siduron (Tupersan) Herbicide Profile 2/85
CHEMICAL NAME: 1-(2-Methylcyclohexyl)-3-phenylurea (56)
TRADE NAME(S): Tupersan (56)
FORMULATION(S): Wettable powder 50% for spray application; 70%
powder for manufacturing use. Various granulars and
mixtures with fertilizer and/or insecticides
available from formulators (56).
TYPE: Substituted urea herbicide
BASIC PRODUCER(S): E.I. duPont de Nemours and Co., Inc.
1007 Market St.
Wilmington, DE 19898
STATUS: General use
PRINCIPAL USES: Selectively controls certain germinating annual weed
grasses such as crabgrass (smooth and hairy), foxtail and barnyardgrass,
in newly seeded or established plantings of bluegrass, fescue, redtop,
smooth brome, perennial ryegrass, orchardgrass, zoysia, and the following
strains of bentgrass: PennCross, Seaside, Highland, Astoria, Nimisila,
C-1, C-7, and C-19. Should not be used on other bentgrass strains nor
on bermudagrass (58).
APPLICATION METHOD(S): Applied as a preemergence treatment to bare soil
as a final operation following spring seeding, or to new fall seedings
or established turf in the spring just before expected emergence of
annual weed grasses (58).
To be developed.
II. PHYSICAL PROPERTIES
MOLECULAR FORMULA: C14 H20 N2 O (62)
MOLECULAR WEIGHT: 232.3 (62)
PHYSICAL STATE: Colorless crystals (pure compound) (62);
light gray powder (Tupersan Weed Killer) (31o).
ODOR: Odorless (active ingredient) (31n)
MELTING POINT: 133-138 C (pure compound) (62)
VAPOR PRESSURE: Negligible (Tupersan Weed Killer) (31o); <8 x 10-4
mmHg at 100 C (pure compound) (58).
SOLUBILITY: 18 mg/l water at 25 C (pure compound) (62)
III. HEALTH HAZARD INFORMATION
OSHA STANDARD: NA
NIOSH RECOMMENDED LIMIT: NA
ACGIH RECOMMENDED LIMIT: NA
A. ACUTE TOXICITY
DERMAL: The maximum feasible dose (5500 mg/kg) applied to
intact or abraded skin of rabbits caused no sign of toxicity (62).
A 10% suspension in dimethyl phthalate was not irritating to
guinea pig skin. A 25% suspension was mildly irritating, while a 40%
suspension was moderately to strongly irritating. It did not produce
an allergic contact dermatitis (31n).
ORAL: LD50 = >7500 mg/kg (rat) (62)
B. SUBACUTE AND CHRONIC TOXICITY:
In two-year feeding studies, the no-observable effect level for
rats was 500 ppm; for dogs 2500 ppm (31n).
IV. ENVIRONMENTAL CONSIDERATIONS
TLM (48 hours) for carp is 18 ppm
TLM (48 hours) for Japanese goldfish is 10-40 ppm
TLM (48 hours) for loach is 10-40 ppm
TLM (48 hours) for tadpole is 10-40 ppm
TLM (72 hours) for crawfish is >40 ppm
TLM (3 hours) for water flea is >40 ppm
LC50 (8 day dietary) for both mallard duckling and bobwhite quail
greater than 10,000 ppm (31n).
Siduron resists leaching, remains in the top layer of soil, and
degrades at a moderate rate. Half-life in soil is 4 to 5 months (31n).
Adsorption of siduron increases as clay content and/or organic
matter content of soil increases; clays of high exchange capacity
adsorb more than those of low exchange capacity. The amount adsorbed
on Keyport silt loam in equilibrium with 1 ppm in soil solution at 22.5
C is 2.5 ppm. Siduron is very resistant to leaching. Movement is least
in soils high in clay and/or organic matter; greatest in sand.
Microbes are the primary factor in the disappearence from soils.
It has been demonstrated that certain soil microorganisms can
utilize siduron as their sole carbon source. Two bacterial and a
single fungal species capable of metabolizing siduron have been
isolated. The bacterial species were tentatively identified as
belonging to genus Pseudomonas, while the fungus was identified as
belonging to the group of Fungi Imperfecti.
After exposure in a thin film to full sunlight for 56 days,
siduron caused injury to germinating crabgrass identical with that
caused by a nonirradiated check sample. Chemical analysis also
verified that siduron was not decomposed by sunlight.
In studies over a 3-year period in a temperate climate under an
annual rainfall of about 45 inches, there has been no evidence of
residual chemical in the soil after 1 year, even with applications much
in excess of those required for weed control (58).
V. EMERGENCY AND FIRST AID PROCEDURES
The chemical information provided below has been condensed
from original source documents, primarily from "Recognition and
Management of Pesticide Poisonings", 3rd ed. by Donald P. Morgan,
which have been footnoted. This information has been provided in
this form for your convenience and general guidance only. In
specific cases, further consultation and reference may be required
and is recommended. This information is not intended as a sub-
stitute for a more exhaustive review of the literature nor for the
judgement of a physician or other trained professional.
If poisoning is suspected, do not wait for symptoms to develop.
Contact a physician, the nearest hospital, or the nearest Poison
KNOWN OR SUSPECTED ADVERSE EFFECTS: Many substituted ureas are
moderately irritating to skin, eyes, and mucous membranes (25).
SKIN CONTACT: Wash contaminated skin with soap and water (25).
INGESTION: Ingestions of small amounts (less than 10 mg/kg
body weight) occurring less than an hour before treatment, are probably
best treated by: Syrup of Ipecac, followed by 1-2 glasses of water.
Dose for adults and children over 12 years: 30 ml. Dose for children
under 12 years: 15 ml (25).
EYE CONTACT: Flush contaminated eyes with copious amounts of
fresh water for 15 minutes (25).
NOTES TO PHYSICIAN:
INGESTIONS of LARGE amounts (more than 10 mg/kg) occurring less than an
hour before treatment, should probably be treated by gastric lavage:
A. INTUBATE stomach and ASPIRATE contents.
B. LAVAGE stomach with slurry of ACTIVATED CHARCOAL IN 0.9% saline.
Leave 30-50 gm activated charcoal in the stomach before
C. SODIUM SULFATE, 0.25 gm/kg in tap water, as a cathartic.
CAUTION: Hydrocarbons (kerosene, petroleum distillates) are
included in some formulations of these chemicals.
Ingestion of very LARGE AMOUNTS may cause CNS
depression. In this case, IPECAC IS CONTRAINDICATED.
Also, gastric intubation incurs a risk of HYDROCARBON
PNEUMONITIS. For this reason observe the following
(1) If the victim is unconscious or obtunded and
facilities are at hand, insert an ENDOTRACHEAL TUBE
(cuffed, if available) prior to gastric intubation.
(2) Keep victim's HEAD BELOW LEVEL OF STOMACH during
intubation and lavage (Trendelenburg, or left
lateral decubitus, with head of table tipped
downward). Keep victim's head turned to the left.
(3) ASPIRATE PHARYNX as regularly as possible to remove
gagged or vomited stomach contents.
INGESTIONS occurring MORE THAN an HOUR before treatment are probably
best treated only by ACTIVATED CHARCOAL, 30-50 gm, and SODIUM or
MAGNESIUM SULFATE, 0.25 gm/kg, as described above.
There are no specific antidotes for these chemicals. Because
manifestations of toxicity do occasionally occur in peculiarly
predisposed individuals, MAINTAIN CONTACT with victim for at least 72
hours so that unexpected adverse effects can be treated promptly (25).
VI. FIRE AND EXPLOSION INFORMATION
GENERAL: May be ignited by heat or open flame. Fine dust dispersed in
air (particularly in confined spaces) may ignite if exposed to high
temperature ignition source. These conditions are unlikely to occur in
normal, outdoor use of this product (Tupersan Weed Killer) (31o).
EXTINGUISHER TYPE: On a small fire use dry chemical, CO2, foam or
water spray. If area is heavily exposed to fire and if conditions
permit, let fire burn itself out since water may increase the
contamination hazard. If conditions do not permit, extinguish with
water spray. If conditions permit, cool containers with water if
exposed to fire. Wear self-contained breathing apparatus (31o).
To be developed.
VIII. PROTECTIVE MEASURES
STORAGE AND HANDLING: Store in a cool, dry place. Do not contaminate
water, food, or feed by storage or disposal. Do not reuse container.
Bury empty container or product that cannot be used in a safe place
away from water supplies or dispose of by alternative procedures
recommended by federal, state, or local authorities. Open dumping is
prohibited. Avoid contact with skin, eyes, and clothing (56).
IX. PROCEDURES FOR SPILLS AND LEAKS
IN CASE OF EMERGENCY, CALL, DAY OR NIGHT
PESTICIDE TEAM SAFETY NETWORK/CHEMTREC
Clean up promptly. Do not flush with water, pick up dry by
sweeping or other effective means (Tupersan Weed Killer) (31o).
X. LITERATURE CITED
25. Morgan, D.P. 1982. Recognition and management of pesticide
poisonings, 3rd ed. U.S. Environmental Protection Agency,
Washington, DC. 120 pp.
31n. E. I. du Pont de Nemours and Co., Inc., Biochemicals Department.
1979. Technical data sheet: siduron. Wilmington, DE.
31o. E. I. du Pont de Nemours and Co., Inc., Biochemicals Department.
1977. Material safety data sheet for Tupersan Weed Killer.
56. Farm Chemicals Handbook, 70th ed. 1984. R. T. Meister, G. L.
Berg, C. Sine, S. Meister, and J. Poplyk, eds. Meister
Publishing Co., Willoughby, OH.
58. Weed Science Society of America, Herbicide Handbook Committee.
1983. Herbicide handbook of the weed science society of
America, 5th ed. Weed Science Society of America, Champaign,
IL. 515 pp.
62. The Pesticide Manual: A World Compendium, 7th ed. 1983. C.R.
Worthing, ed. The British Crop Protection Council, Croydon,
England. 695 pp.