Methoxychlor

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Methoxychlor
Methoxychlor chemical structure.png
Identifiers
CAS number 72-43-5 YesY
PubChem 4115
ChemSpider 3972 YesY
UNII RIA79UD69L YesY
KEGG C11043 YesY
ChEBI CHEBI:6842 N
ChEMBL CHEMBL362919 YesY
Jmol-3D images Image 1
Properties
Molecular formula C16H15Cl3O2
Molar mass 345.65 g mol−1
Appearance Colorless to light-yellow crystals
Odor Slight, fruity odor
Melting point 87 °C (189 °F; 360 K)
Boiling point decomposes
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

Methoxychlor is a synthetic organochlorine used as an insecticide.

Usage[edit]

Methoxychlor is used to protect crops, ornamentals, livestock, and pets against fleas, mosquitoes, cockroaches, and other insects. It was intended to be a replacement for DDT, but has since been banned based on its acute toxicity, bioaccumulation, and endocrine disruption activity.[1]

The amount of methoxychlor in the environment changes seasonally due to its use in farming and foresting. It does not dissolve readily in water, so it is mixed with a petroleum-based fluid and sprayed, or used as a dust. Sprayed methoxychlor settles on the ground or in aquatic ecosystems, where it can be found in sediments.[2] Its degradation may take many months. Methoxychlor is ingested and absorbed by living organisms, and it accumulates in the food chain. Some metabolites may have unwanted side effects.

Banned[edit]

The use of methoxychlor as a pesticide was banned in the United States in 2003[3] and in the European Union in 2002.[4]

Human exposure[edit]

Human exposure to methoxychlor occurs via air, soil, and water,[5] primarily in people who work with the substance or who are exposed to air, soil, or water that has been contaminated. It is unknown how quickly and efficiently the substance is absorbed by humans who have been exposed to contaminated air or via skin contact.[5] In high doses the agent can lead to neurotoxicity as observed in animal experiments.[5] Some of the agent's metabolites have estrogenic effect as shown in adult and developing animals before and after birth[5] One studied metabolite is 2,2-bis(p-hydroxyphenyl)- 1,1,1-trichloroethane (HPTE) which is considered to have reproductive toxicity in the animal model by reducing testosterone biosynthesis.[6][7] Such effects adversely affect the both the male and female reproductive systems. It is expected that this "could occur in humans" but has not been proven.[5] While one study has linked methoxychlor to the development of leukemia in humans, most studies in animals and humans have been negative, thus the EPA has determined that it is not classifiable as a carcinogen. The EPA indicates that levels above the Maximum Contaminant Level of 40 ppb "cause" central nervous depression, diarrhea, damage to liver, kidney, and heart, and - by chronic exposure - growth retardation.[1]

Little information is available regarding effects on human pregnancy and children, but it is assumed from animals studies that methoxychlor crosses the placenta, and it has been detected in human milk[5] Exposure to children may be different than in adults because they tend to play on the ground, further, their reproductive system may be more sensitive to the effects of methoxychlor as an endocrine disruptor.

Food contamination may occur at low levels and it is recommended to wash all foods.[5] A number of hazardous waste sites are known to contain methoxychlor.

Maximum pesticide residue limits for the EU/UK are set at 0.01 mg/kg for oranges and 0,01 mg/kg for apples

Labeling[edit]

The EPA lists methoxychlor as "a persistent, bioaccumulative, and toxic (PBT) chemical by the EPA Toxics Release Inventory (TRI) program",[1] and as such it is a waste minimization priority chemical.

Tradenames for methoxychlor include Chemform, Maralate, Methoxo, Methoxcide, Metox and Moxie.

See also[edit]

References[edit]

  1. ^ a b c United States Environmental Protection Agency (2006-11-26). "Consumer Factsheet on: METHOXYCHLOR". 
  2. ^ Karickhoff et al. "Sorption of Hyrdophobic Pollutants on Natural Sediments.". Water Research 13: 241–248. doi:10.1016/0043-1354(79)90201-x. 
  3. ^ U.S. Environmental Protection Agency (June 30, 2004). "Methoxychlor Reregistration Eligibility Decision (RED) EPA Publication No. EPA 738-R-04-010". Retrieved 2009-10-02. 
  4. ^ European Union - DG SANCO. "EU Pesticides Database". Retrieved 2009-10-02. 
  5. ^ a b c d e f g ATSDR (September 2002). "Public Health Statement about Methoxychlor". , accessed 08-22-2008
  6. ^ Akingbemi BT et al. (2000). "A Metabolite of Methoxychlor, 2,2-Bis(p-Hydroxyphenyl)-1,1,1-Trichloroethane, Reduces Testosterone Biosynthesis in Rat Leydig Cells Through Suppression of Steady-State Messenger Ribonucleic Acid Levels of the Cholesterol Side-Chain Cleavage Enzyme". Biology of Reproduction 62: 571–578. doi:10.1095/biolreprod62.3.571. 
  7. ^ Cummings AW (1997). "Methoxychlor as a model for environmental estrogens.". Crit Rev Toxicol 27 (4): 367–79. doi:10.3109/10408449709089899. PMID 9263644. 

External links[edit]