. W. et al. (1980), Anal. Chem. 52 (12), 1845
Ambrus, A. et al. (1981), J. Assoc. Off. Anal. Chem. 64(3),
743