Adverse Effects
CAS No. 115-26-4

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Activity: Acaracide, Insecticide (organophosphate)

NOTE: WHO: Believed to be obsolete or discontinued for use as pesticides. (Note from FAN: it is permitted for use in India).

Adverse Effects:

November 26, 2002 - European Commission: Dimefox is one of 320 pesticides to be withdrawn in July 2003. "Some 320 substances used in plant protection products (PPPs) including insecticides, fungicides and herbicides are to be withdrawn from the market by 25 July 2003 as part of the European Commission's new approach to the evaluation of active substances in plant protection products.

A highly toxic cholinesterase inhibitor.
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 542]

The no-effect dosage of dimefox based on the most sensitive criterion, red cell cholinesterase, is 0.002 mg/kg/day in humans.
[Hayes, W.J., Jr., E.R. Laws, Jr., (eds.). Handbook of Pesticide Toxicology. Volume 2. Classes of Pesticides. New York, NY: Academic Press, Inc., 1991. 974]

/FROM TABLE/ [Sunshine, I. (ed.). CRC Handbook of Analytical Toxicology. Cleveland: The Chemical Rubber Co., 1969. 563]

Ref: mainly from: Profile for Dimefox from Hazardous Substances Data Base.

Brain (click on for all fluorinated pesticides)

Abstract: The toxicological effects of schradan (152169), dimefox (115264), and parathion (56382) were investigated in rats, pigs, and humans. Schradan was given to rats on diet at concentrations from 0.05 to 5.0 parts per million (ppm) or by intraperitoneal (ip) injection of 0.007 to 2.5 milligrams per kilogram (mg/kg). Pigs were fed 0.1 to 2.5ppm in diet. Human subjects were given 1.4mg 5 days per week to a total of 44mg. Brain and plasma cholinesterase (ChE) were determined in animals. Blood ChE was determined in humans. Rats were fed 0.01 to 5.0ppm dimefox in diets for 28 to 287 days. Pigs received 0.005 to 0.5ppm for 133 days. Humans were given oral doses of 0.0014mg/kg for 14 days, then 0.004mg/kg for 95 days, or 0.0012, 0.002, or 0.0034mg/kg for 70 days. Inhibition of ChE was determined. For parathion, rats were fed 0.05, 0.5, or 5.0ppm in diet for 84 days. Pigs were fed 0.02 to 100ppm in increasing doses from 33 to 122 days. Humans received oral doses of 0.6mg per day until week 4, then increased to 4.8mg to week 13; 7.2mg for 6 weeks; or 1.2 or 2.4mg for 25 to 70 weeks. ChE inhibition was determined. The no effect concentrations were determined for each of the compounds. For schradan, the no effect dose was 0.02mg/kg per day for rats and pigs. In man, 3ppm presented no hazard. Based on changes in red cell ChE, the no effect concentrations of dimefox were 0.003, 0.006, and 0.002mg/kg per day for rat, pig, and man, respectively. Obvious ill effects or illness in man would occur at about 100 times that concentration...
Ref: Edson EF (1964). Summaries of Toxicological Data. No-Effect Levels of Three Organophosphates in the Rat, Pig and Man. Food and Cosmetics Toxicology, Vol. 2, pages 311-316. Abstract available at FAN's abstracts for Dimefox:

Excerpt from abstract: The neurobehavioral toxicity of the organophosphate pesticides sumithion (122145), dimefox (115264), and trichlorphon (52686) was evaluated in rats. Rats were administered perorally 10 milligrams per kilogram per day (mg/kg/day) sumithion, 0.25mg/kg/day dimefox... Acetylcholinesterase activity decreased significantly in the case of dimefox
Ref: Lehotzky K (1982). Effect Of Pesticides On Central And Peripheral Nervous System Function In Rats. Neurobehavioral Toxicology and Teratology, Vol. 4, No. 6, pages 665-669. Abstract available at FAN's abstracts for Dimefox:

CNS (click on for all fluorinated pesticides)

Abstract: The neurobehavioral toxicity of three organophosphate pesticides, sumithion, dimefox and trichlorphon, was evaluated in rats using measures of open field activity, rotorod performance, conditioned escape from shock, and nerve conduction velocity. These measures were correlated with blood and brain cholinesterase level determinations. All three chemicals disrupted behavior ranging from transient disruptions accompanied by alterations in nerve conduction to disruption throughout the exposure. Even in the case of prolonged behavioral disruption, however, some recovery of performance occurred. Cholinesterase in both blood and brain decreased with initial dosing and remained low with continued dosing regardless of changes in the behavioral measures. The results are discussed in terms of the necessity of using mammalian behavioral tests to determine the toxicity of organophosphorous compounds in order to safeguard the health of the human population.
Ref: Lehotzky K (1982). Effect of pesticides on central and peripheral nervous system function in rats. Neurobehav Toxicol Teratol. Nov-Dec;4(6):665-9.

Genotoxic (click on for all fluorinated pesticides)

PubMed abstract: ... In addition, a series of pesticides structurally related to HMPA, such as dimefox, hexamethylmelamine, hexazinone, alachlor, CAM, pirimicarb, dimetilan, thiram and methabenzthiazuron have been tested with the Oregon-K strain. Some of these pesticides had already been shown to be genotoxic in other systems, whereas others have either not been tested or gave negative results in in vitro systems. Although genotoxicity was expressed only within a narrow dose range, all pesticides were genotoxic in the w/w+ system with the Oregon-K strain. Thus, these compounds may be a genotoxic hazard to man...
Ref: Mutagenesis 1994 Jul;9(4):341-6.
The w/w+ SMART is a useful tool for the evaluation of pesticides by Aguirrezabalaga I, Santamaria I, Comendador MA.

Environmental (click on for all fluorinated pesticides)

Toxic to bees.
[Hartley, D. and H. Kidd (eds.). The Agrochemicals Handbook. Old Woking, Surrey, United Kingdom: Royal Society of Chemistry/Unwin Brothers Ltd., 1983.,p. A150/OCT 83]
Ref: Profile for Dimefox from Hazardous Substances Data Base.


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