Profluralin

TOBACCO TISSUE CULTURES WERE USED IN A BIOASSAY SYSTEM FOR DETERMINING THE EFFECT OF PROFLURALIN ON GROWTH. THE MOLAR CONCN REQUIRED TO INHIBIT FRESH WT GAIN BY 50% (I50) WAS DETERMINED. EXOGENOUSLY APPLIED D-ALPHA-TOCOPHEROL ACETATE AT 100 TIMES THE I50 CONCN DECR THE INHIBITION OF TISSUE GROWTH BY PROFLURALIN.

EC50; Species: Anabaena variabilis (Blue-green algae); Conditions: static, 24-26 °C, pH 6.6; Concentration: >10 uM for 48 hr; Effect: population decreased chlorophyll A concentration

EC50; Species: Chlorella pyrenoidosa (Green algae, exponential growth phase); Conditions: static, 24-26 °C, pH 6.6; Concentration: >10 uM for 24 hr; Effect: decreased population doubling time

EC50; Species: Chlorococcum sp. (Green algae, exponential growth phase); Conditions: static, 24-26 °C, pH 6.6; Concentration: >10 uM for 24 hr; Effect: decreased population doubling time

EC50; Species: Lyngbya sp. (Blue-green algae, exponential growth phase); Conditions: static, 24-26 °C, pH 6.6; Concentration: >10 uM for 24 hr; Effect: decreased population doubling time

TERRESTRIAL FATE: Based on a classification scheme(1), Koc values of 8,600(2) and 10,232(3) indicate that profluralin will have no mobility in soil(SRC). Volatilization of profluralin from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 2.9X10-4 atm-cu m/mole(SRC), derived from its vapor pressure of 6.3X10-5 mm Hg(4) and water solubility of 0.1 mg/L(4); however, adsorption may attenuate this process(SRC). Volatilization from dry soil surfaces is not expected(SRC) based on the vapor pressure of this compound(4). Profluralin was photodegraded 47.6% following its application to a clay loam, and subsequent exposure to natural sunlight for 7 days(5). The biodegradation half-life of profluralin in soil was reported as 110 days(6).

AQUATIC FATE: Based on a classification scheme(1), Koc values of 8,600(2) and 10,232(3) indicate that profluralin is expected to adsorb to suspended solids and sediment in the water. Volatilization from water surfaces is expected(4) based upon an estimated Henry's Law constant of 2.9X10-4 atm-cu m/mole(SRC), derived from its vapor pressure of 6.3X10-5 mm Hg(5) and water solubility of 0.1 mg/L(5). Using this Henry's Law constant and an estimation method(4), volatilization half-lives for a model river and model lake are 5 hours and 9 days, respectively; however, adsorption may attenuate volatilization(SRC). The volatilization half-life from a model pond was estimated as 123 days when adsorption was considered(6). According to a classification scheme(7) an estimated BCF value of 3,950(SRC), from a log Kow of 5.58(8) and a regression derived equation(9), suggests the potential for bioconcentration in aquatic organisms will be very high(SRC). Profluralin does not hydrolyze at environmental pH (pH 5-9) and room temperature; however it undergoes photodegradation suggesting photolysis in sunlit surface water may be an important fate process(5).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), profluralin, which has a vapor pressure of 6.3X10-5 mm Hg at 20 °C(1) is expected to exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase profluralin 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 17 hours(SRC) calculated from its rate constant of 2.3X10-11 cu cm/molecule-sec(SRC), derived using a structure estimation method(3). Profluralin absorbs light greater than 290 nm and is susceptible to photolysis(4). Particulate-phase profluralin may be physically removed from the air by wet and dry deposition(SRC).

DUE TO THE STRONG SOIL ADSORPTION CHARACTERISTICS AND APPLICATION METHODS (SOIL INCORPORATION), THE POSSIBILITY OF HAZARDOUS CONDITIONS TO FISH RESULTING FROM RECOMMENDED USAGE IS NIL.

PROFLURALIN IS STRONGLY ADSORBED TO ORGANIC MATTER AND CLAY. THEREFORE, IT IS NOT LEACHED THROUGH THE SOIL OR CARRIED ACROSS THE SOIL SURFACE AS RUNOFF UNLESS SOIL MOVEMENT OR EROSION TAKES PLACE. EVEN WHEN MINOR EROSION OCCURS, RELATIVELY LITTLE PROFLURALIN WILL BE CARRIED FROM THE TREATED AREA IF IT HAS BEEN MECHANICALLY INCORPORATED INTO THE SOIL.

The Koc of profluralin in soil was reported as 8,600(1) and 10,232(2). According to a recommended classification scheme(3), these Koc values suggest that profluralin is immobile in soil(SRC). Profluralin was adsorbed 66 to 74 percent by organic matter and 9 to 10 percent by montmorillonite after 4 hours of equilibration in an experimental study(4). Desorption solutions of water and CaCl2 (1 normal) desorbed profluralin 12.8 and 11.8 percent, respectively, from organic matter and 93.3 and 69 percent, respectively, from montmorillonite(4).

/SIGNS AND SYMPTOMS/ KNOWN OR SUSPECTED ADVERSE EFFECTS: Slightly to moderately irritating to skin, eyes, and mucous membranes. Does not uncouple oxidative phosphorylation. Irritation of eyes, skin, nose or throat may result from overexposure to Tolban 4E. Other symptoms may include nausea, vomiting, abdominal cramps or diarrhea (Tolban 4E). Irritation of eyes, skin, nose or throat may result from overexposure to Tolban 4E. Other symptoms may include nausea, vomiting, abdominal cramps or diarrhea (Tolban 4E).

INVESTIGATIONS WERE CARRIED OUT ON THE DEGRADATION OF PROFLURALIN BY SOIL MICROORGANISMS. THE MOST ACTIVE DEGRADERS WERE TENTATIVELY IDENTIFIED AS ARTHROBACTER SIMPLEX, CELLULOMONAS FLAVIGENUM, AND MICROBACTERIUM FLAVUM. STEPS IN THE DEGRADATION PATHWAY INVOLVE DEALKYLATION OF THE AMINO NITROGEN AND REDN OF AT LEAST ONE OF THE NITRO GROUPS. CO-METABOLIC PROCESSES WERE APPARENTLY INVOLVED, & EXOGENOUS CARBON AND NITROGEN WERE REQUIRED FOR DEGRADATION.

SAMPLES OF (14)C-LABELED PROFLURALIN WERE INCUBATED WITH SEWAGE AEROBICALLY AND UNDER DISCONTINUOUS ANAEROBIOSIS FOR 88 DAYS AND FRESH SEWAGE WAS ADDED AT INTERVALS. YIELD OF RECOVERED PRODUCTS REACHED 87%. NONE OF THE RADIOACTIVITY FROM THE HERBICIDE ENTERED THE NUCLEOSIDE POOL OF THE SEWAGE MICROFLORA.THE LACK OF INCORPORATION OF SUBSTRATE C INTO CELLS AND THE ALMOST STOICHIOMETRIC CONVERSION OF THE SUBSTRATE TO ORGANIC PROD INDICATE THAT MEMBERS OF THE MICROBIAL COMMUNITY WERE COMETABOLIZING THE TEST CMPD.

CGA 10832 WAS METABOLIZED BY ASPERGILLUS FUMIGATUS, FUSARIUM OXYSPORUM, AND PAECILOMYCES SPECIES FUNGI.

THE AVERAGE PERSISTENCE AT RECOMMENDED RATES OF PROFLURALIN IN SOILS SUCH AS: SANDY LOAM, FINE SANDY LOAM, SILT LOAM, SILTY CLAY LOAM, CLAY LOAM IS DEGRADED IN SIX MO 70%, 74%, 74%, 75% AND 82% RESPECTIVELY.

For more Environmental Biodegradation (Complete) data for PROFLURALIN (6 total), please visit the HSDB record page.

An estimated BCF value of 3,950 was calculated for profluralin(SRC), using an experimental log Kow of 5.58(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF value suggests the potential for bioconcentration in aquatic organisms is very high(SRC).

The Henry's Law constant for profluralin is estimated as 2.9X10-4 atm-cu m/mole(SRC), derived from its experimental values for vapor pressure, 6.3X10-5 mm Hg at 20 °C(1), and water solubility, 0.1 mg/L at 20 °C(1). This Henry's Law constant indicates that profluralin is expected to volatilize from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 5 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 9 days(SRC). Volatilization may be attenuated due to adsorption(SRC). The volatilization half-life from a model pond was estimated as 123 days when adsorption was considered(3). Volatilization from dry soil surfaces is not expected(SRC) based on the vapor pressure(1). Profluralin applied at a rate of 1.68 kg/ha to the surface of a Lakeland sand volatilized 3-25% within 3 hours at temperatures of 30, 40, and 50 °C(4).

Formerly used as a selective herbicide; [HSDB]

No longer registered as a pesticide for use in the US; [HSDB]

Farming (Pesticides) [Category: Industry]

For profluralin (USEPA/OPP Pesticide Code: 106601) there are 0 label matches. /SRP: Not registered for current 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./

Selective pre-planting herbicide (former use)

Benzotrifluorides are also important in the production of pesticides. The key intermediate, 4-chloro-3,5-dinitrobenzotrifluoride, is obtained by dinitration of 4-chlorobenzotrifluoride. Reaction with secondary amines gives ... profluralin.

IT CAN BE MADE BY REACTING 4-CHLORO-3,5-DINITRO BENZOTRIFLUORIDE WITH N-CYCLOPROPYLMETHYL-N-N-PROPYLAMINE.

PROFLURALIN SHOULD BE MECHANICALLY INCORPORATED FOR MAXIMUM BIOLOGICAL ACTIVITY. SUITABLE INCORPORATION EQUIPMENT INCLUDES PTO-DRIVEN CULTIVATORS, HOES, TILLERS, DOUBLE DISK, ROLLING CULTIVATORS, AND BED CONDITIONERS. APPLICATION AND INCORPORATION CAN BE PREPLANTING, POST PLANTING, OR AT LAYBY. RATES: SAND, LOAMY SAND, SANDY LOAM (LIGHT) 0.5 TO 0.75 LB/ACRE; LOAM, SILT LOAM, SILT (MEDIUM) 0.75 TO 1.50 LB/ACRE; CLAY LOAM, SILTY CLAY, CLAY (HEAVY) 1.0 TO 1.5 LB/ACRE. DO NOT USE ON MUCK AND PEAT.

IN THE GREENHOUSE, SEEDING IN SOIL TREATED WITH PROFLURALIN (1-2 LB/ACRE) INCR THE SUSCEPTIBILITY OF SOYBEAN TO ROOT ROT, CAUSED BY FUSARIUM OXYSPORUM. IT DECR ROOT DEVELOPMENT AND CAUSED HYPOCOTYL SWELLING, THUS PREDISPOSING THE PLANTS TO FUNGAL INFESTATION.

COTTON ROOT PRUNING OCCURRED IN PLOTS TREATED WITH PROFLURALIN (1.5 AND 3.0 LB/ACRE) AT TEMP OF 17-24 °C USING OVERHEAD IRRIGATION.

Discontinued by Ciba-Geigy Corp.

Registration cancelled April 20, 1984