Aldicarb
Skeletal formula of aldicarb
Ball-and-stick model of aldicarb
Names
IUPAC name
2-Methyl-2-(methylthio)propanal O-(N-methylcarbamoyl)oxime
Other names
Temik
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.003.749 Edit this at Wikidata
EC Number
  • 204-123-2
KEGG
RTECS number
  • UE2275000
UNII
  • InChI=1S/C7H14N2O2S/c1-7(2,12-4)5-9-11-6(10)8-3/h5H,1-4H3,(H,8,10)/b9-5+ checkY
    Key: QGLZXHRNAYXIBU-WEVVVXLNSA-N checkY
  • InChI=1/C7H14N2O2S/c1-7(2,12-4)5-9-11-6(10)8-3/h5H,1-4H3,(H,8,10)/b9-5+
    Key: QGLZXHRNAYXIBU-WEVVVXLNBS
  • CNC(=O)O/N=C/C(C)(C)SC
Properties
C7H14N2O2S
Molar mass 190.26 g·mol−1
Appearance colorless crystals
Odor faint sulfur odor
Density 1.195 g/cm2
Melting point 99.5 °C (211.1 °F; 372.6 K)
Boiling point 251 °C (484 °F; 524 K)
0.573 g/100 mL
Solubility soluble in acetone, benzene, chlorobenzene, diethyl ether, isopropyl alcohol, methylene chloride, toluene
slightly soluble in xylene
Hazards
Lethal dose or concentration (LD, LC):
0.84 mg/kg (oral, rats)[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Aldicarb is a carbamate insecticide which is the active substance in the pesticide Temik. It is effective against thrips, aphids, spider mites, lygus, fleahoppers, and leafminers, but is primarily used as a nematicide.[2] Aldicarb is a cholinesterase inhibitor which prevents the breakdown of acetylcholine in the synapse. Aldicarb is considered "extremely hazardous" by the EPA and World Health Organization and has been banned in more than 100 countries.[3] In case of severe poisoning, the victim dies of respiratory failure.

Aldicarb was first synthesized in 1965 by Payne and Weiden, and was sold on the market for the first time in 1970.[4] The synthesis of aldicarb results in both the E and Z isomers.[5]

Aldicarb is effective where resistance to organophosphate insecticides has developed, and is extremely important in potato production, where it is used for the control of soil-borne nematodes and some foliar pests. Its high level of solubility restricts its use in certain areas where the water table is close to the surface.

Regulatory status

In the United States, aldicarb was approved by the EPA for use by professional pesticide applicators on a variety of crops, including cotton, beans, and others. It is not approved for household use.[6] The EPA started limiting the main aldicarb pesticide, Temik 15G, in 2010, requiring an end to distribution by 2017.[citation needed] Discontinuation of the use on citrus and potatoes began in 2012, with a complete phase out of the product expected by 2018.[7] A new aldicarb pesticide named AgLogic 15G, was approved by the EPA in December 2011 and is said to be entering the market in 2015.[8][needs update] It will be registered for use on cotton, dry beans, peanuts, soybeans, sugar beets, and sweet potatoes.[needs update]

Tres Pasitos, a mouse, rat, and roach killer that contains high concentrations of aldicarb, has been illegally imported into the United States from Mexico and other Latin American countries. The product is highly toxic to animals and people, and according to the EPA "should never be used in [the] home."[9]

Most commonly, aldicarb causes toxic symptoms when it is ingested through food that has been tainted with the insecticide.[5] Once in the body, aldicarb is broken down into aldicarb sulfone and aldicarb sulfoxide. Hydrolysis of aldicarb leads to aldicarb oximes and aldicarb nitriles to reverse the toxicity.[10]

Aldicarb is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.[11] The use of aldicarb has been prohibited in Europe since 2003 due to concerns over the impact on non-target organisms.[12]

History

Aldicarb is manufactured by Bayer CropScience, but was formerly owned and produced by Union Carbide. Union Carbide's agricultural chemicals division was sold to Rhône-Poulenc. Later, Aventis Cropscience was formed from Hoechst AG and Rhone-Poulenc Agrochemical, which lasted until Bayer acquired it in 2002.

In August 1979, groundwater wells in Suffolk County, NY were contaminated with aldicarb residue due to irrigated potato fields nearby. Of the approximately 8,400 wells tested, 13.5% contained more than 7 ug/L of aldicarb, which exceeds standard guidelines.[13]

In July 1985, aldicarb present in watermelons grown in California caused an outbreak of pesticide food poisoning which affected over 2,000 people, and led to a temporary ban on watermelon sales.[7]

In November 2009, corn treated with Temik was placed in and around peanut fields in Eastland County, Texas, near the town of Cisco. The corn was eaten by feral hogs, deer, and other animals, prompting the Texas Parks and Wildlife Department to issue a hunting ban.[14]

Toxicity in mammals

Aldicarb is a fast-acting cholinesterase inhibitor, causing rapid accumulation of acetylcholine at the synaptic cleft. The aldicarb structure is similar to that of acetylcholine, therefore improving its binding to acetylcholinesterase in the body. [4] It is widely used to study cholinergic neurotransmission in simple systems such as the nematode C. elegans.

Exposure to high amounts of aldicarb can cause weakness, blurred vision, headache, nausea, tearing, sweating, and tremors in humans. High doses can be fatal to humans because it can paralyze the respiratory system.[9]

In South Africa (where Aldicarb is popularly known as Two Step) it is widely used by burglars to poison dogs.[15][16][17]

Toxicity in birds

LD50 for a mallard duck is 1.0 mg/kg body weight (acute).[12] According to the Rotterdam Convention's risk assessment, "Ingestion of aldicarb granules poses a great threat to avian species; aldicarb is very toxic to birds and poses a danger to endangered species".[12]

References

  1. ^ Kök, Fatma N; Arıca, M Yakup; Gencer, Oktay; Abak, Kazım; Hasırcı, Vasıf (1999). "Controlled release of aldicarb from carboxymethyl cellulose microspheres: in vitro and field applications". Pesticide Science. 55 (12): 1194–1202. doi:10.1002/(sici)1096-9063(199912)55:12<1194::aid-ps79>3.0.co;2-h.
  2. ^ "Temik". www.bayercropscienceus.us. Retrieved 2011-04-01.
  3. ^ Hettinger, Johnathan (21 November 2023). "EPA considers approving fruit pesticide despite risks to children, records show". The Guardian. Retrieved 21 November 2023.
  4. ^ a b Payne, L. K. Jr.; Stansbury, H. A. Jr.; Weiden, M. H. J. (July 1, 1966). "Synthesis and Insecticidal Properties of Some Cholinergic Trisubstituted Acetaldehyde O-(Methylcarbamoyl)oximes". Journal of Agricultural and Food Chemistry. 14 (4): 356-365. doi:10.1021/jf60146a007. Retrieved November 7, 2021.
  5. ^ a b "PubChem - Aldicarb (CID: 9570071)". PubChem. National Library of Medicine. Retrieved November 7, 2021.
  6. ^ "Aldicarb". extoxnet.orst.edu. The Extension Toxicology Network. June 1996. Retrieved 2007-08-13.
  7. ^ a b "Toxic Pesticide Banned after Decades of Use". Scientific American. August 18, 2010. Retrieved 2012-12-03.
  8. ^ "AgLogic/Meymik 15 G Homepage". AgLogic. AgLogic Chemical. 2014. Retrieved 2015-10-02.
  9. ^ a b Avoid Illegal Household Pesticide Products, US Environmental Protection Agency
  10. ^ "PubChem - Aldicarb (CID: 0570071)". PubChem. Retrieved November 7, 2021.
  11. ^ "40 C.F.R.: Appendix A to Part 355—The List of Extremely Hazardous Substances and Their Threshold Planning Quantities" (PDF) (July 1, 2008 ed.). Government Printing Office. Archived from the original (PDF) on February 25, 2012. Retrieved October 29, 2011. ((cite journal)): Cite journal requires |journal= (help)
  12. ^ a b c "Decision Guidance Document ALDICARB" (PDF). Secretariat of the Rotterdam Convention on the Prior Informed Consent Procedure for Certain Hazardous Chemicals and Pesticides in International Trade. Retrieved 11 July 2023.
  13. ^ International Agency for Research on Cancer (1991). Occupational Exposures in Insecticide Application, and Some Pesticides (PDF). Lyon, France: World Health Organization. p. 93-113. Retrieved November 7, 2021.
  14. ^ Authorities Investigate Contaminated Corn in Eastland County, Texas Parks and Wildlife Department, Nov. 5, 2009
  15. ^ Criminals target dogs with poison, IOL News, June 11, 2006
  16. ^ Dog poisoning with the intention to break into houses, South Africa Today, July 10, 2014
  17. ^ "Dog-poisoning plague hits city". News24. Retrieved 2017-04-21.