dicrotophos (Bidrin) Chemical Profile 4/85
CHEMICAL NAME: 3-(dimethoxy-phosphinyloxy)-N,N-dimethylcis-
DEC INGRED. CODE:
TRADE NAME(S): Bidrin (56)
FORMULATION(S): 240 grams/liter water soluble concentrate and ULV spray.
Shell Chemical Co. formulates an 82% w/w water-miscible product, Bidrin 8
water miscible insecticide (56).
TYPE: Organophosphate insecticide
BASIC PRODUCER(S): Shell Chemical Co.
Div. of Shell Oil
P.O. Box 3871
Houston, TX 77001
STATUS: Restricted use
PRINCIPAL USES: Contact and systemic on ornamentals and fruit crops (1).
Used to control certain economically important pests of cotton. Also for
coffee borer control. Dicrotophos available for control of elm bark
beetles (tree injection system). Enters plant tissue rapidly, thus
enabling many beneficial insects to survive (56).
Important Pests Controlled: Aphids, mites, thrips, fleahoppers,
grasshoppers, boll weevils, lygus bugs, rice stemborers, bollworms,
leafminers, stinkbugs, leafhoppers and many others (8a).
Fast acting. More than 50% of the material is absorbed into the
plant within 8 hours of application. 7-21 days control can be expected
II. PHYSICAL PROPERTIES
MOLECULAR FORMULA: C8 H16 NO5 P (62)
MOLECULAR WEIGHT: 237.2 (62)
PHYSICAL STATE: Yellowish liquid (pure compound); amber liquid
(technical grade, contains about 85% (E)-isomer)
BOILING POINT: 130 C/0.1 mmHg (pure compound); 400 C/760 mmHg
(technical grade) (62).
VAPOR PRESSURE: 9.3 mPa at 20 C (pure compound); 13 mPa at 20 C
(technical grade) (62).
SOLUBILITY: Totally miscible with water (technical grade) (62)
III. HEALTH HAZARD INFORMATION
OSHA STANDARD: None established
NIOSH RECOMMENDED LIMIT: None established
ACGIH RECOMMENDED LIMIT: TWA (Time Weighted Average) = 0.25 mg/m3; skin
A. ACUTE TOXICITY
DERMAL: LD50 for rats ranges from 111-136 mg/kg to 148-181
mg/kg, depending on the carrier and the conditions of
the test; for rabbits 224 mg/kg, slight irritant to
their skin (62).
ORAL: LD50 = 22 mg/kg (rat) (15b)
LD50 = 17-22 mg/kg (rat) (62)
INHALATION: One hour exposure to 910 mg/m3 technical and 2.62
mg/L of 38% dicrotophos was fatal in 80 and 20% of
male rats respectively. Exposure to concentrations
of 0.61 mg/L technical or 2.12 mg/L of 38%
dicrotophos resulted in illness with rapid recovery
on removal from exposure (15b).
LC50 (4-hr) c.90 mg/m3 air (62).
EYES: Slight irritant to eyes of rabbits (62).
B. SUBACUTE AND CHRONIC TOXICITY:
Rats were fed dicrotophos at concentrations of 0, 1, 10 and 100
ppm in their diets for two years. There were no detectable effects at
the 1 ppm concentration. At the higher concentrations there were
effects such as decreased body weights (in comparison to controls) or
reduced cholinesterase concentrations (15b).
Dogs given dicrotophos in their diets at 0, 0.16, 1.6, and 16 ppm
for 2 years showed some instances of slight excessive salivation and at
the 100 ppm concentration fairly consistent excessive salivation, soft
stools and/or tremors. There were no other differences between treated
animals and controls up to the 16 ppm concentration. At 16 ppm
cholinesterase concentration, both plasma and erythrocyte, was decreased
NEL in a 3-generation reproduction study with rats was 2 mg/kg
daily. It is not neurotoxic to hens (62).
IV. ENVIRONMENTAL CONSIDERATIONS
Some hazard to birds, fish, and beneficial insects. Hazardous to
honey bees. Biological magnification unknown. Nonphytotoxic except
for some varieties of grain seed (1).
Dicrotophos is a hydrophilic compound and was shown to be leachable
through soil (Corey 1965). C14-dicrotophos was shown to breakdown
rapidly in a moist (50% field capacity) sandy loam soil, only 18.5% being
recovered after seven to eight days. The rate of breakdown increased
with the moisture content. The hydrolysis of dicrotophos is slow in
water, suggesting that biological degradation might be important in soil.
In field soils (Elgar and MacDonald 1966), dicrotophos (applied as
granules, not incorporated) had an initial half-life of a few days and
monocrotophos residues were not detected at the 0.1-ppm level after eight
weeks from application of dicrotophos at up to eight lb./A (35).
Dicrotophos is relatively stable in neutral or acid solution. It is
more prone to hydrolysis in alkali than in acid, although less so than
many organophosphate insecticides. It was recovered (>95%) unchanged
after two hours in sodium carbonate solution (0.25%, pH 11.5) under
conditions where nine other insecticides showed greater loss (Sun and
Johnson 1965) (35).
LC50 (24-hr) is: for mosquito fish 200 mg/l; for harlequin fish
>1000 mg/l. It is very toxic to honey bees but because surface residues
rapidly decline little effect is seen in practice. Acute oral LD50 for
birds 1.2-12.5 mg/kg (62).
Approximate Residual Period: As systemic lasts 7 to 21 days (1).
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
FREQUENT SYMPTOMS AND SIGNS OF POISONING BY ORGANOPHOSPHATE PESTICIDES
Symptoms of acute poisoning develop during exposure or within 12
hours (usually within four hours) of contact. HEADACHE, DIZZINESS,
WEAKNESS, INCOORDINATION, MUSCLE TWITCHING, TREMOR, NAUSEA, ABDOMINAL
CRAMPS, DIARRHEA, and SWEATING are common early symptoms. Blurred or
dark vision, confusion, tightness in the chest, wheezing, productive
cough, and PULMONARY EDEMA may occur. Incontinence, unconsciousness
and convulsions indicate very severe poisoning. SLOW HEARTBEAT,
salivation, and tearing are common. TOXIC PSYCHOSIS, with manic or
bizarre behavior, has led to misdiagnosis of acute alcoholism. Slowing
of the heartbeat may rarely progress to complete sinus arrest.
RESPIRATORY DEPRESSION may be fatal. Continuing daily absorption of
organophosphate at intermediate dosage may cause an INFLUENZA-LIKE
ILLNESS characterized by weakness, anorexia, and malaise (25).
SKIN CONTACT: If the patient's skin is in contact with Bidrin,
take steps to prevent continuing exposure. If the insecticide has been
spilled or splashed onto the clothes or the skin, remove the
contaminated clothing immediately and wash the skin thoroughly with
soap and water; use lots of water in rinsing. Get medical attention
INGESTION: Induce vomiting immediately by giving 2 tablespoons
of Syrup of Ipecac and 2 glasses of water to an adult. For a child
give 1 tablespoon plus 1 glass water. If Syrup of Ipecac not
available, give 2 glasses of water and tickle the back of the throat
with a finger. If not successful at inducing vomiting, do not waste
time with further attempts. Get medical attention (18b).
INHALATION: Remove patient to fresh air. Get medical attention
EYE CONTACT: Wash out eyes immediately. Flush the eyes
continuously with running water for 15 minutes and get medical attention
NOTES TO PHYSICIAN:
Administer ATROPINE SULFATE intravenously, or intramuscularly, if IV
injection is not possible.
In MODERATELY SEVERE poisoning: Adult dosage: 0.4-2.0 mg repeated
every 15 minutes until atropinization is achieved: tachycardia (pulse
of 140 per minute), flushing, dry mouth, dilated pupils. Maintain
atropinization by repeated doses for 2-12 hours or longer depending on
severity of poisoning.
Dosage for children under 12 years: 0.05 mg/kg body weight, repeated
every 15 minutes until atropinization is achieved. Maintain
atropinization with repeated dosage of 0.02-0.05 mg/kg.
SEVERELY POISONED individuals may exhibit remarkable tolerance to
atropine; two or more times the dosages suggested above may be needed.
Administer PRALIDOXIME (Protopam (TM)-Ayerst, 2-PAM) in cases of severe
poisoning in which respiratory depression, muscle weakness and
twitchings are severe.
Adult dosage: 1.0 gm intravenously at no more than 0.5 gm per minute.
Child's dose (under 12 years): 20-50 mg/kg (depending on severity of
poisoning) intravenously, injecting no more than half the total dose
Dosage of pralidoxime may be repeated in 1-2 hours, then at 10-12 hour
intervals if needed. In very severe poisonings, dosage rates may be
VI. FIRE AND EXPLOSION INFORMATION
Bidrin will burn if exposed to an ignition source. When exposed to
excessive heat from a fire, containers may rupture violently, releasing
toxic and noxious vapors which would be injurious by inhalation or by
skin contact. Adjacent Bidrin should be kept cool, if possible, by use
of water spray (18b).
Generally compatible, but not ordinarily used with other materials
VIII. PROTECTIVE MEASURES
STORAGE AND HANDLING: Do not swallow or get into eyes, on skin, or on
clothing. Do not breathe vapors. Not for use or storage in or around
home. Do not contaminate food or feed products. Keep away from heat
and open flame (56).
PROTECTIVE CLOTHING: Clean, liquid-resistant protective clothing --
including rubber gloves, boots, body covering, and hat -- as required.
Rubber gloves should be replaced frequently and the discarded gloves
destroyed to prevent reuse (18b).
PROTECTIVE EQUIPMENT: Goggles. If engineering controls are inadequate
or cannot be applied, respirators should be used to prevent inhalation
of vapors or mist. Follow OSHA rules and regulations regarding
respiratory protection (18b).
IX. PROCEDURES FOR SPILLS AND LEAKS
IN CASE OF EMERGENCY, CALL, DAY OR NIGHT
PESTICIDE TEAM SAFETY NETWORK/CHEMTREC
Immediately isolate the affected area and keep out unauthorized
personnel. Cleanup should be handled by trained and properly equipped
pesticide decontamination personnel (18b).
X. LITERATURE CITED
1. Harding, W.C. 1979. Pesticide profiles, part one: insecticides
and miticides. Univ. Maryland, Coop. Ext. Serv. Bull. 267.
8a. Thomson, W. T. 1976. Agricultural chemicals - book 1:
insecticides, acaricides, and ovicides. Revised ed. Thomson
Publ., Indianapolis, IN. 232 pp.
15b. American Conference of Governmental Industrial Hygienists. 1971.
Documentation of the threshold limit values for substances in
workroom air with supplements for those substances added or
changed since 1971, 3rd ed., 4th printing (1977). Cincinnati,
OH. 484 pp.
15c. American Conference of Governmental Industrial Hygienists. 1984.
TLVs: threshold limit values for chemical substances and
physical agents in the work environment and biological exposure
indices with intended changes for 1984-85. Cincinnati, OH.
18b. Shell Chemical Company. 1981. Agricultural chemicals safety
manual: Bidrin insecticide safety guide. Houston, TX.
25. Morgan, D.P. 1982. Recognition and management of pesticide
poisonings, 3rd ed. U.S. Environmental Protection Agency,
Washington, DC. 120 pp.
35. Beynon, K.I., D.H. Hutson, and A.N. Wright. 1973. The
metabolism and degradation of vinyl phosphate
insecticides. Residue Rev. 47:55-142.
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.
62. The Pesticide Manual: A World Compendium, 7th ed. 1983. C.R.
Worthing, ed. The British Crop Protection Council, Croydon,
England. 695 pp.