Methoxychlor

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Methoxychlor
Structural formula of methoxychlor
Ball-and-stick model of the methoxychlor molecule
Names
Preferred IUPAC name
1,1′-(2,2,2-Trichloroethane-1,1-diyl)bis(4-methoxybenzene)
Other names
Methoxcide
Dimethoxy-DDT
Methoxy-DDT
p,p'-Dimethoxydiphenyltrichloroethane
Identifiers
3D model (
JSmol
)
Abbreviations DMDT
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard
 100.000.709 Edit this at Wikidata
KEGG
UNII
  • InChI=1S/C16H15Cl3O2/c1-20-13-7-3-11(4-8-13)15(16(17,18)19)12-5-9-14(21-2)10-6-12/h3-10,15H,1-2H3 checkY
    Key: IAKOZHOLGAGEJT-UHFFFAOYSA-N checkY
  • InChI=1/C16H15Cl3O2/c1-20-13-7-3-11(4-8-13)15(16(17,18)19)12-5-9-14(21-2)10-6-12/h3-10,15H,1-2H3
    Key: IAKOZHOLGAGEJT-UHFFFAOYAO
  • ClC(Cl)(Cl)C(c1ccc(OC)cc1)c2ccc(OC)cc2
Properties
C16H15Cl3O2
Molar mass 345.65 g/mol
Appearance Colorless to light-yellow crystals
Odor Slight, fruity odor
Density 1.41 g/cm3 (20°C)[1]
Melting point 87 °C (189 °F; 360 K)
Boiling point decomposes
0.00001% (20°C)[1]
Hazards
Lethal dose or concentration (LD, LC):
5000 mg/kg (oral, rat)
1000 mg/kg (oral, mouse)
>6000 mg/kg (oral, rabbit)[2]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 15 mg/m3[1]
REL (Recommended)
 Ca[1]
IDLH
(Immediate danger)
 Ca [5000 mg/m3][1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Methoxychlor is a synthetic

organochloride insecticide
, now obsolete. Tradenames for methoxychlor include Chemform, Maralate, Methoxo, Methoxcide, Metox, and Moxie.

Usage

Methoxychlor was 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 for use as a pesticide based on its acute toxicity, bioaccumulation, and endocrine disruption activity.[3]

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 detected in sediments.[4] 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

The use of methoxychlor as a pesticide was banned in the United States in 2003[5] and in the European Union in 2002.[6]

Health and Environmental Impacts

The EPA lists methoxychlor as "a

persistent, bioaccumulative, and toxic (PBT) chemical by the EPA Toxics Release Inventory (TRI) program",[3] and as such it is a waste minimization priority chemical. The 2023 Conference of the Parties of the United Nations Stockholm Convention on Persistent Organic Pollutants decided to eliminate the use of methoxychlor, by listing this chemical in Annex A to the Convention.[7]

Human exposure

Human exposure to methoxychlor occurs via air, soil, and water,

Maximum Contaminant Level of 40 ppb "cause" central nervous depression, diarrhea, damage to liver, kidney, and heart, and - by chronic exposure - growth retardation.[3]

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[8] 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.[citation needed]

Food contamination may occur at low levels and it is recommended to wash all foods.[8] 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.

See also

References

  1. ^ a b c d e NIOSH Pocket Guide to Chemical Hazards. "#0388". National Institute for Occupational Safety and Health (NIOSH).
  2. ^ "Methoxychlor". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  3. ^ a b c United States Environmental Protection Agency (2006-11-26). "Consumer Factsheet on: METHOXYCHLOR".
  4. doi:10.1016/0043-1354(79)90201-x
    .
  5. 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.
  6. ^ European Union - DG SANCO. "EU Pesticides Database". Retrieved 2009-10-02.
  7. ^ "Governments accelerate action and take bold decisions to address pollution from chemicals and wastes". Secretariat of the Basel, Rotterdam and Stockholm Conventions. May 15, 2023. Retrieved 7 July 2023.
  8. ^ a b c d e f g ATSDR (September 2002). "Public Health Statement about Methoxychlor" (PDF)., accessed 08-22-2008
  9. PMID 10684797
    .
  10. PMID 9263644
    .

External links
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