Dimethoate

Structural formula
General
Surname	Dimethoate
other names	O , O -Dimethyl- S- methylcarbamoylmethyl-phosphorodithioate dithiophosphoric acid O, O-dimethyl-S- (N-methylcarbamoylmethyl) ester
Molecular formula	C 5 H 12 NO 3 PS 2
Brief description	white solid with an unpleasant odor
External identifiers / databases
CAS number 60-51-5 EC number 200-480-3 ECHA InfoCard 100,000,437 PubChem 3082 Wikidata Q421371
properties
Molar mass	229.2 g mol −1
Physical state	firmly
density	1.28 g cm −3 (at 65 ° C)
Melting point	52-52.5 ° C
boiling point	107 ° C (at 6.6 Pa) (decomposition from 60 ° C)
Vapor pressure	1 m Pa (25 ° C)
solubility	low in water (25 g l −1 at 25 ° C)
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary Caution H and P phrases H: 302-312 P: 280
Toxicological data	387 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Dimethoate is a chemical compound that is widely used as an insecticide . It belongs to the dithiophosphoric acid esters (so-called "organophosphates"). Insecticides in this group act as contact poisons. Like other phosphoric acid esters, dimethoate inhibits cholinesterases , which have an essential function in the nervous system .

history

Dimethoate was approved for American Cyanamid in the United States in 1962.

Chemical properties

Dimethoate belongs to the group of dithiophosphoric acid esters. It is relatively stable in water and acidic solution at room temperature, but unstable in alkaline solution. When heated, it converts to O , S -dimethylphosphorodithioate .

The substance acts as a strong neurotoxin on numerous organisms, including all insects , all mammals and thus also humans. The strength of the effect depends on the mass of the individual, as dimethoate is distributed in the body. This neurotoxin is always dangerous if it reaches a function-damaging concentration at the time of intake. For treated plants that are intended for human consumption, waiting times of different lengths are prescribed depending on the crop.

use

Dimethoate is used as an insecticide against pests such as aphids , cicadas , bed bugs, but also against house flies. It also acts as an acaricide and nematocide . The effect is based on the inhibition of acetylcholinesterase , whereby the actually active substance (the oxygen analog) is only produced through metabolism .

The substance is classified as harmful to human health due to its nerve-damaging effect . Only less than 1 mg / kg may be found in previously treated fruit and vegetables. The concentration drops to a harmless level within days after use.

In order to avoid the risk of accidental overdosing for private users, the amount dispensed per package is limited. Significantly higher packing and concentration units are available for agricultural use.

The effect of dimethoate on beneficial organisms such as bees and ants is discussed occasionally . It is classified as hazardous to bees in group B1 and must not be applied to flowering plants or plants (including weeds) flown by bees. The neurotoxin is always harmful in direct contact (direct spraying, visiting flowers immediately after the treatment) if it exceeds the amount that the individual can tolerate. Otherwise, it will leave the insect body over time without any behavioral effects. The contaminating amount of the volatile substance is not brought into the state budget by the individual. A conceivable long-term effect on colonizing insects is therefore unlikely.

Various forms of administration are readily available commercially, including solutions, aerosol presentations or easy-to-use sprays. By far the most common use for private individuals is as an aqueous solution for use against "biting and sucking insects", including aphids. In addition, presentations are available that can be used in lower concentrations and in alternating combinations against specific organisms.

regulation

In February 2016, France banned all PPPs containing dimethoate due to health concerns, and imports of cherries treated with dimethoate are no longer permitted there. The French Ministry of Agriculture is campaigning for dimethoate to be banned across the EU. This initiative is supported by Italy and Spain, but the EU Commission is against an immediate ban through an emergency measure.

The European Food Safety Authority (EFSA) announced that health risks from dimethoate cannot be excluded with the currently available data.

The approval of plant protection products (PPPs) with the active ingredient dimethoate expired in the EU countries in July 2019.

Trade names

• Perfection
• Bi 58
• ROXION
• Rogor 40 l
• Danadim Progress
• Lizetan

Web links

• Health and Safety Guide (HSG) for Dimethoate

Individual evidence

1. ↑ ^{a b c d e f g h i} Entry on dimethoate in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
2. ↑ Entry on Dimethoate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
3. ↑ Entry on dimethoate. In: Römpp Online . Georg Thieme Verlag, accessed on October 1, 2014.
4. ↑ Revised Interim Reregistration Eligibility Decisions for dimethoate. (PDF 1.3 MB) United States Environmental Protection Agency , OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES, October 30, 2008, p. 53 , archived from the original on July 30, 2013 ; accessed on June 20, 2019 . 
5. ↑ Gary W. Barrett, Rezneat M. Darnell: Effects of dimethoate on Small Mammal Populations. In: American Midland Naturalist. 77, 1967, p. 164, doi : 10.2307 / 2423436 .
6. ^ Environmental Health Criteria (EHC) for Dimethoate , accessed November 19, 2014.
7. ↑ ^{a b} WHO / FAO Data Sheet on Pesticides (PDS) for Dimethoate ( Memento from July 2, 2014 in the Internet Archive )
8. ↑ Bienen & natur editorial staff: What does bee-safe really mean? In: bees & nature. August 1, 2012, accessed June 3, 2019 . 
9. ↑ BUND: Biological and chemical investigations on bees ( Memento from December 5, 2014 in the Internet Archive ) (PDF; 552 kB).
10. ↑ Bundestag: German Bundestag. Printed matter 17/6206 of June 15, 2011. The response of the federal government in a letter from the Federal Ministry of Food, Agriculture and Consumer Protection of June 10, 2011 to the small request for the approval of pesticides containing dimethoate to control cherry fruit flies and the consequences for the environment and Consumer protection. (PDF; 168 kB).
11. ↑ France says to ban imports of cherries treated with dimethoate . Reuters, April 15, 2016.
12. ^ Directorate-General for Health and Food Safety of the European Commission: Entry on Dimethoate in the EU pesticide database; Entry in the national registers of plant protection products in Switzerland , Austria and Germany ; accessed on December 8, 2019.