Metribuzin

214.28800

214.29

244-209-7

QO836138OV

0516

3077

DTXSID6024204

Colorless crytals|White crystalline solid

2933699014

99.10000

0.95270

Metribuzin is a colorless crystalline solid. Used as an herbicide. (NIOSH, 2016)

1.28 g/cm³ @ Temp: 20 °C

126.2 °C

132 °C @ Press: 0.02 Torr

142.7ºC

1.617

Slightly soluble

APPROX 4ºC

0.000531mmHg at 25°C

LD50 orally in rats: 2200 mg/kg; LC50 in rainbow trout: >10 ppm (Loeser, Kimmerle)

Noncombustible Solid

Weak characteristic odor

pKa= 1.0

150.5 Ų [M+H]+ [CCS Type: DT, Method: stepped-field]|171.27 Ų [M+Na]+ [CCS Type: DT, Method: stepped-field]|146.95 Ų [M+H]+ [CCS Type: TW]|150.94 Ų [M-H]-|149.5 Ų [M+H]+

Slight sulfurous odor /Technical metribuzin/

No rapid reaction with air. No rapid reaction with water.

Amides and Imides

A triazine derivative. Amines are chemical bases. They neutralize acids to form salts plus water. These acid-base reactions are exothermic. The amount of heat that is evolved per mole of amine in a neutralization is largely independent of the strength of the amine as a base. Amines may be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. Flammable gaseous hydrogen is generated by amines in combination with strong reducing agents, such as hydrides.

Noncombustible Solid

Non-corrosive

III

9

UN3077 9/PG 3

3

R22; R50/53

S2; S60; S61; S36; S26; S16

XZ2990000

Xn

Store in an area without drain or sewer access.

P210-P280-P305 + P351 + P338

H225-H302-H302 + H312 + H332-H312-H319-H332

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.|Bury empty container or product that cannot be used in a safe place away from water supplies, or dispose of by alternative procedures recommended by federal, state or local authorities. Open dumping is prohibited.

Combustible.

|Warning|H302: Harmful if swallowed [Warning Acute toxicity, oral]|P264, P270, P273, P301+P312, P330, P391, and P501|H303: May be harmful if swallowed [Warning Acute toxicity, oral]|P31, and 312

Use water spray, powder.

Skin: Wear appropriate personal protective clothing to prevent skin contact. Eyes: Wear appropriate eye protection to prevent eye contact. Wash skin: The worker should immediately wash the skin when it becomes contaminated. The worker should wash daily at the end of each work shift. Remove: Work clothing that becomes wet or significantly contaminated should be removed and replaced. Change: Workers whose clothing may have become contaminated should change into uncontaminated clothing before leaving the work premise. (NIOSH, 2016)|(See protection codes)

Nonflammable

Avoid contact with skin, eyes, and clothing. Remove contaminated clothing and wash with soap and hot water before reuse.|SRP: Contaminated protective clothing should be segregated in such a manner so that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. Quality assurance to ascertain the completeness of the cleaning procedures should be implemented before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at end of shift, but should remain at employee's place of work for cleaning.

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./|The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials.|The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article.

Vacated 1989 OSHA PEL TWA 5 mg/cu m is still enforced in some states.

Do NOT let this chemical enter the environment. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting. Then store and dispose of according to local regulations.

Store in an area without drain or sewer access.

Evaporation at 20 °C is negligible; a harmful concentration of airborne particles can, however, be reached quickly.

Exposure at high levels could cause depression of the central nervous system.

NO open flames.

PREVENT DISPERSION OF DUST!

Use ventilation (not if powder), local exhaust or breathing protection.

Protective gloves.

Wear safety spectacles.

SEDIMENT: Metribuzin was detected in sediment samples at the Sarno and Volturno Rivers near Naples, Italy at levels of 12 and 220 ng/g (dry wt),respectively(1); these rivers are effected by multiple pollution sources from industrial, domestic and agricultural origins, and are located in heavily populated areas(1).|SOIL: In 1989, the mean concn of metribuzin in soil at agrochemical facilities in Illinois was determined to be 92 ug/kg(1).

RURAL/REMOTE: The maximum concn and percent detections of metribuzin in air over the Mississippi River from New Orleans, LA to St. Paul, MN during June 1994 was 6.6 ng/cu-m and 100%, respectively(1).

LD50 Rat oral 1100 mg/kg|LD50 Rat dermal >2000 mg/kg|LD50 Rabbit dermal >2000 mg/kg|LD50 Mouse oral 698-711 mg/kg|For more Non-Human Toxicity Values (Complete) data for METRIBUZIN (16 total), please visit the HSDB record page.

Metribuzin's use as an herbicide(1,2) is expected to result in its direct release to the environment(SRC).

TERRESTRIAL FATE: In soil, metribuzin was degraded to carbon dioxide. Autoclaving of soil decreased metribuzin metabolism. Those metabolites observed in plants (metribuzin, 3,5-diketo and deaminated diketo) were also observed in the soil. Deaminated diketo was the primary metabolite in soil. Metribuzin, applied in June to a fine sandy loam soil, degraded during the growing season to the extent that less than 10% of applied herbicide was present by October 25, freeze-up time. Metribuzin, 3,5-diketo and deaminated diketo were observed in soil samples and metabolite residue levels were at their maximum near the middle of July. In a study with Guelp loam, the half-life of metribuzin was about 3 months. Under greenhouse conditions with soils from the lower alluvial floodplain of the Mississippi River, metribuzin half-life varied from 17 to 28 days and followed first-order kinetics. In four Manitoba soils under dry conditions at 15 C, some nonbiological degradation of metribuzin occurred. The rate law was somewhat less than first-order and half-lives varied from 90 to 115 days. Field soil samples awaiting analysis underwent degradation. At -37C, about 50% of the herbicide could be lost in 282 days. 3,5-Diketo and deaminated diketo also degraded under storage conditions. In laboratory studies with a sandy loam soil, metribuzin calculated half-life was about 329, 44 and 16 days at 5, 20 and 35C, respectively. Metribuzin and deaminated diketo were observed.|TERRESTRIAL FATE: Based on a classification scheme(1), an average Koc value of 60(2) suggests that metribuzin is expected to have high mobility(SRC). Little leaching occurs on soils with high organic content, but metribuzin is readily leached in sandy soils(2,4). Adsorption of metribuzin decreases as soil pH increases(2). Loss from soil surfaces via volatilization is not an important fate process(2,3). Volatilization of metribuzin from moist soil surfaces is not expected to be an important fate process given an estimated Henry's Law constant of 1.2X10-10 atm-cu m/mole(SRC), derived from its vapor pressure, 4.4X10-7 mm Hg(5), and water solubility, 1050 mg/l(5). Metribuzin is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(5). Metribuzin had a half-life of 2.5 days on sandy loam soil irradiated outdoors in Kansas City, MO at temperatures up to 31 °C(6). The major photolytic products of metribuzin were pentylidene and hexylidene metribuzin in soil(6). Biodegradation is the primary means of metribuzin dissipation from soils(2). The activity of soil microorganisms, higher temperatures, and aerobic conditions increase the rate of metribuzin biodegradation(2). Half-lives are 172 and 439 days for sandy loam under aerobic and anaerobic conditions, respectively(2). Primary metabolites are the deaminated, diketo, and deamined diketo metabolites(2). The calculated field dissipation half-lives of metribuzin in sandy loam soils in California were 128 and 40 days at Watsonville and Fresno, respectively(6).|AQUATIC FATE: Based on a classification scheme(1), an average experimental Koc value of 60(2), indicates that metribuzin is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected based upon an estimated Henry's Law constant of 1.2X10-10 atm-cu m/mole(SRC), derived from its vapor pressure, 4.35X10-7 mm Hg(3), and water solubility, 1100 mg/l(3). Photodecomposition is an important process for the degradation of metribuzin in aqueous solution(3). Metribuzin was found to have a half-life of 4.3 hours in surface water from Kansas City, MO (pH 6.6) irradiated with natural sunlight at 25 °C(4). The identified degradate was deaminated metribuzin(4). A BCF of 10 was measured for Golden ide fish (Leuciscus idus melanotus)(5). According to a classification scheme(6), this whole body BCF suggests the potential for bioconcentration of metribuzin in aquatic organisms is low(SRC). No data were located on the biodegradation of metribuzin in water; however, microbial degradation is the primary fate process of metribuzin in soil(2,3), which suggests that biodegradation may be an important fate process in water(SRC).|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), metribuzin, which has a vapor pressure of 4.35X10-7 mm Hg at 20 °C(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase metribuzin 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 21 hrs(SRC), calculated from its rate constant of 1.8X10-11 cu cm/molecule-sec at 25 °C(SRC) determined using a structure estimation method(3). Particulate-phase metribuzin may be removed from the air by wet and dry deposition(SRC).

Photolysis of metribuzin in methanol yielded 6-t-butyl-5-hydroxy-3-methylthio-as-triazine, 3,5-diketo, deaminated diketo and methylsulfonic acid. In acetone, in addition to these compounds, a condensation product observed was identified as 6-t-butyl-4-isopropylidenamino-3-methyl-thio-as-triazin-5-(4H)-one. Product identification utilized IR, NMR and UV.|The rate constant for the vapor-phase reaction of metribuzin with photochemically-produced hydroxyl radicals has been estimated as 1.8X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of approximately 1 day at an atmospheric concn of 5X10+5 hydroxyl radicals per cu cm(1). The hydrolysis half-life of metribuzin is 90 days according to the California Department of Food and Agriculture; conditions and experimental procedure not reported(2). Metribuzin has a half-life of 4.3 hours in pH 6.6 water irradiated with natural sunlight in Kansas City, MO at 25 °C(3). The identified degradate was deaminated metribuzin (DA; major degradate), and 3 unknown degradates each comprised <5.2%(3). Metribuzin had a half-life of 2.5 days on sandy loam soil irradiated outdoors in Kansas City, MO at temperatures up to 31 °C(3). The major photolytic products of metribuzin were pentylidene and hexylidene metribuzin in soil(3). Even though direct photolysis in water and on soil appears to degrade metribuzin rapidly in the laboratory, only metribuzin that is on the surface of soil is affected by direct photolysis(3).

The bioconcentration factor (BCF) of metribuzin in the Golden ide fish (Leuciscus idus melanotus) was experimentally determined to be 10 in a 3 day static test(1). According to a classification scheme(2) and this BCF value, metribuzin is not expected to bioconcentrate in aquatic organisms(SRC).

51.29 L/kg|The average Koc of metribuzin is 60(1). Parent metribuzin was very mobile in sandy (0.58% OC), sandy loam (0.64% OC), silt loam (1.7% OC), and clay loam (1.3% OC) soils with adsorption(1). Freundlich constant values of 0.25, 0.02, 0.22, and 0.20, respectively desorption Freundlich values were 0.56, 0.14, 0.51, and 0.41, respectively(1). Adsorption Koc were 47, 3, 15, and 17 and desorption Koc values were 106, 24, 33, and 36, respectively(1). The Koc values for metribuzin in Alaskan subarctic agricultural silt loam soils ranges from 34-56(2). Experimental Koc values have been measured for sand (Koc=47; 1% OM, pH 4.3), sandy loam (Koc=3; 1.1% OM, pH 6.6), silt loam (Koc=14; 3% OM, pH 5.9), and clay loam (Koc=17; 2.2% OM, pH 6.4) soils(1). Metribuzin has high affinity for soil organic matter, but is less tightly adsorbed to clay(1). Adsorption of metribuzin decreases as soil pH increases(1). According to a classification scheme(4), these Koc values suggest that metribuzin is expected to have high mobility in soil(SRC).

The Henry's Law constant for metribuzin is estimated as 1.2X10-10 atm-cu m/mole(SRC) derived from its vapor pressure, 4.35X10-7 mm Hg(1), and water solubility, 1050 mg/l(1). This Henry's Law constant indicates that metribuzin is expected to be essentially nonvolatile from water surfaces(2). In growth chamber studies using Ontko and Chehalis soils, volatilization rates of applied metribuzin over a 12 day period were negligible(1). However, using glass plates, it was shown that approximately 50% of applied metribuzin volatilized within 24 hrs, slowing to a 15-20% loss over the next 11 days. A field study was conducted using a Charlottetown fine sandy loam (2.1% OM, 55.1% sand, 30.2% silt, 14.7% clay, pH=6.1) and Berwick loamy sand (4.2% OM, 71.2% sand, 10.8% silt, 18.0% clay, pH=5.2), Prince Edward Island, Canada, with metribuzin applied at 0.5 kg/ha in 400 L/ha of water(4). Calculated mean half-lives in Berwirk loamy sand were 5.9 and 16.2 days in surface and incorporated metribuzin, respectively, and in Charlottetown fine sandy loam were 5.3 and 14.0 days, respectively(4). In both soil types, half-lives were nearly doubled when the soil was covered over(4). While the loss processes were not identified specifically as volatilization or pohtodegradation, the increase in persistence suggests that abiotic degradation of metribuzin is influenced by tillage practices and ground cover(4). Metribuzin is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 4.35X10-7 mm Hg(1).

SURFACE WATER: Metribuzin was detected in 18 of 174 lakes/reservoirs in the United States at an average concn of 0.029 ug/l(1). Metribuzin was detected at a concn of 0.33 ug/l in 1 of 7 surface water samples taken in April-October of 1985 from Tuttle Creek Lake, Kansas(2). In 1975-1977, metribuzin was detected at an average concn of 0.02 ug/l in 11 agricultural watersheds in Ontario, Canada(3). During 1983 to 1991, metribuzin time-weighted average concns in Lake Erie tributaries, which drain agricultural watersheds, were: 0.29 ug/l in the Maumee River, 0.28 ug/l in the Sandusky River, 0.24 ug/l in Honey Creek, 0.23 ug/l in Rock Creek, 0.20 ug/l in Lost Creek, 0.07 ug/l in the Cuyahoga River, and 0.11 ug/l in the Raisin River(4). Metribuzin was detected in Shell Creek, a tributary to the Platte River in Nebraska, at a concn range of 0.5-1.7 ug/l in 11 samples taken about 72 hr after a spring rainstorm; no metribuzin was detected in the creek prior to the storm(5). Metribuzin was detected in 1984-85 in subbasins within the Cedar River, Iowa(6). In 1977, metribuzin was qualitatively identified in water from Lake Huron, Lake Erie, the St. Clair River, Lake St. Clair and the Detroit River(7).|SURFACE WATER: In 6 of 55 samples drawn at the mouth of the Thames River, Ontario, Canada, the average metribuzin concn was 1.1 ug/l during the months May-August, 1981-85(1). Metribuzin average concns in samples drawn during 1982-86 from the Sydenham River, Ontario, Canada, were: 1.2, 1.5, 7.7, 0.8 and 1.7 ug/l in 3, 1, 3, 1 and 1 samples, respectively(2). On September 24, 1990, metribuzin was detected at a concn of 1550 ng/l in the Grand River, Ontario, Canada(3). The median concn of metribuzin was 0.9 ug/l, in lake and river/stream water from 2% of all samples collected in select counties in Arkansas from 1989 to 1991(4). The maximum concn of metribuzin in rural waste water treatment plant effluent in Germany was 1.2 ug/l between the years of 1996 and 1997(5).|SURFACE WATER: USGS reconnaissance surveys of numerous midwestern streams in 1989, 1990, 1994, and 1995 were conducted to determine pre-application, post-application, and Fall concns of metribuzin(1). Pre-application and Fall metribuzin concns were much less than 1 ug/l and generally below the detection limit of 0.05 ug/l(1). Since post-application samples were generally collected during the first major runoff event after application, the concns in those samples may often approximately represent peak concns(1). The 90th percentile (upper 10th percentile) post-application metribuzin concns for 1989, 1994, and 1995 were 1.4, 1.2 and 0.5 ug/l, respectively(1). Based upon data on other major use herbicides, peak metribuzin concns in streams may generally be higher than in rivers and reservoirs but elevated levels of metribuzin may be present longer in rivers and reservoirs(1). Concns in edge of the field farm ponds may be substantially greater than in streams(1). The USGS sampled 8 locations on rivers within the Mississippi Basin from April 1991 through September 1992(1). Dissolved metribuzin was detected above a detection limit of 0.05 ug/l at all of the locations, but in less than 3% to 28% of the samples at each location(1). The maximum concn detected was 0.38 ug/l(1). Only 5 additional samples had metribuzin concns > 0.2 ug/l(1). In 76 midwestern reservoirs sampled at least eight times from April 1992 through September 93, metribuzin was detected above a detection limit of 0.05 ug/l in 4.9% of the 732 samples collected from 20% of the 77 reservoirs samples(1). The only concns > 0.5 ug/l were 0.67 ug/l (Huntington Lake IN), 0.67 ug/l (Mississinewa Lake IN), and 0.91 ug/l, and 1.3 ug/l (Salamonie Lake IN)(1). The State of Illinois recently summarized pesticide data for surface water samples collected from 34 stations from October 1, 1985 through February 15, 1994(1). A total of 1278 samples were analyzed for metribuzin at a detection limit of 0.05 ug/l(1). Apparently assuming non-detects were equal to the detection limit, Illinois reported maximum, 95th percentile and mean unfiltered sample (total) metribuzin concns of 3.7 ug/l, 0.11 ug/l, and 0.065 ug/l, respectively(1).|GROUNDWATER: Metribuzin was detected in ambient groundwater in United States at 136 of 5,010 sources with an average concn of 0.048 ug/l(1). According to the USEPA's Groundwater Data Base, metribuzin has been quantified in groundwater from Iowa, Illinois, Kansas, Maine, Minnesota and Wisconsin at an average concn range of 0.05-2.10 ppb(2). The occurrence and maximum concn of metribuzin in shallow groundwater in the United States collected as part of the National Water-Quality Assessment (NAWQA) completed during 1993-95, was 3.1% of all sites(N=1034) and 0.3 ug/l, respectively(3). Metribuzin was qualitatively detected in 2 groundwater wells in Wisconsin during the early 1980s(4). Metribuzin was detected in groundwater(drain tiles, observation wells, or lysimeters) in Iowa at a mean concn of 2.9 ug/l during the year 1991(5). The mean concn metribuzin in a shallow aquifer in an agricultural area (near Kelly, IA) ranged from 0.1 to 0.6 in 1992(6). The highest concn of metribuzin in surface waters(ie, canals) of south Florida from November 1991 to June 1995 was 0.51 ug/l(7). Metribuzin was detected in 1 of 77 wells in the alluvial aquifer of the Arkansas Delta(AR) at a concn of 0.0054 ug/l(8).|For more Environmental Water Concentrations (Complete) data for METRIBUZIN (7 total), please visit the HSDB record page.

Metribuzin was qualitatively identified in 1 root vegetable composite from Total Diet samples taken in 1975(1). Metribuzin was found in 1 of 1219 samples of domestic and imported tomatoes at trace quantities (Trace, present but below the level of detection)(2).

Dairy cattle fed a diet of 3 and 10 ppm metribuzin had ranges of concns of total metribuzin residues(metribuzin and metabolites) in milk of <4-6 and <4-7 ppb, respectively(1).

Occupational exposure to metribuzin may occur through inhalation and dermal contact with this compound at workplaces where metribuzin is produced or used(SRC). Monitoring data indicate that the general population may be exposed to metribuzin via consumption of contaminated foods(1), consumption of contaminated drinking water(2,3), or inhalation resulting from spraying nearby agricultural areas(4).|In pesticide formulating plants, exposure to pesticides, such as metribuzin, may be from spillage; furthermore, there is a high potential for exposure at mixing and bagging stations(1). Metribuzin is applied to several crops via aerial or ground spraying(2). Crop workers may be exposed during application; however, their main exposure results from contact with treated foliage or to pesticide or pesticide-contaminated material made airborne through agitation of foliage during work activity(1). Incidental to treating a crop, some pesticides, such as metribuzin, may drift onto workers in neighboring fields or in nearby suburban areas without there being any intent to treat those areas(1).|Manufacture, formulation and application of /metribuzin/.|Baseline inhalation exposure values of metribuzin for workers ranged from 0.006-91.14 mg/day for various uses (as herbicide) and application methods(1).

Pesticides used to destroy unwanted vegetation, especially various types of weeds, grasses (POACEAE), and woody plants. Some plants develop HERBICIDE RESISTANCE. (See all compounds classified as Herbicides.)

Absorbed through the leaves from surface treatment, but the major significant route for uptake is via root system. ... Uptake through the roots is best described as osmotic diffusion. Metribuzin is translocated upward in the xylem and moves distally when applied at the base of leaves.|After absorption, it is rapidly distributed and rapidly excreted unchangd or metabolized (oxidized) and excreted via the urine.

When (14)C metribuzin was applied to tomatoes, preliminary evidence indicated that the first (14)C metabolite may be a complex with deaminated diketometribuzin or metribuzin.|Metribuzin applied to roots of soybean (Glycine max (Leguminatae) Merr. 'Cutler') seedlings was rapidly absorbed and translocated to the shoots. The major product observed was deaminated metribuzin. The 3,5-diketo and deaminated diketo derivatives were also observed. Identity of these metabolites was determined by cochromatography and MS. Roots and shoots both produced these compounds. The aglycones of four acid labile carbohydrate conjugates formed were identified as 3,5-diketo derivative and deaminated derivative.|Potatoes were planted in soil treated with metribuzin. Analyses of plant material showed the presence of metribuzin, 3,5-diketo and deaminated derivative as well as conjugated material. Analyses indicated that deaminated diketo was the aglycone of one conjugate. When these studies were repeated in the same soil, another metabolite was found in the top part of the plants and identified as trimethylpyruvic acid semicarbazone. Similar results were observed with carrots and the soil in which these plants had been grown.

Inhibits photosynthesis

Exposure Routes: inhalation, ingestion, skin and/or eye contact Target Organs: central nervous system, thyroid, liver (NIOSH, 2016)

Eye: If this chemical contacts the eyes, immediately wash the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Contact lenses should not be worn when working with this chemical. Skin: If this chemical contacts the skin, wash the contaminated skin with soap and water. Breathing: If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. Other measures are usually unnecessary. Swallow: If this chemical has been swallowed, get medical attention immediately. (NIOSH, 2016)|(See procedures)

Fresh air, rest.

Rinse and then wash skin with water and soap.

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Skin decontamination: Skin contamination should he treated promptly by washing with soap and water. Contamination of the eyes should be treated immediately by prolonged flushing of the eyes with large amounts of clean water. If dermal or ocular irritation persists, medical attention should be, obtained without delay.|Gastrointestinal decontamination: Ingestion of these herbicides are likely to be followed by vomiting and diarrhea due to their irritant properties. Management depends on: (1) the best estimate of the quantity ingested, (2) time elapsed since ingestion, and (3) the clinical status of the subject. Activated charcoal is probably effective in limiting irritant effects and reducing absorption of most or all of these herbicides. Aluminum hydroxide antacids may be useful in neutralizing the irritant actions of more acidic agents. Sorbitol should be given to induce catharsis if bowel sounds are present and if diarrhea has not already commenced. Dehydration and electrolyte may be severe enough to require oral or intravenous fluids. There are no specific antidotes for poisoning by these herbicides. In the case of suicidal ingestions, particularly, the possibility must always be kept in mind that multiple toxic substances may have been swallowed. If large amounts of herbicide have been ingested and the patient is seen an hour of the ingestion, gastrointestinal decontamination should be considered. If the amount of ingested herbicides was small, if effective emesis has already occurred, or if treatment is delayed, administer activated charcoal and sorbitol mouth.|Intravenous fluids: If serious dehydration and electrolyte depletion have occurred as a result of vomiting and diarrhea, monitor blood electrolytes and fluid balance and administer intravenous infusions of glucose, normal saline, Ringer's solution, or Ringer's lactate to restore extracellular fluid volume and electrolytes. Follow this with oral nutrients as soon as fluids can be retained.

Single and repeated patch tests in humans showed no irritation or dermal sensitization.

4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one

The substance can be absorbed into the body by inhalation of its aerosol and by ingestion.|inhalation, ingestion, skin and/or eye contact

In Animals: central nervous system depression; thyroid, liver enzyme changes

central nervous system, thyroid, liver

Use of metribuzin in the United States was 4.8 million lbs in the year 1987.

USEPA/OPP Pesticide Code 101101; Trade Names: Sencor; Bay 94337; Lexone; Canopy.|Wettable powder; water dispersible granules; suspension concentrate|Combinations: saline (with trifluralin); Turbo (with metolachlor).|Liquid suspension, water dispersible granules, dry flowable

Metribuzin in pesticide formulations is determined by GC method equipped with FID. Di-n-butyl phthalate is used as an internal standard. Method is suitable for technical metribuzin and formulations.|EPA Method 507.Determination of nitrogen and phosphorus containing pesticides by GC with a nitrogen-phosphorus detector. The method is applicable to certain nitrogen and phosphorus containing pesticides in ground water and finished drinking water. Under the prescribed conditions, metribuzin has an estimated detection limit of 0.15 ug/l as defined by EPA.|EPA Method 633.GC with nitrogen phosphorus detector for the determination of organonitrogen pesticides in industrial and municipal wastewater. Under the prescribed conditions for metribuzin, the method detection limit is 0.46 ug/l as determined by EPA Office of Water's Industrial Technology Division.|A method for the direct determination of metribuzin and metabolites by high-performance liquid chromatography. Recovery 83-90 %. Applicable to concns between 5-200 ug/l in water.

Agrochemicals -> Herbicides|Herbicides|Pesticides -> Herbicides -> Triazinone herbicides|Environmental transformation -> Pesticides (parent, predecessor)|HERBICIDES

Metribuzin has known environmental transformation products that include Metribuzin-desamino and Metribuzin-diketo.|Metribuzin has known environmental transformation products that include M01 (desamino-metribuzin), M02 (diketo-metribuzin), M03 (desamino-diketo-metribuzin), M17 (4-methyl-DADK-metribuzin), and U1 (Desmethylthio-metribuzin).