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Your Location：Home>Product Center >> Pesticide API and intermediates >> 2,4-Dichlorophenoxyacetic acid
  • 2,4-Dichlorophenoxyacetic acid
Name:2,4-Dichlorophenoxyacetic acid
CAS No:94-75-7

PRODUCT DESCRIPTION

【Name】
2,4-Dichlorophenoxyacetic acid
【CAS Registry number】
94-75-7
【Synonyms】
amidox
b-selektonon
u-5043
crotilin
decamine
dicopur
dicotox
ipaner
netagrone
pennamine
weedone-2,4-dp
helena 2,4-d
2,4-d lv6
weedar 64a
chloroxone
bh 2,4-d
agrotect
amoxone
weed tox
weedtrol
emulsamine bk
envert dt
dormone
2,4-D
【EINECS(EC#)】
202-361-1
【Molecular Formula】
C8H6Cl2O3 (Products with the same molecular formula)
【Molecular Weight】
221.04
【Inchi】
InChI=1/C8H6Cl2O3/c9-5-1-2-7(6(10)3-5)13-4-8(11)12/h1-3H,4H2,(H,11,12)
【InChIKey】
OVSKIKFHRZPJSS-UHFFFAOYSA-N
【Canonical SMILES】
C1=CC(=C(C=C1Cl)Cl)OCC(=O)O
【MOL File】
94-75-7.mol

Chemical and Physical Properties

【Appearance】
off-white to tan
【Density】
1.563
【Melting Point】
137-141℃
【Boiling Point】
160℃ (0.4 torr)
【Refractive Index】
1.576
【Flash Point】
160 oC (0.4 torr)
【Water】
Slightly soluble. Decomposes. 0.0890 g/100 mL
【Solubilities】
160 oC (0.4 torr)
【Color/Form】
off-white to tan
【Stability】
Stable, but moisture-sensitive and may be light-sensitive. Incompatible with strong oxidizing agents, corrodes many metals. Decomposes in water.
【HS Code】
29189090
【Storage temp】
APPROX 4°C
【Spectral properties】
SADTLER REF NUMBER: 13141 (IR, PRISM); 8174 (IR, GRATING); MAX ABSORPTION (WATER, 0.1 N HCL): 282 NM (LOG E= 3.26); 289 NM (LOG E= 3.20) SHOULDER
The undissociated molecule in 0.1 M hydrochloric acid has a molar absorptivity of 1820 molar/cm at 282 nm; the anion in 0.01 M phosphate buffer is 2070 at 283.5 nm.
IR: 2221 (Coblentz Society Spectral Collection)
UV: 3427 (Sadtler Research Laboratories Spectral Collection)
1H-NMR: 10803 (Sadtler Research Laboratories Spectral Collection)
MASS: 52494 (NIST/EPA/MSDC Mass Spectral Database 1990 Version)
Intense mass spectral peaks: 162 m/z (100%), 164 m/z (69%), 220 m/z (61%), 222 m/z (39%)
Intense mass spectral peaks: 111 m/z, 133 m/z, 175 m/z
【Computed Properties】
Molecular Weight:221.03744 [g/mol]
Molecular Formula:C8H6Cl2O3
XLogP3:2.8
H-Bond Donor:1
H-Bond Acceptor:3
Rotatable Bond Count:3
Exact Mass:219.969399
MonoIsotopic Mass:219.969399
Topological Polar Surface Area:46.5
Heavy Atom Count:13
Formal Charge:0
Complexity:186
Isotope Atom Count:0
Defined Atom Stereocenter Count:0
Undefined Atom Stereocenter Count:0
Defined Bond Stereocenter Count:0
Undefined Bond Stereocenter Count:0
Covalently-Bonded Unit Count:1
Feature 3D Acceptor Count:3
Feature 3D Anion Count:1
Feature 3D Ring Count:1
Effective Rotor Count:3
Conformer Sampling RMSD:0.6
CID Conformer Count:26

Safety and Handling

【Hazard Codes】
Xn:Harmful
【Risk Statements】
R22;R37;R41;R43;R52/53
【Safety Statements 】
S2;S24/25;S26;S36/37/39;S46;S61
【HazardClass】
6.1
【Safety】

Hazard Codes:?HarmfulXn?IrritantXi?ToxicT?FlammableF?
Risk Statements: 22-37-41-43-52/53-39/23/24/25-23/24/25-36/37/38-11
?R22: Harmful if swallowed.?
R37: Irritating to respiratory system?
R41: Risk of serious damage to the eyes.?
R43: May cause sensitization by skin contact.?
R52/53: Harmful to aquatic organisms, may cause long-term adverse effects in the aquatic environment.?
R23/24/25: Toxic by inhalation, in contact with skin and if swallowed.?
R36/37/38: Irritating to eyes, respiratory system and skin.?
R11: Highly flammable. 
Safety Statements: 24/25-26-36/37/39-46-61-2-45-36/37-27-16?
S24/25: Avoid contact with skin and eyes.?
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.?
S36/37/39: Wear suitable protective clothing, gloves and eye/face protection.?
S46: If swallowed, seek medical advice immediately and show this container or label.?
S61: Avoid release to the environment. Refer to special instructions / safety data sheets.?
S2: Keep out of the reach of children.?
S45: In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.)?
S36/37: Wear suitable protective clothing and gloves.?
S27: Take off immediately all contaminated clothing.?
S16: Keep away from sources of ignition. 
RIDADR: UN 3077 9/PG 3
WGK Germany: 2
RTECS: AG6825000
HazardClass: 6.1 
PackingGroup: III 
HS Code: 29189090

【PackingGroup 】
III
【Skin, Eye, and Respiratory Irritations】
Dust may irritate eyes.
Acute eye or skin irritation ... has been reported in agricultural and forestry workers following occupational exposure.
Irritates eyes, causes gastrointestinal disturbances.
【Cleanup Methods】
1) Ventilate area of spill. 2) For small quantities, sweep onto paper or other suitable material, place in an appropriate container and burn in a safe place (such as a fume hood). Large quantities may be reclaimed.
Land spill: Dig a pit, pond, lagoon, or holding area to contain liquid, or solid material. /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ Cover solids with a plastic sheet to prevent dissolving in rain or fire fighting water.
Water spill: Use natural deep water pockets, excavated lagoons, or sand bag barriers to trap material at bottom. If dissolved, in region of 10 ppm or greater concentration, apply activated carbon at ten times the amount spilled. Remove trapped material with suction hoses. Use mechanical dredges or lifts to remove immobilized masses of pollutants and precipitates.
【Transport】
UN 2765
【Fire Fighting Procedures】
Extinguishant: Carbon dioxide, dry chemical, foam, and water.
Extinguish fire using agent suitable for type of surrounding fire.
【Fire Potential】
Material itself does not burn or burns with difficulty.
【Formulations/Preparations】
USEPA/OPP Pesticide Code 030001; Trade Names: Weed-broom (Use 3 code Nos. 012301, 013803 and 030001).
Emulsifiable concentrate, soluble concentrate, water-soluble powder, granules
95% technical, technical esters, and formulated product grades
Brush-rhap LV 2D-2T Rhodia Low Volatile Brush Killer No 2
2,4-D and 2,4,5-T mixed with Banvel /Former/
2,4-D with Benazolin
Types of formulations: Granular; amine and ester liquids; Dust; and Aerosol spray (foam).
Forms available: sodium salt (60-85% acid), amine salts (10-60% acid), esters (10-45% acid)
Acme Super Brush Killer (with dicamba); Acme Brush Killer 875 (with dicamba + MCPP); U 46 DP (dichlorprop); Duplosan DP-D ... (dichlorprop-P); Actril DS ... (ioxynil); U 46 Combi-Fluid (MCPA); Chipco Turf Kleen; 2 Plus 2 (MCPP); U 46 KV-Combi-Fluid ( mecoprop); Duplosan KV-Combi ...(mecoprop-P); Gordon's Vegemec Vegetation Killer (prometon); Gordon's Phenomee (MCPP) Lentemul.
Gesapax H (2,4-D + ametryn (1.4 : 1)); Gesaprim D (2,4-D + atrazine (1 : 2.5)); Hytrol (2,4-D + amitrole + diuron + simazine); Klinopalm (2,4-D + ametryn + sodium hydrogen methylarsonate (1.4 : 1 : 3)); Modown DG (2,4-D + bifenox); Rilof H (2,4-D + piperophos (about 1 : 2 to 2 : 3)); 2,4-D + amitrole + atrazine; 2,4-D + amitrole + TCA; 2,4-D + atrazine + sodium chlorate; 2,4-D + chlorfenac; 2,4-D + dichlorprop + picloram; 2,4-D + maleic hydrazide; 2,4-D + monuron-TCA; 2,4-D + picloram + tebuthiuron; 2,4-D + triclopyr.
Brush Killer 170 (butoxyethanol esters of 2,4-dichlorophenoxypropionic acid & 2,4-D)
Acme Vegetation Killer (2,4-D + Prometone)
Allied Chemical Low Volatile 1-1/3-2/3 Brush Killer (2,4-D + 2,4,5-T + isooctyl esters of 2,4-D & 2,4,5-T) /Former/
Brush-Rhap B-2-2 (2,4-D + 2,4,5-T) /Former/
Brush-Rhap LV-2-2-0 (2,4-D + 2,4,5-T) /Former/
Chempar Low Volatile Brush Killer No 2 (2,4-D + 2,4,5-T) /Former/
De-Pester Ded-Weed for Lawns (2,4-D + 2,4,5-T + kerosene) /Former/
Emulsavert 248 (2,4-D + 2,4,5-T + N,N-dimethyloleylamine salts of 2,4-D & 2,4,5-T) /Former/
Jet-Weed Killer Power Pellets (2,4-D + silvex)
Kansel (2,4-D + dicamba)
Limit (chloro-N,N-diallylacetamide + 2,4-D)
Nutro Dandelion & Turf Weed Killer (2,4-D + dicamba)
Nutro Weed Bomb (2,4-D + MCPP)
Pill Kill Kartridges for Dandelions and Broadleaf Weeds (2,4-D + silvex)
Pratt Lawn Weed Killer (2,4-D + 2,4,5-TP)
Pratt's Crabgrass & Broadleaf Weed Killer (octyl ammonium methyl arsonate + 2,4-D)
Proturf Broad Spectrum Weedicide (2,4-D + dicamba)
Proturf Broad Spectrum Weedicide II (2,4-D + 2-(2-methyl-4-chlorophenoxy)propionic acid)
Proturf Fertilizer Plus Dicot Weed Control (2,4-D + dicamba)
Proturf Fertilizer Plus Dicot Weed Control II (2,4-D + 2-(2-methyl-4-chlorophenoxy)propionic acid)
Reasor-Hill Brush Rhap (2,4-D + 2,4,5-T) /Former/
Rhodia Low Volatile Brush Killer No 2 (2,4-D + 2,4,5-T) /Former/
Robot Gardener Weed & Crabgrass Killer (potassium cyanate + 2,4-D)
Turf Builder Plus 2 (2,4-D + 2-(2-methyl-4-chlorophenoxy)-propionic acid)
【DOT Emergency Guidelines】
/GUIDE 131: FLAMMABLE LIQUIDS-TOXIC/ Health: TOXIC; may be fatal if inhaled, ingested or absorbed through skin. Inhalation or contact with some of these materials will irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution. /Phenoxyacetic acid derivative pesticide, liquid, flammable, poisonous; Phenoxyacetic acid derivative pesticide, liquid, flammable, toxic; Phenoxyacetic acid derivative pesticide, liquid, poisonous, flammable; Phenoxyacetic acid derivative pesticide, liquid, toxic, flammable/
/GUIDE 131: FLAMMABLE LIQUIDS-TOXIC/ Fire or Explosion: HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion and poison hazard indoors, outdoors or in sewers. Those substances designated with a "P" may polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water. /Phenoxyacetic acid derivative pesticide, liquid, flammable, poisonous; Phenoxyacetic acid derivative pesticide, liquid, flammable, toxic; Phenoxyacetic acid derivative pesticide, liquid, poisonous, flammable; Phenoxyacetic acid derivative pesticide, liquid, toxic, flammable/
/GUIDE 131: FLAMMABLE LIQUIDS-TOXIC/ Public Safety: CALL Emergency Response Telephone Number ... . As an immediate precautionary measure, isolate spill or leak area for at least 50 meters (150 feet) in all directions. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate closed spaces before entering. /Phenoxyacetic acid derivative pesticide, liquid, flammable, poisonous; Phenoxyacetic acid derivative pesticide, liquid, flammable, toxic; Phenoxyacetic acid derivative pesticide, liquid, poisonous, flammable; Phenoxyacetic acid derivative pesticide, liquid, toxic, flammable/
/GUIDE 131: FLAMMABLE LIQUIDS-TOXIC/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer. It may provide little or no thermal protection. Structural firefighters' protective clothing provides limited protection in fire situations ONLY; it is not effective in spill situations where direct contact with the substance is possible. /Phenoxyacetic acid derivative pesticide, liquid, flammable, poisonous; Phenoxyacetic acid derivative pesticide, liquid, flammable, toxic; Phenoxyacetic acid derivative pesticide, liquid, poisonous, flammable; Phenoxyacetic acid derivative pesticide, liquid, toxic, flammable/
/GUIDE 131: FLAMMABLE LIQUIDS-TOXIC/ Evacuation: ... Fire: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. /Phenoxyacetic acid derivative pesticide, liquid, flammable, poisonous; Phenoxyacetic acid derivative pesticide, liquid, flammable, toxic; Phenoxyacetic acid derivative pesticide, liquid, poisonous, flammable; Phenoxyacetic acid derivative pesticide, liquid, toxic, flammable/
/GUIDE 131: FLAMMABLE LIQUIDS-TOXIC/ Fire: CAUTION: All these products have a very low flash point. Use of water spray when fighting fire may be inefficient. Small fires: Dry chemical, CO2, water spray or alcohol-resistant foam. Large fires: Water spray, fog or alcohol-resistant foam. Move containers from fire area if you can do it without risk. Dike fire control water for later disposal; do not scatter the material. Use water spray or fog; do not use straight streams. Fire involving tanks or car/trailer loads: Fight fire from maximum distance or use unmanned hose holders or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks engulfed in fire. For massive fire use unmanned hose holders or monitor nozzles; if this is impossible, withdraw from area and let fire burn. /Phenoxyacetic acid derivative pesticide, liquid, flammable, poisonous; Phenoxyacetic acid derivative pesticide, liquid, flammable, toxic; Phenoxyacetic acid derivative pesticide, liquid, poisonous, flammable; Phenoxyacetic acid derivative pesticide, liquid, toxic, flammable/
/GUIDE 131: FLAMMABLE LIQUIDS-TOXIC/ Spill or Leak: Fully encapsulating, vapor protective clothing should be worn for spills and leaks with no fire. ELIMINATE all ignition sources (no smoking, flares, sparks or flames in immediate area). All equipment used when handling the product must be grounded. Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. A vapor suppressing foam may be used to reduce vapors. Small spills: Absorb with earth, sand or other non-combustible material and transfer to containers for later disposal. Use clean non-sparking tools to collect absorbed material. Large spills: Dike far ahead of liquid spill for later disposal. Water spray may reduce vapor; but may not prevent ignition in closed spaces. /Phenoxyacetic acid derivative pesticide, liquid, flammable, poisonous; Phenoxyacetic acid derivative pesticide, liquid, flammable, toxic; Phenoxyacetic acid derivative pesticide, liquid, poisonous, flammable; Phenoxyacetic acid derivative pesticide, liquid, toxic, flammable/
/GUIDE 131: FLAMMABLE LIQUIDS-TOXIC/ First Aid: Move victim to fresh air. Call 911 or emergency medical service. Give artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; give artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult. Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush skin or eyes with running water for at least 20 minutes. Wash skin with soap and water. Keep victim warm and quiet. In case of burns, immediately cool affected skin for as long as possible with cold water. Do not remove clothing if adhering to skin. Effects of exposure (inhalation, ingestion or skin contact) to substance may be delayed. Ensure that medical personnel are aware of the material(s) involved and take precautions to protect themselves. /Phenoxyacetic acid derivative pesticide, liquid, flammable, poisonous; Phenoxyacetic acid derivative pesticide, liquid, flammable, toxic; Phenoxyacetic acid derivative pesticide, liquid, poisonous, flammable; Phenoxyacetic acid derivative pesticide, liquid, toxic, flammable/
/GUIDE 153: SUBSTANCES - TOXIC AND/OR CORROSIVE (COMBUSTIBLE)/ Health: TOXIC; inhalation, ingestion, or skin contact with material may cause severe injury or death. Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution. /Phenoxyacetic acid derivative pesticide, liquid, poisonous; Phenoxyacetic acid derivative pesticide, liquid, toxic; Phenoxyacetic acid derivative pesticide, solid, poisonous; Phenoxyacetic acid derivative pesticide, solid, toxic/
/GUIDE 153: SUBSTANCES - TOXIC AND/OR CORROSIVE (COMBUSTIBLE)/ Fire or Explosion: Combustible material: may burn but does not ignite readily. When heated, vapors may form explosive mixtures with air: indoors, outdoors, and sewers explosion hazards. Those substances designated with a "P" may polymerize explosively when heated or involved in a fire. Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. Runoff may pollute waterways. Substance may be transported in a molten form. /Phenoxyacetic acid derivative pesticide, liquid, poisonous; Phenoxyacetic acid derivative pesticide, liquid, toxic; Phenoxyacetic acid derivative pesticide, solid, poisonous; Phenoxyacetic acid derivative pesticide, solid, toxic/
/GUIDE 153: SUBSTANCES - TOXIC AND/OR CORROSIVE (COMBUSTIBLE)/ Public Safety: CALL Emergency Response Telephone Number ... . As an immediate precautionary measure, isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate enclosed areas. /Phenoxyacetic acid derivative pesticide, liquid, poisonous; Phenoxyacetic acid derivative pesticide, liquid, toxic; Phenoxyacetic acid derivative pesticide, solid, poisonous; Phenoxyacetic acid derivative pesticide, solid, toxic/
/GUIDE 153: SUBSTANCES - TOXIC AND/OR CORROSIVE (COMBUSTIBLE)/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer. It may provide little or no thermal protection. Structural firefighters' protective clothing provides limited protection in fire situations ONLY; it is not effective in spill situations where direct contact with the substance is possible. /Phenoxyacetic acid derivative pesticide, liquid, poisonous; Phenoxyacetic acid derivative pesticide, liquid, toxic; Phenoxyacetic acid derivative pesticide, solid, poisonous; Phenoxyacetic acid derivative pesticide, solid, toxic/
/GUIDE 153: SUBSTANCES - TOXIC AND/OR CORROSIVE (COMBUSTIBLE)/ Evacuation: ... Fire: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. /Phenoxyacetic acid derivative pesticide, liquid, poisonous; Phenoxyacetic acid derivative pesticide, liquid, toxic; Phenoxyacetic acid derivative pesticide, solid, poisonous; Phenoxyacetic acid derivative pesticide, solid, toxic/
/GUIDE 153: SUBSTANCES - TOXIC AND/OR CORROSIVE (COMBUSTIBLE)/ Fire: Small fires: Dry chemical, CO2 or water spray. Large fires: Dry chemical, CO2, alcohol-resistant foam or water spray. Move containers from fire area if you can do it without risk. Dike fire control water for later disposal; do not scatter the material. Fire involving tanks or car/trailer loads: Fight fire from maximum distance or use unmanned hose holders or monitor nozzles. Do not get water inside containers. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks engulfed in fire. /Phenoxyacetic acid derivative pesticide, liquid, poisonous; Phenoxyacetic acid derivative pesticide, liquid, toxic; Phenoxyacetic acid derivative pesticide, solid, poisonous; Phenoxyacetic acid derivative pesticide, solid, toxic/
/GUIDE 153: SUBSTANCES - TOXIC AND/OR CORROSIVE (COMBUSTIBLE)/ Spill or Leak: ELIMINATE all ignition sources (no smoking, flares, sparks or flames in immediate area). Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS. /Phenoxyacetic acid derivative pesticide, liquid, poisonous; Phenoxyacetic acid derivative pesticide, liquid, toxic; Phenoxyacetic acid derivative pesticide, solid, poisonous; Phenoxyacetic acid derivative pesticide, solid, toxic/
/GUIDE 153: SUBSTANCES - TOXIC AND/OR CORROSIVE (COMBUSTIBLE)/ First Aid: Move victim to fresh air. Call 911 or emergency medical service. Give artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; give artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult. Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush skin or eyes with running water for at least 20 minutes. For minor skin contact, avoid spreading material on unaffected skin. Keep victim warm and quiet. Effects of exposure (inhalation, ingestion or skin contact) to substance may be delayed. Ensure that medical personnel are aware of the material(s) involved and take precautions to protect themselves. /Phenoxyacetic acid derivative pesticide, liquid, poisonous; Phenoxyacetic acid derivative pesticide, liquid, toxic; Phenoxyacetic acid derivative pesticide, solid, poisonous; Phenoxyacetic acid derivative pesticide, solid, toxic/
【Reactivities and Incompatibilities】
Contact with strong oxidizers may cause fires or explosions.
Strong oxidizers.
2,4-D is a strong acid, & forms water-soluble salts with alkali metals & amines.
【Other Preventative Measures】
Handle carefully. Do not contaminate water, food or feed by product storage or disposal. ... Do not use spray equipment contaminated with this product for any other purposes unless thoroughly cleaned with a suitable cleaner. ... Do not apply where irrigation water may be contaminated.
Respirators may be used when engineering and work practice controls are not technically feasible, when such controls are in the process of being installed, or when they fail and need to be supplemented. Respirators may also be used for operations which require entry into tanks or closed vessels, and in emergency situations. ... If employees' clothing ... becomes contaminated with 2,4-D, employees should change into uncontaminated clothing before leaving the work premises. Clothing contaminated with 2,4-D should be placed in closed containers for storage until it can be discarded or until provision is made for the removal of 2,4-D from the clothing. If the clothing is to be laundered or otherwise cleaned to remove 2,4-D, the person performing the operation should be informed of 2,4-D's hazardous properties. Non-impervious clothing which becomes contaminated with 2,4-D should be removed promptly and not reworn until the 2,4-D is removed from the clothing.
Eating and smoking should not be permitted in areas where solid 2,4-D is handled, processed, or stored. Employees who handle 2,4-D or liquids containing 2,4-D should wash their hands thoroughly with soap or mild detergent before eating, smoking, or using toilet facilities.
/Individuals/ not wearing protective equipment and clothing should be restricted from areas of spills until cleanup has been completed.
In addition to respirator selection, a complete respiratory protection program should be instituted which includes regular training, maintenance, inspection, cleaning, and evaluation /of equipment/.
SRP: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.
If material /is/ not involved in fire: Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Keep upwind. ... Avoid breathing vapors or dusts. Wash away any material which may have contacted the body with copious amounts of water or soap and water.
Smoking, eating, and drinking before washing should be absolutely prohibited when any pesticide ... is being handled or used. /Pesticides/
/When/ cleaning glassware and spray equipment: wash thoroughly with water and detergent soln. Alcohol or ketone type solvents may be used with ester formulations. Preferably, equipment should not be used for application of other pesticides or fertilizers.
The worker should immediately wash the skin when it becomes contaminated.
Work clothing that becomes wet or significantly contaminated should be removed and replaced.
Workers whose clothing may have become contaminated should change into uncontaminated clothing before leaving the work premises.
Handle carefully. Do not contaminate water, food, or feed by product storage or disposal. Do not use spray equipment contaminated with this product for any other purposes unless thoroughly cleaned with a suitable cleaner. Do not apply where irrigation water may be contaminated.
【Protective Equipment and Clothing】
If the use of respirators is necessary, the only respirators permitted are those that have been approved by the Mine Safety and Health Administration (formerly Mining Enforcement and Safety Administration) or by the National Institute for Occupational Safety and Health. ... Employees should be provided with and required to use impervious clothing, gloves, face shields (eight-inch minimum), and other appropriate protective clothing necessary to prevent repeated or prolonged skin contact with 2,4-D or liquids containing 2,4-D. ... Employees should be provided with and required to use dust- and splash-proof safety goggles where 2,4-D or liquids containing 2,4-D may contact the eyes.
Wear appropriate personal protective clothing to prevent skin contact.
Wear appropriate eye protection to prevent eye contact.
Respirator Recommendations: Up to 100 mg/cu m: (APF = 10) Any chemical cartridge respirator with organic vapor cartridge(s) in combination with a dust, mist, and fume filter/(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister having a high-efficiency particulate filter/(APF = 25) Any powered, air-purifying respirator with organic vapor cartridge(s) in combination with a dust, mist, and fume filter/(APF = 10) Any supplied-air respirator/(APF = 50) Any self-contained breathing apparatus with a full facepiece.
Respirator Recommendations: Emergency or planned entry into unknown concentrations or IDLH conditions: (APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode/(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus.
Respirator Recommendations: Escape: (APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister having a high-efficiency particulate filter/Any appropriate escape-type, self-contained breathing apparatus.
【Octanol/Water Partition Coefficient】
log Kow= 2.81
【Disposal Methods】
Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste numbers D016 and U240, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.
Landfill: Recommendable method: Incineration. Not recommendable method: Discharge to sewer. Peer-review: Incinerate at high temp or PCDDs may be formed.
Incineration and landfill: 2,4-D /2,4-dichlorophenoxyacetic acid/ is known to be readily detoxified by soil microorganisms and at low dosages is normally decomposed in one to four weeks. The detection of 2,4-dichlorophenol, 4-chlorocatechol, chloromuconic and succinic acids from either soil or pure culture studies suggests a sequence of reactions involving ring hydroxylation and cleavage and further metabolism of the open chain structure to carbon dioxide. The non-persistence and detoxification of 2,4-D in soil indicate that burial in non-crop areas away from water supplies would be an acceptable method for the disposal of small quantities of 2,4-D. Incineration at high temperatures with sufficient residence time leads to complete detoxification of 2,4-D and is the most environmentally acceptable method for 2,4-D disposal. For the decontamination of 2,4-D containers-drums: triple rinse and drain procedure ("triple rinse" means the flushing of containers three times of the normal diluent equal to approximately 10% of the container's capacity and adding the rinse liquid to the spray mixture or disposing of it by the method prescribed for disposing of the pesticide). Small containers should be punched full of holes, crushed and taken to a landfill.
Chemical treatment: Detoxification requires treatment with chloride of lime or sodium carbonate. Rinse containers with a 5% soln of caustic soda. Farms are allowed to destroy if necessary up to 10 kg of the pesticide. Removal of 17% of 2,4-D /(2,4-dichlorophenoxy)acetic acid/ from water is achieved by coagulation and complete water treatment by ozonation; the use of activated charcoal is an effective treatment technique.
Herbicide orange /was incinerated/ by the use of two identical refractory lined furnaces on board the Mt Vulcanus while at sea. The average wall temperature was 1273 deg C and average flame was 1500 deg C. A residence time of 1.0 second was used. Combustion efficiency was > 99.98%. Destruction efficiency was: 2,4-D > 99.9%; 2,4,5-T > 99.9%; Total hydrocarbon 99.982 to 99.992%; Herbicide orange > 99.999%; 2,3,7,8-tetrachlorodibenzo-p-dioxin > 99.93 to > 99.99%; Chlorinated hydrocarbons > 99.999%. /From table/
The following wastewater treatment technology have been investigated for 2,4-D and related herbicides: Concentration process: Resin adsorption.

Use and Manufacturing

【Use and Manufacturing】
Methods of Manufacturing

By chlorination of molten phenoxyacetic acid; from 2,4-dichlorophenol, sodium and ethyl chloroacetate followed by hydrolysis of ester.
2,4-D is produced commercially by chlorination of phenol to form 2,4-dichlorophenol, which reacts with monochloroacetic acid to form 2,4-D.
U.S. Exports

(1972) 3.18X10+9 G (2,4-D & SALTS & ESTERS)
(1978) 2.97X10+9 G (2,4-D INCL ESTERS & SALTS)
(1983) 4.65X10+9 G (2,4-D INCL ESTERS & SALTS)
(1985) 1.60X10+9 g
(1987) 8.74X10+6 lb
U.S. Imports

(1977) 1.14X10+9 G
(1982) 3.24X10+9 G
(1983) 9.89X10+6 lb
U.S. Production

(1978) 2.19X10+10 G-DEMAND (2,4-D INCL ESTERS & SALTS)
(1982) 2.05X10+10 G-DEMAND (2,4-D INCL ESTERS & SALTS)
(1991) Exceeded 5000 lb or US $5000 in value
(1946) 5.5 million lbs; (1950) 14 million lbs; (1960) 36 million lbs; (1964) 54 million lbs; (1990) 52-67 million lbs; (2001) 47 million lbs.
Consumption Patterns

HERBICIDE FOR PASTURE & RANGELAND, 26%; FOR WHEAT, 26%; FOR CORN, 14%; FOR OTHER GRAINS EXCEPT SORGHUM, 12%; FOR INDUSTRIAL/COMMERCIAL USES, 11%; FOR LAWNS & TURF, 3%; FOR AQUATIC USES, 3%: FOR GRAIN SORGHUM, 3%; FOR OTHER FIELD CROPS-EG, CITRUS, FRUITS, NUTS, & VEGETABLES, 2%; (1982)
75% AS A SELECTIVE HERBICIDE FOR BROADLEAF WEEDS & BRUSH, ON SMALL GRAINS, CORN, SORGHUM, RICE, OTHER MINOR CROPS, & GRAZING LAND; 13% FOR INDUSTRIAL & COMMERCIAL USE ON NON-CROPLAND; 6% BY GOVERNMENT AGENCIES ON NON-CROPLAND; 6% FOR HOME & GARDEN USE ON TURF (1972).
PASTURE & RANGELANDS, 26%; WHEAT, 26%; CORN, 14%; INDUSTRIAL/COMMERCIAL USES, 11%; LAWNS & TURF, 4%; AQUATIC USES, 3%; GRAIN SORGHUM, 3%; RICE, 1%; OTHER GRAINS, 11%; OTHER FIELD CROPS-EG, DECIDUOUS NUTS & FRUITS, CITRUS, & VEGETABLES, 2% (1982).
【Usage】

Herbicide. Used to increase latex output of old rubber trees

【Sampling Procedures】
Air Sampling Procedure: Commercial activated silica gel (60/70 mesh) was treated by Soxhlet extraction for two days using boiling methanol. The gel was then dried in an oven at 200 deg C for two days. Five grams of the gel was then packed into polyethylene air samplers ... and shielded from moisture. ... The samplers were placed on the vertical inlet of a vacuum line, 7 ft above ground level. The samplers were encased in a cage of mesh and the air flow was maintained at 10 l/min. The samplers were changed daily, wrapped to exclude moisture, and stored in a refrigerator until analysis. /SRP: Method is for the free acid and esters, not salts/
NIOSH Method 5001. Analyte: 2,4-D and 2,4,5-T. Matrix: Air. Sampler: Filter (glass fiber, binder less). Flow Rate: 1 to 3 l/min. Sample Size: 100 liters. Shipment: Routine. Sample Stability: At least 1 week @ 25 deg C. /2,4-D and 2,4,5-T/

Biomedical Effects and Toxicity

【Pharmacological Action】
- Pesticides used to destroy unwanted vegetation, especially various types of weeds, grasses (POACEAE), and woody plants. Some plants develop HERBICIDE RESISTANCE.
【Biomedical Effects and Toxicity】
2,4-D ... was readily absorbed by humans after oral ingestion (5 mg/kg), & maximal plasma concns of 30 ug/ml were attained after 7-12 hr; 75% of the dose was excreted unchanged in the urine within 96 hr, & no metabolites were detected.
When (14)C-2,4-D was injected iv into volunteers, 100% was recovered in the urine. The rate of excretion ranged from about 3-5% of the dose/hr during the first 12 hr; it then declined gradually, but a trace was still detectable in urine collected 96-120 hr after injection. Following dermal application, only 5.8% appeared in the urine within 5 days. ... Six volunteers ... /ingested/ one dose of 2,4-D at the rate of 5 mg/kg. Absorption was rapid; the cmpd appeared in the blood within 1 hr, & reached its max level of 25-50 ppm in 7-12 hr in different men. 2,4-D appeared in urine within 2 hr. Ninety-six hr after ingestion, 76% of dose had been excreted unchanged in urine.
Distribution of 2,4-D occurs throughout the body, but there is no evidence that it is accumulated. Transformation in mammals appears to occur only to a slight extent & mainly involves the production of 2,4-D conjugates with sugars or amino acids. A single dose is excreted within a few days, mainly with the urine, & to a much lesser extent in the bile & feces.
Pretreatment of rats with 2,4-D (250 mg/kg, sc) so occupied binding sites on plasma proteins that the distribution of (14)C-2,4-D admin iv 3.5 to 4.5 hr later was changed relative to controls, the concn being less in the plasma & kidney & greater in the liver, brain, spinal fluid, testis, lung, heart, & muscle.
... Human beings excrete 2,4-D mainly in the urine, & the blood plasma clearance times depend on the dose, individual characteristics, & the presence or absence of cmpds that may competitively inhibit 2,4-D excretion. For single oral doses of 2,4-D, the biological half-life in blood plasma is about one day, depending on the circumstances. However, forced alkaline diuresis may reduce this to as little as 3.7 hr.
FOUR MEN SPRAYING 2% EMULSION IN KEROSENE FROM TRACTORS WERE EXPOSED TO PHENOXY ACIDS. AIRBORNE CONCNS WITH STATIONARY SAMPLING POINT & FROM THE INDIVIDUAL BREATHING ZONE SHOWED A MEAN 2,4-D & 2,4,5-T CONCN OF 0.1-0.2 MG/CU M. PLASMA & URINE LEVELS WERE FOLLOWED DURING THE WK OF EXPOSURE & FOR 36 HR AFTER EXPOSURE. THE HIGHEST LEVELS OF PHENOXY ACIDS WERE FOUND IN URINE WITH A MEAN OF 8 (2,4-D) & 4.5 (2,4,5-T) UG/ML & RANGING FROM 3-14 UG/ML FOR 2,4-D & FROM 1-11 UG/ML FOR 2,4,5-T IN THE AFTERNOON AFTER A DAY OF EXPOSURE. THE MEAN 24 HR EXCRETION IN URINE WAS 9 MG OF 2,4-D & APPROX 1 MG OF 2,4,5-T. [KOLMODIN-HEDMAN B, ERNE K; ARCH TOXICOL (SUPPL) 4: 318-21 (1980)] PubMed Abstract
2,4-D was distributed evenly among various tissues in several species, after acute or chronic exposure. ... Plasma levels were usually slightly higher than other tissues, followed by renal levels, & then hepatic & pulmonary levels, although all were within the same order of magnitude. 2,4-D was further distributed to the plasma fraction of whole blood primarily, & to the cytosol subfraction in cells. 2,4-D showed high affinity binding to the albumin fraction of serum. 2,4-D was not accumulated in fat or muscle of sheep or cattle during a 28 day feeding experiment.
The rate of dermal absorption of 2,4-D has been measured in human volunteers; 100% of the dose was excreted in the urine during the subsequent 5 days. The biological half-life for excretion was 13 hr. (14)C-2,4-D was then applied to the forearm, & excretion of radioactivity was monitored over the subsequent 8 days. Using this method, 5.8% of the dose was absorbed & excreted. This rate was increased to 14.7% by occluding the application site with plastic film for 24 hr after dosing.
Plasma 2,4-D concn did not exceed 0.2 mg/l in workers exposed to 2,4-D ester at an atmospheric concn of 0.1 to 0.2 mg/l; no accumulation was noted during the work wk. ... Workers ... excreted 2,4-D urine concns of 3-14 mg/l after a day of exposure.
AFTER SC INJECTION OF 2,4-D & ITS BUTYL & ISOOCTYL ESTERS INTO MICE @ 100 MG/KG, ESTERS WERE ELIM RAPIDLY, & ONLY 5-10% OF THE 2,4-D REMAINED AFTER 1 DAY. ... 2,4-D WAS ELIM IN MILK OF COWS MAINTAINED IN PASTURES TREATED WITH 2,4-D OR ITS BUTYL OR ISOOCTYL ESTER.
... ISOOCTYL ESTER OF 2,4-D DISAPPEARED FROM BODIES OF INJECTED MICE MORE RAPIDLY THAN 2,4-D ACID.
/RELATIVE/ RATES OF DISAPPEARANCE FROM PLASMA OF 2,4-D OR ITS BUTYL & ISOOCTYL ESTERS FOLLOWING SINGLE SC INJECTIONS OF 100 MG/KG BODY WT OF COMPOUNDS TO FEMALE C57BL/6 MICE WERE: BUTYL ESTER > ISOOCTYL ESTER > 2,4-D.
AFTER ORAL ADMIN OF 0.05 MG/KG BODY WT TO RATS, TRACES WERE DETECTED IN MILK OF LACTATING ANIMALS FOR 6 DAYS. WITHIN 24 HR AFTER ADMIN 2,4-D TO PREGNANT RATS, 16.8% OF DOSE WAS DETECTED IN UTERUS, PLACENTA, FETUS & AMNIOTIC FLUID. 2,4-D ... PASSES THE PLACENTAL BARRIER IN PIGS.
The amounts of 2,4-D excreted by workers occupationally exposed to 2,4-D has been used to estimate total doses absorbed by these workers. Aerial applicators excreted an average 0.012 mg/kg body weight/day of 2,4-D after a 12 day exposure period; Ground applicators excreted a mean of 0.013 mg/kg of 2,4-D over a 6-day period after a 1 day exposure.
WHEN 2,4-D WITH LABELED CARBON WAS ADMIN ORALLY TO SHEEP, 96% OF DOSE WAS EXCRETED UNCHANGED IN URINE IN 72 HR, SLIGHTLY 
In 1.4 minutes, 50% of intratracheally instilled doses of 2,4-D were absorbed by the /rat's/ lung, indicating that alveolar transport was probably by diffusion.
Levels of 2,4-D were measured in the rat brain and cerebrospinal fluid after a 100 mg/kg (slightly toxic) dose. In comparison, (250 mg/kg) produced myotonia and lethargy and resulted in 11- and 39-fold increases in 2,4-D concentration in the brain and cerebrospinal fluid respectively, while 500 mg/kg produced 18- and 67-fold increases, in 2,4-D concentrations, respectively. Increases in hepatic 2,4-D levels were also produced, although less dramatic.
... Female dogfish sharks (Squalus acanthias) were admin (14)C-2,4-D iv. Urine, bile, & blood were collected & analyzed for radioactivity, along with tissues. Urine contained 53% of the admin dose of 2,4-D in 4 hr, 68% in 1 day, & 90% in 6 days. 2% of the dose was excreted in bile in 6 days. From 94-98% of the radioactivity in urine & bile was conjugated to taurine, 2-4% was present as 2,4-D, acid & 4% as 2 unidentified metabolites. The half-life of plasma clearance of 2,4-D was 44 min. Tissue levels for the kidney & liver were 2-40 times that for the plasma, & were lower than plasma levels for muscle, brain, & cerebrospinal fluid. Plasma binding ... was about 57% for concns up to 50 ug/ml herbicide. ...
The chlorinated phenoxy acid herbicides appear to have similar pharmacokinetics. They are rapidly & almost completely absorbed from an oral dose. They distribute to other tisues & are highly protein-bound in the plasma. The chlorinated phenoxy acid herbicides are rapidly eliminated unchanged in the urine by an active process in the kidneys. Increasing doses apparently influence absorption, metab, distribution & elimination of the chlorinated phenoxy acid herbicides so that biological effects are increased. Combinations of chlorinated phenoxy acid herbicides are likely to result in additive or potentiated biological effects. Data suggest that chlorinated phenoxy acid herbicide toxicosis may be alleviated by treatment with fluids & bicarbonate to increase urinary pH & volume, thereby increasing excretion. [Arnold EK, Beasley VR; Vet Hum Toxicol 31 (2): 121-5 (1989)] PubMed Abstract
The distribution of 3 common (14)C-labelled chlorophenoxyacetic acid herbicides (2,4-dichlorophenoxyacetic acid or 2,4-D, 2-methyl-4-chlorophenoxyacetic acid or MCPA, 2,4,5-trichlorophenoxyacetic acid or 2,4,5-T) into the different brain areas was studied in rats pretreated with toxic doses of the herbicides (238-475 mg/kg). Also, their binding to proteins in rat plasma was determined in vitro by increasing the concns of chlorophenoxyacetic acids in the incubate from 0 to 1 mg/ml. Both 2,4-D & 2-methyl-4-chlorophenoxyacetic acid pretreatments increased brain concns of (14)C-labelled herbicides more markedly than 2,4,5-T pretreatments. No essential differences were found in the distribution between the different brain areas. Protein-unbound fractions of 2,4-D & 2-methyl-4-chlorophenoxyacetic acid in the plasma were higher than those of 2,4,5-T but the highest herbicide concn increased the protein-unbound fraction of 2,4,5-T more (7-13 fold) than of 2,4-D & 2-methyl-4-chlorophenoxyacetic acid (5 fold). The greater incr in the penetration into the brain of 2,4,-D & 2-methyl-4-chlorophenoxyacetic acid than of 2,4,5-T during their intoxication is due to factors other than the changes in their binding to plasma proteins & enhanced diffusion through the blood brain barrier. [Tyynel a K et al; Arch Toxicol 64 (1): 61-5 (1990)] PubMed Abstract
This study was designed to measure potential dermal and respiratory exposure during the application of 2,4-dichlorophenoxy acetic acid, with 5 types of application equipment commonly used in the United Kingdom. For all 5 sprayers, potential respiratory exposure, where detectable at all, was negligible compared with potential dermal exposure. [Abbott IM et al; American Industrial Hygiene Association Journal 48 (2): 167-75 (1987)] PubMed Abstract
The exposure of forestry ground crews applying 2,4-dichlorophenoxy acetic acid (2,4-D), dichloroprop, and picloram was determined as a function of varying application methods and safety measures. Backpack sprayers received very high exposures to herbicides due to absorption of the chemicals through their clothes and skin (0.04 to 0.24 mg/kg body weight for 2,4-D). ...
Renal slices were prepared from kidneys of male Sprague-Dawley rats and were preloaded by incubation with 7.65 ug of (14)Carbon 2,4-D in 3 ml buffer for 1 hr at 25 deg C. The slices were then transferred through a series of 18 sequential 1 min washes and the radioactivity transferred into each wash solution and the amount that remained in the tissue was counted. The rate constant for efflux was then calculated. Tissue extracts were analyzed by paper electrophoresis for radioactive metabolites of 2,4-D. The kinetics of efflux were comprised of a fast and a slow component. Compounds that significantly increased the slow phase when added to the efflux medium were probenecid, dinitrophenol, stilbene derivative, iodoacetamide, succinate; Succinate and lactate both increased the rate for the fast phase. The rate of 2,4-D efflux was temperature dependent, with faster rates for 15 deg C and 35 deg C than at 25 deg C. Efflux was significantly increased (slow phase only) in potassium free buffer, but was unaltered in calcium-free buffer. Uptake of 2,4-D was linear for 7 hr and transported 2 times more 2,4-D into the kidney than was transported out by the efflux mechanism. At 20 uM, 2,4-D produced a 50% inhibition of para-aminohippurate accumulation in renal cortical slices. ... /SRP: Formulation not specified/
Absorption and urinary excretion of 2,4-dichlorophenoxyacetic acid sodium and 2,4-dichlorophenoxyacetic acid dimethylammonium salts were examined after single oral and mid-dorsal skin applications of the herbicides to male rats. Doses of 2.6 mg 2,4-D/kg body wt (2,4- dichlorophenoxyacetic acid sodium) and 1.9 mg 2,4-D/kg body wt (2,4- dichlorophenoxyacetic acid dimethylammonium) were applied. Quantitatively, with both salts, most of the orally administered herbicide (over 90%) was excreted in urine within 28 hr. However, 2,4-D urinary peak concentrations were measured 4.5 and 20.5 hr after dosing with 2,4-dichlorophenoxyacetic acid dimethylammonium and 2,4- dichlorophenoxyacetic acid sodium, respectively. Additionally, the volume of urine in the oral study was significantly increased with both salts when compared with the controls or the dermal exposure. After topical application, 2,4-D absorption was much lower than in the oral study. Urinary excretion only reached about 10 and 15% of the applied dose for 2,4-dichlorophenoxyacetic acid sodium and 2,4- dichlorophenoxyacetic acid dimethylammonium, respectively, by 5 days post-treatment. Further, it was found some elevations in hepatic cytochrome p450 activities. Ethylmorphine N-demethylase was only slightly induced by the herbicides while ethoxyresorufin O-deethylase activity was increased nearly 2 fold by 2,4-dichlorophenoxyacetic acid sodium. [Knopp D, Schiller F; Arch Toxicol 66 (3): 170-4 (1992)] PubMed Abstract
2,4 D was rapidly absorbed, distributed, and excreted after oral administration to mice, rats, and goats. At least 86-94% of an oral dose was absorbed from the gastrointestinal tract in rats. 2,4 D was excreted rapidly and almost exclusively (85-94%) in urine by 48 hr after treatment, primarily as unchanged 2,4 D.
Absorption of 2,4-D appears to be rapid & complete from the GI tracts of humans & experimental animals ... . Although ingestion is usually a relatively minor route of exposure, most toxicity testing of 2,4-D has been conducted by oral exposure. Because 2,4-D is absorbed more efficiently through the GI tract than through the skin, 2,4-D should be more toxic when ingested than when applied to the skin.
Once absorbed, 2,4 D was widely distributed throughout the body, but did not accumulate because of its rapid clearance from the plasma & rapid urinary excretion ... . The excretion, tissue residues, & metab of 14C 2,4-D were investigated in a lactating goat given an oral dose of 483 ppm for 3 consecutive days in a capsule. About 90% of the dose was recovered in the urine and feces. Milk, liver, kidneys, composite fat, and composite muscle accounted for 
Almost all of a 2,4-D oral dose in absorbed in humans within 24 hr. Peak plasma concns are reached between 4-24 hr ... . Six human volunteers received 5 mg/kg (370 mg/70 mg) of 2,4-D orally. The average peak plasma concn was 35 mg/L at 24 hr. The mean plasma half-life in this study was 33 hr. They are highly protein bound in plasma. Elimination is rapid. 2,4-D metabolites other than conjugates have not been detected in human urine. During the 4 days following the ingestion by the 6 subjects above, 77% of the dose was eliminated unchanged in the urine. All remained asymptomatic. In another study five male human volunteers ingested a single oral dose of 5 mg/kg 2,4-D. No detectable clinical effects were noted. The average plasma T1/2 was 11.6 hr with a mean urine T1/2 of 17.7 hr. 83% of the ingested oral dose was excreted as the parent cmpd, & 12.8% of the oral dose was excreted in the urine as an acid-labile conjugate.
...The physiologic distribution of ... 2,4-D in humans is not fully understood, but it appears that /it/ may distribute into only one or two compartments. This would be in contrast to other mammals, in which multiple compartments are found. It also appears that humans store 2,4-D in the liver & kidneys after high-level exposure, while the liver, kidney, lungs, spleen, & heart of other mammalian species have been found to have high 2,4-D levels. Urinary excretion is the primary route for elimination ... . It is important to note that it has been found that elimination is not first order; that is, the rate of excretion of ... 2,4-D depends on the initial concn. When the kinetics of a bioreaction are not first order, extrapolation of effects from high concns to low ones, or vice versa, usually is not possible unless the kinetics have been carefully studied & the rate constants calculated.
2,4-Dichlorophenoxyacetic acid (2,4-D), a widely used broadleaf herbicide, is under investigation in a study of peroxisome proliferators. To supplement that study, male and female rats, mice, and hamsters were dosed with 14C-2,4-D orally at 5 and 200 mg/kg and tissue distributions were determined. Blood, liver, kidney, muscle, skin, fat, brain, testes, and ovaries were examined. At early time points tissues from female rats consistently contained higher amounts of radioactivity than did corresponding tissues from males (up to 9 times). By 72 hr, tissue levels were equivalent and males and females had excreted equal amounts of radioactivity. This sex difference was absent in mice. In hamsters, males had higher tissue levels than females. Taurine, glycine, and glucuronide conjugates of 2,4-D were excreted along with parent. Metabolite profiles differed between species qualitatively and quantitatively; however, differences between sexes were minimal. Plasma elimination curves were generated in male and female rats after iv and oral administration. Kinetic analysis revealed significant differences in elimination and exposure parameters consistent with a greater ability to clear 2,4-D by male rats relative to females. [Griffin RJ, et al; Drug Metab Dispos 25 (9): 1065-1071 (1997)] PubMed Abstract
The role of biliary elimination in the metabolic disposition of 2,4-D was evaluated in male and female Sprague-Dawley rats, B6C3F1 mice, and Syrian hamsters. Following cannulation of the bile duct, an intragastric (ig) dose of 2,4-D (200 mg/kg) was administered and bile was collected at 30- or 60-min intervals for up to 6 h. Bile flow rates were constant in rats, increased in mice, and decreased in hamsters throughout the collection periods. Total recovery of radioactivity was greatest in male mice (about 7% of administered dose over 4 h). Female mice and rats of both sexes excreted about 3% over the same interval and male and female hamsters about 1%. About 71-88% of the activity in bile was parent compound. The glycine conjugate of 2,4-D was found in bile from mice, rats, and hamsters and the taurine conjugate in bile from mice. The only sex-dependent difference in the metabolite profile was in mice. Male mice excreted twice as much glycine conjugate as female mice. An additional minor metabolite (4-7%) was present in rat and mouse bile. This was tentatively identified as 2,4-D-glucuronide based on its hydrolysis by beta-glucuronidase. One more very minor metabolite (3%) was detected in rat bile but was not characterized due to its lability. [Griffin RJ, et al; J Toxicol Environ Health 51 (4): 401-413 (1997)] PubMed Abstract
The distribution of 2,4-dichlorophenoxyacetic acid (2,4-D) was examined in maternal & fetal rabbits. Pregnant New Zealand rabbits (28-30 d gestational age) were anesthetized with ketamine/xylazine & the femoral vein & artery were catheterized for compound admin & sampling. Dams received iv [14C]2,4-D (12.5 microCi/kg) with unlabeled sodium 2,4-D (1, 10, or 40 mg/kg) in saline. Blood & tissue were collected up to 2 hr after dosing. Fetal to maternal plasma AUC ratios were 0.09, 0.07, & 0.16 after the 1, 10, or 40 mg/kg dose, respectively. Extraplasma AUCs were greatest in maternal kidney & uterus & lowest in maternal & fetal brain. A >fourfold elevation in fetal AUC was found when the dose was increased from 10 to 40 mg/kg, suggesting saturation of maternal plasma binding of 2,4-D. Although the in vitro fetal brain tissue to incubation media ratio was unity (1.03 + or - 0.1, mean + or - SD), fetal brain AUCs were 10% or less of the fetal plasma AUCs, indicating the brain barrier system to 2,4-D is functioning in the late-gestation fetal rabbit.[Sandberg JA, et al; J Toxicol Environ Health 49 (5): 497-509 (1996)] PubMed Abstract
... Transport of the herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), was examined in rat renal cortical slices and basolateral membrane vesicles. In slices, uptake of 2,4-D increased steadily over time, approaching steady-state tissue/medium ratios of approximately 8 after 60 min. Probenecid, PAH and chlorophenol red inhibited steady-state uptake of 2,4-D. Accumulation of 10 microM 2,4-D was stimulated 2-fold by 60 microM glutarate; other dicarboxylic acids failed to stimulate uptake. In the presence of sodium, the addition of 5 mM LiCl or 2 mM ouabain to the bathing medium abolished glutarate stimulation. Removal of sodium from the bathing medium reversibly inhibited uptake as much as 75%. Furthermore, PAH inhibited 2,4-D uptake by slices in a dose-dependent manner, and increasing the external 2,4-D concentration decreased the inhibitory potency of PAH. In basolateral membrane vesicles, unlabeled 2,4-D inhibited sodium glutarate-coupled uptake of 3H-labeled PAH and 2,4-D in a concentration-dependent manner. Moreover, concentrative uptake of 2,4-D into vesicles could be driven by an outwardly directed gradient of glutarate or alpha KG that was generated by lithium-sensitive Na+/dicarboxylate cotransport or imposed experimentally. An outwardly directed gradient of unlabeled 2,4-D or PAH also stimulated uptake of 2,4-D. [Villalobos AR, et al; J Pharmacol Exp Ther 278 (2): 582-589 (1996)] PubMed Abstract
... With control acetone vehicle, in vivo absorption of 2,4-D in the rhesus monkey was 8.6 +/- 2.1% of the dose, which compared closely to published human absorption of 6.0 +/- 2.4%. Percutaneous absorption from soil loads of 1 & 40 mg/cm2 were 9.8 +/- 4.0 & 15.9 +/- 4.7%, respectively, values similar to acetone vehicle. In vitro absorption in human skin calculated from skin contact accumulation over 24 hr was 1.8 +/- 1.7, 1.7 +/- 1.3, & 1.4 +/- 1.2% for soil loads of 5, 10, & 40 mg/cm2, respectively. Thus, soil load did not affect 24 hr percutaneous absorption. Current EPA recommended calculated reductions due to soil load are not supported by these results with 2,4-D. Percutaneous absorption of 2,4-D from acetone vehicle for 8 hr dosing period was 3.2 +/- 1.0%, one-third the value of 8.6 +/- 2.1% over 24 hr. With soil vehicle, absorption for 8 hr was only 0.03 +/- 0.02% for 40 mg/cm2 soil load & 0.05 +/- 0/.004% for 1 mg/cm2 soil load. Absorption for 16 hr was 2.2 +/- 1.2%. Absorption over time was linear for acetone vehicle, where total dose is deposited on skin, but not linear for soil vehicle, which had an 8 hr delay (lag time). This equates with a normal 8 hr work day where most of the contaminated soil can be washed off the skin. [Wester RC, et al; J Toxicol Environ Health 47 (4): 335-344 (1996)] PubMed Abstract
The influx of 2,4-dichlorophenoxyacetic acid (2,4-D) into Chinese hamster ovary (CHO) cells was studied. The cells mainly took up but did not metabolize the undissociated form of the herbicide. The uptake of 2,4-D was carried out against a concentration gradient and was inhibited by sodium azide and dinitrophenol. The results presented here show that the herbicide influx was an active, energy dependent process. (Na+ + K+)ATPase does not seem to be involved because ouabain, an inhibitor of the enzyme, did not affect the 2,4-D uptake. [Bergesse JR, Balegno HF; Toxicol Lett 81 (2-3): 167-173 (1995)] PubMed Abstract
Percutaneous absorption of the 14C-ring-labeled phenoxy herbicide 2,4-D-amine (2,4-dichlorophenoxyacetic acid dimethylamine) was examined following topical applications of the herbicide to the palm and forearm of human volunteers. The effect of two vehicles (water and acetone) and the mosquito repellent DEET (N,N-diethyl-m-toluamide) on dermal absorption of 2,4-D-amine also was investigated. The total percent dermal absorption was calculated from the mean percent urinary recoveries and was not corrected for nonurinary excretion. The data revealed 14 +/- 4.5% (standard deviation) and 10 +/- 11.5% palmar absorption of 2,4-D-amine applied in water, with and without DEET, respectively, and 7 +/- 6.2% and 13 +/- 5.0% forearm absorption of the herbicide applied in water or acetone, respectively. Soap-and-water skin washes conducted at 24 h posttreatment removed up to 34% of the applied dose. Successive tape strips of skin taken at 24 h posttreatment demonstrated generally decreasing herbicide levels in the outer layers. The data bring into question the complete validity of the rhesus monkey model to predict human dermal absorption. [Moody RP et al; J Toxicol Environ Health 36 (3): 241-50 (1992)] PubMed Abstract
The percutaneous penetration of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-D dimethylamine salt (DMA) was evaluated separately in five male volunteers who participated in both experiments. Urine samples collected for 144 h following dermal applications of 10 mg to the dorsum of the hand (9 cm2) were analyzed for 2,4-D. Following the acid application, an average of 4.46 +/- 0.849% was recovered in the urine and a significantly lower amount of 1.76 +/- 0.568% following the DMA application. Significantly higher amounts of 2,4-D DMA (7.68 +/- 0.493 mg) were washed off the hand 6 h following application as compared with 2,4-D acid (5.35 +/- 0.384 mg). These results indicate that, in addition to the differences in physical and chemical properties of the two compounds that will affect absorption, the amount of the chemical absorbed is related inversely to the amount of washed off. Urinary excretion of 2,4-D was not complete in all volunteers 144 h following either application, but in all cases it was approaching the limit of detection. An average of 84.8 +/- 2.55% and 76.8 +/- 8.05% of the total recovered in 144 h was recovered in the urine 96 h following 2,4-D acid and 2,4-D DMA application, respectively. Average, approximated half-lives for excretion were 39.5 +/- 8.1 h for the acid application and 58.5 +/- 13.2 h for the DMA application. [Harris SA, Solomon KR; J Toxicol Environ Health 36 (3): 233-40 (1992)] PubMed Abstract

Environmental Fate and Exposure Potential

【Environmental Fate/Exposure Summary】
AQUATIC FATE: Persistence in aquatic systems depends on the water type, organic particulate matter, rain, sunlight, temperature, microbial degradation, volatilization, and oxygen content of the water. Accumulation in bottom sediments may also be a factor, but in general, not for the phenoxys. Microbial activity is the major means for detoxification of the phenoxys in soils, but is relatively unimportant in natural waters, but dominates in bottom mud sediments and in sludge.
TERRESTRIAL FATE: Based on a classification scheme(1), Koc values ranging from 20 to 136(2-4), indicates that 2,4-D is expected to have high to very high mobility in soil(SRC). The pKa of 2,4-D is 2.73(5), indicating that this compound will primarily exist in the anion form in the environment and anions generally do not adsorb to soil more strongly than their neutral counterparts(6). Volatilization from moist soil surfaces is not expected to be an important fate process based upon this compound's pKa which indicates 2,4-D will exist almost entirely as an anion(SRC). 2,4-D is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure of 8.3X10-8 mm Hg at 20 deg C(5). Half-lives for 2,4-D volatilization from soil of 660 days (from 1 cm) and 7.1 yr (from 10 cm) were calculated by assuming a zero degradation rate(7). Biodegradation is by far the most important loss process for 2,4-D in most soils, leading to various hydroxylic aromatic products(8-10). The rate of degradation is affected by the conditions, especially the concns of 2,4-D and water content temperature and the organic content of soil and the status of preexposure of the soil to 2,4-D or its salts or its esters(11-12). Typical half-lives are short, ranging from 
TERRESTRIAL FATE: Laboratory studies were conducted to determine the adsorption, desorption, hydrolysis, and breakdown of commercially formulated isooctyl ester and dimethylamine salt of 2,4-D in a Naff silt loam soil(1). More 2,4-D was adsorbed to the surface soil than to soil at lower depths, and the percentage of 2,4-D adsorbed decreased as the total amount of 2,4-D present increased(1). Adsorbed 2,4-D was gradually desorbed from soil by successively exchanging the solution in equilibrium with soil with distilled water(1). Formulated 2,4-D isooctyl ester applied to moist soil underwent hydrolysis to the anionic form at a rapid rate, with 80% of the ester hydrolyzed in 72 hr(1). High amounts of 2,4-D in runoff (sediment and water) retarded the active degradation of carboxyl 14C 2,4-D when 2,4-D was incubated in runoff from a wheat field treated with various formulations and rates of 2,4-D(1). At the end of the 10 wk of incubation in runoff or in soil, only 1% of the 14C 2,4-D originally applied to the soil could be identified as 2,4-D(1). In another study, the degradation kinetics of 14C-labeled 2,4-D were studied in a number of soils(2). Degradation rates in soils were not simple first order but generally increased until approx 20% of chemical remained, after which they declined(2). Average 50% decomposition time of 4.0 days was observed for 2,4-D(2).
AQUATIC FATE: Based on a classification scheme(1), Koc values ranging from 20 to 136(2-4), indicates that 2,4-D is not expected to adsorb to suspended solids and sediment(SRC). The pKa of 2,4-D is 2.73(5), indicating that this compound will primarily exist in the anionic form in the environment and anions generally do not adsorb to organic carbon and clay more strongly than their neutral counterparts(6). Volatilization from water surfaces is not expected to be an important fate process based upon this compound's pKa which indicates 2,4-D will exist almost entirely in the ionized form at pH values of 5 to 9(SRC). According to a classification scheme(7), a BCF of 1 for bluegill sunfish(8), suggests that bioconcentration in aquatic organisms is low(SRC). When 2,4-D is released to water, it will tend to biodegrade with the rate especially dependent upon level of nutrients present, temperature, availability of oxygen, and whether or not the water has a prior history of contamination by 2,4-D or other phenoxyacetic acids(9). Typical half-lives of 10 to >50 days have been reported with longer half-lives expected in oligotrophic waters and where a high concn of 2,4-D is present(9,10). Degradation in sediments and lake muds is expected to be rapid with half-lives of 
ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2,4-D, which has a vapor pressure of 8.25X10-8 mm Hg at 20 deg C is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase 2,4-D may be removed from the air by wet and dry deposition(SRC). The primary source of 2,4-D in air is spray applications of the herbicide or its mixture(2-5). Spray drift is capable of carrying it up to a few km(6). No data were found concerning direct photolysis of 2,4-D in the atmosphere, although 2,4-D exhibits an absorption maximum at 288 nm which extends to wavelengths >290 nm suggesting that 2,4-D may be susceptible to direct photolysis(7).
Soil persistence and lateral movement of 2,4-D (2,4-dichlorophenoxy acetic acid) and picloram (4-amino-3,5,6-trichloropicolinic acid) were examined following their application as a stem-foliage spray for brush control on two power line rights-of-way. Ditches to collect runoff water were located 3, 10, 20, and 30 m downslope from the treated areas. Runoff water and soil samples were collected after 0.14, 0.43, 0.57, 1, 2, 4, 7, 8, 11, 15, 16, and 48 weeks and were analyzed for picloram and 2,4-D residues. Only 3 of 85 soil samples downslope from the target areas contained residues of 2,4-D, and only 1 of 85 down slope samples contained a detectable residue of picloram. Of 56 runoff water samples, only 11 contained 2,4-D residues and only 1 contained residues of picloram. The greatest distances down-slope at which residues were detected in runoff water were 20 and 10 m for 2,4-D and picloram, respectively. No residues of either herbicide were recovered in soil or water at 15 weeks or 48 weeks after spraying. Despite normal rainfall frequency and amounts in the first several weeks after spraying in mid-June, significant runoff of either herbicide was not evident at either study site. [Meru S et al; Arch Environ Contam Toxicol 19 (4): 572-7 (1990)] PubMed Abstract

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