Propachlor

Pesticide -> EPA IRIS

Herbicides

Active substance -> EU Pesticides database: Not approved

Pesticides -> Herbicides, Chloracetanilide

Environmental transformation -> Pesticides (parent, predecessor)

Pesticides -> Herbicides -> Amide herbicides -> Anilide herbicides -> Chloroacetanilide herbicides

log Kow = 2.18

2.36

Light tan solid

WHITE, CRYSTALLINE SOLID

Sol in common org solvents except aliphatic hydrocarbons

In acetone 448, benzene 737, toluene 342, ethanol 408, xylene 239, chloroform 602, carbon tetrachloride 174, diethyl ether 219 (all in g/kg, 25 °C).

SLIGHTLY SOL IN DIETHYL ETHER

In water, 580 mg/L at 25 °C

77 °C

Decomp temp: 170 °C

0.00074 [mmHg]

Vapor pressure at 110 °C: 0.03 mm Hg

7.4X10-4 mm Hg at 25 °C

Warning

H302: Harmful if swallowed [Warning Acute toxicity, oral]

P261, P264, P264+P265, P270, P272, P273, P280, P301+P317, P302+P352, P305+P351+P338, P321, P330, P333+P317, P337+P317, P362+P364, P391, and P501 (click each P-code to see the statement)

Warning

H302 (100%): Harmful if swallowed [Warning Acute toxicity, oral]

P261, P264, P264+P265, P270, P272, P273, P280, P301+P317, P302+P352, P305+P351+P338, P321, P330, P333+P317, P337+P317, P362+P364, P391, and P501 (click each P-code to see the statement)

Hazard Traits - Carcinogenicity; Hepatotoxicity and Digestive System Toxicity; Other Toxicological Hazard Traits

Regulation (EC) No 1107/2009 (amended)

2008/742

Propachlor: Does not have an individual approval but may be used under an appropriate group standard

The New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.)

FIRE POINT, 316 °C.

Nonflammable

It is in the acetanilide class of herbicides along with acetochlor, butachlor, metolachor, and alachlor; [Reference #1] Slight increase in unspecified anomalies reported in Russian study not available for review; [REPROTOX] Allergic contact dermatitis confirmed by patch testing in farmers and manufacturing workers; [Reference #2]

USEPA/Office of Pesticide Programs; Reregistration Eligibility Decision Document - Propachlor. 249 p. EPA 738-R-015 (November 1998) In evaluating pesticides for reregistration, EPA obtains and reviews a complete set of studies from pesticide producers, describing the human health and environmental effects of each pesticide. To implement provisions of the Food Quality Protection Act of 1996, EPA considers the special sensitivity of infants and children to pesticides, as well as aggregate exposure of the public to pesticide residues from all sources, and the cumulative effects of pesticides and other compounds with common mechanisms of toxicity. The Agency develops any mitigation measures or regulatory controls needed to effectively reduce each pesticide\'s risks. EPA then reregisters pesticides that meet the safety standard of the FQPA and can be used without posing unreasonable risks to human health or the environment. When a pesticide is eligible for reregistration, EPA explains the basis for its decision in a Reregistration Eligibility Decision (RED) document.[Available from, as of May 18, 2007: http://www.epa.gov/pesticides/reregistration/status.htm]

Environmental Health Criteria 147: Propachlor (1993) by the International Programme on Chemical Safety (IPCS) under the joint sponsorship of the United Nations Environment Programme, the International Labour Organisation and the World Health Organization. The Environmental Health Criteria (EHC) documents produced by the International Programme on Chemical Safety include an assessment of the effects on the environment and on human health of exposure to a chemical or combination of chemicals, or physical or biological agents. They also provide guidelines for setting exposure limits.

WHO; IPCS Health and Safety Guide No. 77. Propachlor (1992). The purpose of a Health and Safety Guide is to facilitate the application of Environmental Health Criteria (EHC) documents in national chemical safety programmes. The first three sections of a Health and Safety Guide highlight the relevant technical information in the corresponding EHC. Section 4 includes advice on preventive and protective measures and emergency action ... . The section on regulatory information has been extracted from the legal file of the International Register of Potentially Toxic Chemicals (IRPTC) and from other United Nations sources.

Tolerances are established for residues of the herbicide 2-chloro-N-isopropylacetanilide and its metabolites (calculated as 2-chloro-N-isopropylacetanilide) in or on the following raw agricultural commodities: [Table#2982]

Based on the reviews of the generic data for the active ingredient propachlor, the Agency has sufficient information on the health effects of propachlor and on its potential for causing adverse effects in fish and wildlife and the environment. The Agency has determined that propachlor products, labeled and used as specified in this Reregistration Eligibility Decision, will not pose unreasonable risks or adverse effects to humans or the environment. Therefore, the Agency concludes that products containing propachlor for all liquid and granular formulations are eligible for reregistration.

As the federal pesticide law FIFRA directs, EPA is conducting a comprehensive review of older pesticides to consider their health and environmental effects and make decisions about their future use. Under this pesticide reregistration program, EPA examines health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether they are eligible for reregistration. In addition, all pesticides must meet the new safety standard of the Food Quality Protection Act of 1996. Propachlor is found on List A, which contains most food use pesticides and consists of the 194 chemical cases (or 350 individual active ingredients) for which EPA issued registration standards prior to FIFRA, as amended in 1988. Case No: 0177; Pesticide type: Herbicide; Registration Standard Date: 12/01/84; Case Status: OPP is reviewing data from the pesticide's producers regarding its human health and/or environmental effects, or OPP is determining the pesticide's eligibility for reregistration and developing the Reregistration Eligibility Decision (RED) document.; Active ingredient (AI): Propachlor; Data Call-in (DCI) Date(s): 09/23/91, 10/13/95; AI Status: The producers of the pesticide has made commitments to conduct the studies and pay the fees required for reregistration, and are meeting those commitments in a timely manner.

Propachlor

Marine pollutant

This chemical is a combustible solid. Use dry chemical, carbon dioxide, water spray, or alcohol foam extinguishers. Poisonous gases are produced in fire including nitrogen oxides and chlorine. If material or contaminated runoff enters waterways, notify downstream users of potentially contaminated waters. Notify local health and fire officials and pollution control agencies. From a secure, explosion-proof location, use water spray to cool exposed containers. If cooling streams are ineffective (venting sound increases in volume and pitch, tank discolors, or shows any signs of deforming), withdraw immediately to a secure position. If employees are expected to fight fires, they must be trained and equipped in OSHA 1910.156.

Store technical material and formulations away from heat, under lock and key, and out of reach of children, animals and unathorized personel. Store in an area designated for herbicide storage, preferably without drains. Store away from food and animal feed.

Store in tightly closed containers in a cool, well vented area away form strong oxidizers. Where possible, automatically transfer material from drums or other storage containers to process containers. Sources of ignition such as smoking and open flames are prohibited where this chemical is handled, used, or stored. Metal containers involving the transfer of this chemical should be grounded and bonded. Whenever this chemical is used, handled, manufactured, or stored, use explosion-proof electrical equipment and fittings.

Prevent exposure by the use of appropriate protective clothing and masks. Keep spectators away from any spillage. Empty any product remaining in damaged or leaking containers into a clean empty drum, and label. Absorb spillage with lime, damp sawdust, sand, or earth and dispose of safely (see below). If spillage is large, contain it by building a barrier of earth or sandbags. Avoid contamination of drains and waterways. Spills of powders should be cleaned up using a dustless method (e.g., by a vacuum cleaner suitable for use with toxic dusts). Alternatively, mix with damp sawdust and place in separate container for subsequent disposal. Dry brushing should not be carried out, as this creates dust clouds.

Evacuate persons not wearing protective equipment from area of spill or leak until clean-up is complete. Remove all ignition sources. Collect powdered material in the most convenient and safe manner and deposit in sealed containers. Ventilate area after clean-up is complete. It may be necessary to contain and dispose of this chemical as a hazardous waste. If material or contaminated runoff enters waterways, notify downstream users of potentially contaminated waters. Contact your Department of Environmental Protection or your regional office of the federal EPA for specific recommendations. If employees are required to clean-up spills, they must be properly trained and equipped. OSHA 1910.120(q) may be applicable.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

Alkaline hydrolysis would yield N-isopropylaniline. However, incineration at 850 °C together with flue gas scrubbing is the preferred disposal method.

Propachlor should be incinerated in a unit operating at 850 °C equipped with off gas scrubbing equipment. Recommendable method: Incineration.

Surplus product, spilled material, contaminated absorbents, containers, etc., should be burned in a high-temperature incinerator (at least 800 C) with effluent gas scrubbing, designed for pesticide disposal. When no incinerator is available, bury in an approved dump or in an area where there is no risk of contamination of surface water. Comply with any local legislation applying to waste disposal.

Improper disposal of excess pesticide, spray mixtures or rinsate is a violation of federal law. If these wastes cannot be disposed of according to label use instructions, contact your State Pesticide or Environmental Control Agency or the Hazardous Waste representative at the nearest EPA Regional Office for guidance. Emptied container retains product residue. Observe all labeled safeguards until container is destroyed. Completely empty bag into equipment. Then dispose of empty bag in a sanitary landfill or by incineration, or, if allowed by state and local authorities, by burning. If burned, stay out of smoke. /Ramrod flake/

Those engaged in the production, formulation, and transportation and propachlor, and users, should be aware of the effects and hazards of the chemical. They should be systematically educated and trained in the practice of safety rules, good housekeeping, and personal hygiene, i.e., cleanliness, washing, and the use of their personal protection equipment

Do not get in eyes, on skin, or on clothmg. Wear goggles, face shield or safety glasses and rubber gloves. Wash thoroughly with soap and water after handling. /Ramrod Flake/

FIRST AID: IF IN EYES, immediately flush with plenty of water for at least 15 minutes. Get medical attention. IF ON SKIN, immedIately flush with plenty of water while removing contaminated clothing. Get medical attention. As soon as soap is available, wash skin thoroughly with soap and water. Wash clothing before reuse. Sensitized persons should avoid further contact and reuse of contaminated clothing. - - IF SWALLOWED, remove visible particles from mouth and rinse mouth thoroughly with water. Swallow water to dilute. Get medical attention. NEVER GIVE ANYTHING BY MOUTH TO AN UNCONSCIOUS PERSON. /Ramrod Flake/

SKIN: Prevention and Protection: Use proper application technique, and proper skin protection: clean, rubber, PVC, or neoprene gloves. First Aid: Remove contaminated clothing; wash skin with soap and water; launder contaminated clothing before reuse

For more Preventive Measures (Complete) data for PROPACHLOR (6 total), please visit the HSDB record page.

Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:

Wear protective gloves and clothing to prevent any reasonable probability of skin contact. Contact lenses should not be worn when working with this chemical. Wear dust-proof chemical goggles and face shield unless full face-piece respiratory protection is worn. Employees should wash immediately with soap when skin is wet or contaminated. Provide emergency showers and eyewash.

WEAR RUBBER GLOVES AND WASH THOROUGHLY AFTER HANDLING. CONTAMINATED CLOTHING SHOULD BE LAUNDERED BEFORE REUSE.

Consider gastric lavage, as well was dilution with milk or water after ingestion. Administer charcoal as a slurry following ingestion; however, activated charcoal should not be given to patients ingesting strong acidic or basic caustic chemicals. In case of inhalation, move patient to fresh air. Monitor for respiratory distress. If cough or difficulty breathing develops, evaluate for respiratory tract irritation, bronchitis, or pneumonitis. Administer oxygen and assist ventilation as required. Treat bronchospasm with inhaled beta2 agonist and oral or parenteral corticosteroids. Irrigate exposed eyes with copious amounts of room temperature water for at least 15 minutes. Following dermal exposure, remove contaminated clothing and wash exposed area thoroughly with soap and water. Treat dermal irritation or burns with standard topical therapy. Patients developing dermal hypersensitivity reactions may require treatment with systemic or topical corticosteroids or antihistamines. Administer symptomatic treatment as necessary. (T36)

LD50 PHEASANT ORAL 735 MG/KG /TECHNICAL MATERIAL/

LC50 /Anas platyrhynchos/ (Mallard duck) dietary >5000 ppm/8 day /technical propachlor/

LC50 /Colinus virginianus/ (Bobwhite quail) dietary >5000 ppm/8 day /technical propachlor/

TLM FATHEAD MINNOWS 0.49 MG/L/96 HR /TECHNICAL MATERIAL/ /CONDITIONS OF BIOASSAY NOT SPECIFIED/

For more Ecotoxicity Values (Complete) data for PROPACHLOR (16 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), Koc values of 73-125 measured in three soils(2), indicate that propachlor is expected to have high mobility in soil(SRC). Volatilization of propachlor from moist soil surfaces is expected to occur slowly(SRC) given an estimated Henry's Law constant of 3.6X10-7 atm-cu m/mole(SRC), derived from its vapor pressure of 7.5X10-4 mm Hg(3) and water solubility of 580 mg/L(3). Volatilization from dry soil surfaces is not expected to be an important environmental fate process(SRC) based on the vapor pressure of this compound(3). The biodegradation half-life of propachlor in a sandy loam soil incubated in the dark at 24.0 to 26.0 °C was 2.7 days(2). Field dissipation half-lives ranged from 1 to 5.8 days following application of propachlor at a rate of 6 lbs/A to fields located in Iowa, Nebraska and Texas(2).

Propachlor was applied to soil and to onions as pre- and post-emergence treatments. Residues of free N-isopropylaniline or propachlor were not present in the onions when harvested nor in soil when sampled one year afer treatment. Analyses of the onions and soil, however, did show the presence of a conjugated metabolite which was shown after hydrolysis to be N-isopropylaniline. Residues of this conjugate were present as much as 2 years after application.

Ring-(14)C-labeled alachlor and propachlor were studied in a model eco-system. Alachlor was degraded into eight compounds and propachlor into seven compounds. None were identified. In each case some of the material was unextractable. There was no evidence of magnification of the two compounds or their metabolites in the food chain.

AQUATIC FATE: Based on a classification scheme(1), Koc values of 73-125 measured in soil(2), indicate that propachlor is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected to be an important environmental fate process(3) based upon an estimated Henry's Law constant of 3.6X10-7 atm-cu m/mole(SRC), derived from its vapor pressure of 7.5X10-4 mm Hg(4) and water solubility of 580 mg/L(4). According to a classification scheme(5), BCF values of 1-71 measured in fish(2,6), suggests the potential for bioconcentration in aquatic organisms is low to moderate(SRC). Propachlor was stable to hydrolysis at pH 5, 7, and 9, and was slow to degrade in an aqueous photolysis study(2). Propachlor, at 5.9 ppm, degraded slowly, with a calculated half-life of 146 days for a lake water-sediment system incubated under anaerobic conditions in the dark at 24 to 26 °C for 12 months(2). Under aerobic conditions, propapchlor degraded with a half-life of 2.7 days in a sandy loam(2).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), propachlor, which has a vapor pressure of 7.5X10-4 mm Hg at 25 °C(1) is expected to exist solely in the vapor phase in the ambient atmosphere. Vapor-phase propachlor is degraded in the atmosphere by reaction with photochemically produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be about 18 hours(SRC) calculated from its rate constant of 2.1X10-11 cu cm/molecule-sec(SRC), derived using a structure estimation method(3). Direct photolysis in the atmosphere is not expected to be an important fate process since propachlor was very slow to degrade in an aqueous photolysis study.

Propachlor was applied to onions grown in organic soils in Ontario, Canada in 1974 as pre-emergence and early and late postemergence treatment at rates of 7.2 and 12 kg/ha active ingredient(1). The concn of N-isopropylaniline (metabolite of propachlor) ranged from 0.03 to 0.40 mg/kg compared to a concn of 0.03 mg/kg in onions from untreated fields(1). When the treatment rates were reduced to 3.0 to 6.0 kg/ha and onions were harvested 19-193 days following application in 1985, the concn of onion-bound metabolite ranged less than 0.01 to 0.08 mg/kg(2). In a pesticide residue screening program, propachlor was not detected (detection limit, 0.5 mg/kg) in 6970 domestic and imported produce(3). Propachlor was identified, not quantified, in the 2001 FDA Market Basket Survey of domestic and imported food items(4). It was monitored for but not detected in the 2000, 2002, and 2003 Market Basket Surveys(4).

... A study /was carried out/ to determine the rates and routes of excretion of orally administered synthetic 14C-labelled propachlor plant metabolites in lactating goats and to quantify and identify the radioactive metabolites in the goat milk, tissues, urine and feces. The daily dose level for the three treated goats was 15 mg/kg administered on 5 consecutive days (the actual dose levels for the treated goats were 13, 14.5 and 13 mg/kg, respectively). Each treated goat received a total of 130.5 mg of the 13C/14C-labelled propachlor plant metabolites mixture during the dosing period. A control animal received placebo capsules. ...The radioactivity found in the milk accounted for only 0.084, 0.10 and 0.13% (average 0.10%) of the administered dose. These values corresponded to metabolite concentrations in the milk of 11.9, 14.8 and 18.0 ug/L (average 14.9 ugL). ...The loss of radioactivity from tissues, milk and excrement occurred rapidly, and after 5 days of depuration the milk and tissue radioactivity levels were below the limit of detection, except in the case of the liver (5.7 u/kg).

EXPERIMENTAL: RESIDUES FROM (14)C PROPACHLOR IN MILK FROM GOAT GIVEN 1.3 MG PROPACHLOR WERE ABOUT 2-4 PPB EQUIV OF PROPACHLOR.

Propachlor can be absorbed into mammals through the respiratory and gastrointestinal tract as well as through the skin. It does not accumulate in the body. After 48 hr it is not detectable in the organism. Most animal species (rats, pigs, chickens) metabolize propachlor through the mercapturic acid pathway. Cysteine conjugates are formed by glutathione conjugations and this conjugate has been proposed as an intermediate in the metabolic formation of mercapturic acids. Bacterial C-S lyase participates in the further metabolism of the cysteine conjugate of propachlor and in the formation of the final methylsulfonyl-containing metabolites, which are mainly excreted in the urine ... and insoluble residues, which are excreted in the feces ... The propachlor C-S lyase is not active in germ-free rats. Studies showed some differences in metabolism between the rat and pig. The bile is the major route of elimination of /mercapturic acid pathway/ metabolites in the rat, but it has been proved that an extrabiliary route of metabolism exists in the pig. Metabolic studies on calves showed that they may be unable to form mercapturic acids from glutathione conjugates, which may make them more susceptible to poisoning. ... Signs of acute intoxication /in laboratory animals/ are predominantly central nervous system effects (excitement and convulsion followed by depression). ... Propachlor caused severe irritation effects on eyes and skin. Propachlor has been tested in short- and long-term exposure studies on rats, mice and dogs. The liver and kidneys are the target organs. ... Propachlor was not found to be carcinogenic in mice and rats. ... The experimental data available provide insufficient evidence of the mutagenic potential. When tested as a single dose ... in rats and mice, propachlor showed positive evidence of embryotoxicity. Embryotoxic effects were also observed in repeated dose regimens. ... However, in another rat study ... no embryotoxicity was observed. ... In a two-generation reproduction study, there was no definite evidence of adverse effects. A few cases of contact and allergic dermatitis of farmers and production workers exposed to propachlor ... have been reported. ... There have been no reports of symptoms or diseases either among occupationally exposed humans or the general population, other than the few reports of its effects on the skin of occupationally exposed workers. ... In studies on soil microorganisms, nitrifying bacteria were the most sensitive group to the inhibitory effects of propachlor ... Cellulose-decomposing bacteria were the least sensitive. High adsorption to clay particles in soil and high temperatures both reduce the inhibitory effects. ... Propachlor is considered to be moderately to highly toxic to aquatic organisms. Propachlor is not toxic to earthworms at exposure concentrations in soil expected from normal use ... Propachlor will not pose a hazard to /bees/. Some beneficial parasitic insects have been reported to be adversely affected by propachlor in laboratory and field studies. Propachlor is more toxic to birds when administered via the stomach than when fed in the diet. ... Propachlor does not pose a hazard to birds in the field, even with the granular formulation.

Propachlor poisoning causes an induction of microsomal hepatic UDPGT activity, which produces increased clearance of thyroid hormone, T4. Decreased levels of T4 would result in increased levels of thyroid stimulating hormone (TSH). Increased levels of TSH would result in the hyperplastic and eventually tumorigenic response of the thyroid. Propachlor metabolites also bind to nAChRs in the nervous system and cause endocrine disruption in humans by binding to and inhibiting the estrogen receptor. (T10, A570, T152)

/BIRDS and MAMMALS/ Propachlor is more toxic to birds when administered via the stomach than when fed in the diet. Acute LD50 values range between 137 and 735 mg/kg body weight for different bird species. The LC50 values from dietary exposure exceed 5620 mg/kg diet in birds. Propachlor does not pose a hazard to birds in the field, even with the granular formulation.

/BIRDS and MAMMALS/ ... data for pheasants /indicate/ an acute oral LD50 of 735 mg/kg body weight. Increased respiration, loss of reflexes, mydriasis, salivation and intermittent tonic/clonic convulsions were found among birds receiving dose levels of 900 and 1350 mg/kg. The onset of symptoms occurred approximately 15 min following dosing and persisted until death 3-5 hr later...

/OTHER TERRESTRIAL SPECIES/ the side effects of propachlor on some beneficial insects /were studied/ ... .The egg parasite Trichogramma cacoeciae March reacted very strongly in laboratory as well as in field conditions to the effects of the herbicide. Contact toxicity tested using residues of propachlor on glass plates (residue level not stated) caused a reduction of the degree of parasitization leading to total mortality of the population in contaminated cages. In a study on the contact toxicity of the spray deposit on single leaves as well as on whole plants, the parasitization of Trichogramma was reduced by 100 and 83%, respectively. ... In addition to this direct contact effect of spray deposits, systemic application also caused an effect after transport of the herbicide through the soil and the plant. This was demonstrated by a reduction of the degree of parasitization compared with untreated controls. Propachlor does not seem to have any influence on Chysopa carnea Steph larvae. No effect was visible either in tests of contact toxicity or contaminated sandy soil, in choice studies on a repellent action of the residue or after topical application of the preparation. After oral application through an artificial food chain, no influence could be demonstrated. Only overdosage increased the mortality rate of the test larvae. No repellent effect of the herbicide on adults was demonstrated ... . The syrphid Epistrophe balteata DeG was more sensitive. Both in contact toxicity studies and in studies for a possible repellent effect, an influence of propachlor on the larval stages was shown. Oral intake through an artificial food chain did not have an effect on the larvae. When the herbicide was sprayed directly on the plant, an increase in larval mortality was observed. Adults of this syrphid also showed reactions to herbicides; during egg deposition, females avoided surfaces previously treated

/OTHER TERRESTRIAL SPECIES/ The potential toxicity of a 65% formulation of propachlor to Aleochara bilineta Gyll was assessed ... .. The imagos were dug into moist sand and the test substance was added at recommended use rates (8 kg in 400 L/ha water). For the assessment of parasitical capacity, pupae of Delia antiqua were dug into the sand. At the termination of the test, the sum of hatched Aleochara larvae in the pupae was determined. These were compared to the number of control organisms treated with tap water. The parasitic capacity of the test beetles was decreased by 11.4% when compared to controls.

For more Ecotoxicity Excerpts (Complete) data for PROPACHLOR (6 total), please visit the HSDB record page.

Tolerances are established for residues of the herbicide 2-chloro-N-isopropylacetanilide and its metabolites (calculated as 2-chloro-N-isopropylacetanilide) in or on the following raw agricultural commodities: [Table#2982]

Based on the reviews of the generic data for the active ingredient propachlor, the Agency has sufficient information on the health effects of propachlor and on its potential for causing adverse effects in fish and wildlife and the environment. The Agency has determined that propachlor products, labeled and used as specified in this Reregistration Eligibility Decision, will not pose unreasonable risks or adverse effects to humans or the environment. Therefore, the Agency concludes that products containing propachlor for all liquid and granular formulations are eligible for reregistration.

As the federal pesticide law FIFRA directs, EPA is conducting a comprehensive review of older pesticides to consider their health and environmental effects and make decisions about their future use. Under this pesticide reregistration program, EPA examines health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether they are eligible for reregistration. In addition, all pesticides must meet the new safety standard of the Food Quality Protection Act of 1996. Propachlor is found on List A, which contains most food use pesticides and consists of the 194 chemical cases (or 350 individual active ingredients) for which EPA issued registration standards prior to FIFRA, as amended in 1988. Case No: 0177; Pesticide type: Herbicide; Registration Standard Date: 12/01/84; Case Status: OPP is reviewing data from the pesticide's producers regarding its human health and/or environmental effects, or OPP is determining the pesticide's eligibility for reregistration and developing the Reregistration Eligibility Decision (RED) document.; Active ingredient (AI): Propachlor; Data Call-in (DCI) Date(s): 09/23/91, 10/13/95; AI Status: The producers of the pesticide has made commitments to conduct the studies and pay the fees required for reregistration, and are meeting those commitments in a timely manner.

(FL) FLORIDA 91 ug/L

(MN) MINNESOTA 90 ug/L

Butachlor and Propachlor are metabolized to the corresponding 4-aminophenol derivative, a precursor of a benzoquinone imine. ... Registrant's data for Alachlor show binding of the DEBQI metabolite to rat nasal protein at doses which deplete hepatic glutathione and which cause nasal tumors, supporting a non-genotoxic mode of action for nasal tumorigenicity. Data for Acetochlor also show binding of the corresponding dialkyl-benzoquinone imine at a dose that produces nasal tumors in S-D rats. Independent studies ... have presented direct evidence for the in vivo production of benzoquinone imine metabolites from Acetochlor, Alachlor, Butachlor and Metolachlor in male S-D rats. In the case of Propachlor, the N-acetyl derivative of the 4-aminophenol derivative and its glucuronide were found in urine of rats dosed orally with Propachlor. Data in the literature indicate that N-acetyl- 4-aminophenol can be activated to a benzoquinone imine and has been found to cause necrosis in rat and human liver. In the case of propachlor, although it does not form nasal turbinate tumors, the 4-aminophenol precursor of the benzoquinonone imine has been identified as a metabolite.

Mechanistic studies of thyroid follicular cell tumorigenesis performed with Alachlor indicate a hormonally-mediated mechanism for thyroid neoplasia. Administration of Alachlor results in induction of microsomal hepatic UDPGT activity, which produces increased clearance of thyroid hormone, T4. Decreased levels of T4 would result in increased levels of thyroid stimulating hormone (TSH). Increased levels of TSH would result in the hyperplastic and eventually tumorigenic response of the thyroid. ... For Propachlor, thyroid C-cell tumors have been observed after chronic high dose administration of the compound. However, as C cells are engaged in calcitonin production and not T3/T4 production, the mechanism of induction for these tumors is expected to be different.

Propachlor is rapidly metabolized. ... Most of the animal species studied metabolize propachlor through the mercapturic acid pathway (MAP). The intestinal microflora is involved in the metabolism of MAP intermediates ... . Metabolites of propachlor, in which chlorine from the parent compound (2-chloro- isopropylacetanilide) is removed by a nucleophilic displacement ... by a cysteine group or methylsulfonyl group (CH3SO2), are present in the urine of rats dosed orally with propachlor ... . It has been shown that a cysteine conjugate of propachlor is the source of sulfur in methylsulfonyl- containing metabolites, but that the carbon in the methylsulfonyl group does not come from the cysteine moiety. Propachlor is conjugated firstly with glutathione and the reaction is mediated by glutathione transferases. The glutathione conjugation provides a means for inactivation of reactive electrophiles. Glutathione conjugates have the required physico-chemical properties for biliary excretion and will generally be present, together with their catabolites cysteinyl-glycine, cysteine and N-acetylcysteine-mercapturic acid, in relatively high concentrations in the bile ... . After excretion with the bile, they are metabolized in the intestine where the C-S lyase present cleaves the cysteine conjugate, allowing further metabolism of sulfur to a methylsulfonyl-containing moiety ... . In germ-free rats ... and rats treated by antibiotics ... 14C was excreted from 14C-propachlor as MAP metabolites, but there were no methylsulfonyl-containing metabolites in urine. Inextractable residues were eliminated in the feces. This shows that MAP metabolites are available as substrates for the intestinal microflora. Of the MAP metabolites studied, the glutathione and cysteine conjugates are the best substrates both for production of 2-mercapto- N-isopropyl-acetanilide and for parallel formation of insoluble 14C residues ... which are excreted in the feces.

Three or more enterohepatic cycles for propachlor metabolism in normal rats have been described. In the first, propachlor is metabolized via the mercapturic acid pathway and the conjugates are excreted in the bile. The second cycle is initiated when the biliary mercapturic acid pathway metabolites are metabolized by microbial/intestinal C-S lyase into reabsorbable metabolites (possibly 2-mercapto- N-isopropylacetanilide). The reabsorbable metabolites are further metabolized to glucuronides by glucuronidase enzymes, and these are secreted with the bile. These biliary glucuronides subsequently initiate the third cycle in the enterohepatic circulation of propachlor metabolites. No doubt the intestinal microorganisms complicate the metabolism of propachlor (in comparison with the situation in germ-free and antibiotic-treated rats) and create new non-polar compounds from the products of the mercapturic acid pathway, which are reabsorbed into the blood. These new compounds have to be converted again into polar products in order to be excreted

... Propachlor is initially metabolized via the mercapturic acid pathway; the molecule is conjugated to glutathione and excreted in the bile along with the catabolites cysteinyl-glycine, cysteine, and N-acetylcysteine-mercapturic acid. The biliary mercapturic acid metabolites undergo deconjugation via intestinal/microbial carbon/sulfur (C-S) lyase activity and can be reabsorbed. The reabsorbed metabolites are subsequently glucuronidated and eliminated in the urine or bile. Glucuronides eliminated in the bile can undergo further enterohepatic recirculation. Elimination of propachlor is rapid; more than 90% of a single dose is excreted within 48 hr, primarily in the urine. ...

During 1st 6 to 24 hr, metabolism of propachlor was similar in corn seedlings & in excised leaves of corn, sorghum, sugarcane, & barley. ... rapidly metabolized to water-sol products by all tissues examined. Two compd were identified as glutathione & glutamylcysteine conjugates of propachlor.

For more Metabolism/Metabolites (Complete) data for PROPACHLOR (23 total), please visit the HSDB record page.

Propachlor can be absorbed in mammals through the respiratory and gastrointestinal tracts as well as through the skin. It does not accumulate in the body, since it is rapidly metabolized through the mercapturic acid pathway (MAP). Cysteine conjugates are formed by glutathione conjugation and this conjugate has been proposed as an intermediate in the metabolic formation of mercapturic acid conjugation. It has been shown that a cysteine conjugate of propachlor is the source of sulfur in methylsulfonyl- containing metabolites, but that the carbon in the methylsulfonyl group does not come from the cysteine moiety. Propachlor is conjugated firstly with glutathione and the reaction is mediated by glutathione transferases. The glutathione conjugation provides a means for inactivation of reactive electrophiles. Glutathione conjugates have the required physico-chemical properties for biliary excretion and will generally be present, together with their catabolites cysteinyl-glycine, cysteine and N-acetylcysteine-mercapturic acid, in relatively high concentrations in the bile. After excretion with the bile, they are metabolized in the intestine where the C-S lyase present cleaves the cysteine conjugate, allowing further metabolism of sulfur to a methylsulfonyl-containing moiety. Eleven urinary metabolites, six of which are 2-methylsulfonylacetanalides have been isolated. The major fecal metabolite is identified as the cysteine conjugate. (L904, L905, L906)

Propachlor may be absorbed through the respiratory and gastrointestinal tracts as well as through the skin. Following a single oral administration in mammals, it is rapidly taken up into the blood and internal organs, reaching its maximum blood concentration in 1 hr. After 48 h it is no longer detectable in the organs ... . An estimated 68% of a single 10 mg dose of ring-labelled 14C-propachlor administered to 12 rats was recovered in urine 56 hr later. These results are supported by those of other studies in which 54-64% ... and 68.8% ... of the administered dose was recovered in urine 24 hr and 48 hr after dose administration, respectively.

... A study using six anesthetized 2- to 21-day-old male Guernsey calves weighing 28 to 61 kg /was conducted/ in which either the left kidney was perfused (via the left renal artery) or the left ureter was perfused with metabolites of propachlor. The glutathione conjugate of propachlor (2- S-glutathionyl- N-acetyl-acetanilide) was metabolized in both kidney and ureter to the cysteine conjugate. When the mercapturic acid conjugate of propachlor was presented to the kidney, it was eliminated in urine. First-pass metabolism and elimination of the glutathione conjugate by the kidney was 16% of the dose, whereas first-pass elimination of the mercapturic acid was 33%. Absorption of the glutathione conjugate of propachlor or its metabolites, or of glycine by the ureter was nil. The cattle may be unable to form mercapturic acids from glutathione conjugates of some xenobiotics, which may result in their being more easily poisoned by these xenobiotics than chickens, pigs and rats.

When 14C-propachlor was given to rats, 56-64% of the dose was excreted in urine in the first 24 hr and 5.7-7.0% in 24-48 hr. In the feces, 8-13% and 2.2-7.7% were eliminated in 0-24 hr and 24-48 hr, respectively; 0.4% of the 14C was eliminated as CO2 and 5-11% was in the carcass. In total 80-97% was eliminated in 48 hr.

...The metabolites of propachlor formed in normal rats treated with propachlor are excreted mainly through urine (68%) and feces (19%). Eleven urinary metabolites were isolated from rats given 14C-labelled propachlor orally. The major metabolite was the mercapturate (17%), and six of the metabolites were 2-methylsulfonylacetanilides. Fecal residues (19%) of the administered dose, insoluble in common solvents or by treatment with diluted acid or base, were also determined. Rats with cannulated bile ducts secreted 66% of an oral dose of propachlor in the bile as the glutathione conjugate, cysteine conjugate, mercapturate and the mercapturate sulfoxide. Germ-free rats given orally 14C-labelled propachlor excreted 98% of the dose in the urine and feces within 48 hr. Three metabolites were isolated from the excreta and the fecal radioactive metabolites were water soluble. The major metabolite was mercapturate and the other metabolites were the cysteine conjugate (present only in the feces) and mercapturate sulfoxide ... . Mercapturate sulfoxide was isolated from the excreta of germ-free rats ... /and/ ... presence in the bile of rats and urine of chickens and pigs dosed with propachlor /was also demonstrated/. ... As in the case of the glutathione and cysteine conjugates, the sulfoxide is not excreted at detectable levels by normal rats and was detected only in the bile ... . It may become a substrate for the intestinal flora, but the ultimate in vivo fate of this metabolite is unknown. ...Differences between some species /were reported/ concerning the metabolism of propachlor in the MAP. Clear but unexplained differences are that rats excrete no cysteine conjugate and chickens form no methylsulfonyl-containing metabolites, whereas sheep excrete large amounts of cysteine conjugate in urine.

For more Absorption, Distribution and Excretion (Complete) data for PROPACHLOR (10 total), please visit the HSDB record page.

Used to control grasses and broadleaf weeds in the first season on grain, sorghum, corn, and for onion seed in Washington and Oregon; [Reference #1]

Farming (Pesticides) [Category: Industry]

For Propachlor (USEPA/OPP Pesticide Code: 19101) ACTIVE products with label matches. /SRP: Registered for use in the U.S. but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./

Propachlor, 2-chloro-N-isopropylacetanilide, is a selective herbicide used in commercial settings for the preemergence weed control of annual grasses and broadleaf weeds in grain sorghum (milo), field corn, hybrid seed corn, and silage corn, and for weed control "in the first season, growth establishment phase" for onion seed use in Washington and Oregon.

It is a pre-emergence herbicide for annual grass and broadleaf weed control in corn and sorghum.

HERBICIDE FOR GRASSES & BROADLEAF WEEDS ON CORN, SORGHUM, SOYBEANS, SUGAR BEETS AND OTHER FIELD CROPS, FORAGE CROPS, PASTURE LAND, & RANGE LAND, SUMMER FALLOW, & ON VEGETABLES

AS A HERBICIDE FOR ANNUAL GRASSES & BROADLEAF WEEDS: 90% USED ON CORN; 6% ON SORGHUM; 2% ON SOYBEANS; 1% ON VEGETABLES; & 1% IN OTHER APPLICATIONS (ON SUGAR BEETS & OTHER FIELD CROPS, FORAGE CROPS, PASTURE & RANGE LAND, & SUMMER FALLOW) (1971)

Based on available pesticide usage information for 1987 through 1996, average annual domestic usage of propachlor is approximately 2.1 million pounds active ingredient (a.i.). In terms of pounds a.i., total usage is allocated primarily to sorghum (75%) and field corn (24%). On average, 6% of sorghum acreage is treated, while less than 1% of field corn, and bulb crops (including onions) were treated. Except for sorghum, usage generally has been declining over the past few years based on the raw usage data.

Propachlor is produced by reaction of aniline with 2-chloroisopropane, followed by treatment with chloroacetyl chloride.

REACTION OF N-ISOPROPYL ANILINE AND CHLOROACETYLCHLORIDE

Prepn: P.C. Hamm, A.J. Speziale, US 2863752 (1958 to Monsanto).

GRANULAR RAMROD 20 Active Ingredient 20.00% Propachlor; RAMROD FLAKE Active Ingredient 96.50% Propachlor; RAMROD FLOWABLE HERBICIDE Active Ingredient 42.00% Propachlor

DREXEL PROPACHLOR FLAKE TECHNICAL Active Ingredient 96.50% Propachlor

TECHNICAL MATERIAL CONTAINS MINIMUM OF 95% ACTIVE INGREDIENT.

65% WETTABLE POWDER, 20% GRANULE; DOW INTRODUCED NEW LIQUID FLOWABLE (4 LB/GAL) IN US IN 1977.

For more Formulations/Preparations (Complete) data for PROPACHLOR (6 total), please visit the HSDB record page.

Pharmaceuticals

Herbicides

Environmental transformation -> Pesticides (parent, predecessor)

Pesticides -> Herbicides -> Amide herbicides -> Anilide herbicides -> Chloroacetanilide herbicides

HERBICIDES

Propachlor can be applied with groundboom sprayers, tractor drawn granular broadcast spreaders, and granular row planters. Application rates vary from 3.0 to 6.0 pounds active ingredient per acre depending upon the application scenario. Propachlor can be applied to the following crops/ areas: field corn, hybrid seed corn, silage corn, grain sorghum (milo), and onions grown for seed. /All/ Currently registered products containing propachlor are intended for occupational uses.

PROPACHLOR ... DESIGNED TO PERFORM UNDER BROAD SET OF CLIMATIC & GEOGRAPHIC CONDITIONS ... AS PREEMERGENT HERBICIDE ... TO CONTROL BROADER SPECTRUM OF BROADLEAF WEEDS AS WELL AS TO CONTROL BARNYARDGRASS, FOXTAIL, BROMEGRASS, CHEATGRASS & CRABGRASS.

IN US IN 1971, FARMERS USED ... 23.7 MILLION LB OF PROPACHLOR. IT WAS EST THAT 23 MILLION LB OF PROPACHLOR WERE PRODUCED IN US IN 1961.

COMPATIBLE WITH WATER OF 1,000 PPM OF HARDNESS, USUALLY COMPATIBLE WITH SPRAYABLE FLUID FERTILIZERS.

Preemergence soil surface, early postemergence, and preplant incorporated. Rates: 3 to 6 lb/acre broadcast. Usual carrier: granular formulation in attapulgite/montmorillonite clay. Liquid flowable in 15 gallons per acre or more of water broadcast.