Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF CHEMICAL SAFETY 

& POLUTTION PREVENTION

MEMORANDUM

Date: 09/12/2012

SUBJECT: Quinclorac on Rhubarb and Low Growing Berries (except Strawberry). 

Summary of Analytical Chemistry and Residue Data. 

Residue Chemistry Considerations for Registration Review of Quinclorac and 

Quinclorac Dimethyl Amine.

 

PC Codes: 028974, 128974 DP Barcode: D397719, 404569, 404912

Decision No.: 459055 and 468877 Registration No.: 42750-169

Petition No.: 1E7957 Regulatory Action: Section 3 Registration and 

Registration Review

Risk Assessment Type: NA Case No.: 7222

TXR No.: NA CAS No.: 84087-01-4, 84087-48-9

MRID No.: 48697501, 48697502 40 CFR: 180.463

 

From: Susan V. Hummel, Chemist

Gary Otakie, Chemist

 Risk Assessment Branch 4, Health Effects Division (7509P)

Through: Thurston G .Morton, Chemist

 Risk Assessment Branch 4, Health Effects Division (7509P)

To: Sidney Jackson and Barbara Madden, PM#5

 RIMUERB, Registration Division (7505P)

 Erik Kraft and Kable Davis, PM#25

 Herbicide Branch, Registration Division (7505P)

Wilhelmina Livingston, RM#60

Pesticide Reevaluation Division (7508P)

Executive Summary

Quinclorac [3,7-Dichloro-8-quinolinecarboxylic acid] is a selective post-emergent herbicide used 

for the control of various annual grasses and broadleaf weeds in barley, wheat, rice, sorghum and 

grasses grown for seed. Permanent tolerances have been established for residues of quinclorac 
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

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per se in/on barley, rice, sorghum and wheat at levels ranging from 0.1 ppm in wheat straw to 

1200 ppm in aspirated grain fractions [40 CFR §180.463(a)]. Permanent tolerances have also

been established for residues of quinclorac, per se, in/on livestock commodities at levels ranging 

from 0.05 to 1.5 ppm. In addition, there is a tolerance for residues quinclorac on cranberry in 

§180.463(b), as a result of a Section 18 emergency exemption at 15 ppm.

The Inter Regional Project No. 4 (IR-4) has submitted a request for tolerances and registration of 

quinclorac on low growing berries, except strawberries, subgroup 13-07H, and rhubarb. 

Tolerances were proposed for residues of quinclorac in low growing berries, except strawberries, 

subgroup 13-07H, at 1.1 ppm, and rhubarb at 0.4 ppm.

A new physical form of quinclorac (EPA Reg. No. 7969-272) has recently been registered: Drive 

XLR-8 (Reg. No 7969-272), Paramount L Herbicide (Reg. No. 7969-315), Facet L Herbicide 

(EPA Reg. No. 7969-316), and Quinclorac 1.5 DMA (Reg. No 42750-224). These products are 

DMA (dimethylamine) salt forms of quinclorac. These products were not proposed for the new 

uses of quinclorac, proposed in the current petition, but are registered for use on rice and 

ornamental turf. 

The qualitative nature of quinclorac residues in plants was considered adequately understood for 

the currently registered crops, based upon the metabolism studies on rice, sorghum, and wheat. 

Additional metabolism data are needed on a fruit commodity to support use on berries. Further 

metabolism data may be needed if uses are further expanded. The qualitative nature of 

quinclorac residues in livestock is also understood based upon the adequate goat and poultry

metabolism studies. The Agency had concluded that parent is the only residue of concern in both 

plant and livestock commodities for purposes of the tolerance expression and risk assessment. 

However, the official enforcement method includes a methylation step, so the methyl ester of 

quinclorac is implicitly included as a residue of concern.

An adequate enforcement method is available for enforcing quinclorac tolerances on plants and 

livestock, a GC/ECD method that uses methylation with diazomethane. There are available FDA 

multi-residue method (MRM) testing data that indicate that quinclorac is completely recovered 

using Protocol B. 

Adequate analytical methods are available for determining residues of quinclorac, per se, in/on 

plant parts, an LC/MS/MS method (BASF Method A9708/1). The validated LOQ for quinclorac 

is 0.05 ppm. However, this method would not determine the methyl ester of quinclorac, which is 

implicitly included in the residue of concern.

Adequate cattle and poultry feeding studies are available and support the use of of quinclorac.

Adequate rotational crop studies are available and support the use of quinclorac.
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Regulatory Recommendations and Residue Chemistry Deficiencies

860.1200 Directions for Use. 

1. Cranberry is an aquatic crop, and as such, a label restriction is needed regarding the use of 

treated rice and cranberry fields for aquaculture. Alternatively, the petitioner may

determine residues in catfish and crayfish raised in treated fields and propose 

tolerances for these commodities, if necessary. The label provided for 

Quinclorac/QuinStar 4-L does not contain any restriction against aquaculture.

2. For Registration Review, the PM must ensure that all labels for quinclorac on rice and 

cranberry contain a label restriction restricting the use of treated rice and cranberry

fields for aquaculture.

860.1300 Nature of the Residue in Plants

3. While the metabolism of quinclorac is adequately understood with regard to the 

currently registered uses, there are no plant metabolism data for quinclorac on 

commodities similar to cranberry. 

4. These data are not being required at this time. However, any further expansion of the use 

of quinclorac to other commodities grown on larger acreages than rhubarb and 

cranberry, will trigger a requirement of additional metabolism data.

860.1400 Water, Fish, and Irrigated Crops

5. Data on catfish and crayfish are required, or the label must prohibit use of treated water 

from rice and cranberry fields for aquaculture.

For registration review, the PM must ensure that all quinclorac labels with uses on 

rice and cranberry contain such a restriction.

860.1480 Meat, Milk, Poultry, and Eggs

6. Tolerances in livestock commodities are not pertinent to the current petition. However, 

tolerances in livestock commodities will be changed in connection with Registration 

Review.

860.1500 Crop Field Trials

7. Field trial data are adequate to determine quinclorac, per se. IR-4 should note the current 

guidance for differentiating field trial sites.

8. Field trial data are adequate to support the existing uses of quinclorac on rice, grain 

sorghum, barley (imported), and pasture and range grasses.

9. The established tolerance on aspirated grain fractions should be revoked as it is not 

needed. The tolerance on rice straw may be revoked, as rice straw is no longer 

considered a significant livestock feedstuff.

860.1650 Submittal of Analytical Reference Standards

10. Albaugh must supply the Pesticide Repository with analytical standards for quinclorac 

and the quinclorac methyl ester.

11. An analytical standard for the quinclorac DMA salt must be submitted to the EPA 

National Pesticide Standards Repository.

860.1550 Proposed Tolerances

12. A tolerance for residues of quinclorac on rhubarb may be set at 0.5 ppm. A tolerance for 

residues of quinclorac on low growing berries, except strawberries, subgroup 13-07H, 
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

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may be set at 1.5 ppm. At the time of publication of this tolerance, the tolerance for 

residues quinclorac on cranberry in § 180.463(b) should be revoked, since the 

tolerance being set will cover the Section 18 use.

13. In addition, IR-4 should be reminded to use the OECD tolerance calculation procedures.

14. Revisions to current tolerances for registration review are documented in Table 7.

Background

Quinclorac is a herbicide for the selective post-emergent control of various annual grasses and 

broadleaf weeds. Quinclorac is adsorbed via the root system and partially through the foliage

and acts as an inhibitor of cell wall synthesis. The nomenclature of quinclorac and quinclorac

DMA salt are summarized in Table 1, and the physicochemical properties of are summarized in 

Table 2. 

Table 1. Quinclorac and Quinclorac (DMA salt) Nomenclature.

Compound

N

Cl

Cl

O

OH

Common name Quinclorac,

Company experimental name BAS 514 34H 

IUPAC name 3,7-dichloroquinoline-8-carboxylic acid

CAS name 3,7-dichloro-8-quinolinecarboxylic acid

CAS registry number 84087-01-4

Molecular weight 242.1

End-use product (EP) Drive® 75 DF 

Compound

N

Cl

Cl

O O

HN

CH3

CH3

H

+
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Table 1. Quinclorac and Quinclorac (DMA salt) Nomenclature.

Common name Quinclorac, DMA salt

Company experimental name BAS 514 51H 

IUPAC name 3,7-dichloroquinoline-8-carboxylic acid, DMA salt

CAS name 3,7-dichloro-8-quinolinecarboxylic acid, DMA salt

CAS registry number 84087-48-9

Molecular weight 287.2

End-use product (EP) Drive®XLR8 Herbicide, EPA Reg. No. 7969-272; Paramount® L Herbicide, 

EPA Reg. No. 7969-GRA; Facet L Herbicide, EPA Reg. No. 7969-GRL

Note: Physicochemical properties of the technical grade quinclorac are reported below. 

Only several physicochemical properties of the DMA salt of quinclorac are available.

Table 2. Physicochemical Properties of the Technical Grade Quinclorac.

Parameter Value Reference

Melting point/range ~269°C D342446, M. Doherty, 

9/11/07

pH 3.4-3.5 RCB 3283 S. Hummel, 

2/26/88

Density ~560 g/L D342446, M. Doherty, 

Water solubility (20°C) 9/11/07 0.0064 g/100 mL

Solvent solubility (g/100 mL at 20°C to 

25°C)

ethanol 0.2 toluene <0.1

Lutrol® <0.1 acetone 0.2

olive oil <0.1 n-octanol <0.1

acetonitrile <0.1 1,2-propandiol <0.1

ethyl acetate 0.1 dichloromethane <0.1

ethyl ether 0.1 n-hexane <0.1

Vapor pressure (20°C) <1.0×10-7 mbar (<0.75×10-7 Torr)

Dissociation constant, pKa 4.34 at 20°C

4.35 at 25°C

Octanol/water partition coefficient, log 

POW (20°C)

1.76 at pH 4

-0.74 at pH 7

3.74 at pH 10

UV/visible absorption spectrum 314 nm, 300 nm, 278 nm (95% ethanol) MRID 48051092
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Table 2. Physicochemical Properties of the Quinclorac, DMA Salt.

Parameter Value Reference

Melting point/range NA

pH NA

Density NA

Water solubility (20°C) NA

Solvent solubility (g/100 mL at 20°C to 

25°C)

NA

Vapor pressure (20°C) NA

Dissociation constant, pKa 4.33 ± 0.15 (Temperature not reported) MRID 48051092

Octanol/water partition coefficient, log 

POW (20°C)

NA

UV/visible absorption spectrum 314 nm, 300 nm, 278 nm (95% ethanol) MRID 48051092

In addition, the registrant has submitted a comparative study of the dissociation behavior of 

quinclorac and its dimethylamine salt (MRID 48051902, “Comparative study of the Dissociation 

Behavior of Quinclorac Acid and its Dimethylamine Salt”). The UV/Vis spectra of quinclorac 

TGAI and the UV/Vis spectra and dissociation constant of quinclorac DMA were presented. The 

results of the study show that in aqueous solutions, the chemical form of the quinclorac 

dimethylamine salt is the same as that of the quinclorac acid form. 

860.1200 Directions for Use

There are currently five quinclorac EPs registered to BASF in the U.S. for use on food/feed 

crops, three of which contain only quinclorac and two that are multiple active ingredient (MAI) 

formulations. The single active ingredient formulations include a 50% WP and a 75% DF for 

use on rice (EPA Reg. Nos. 7969-93 and 7969-313) and a 75% DF for use on wheat, sorghum, 

and grasses grown for seed (EPA Reg. No. 7969-113). The two MAI formulations are both 75% 

DF formulations; one contains 15% quinclorac and 60% 2,4-D and is registered for use on wheat 

and sorghum (EPA Reg. No. 7969-152), and the other contains 62% quinclorac and 13% 

imazethapyr and is registered for use on rice. 

Proposed new uses. IR-4 is proposing use of the Quinclorac 4-L AG (Reg. No. 42750-169), 

registered to Albaugh, Inc., containing 3.8 lb quinclorac/gallon, in connection with the current 

petition. 
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Table 3. Summary of Proposed Directions for Use Quinclorac 4-L AG

Formulation

[EPA Reg. No.],

a.i. 

Applic. Timing, Type, and 

Equip. 1

Applic. Rate

(lb ai/A)

Max. 

Seasonal 

Applic. Rate

(lb ai/A)

PHI

(days) Use Directions and Limitations 2

Rhubarb

Quinclorac 4-L

42750-169, 

3.8 lb/gal DF, 

Quinclorac

Foliar ground application 

in 10 gal water, timing not 

specified. A second 

application at least 30 days 

after the first application

0.37 0.75 30 Crop oil concentrate permitted.

Low Growing Berries, except Strawberry, subgroup 13-07H

Quinclorac 4-L

42750-169, 

3.8 lb/gal DF, 

Quinclorac

Foliar ground application 

in 10 gal water, timing not 

specified. A second 

application at least 30 days 

after the first application

0.50 1.0 60 Adjuvants not mentioned.

Conclusions. Cranberry is an aquatic crop, and as such, a label restriction is needed regarding 

the use of treated rice and cranberry fields for aquaculture. Alternatively, the petitioner can 

determine residues in catfish and crayfish raised in treated fields and propose tolerances for these 

commodities, if necessary. The label provided for Quinclorac/QuinStar 4-L does not contain any

restriction against aquaculture.

Existing Uses. Existing uses of quinclorac include use on rice, grain sorghum, wheat, pasture 

and rangeland grasses, and use on barley in Canada for import into the US. The dimethylamine 

salt of quinclorac has recently been registered for use on rice, grain sorghum, and wheat.

The current uses are as described under 860.1500 Field Trials.

860.1300 Nature of the Residue - Plants

D241204, J. Stokes, 11/6/1998

The qualitative nature of quinclorac residues in plants was considered adequately understood for 

the currently registered uses, based upon the metabolism studies on rice, grain sorghum, and 

wheat. In each of these studies, the major 14C-residue in/on various matrices was identified as 

parent compound. Based on the metabolite profiles observed in these studies, quinclorac 

undergoes hydroxylation of the quinoline ring of the parent, followed by conjugation with

glucose and other biologically available compounds at the hydroxlated site. Some radioactive 

residues are incorporated into the high molecular weight natural products. Based on the above 

studies, HED concluded that parent is the only residue of concern in plant commodities for 

purposes of the tolerance expression and risk assessment. However, all three metabolism studies 

are on grain commodities. A 4th metabolism study, on canola, is available but has not been 

reviewed.

Metabolism in Rice. (MRID 41063534). The metabolism of 14C-ring labeled quinclorac in 

rice plants was studied under growth chamber and field conditions. Growth chamber plants were 

treated at 1.4 lb.ai/A 14C-BAS 514H, an exaggerated dosage rate, at the four leaf stage of plant 

development. Growth-chamber rice plant samples were harvested for analysis at PHI=97 days. 
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Field plants were treated at 0.75 lb/A 14C-BAS 514H, at the 3-5 leaf stage. The treatment level 

of field plants simulates the expected herbicide use rate. Field rice plants were harvested at PHI= 

28 and 118 days. Greater than 84% of the TRR in rice grain or straw was identified as the parent 

compound, quinclorac. 

Metabolism in Sorghum: (MRID #44322211). Preemergence and post emergence applications 

of radiolabeled quinclorac were made to a confined sorghum plot. The soil was a loamy sand 

soil with low organic matter. Treatment levels were 0.47 lb ai/A preemergence (0 DAT) and 

0.45 lb a.i./A postemergence (25 DAT) for a total of 0.92 lb ai/A. Crop samples were collected 

and analyzed at various stages of maturity, including forage samples collected at twenty-five days 

after the postemergence treatment, and mature stover and grain collected at the final harvest (120 

DAT). 

TABLE 4. Distribution and Identification of Residues from Sorghum RACs Treated at 

0.92 lb a.i./A. 

RAC

Radioactive Residues

Identified Unidentified Residuum

quinclorac quinclorac methyl ester Soluble polars Organosoluble

ppm %TRR ppm %TRR ppm %TRR ppm %TTR ppm %TRR ppm

forage 4.01 73.4 2.94 3.6 0.145 18.7 0.750 4.7 0.188 <1 <0.01

fodder 0.87 21.5 0.186 5.9 0.051 52.4 0.455 19.4 0.169 <1 <0.01

grain 0.83 73.5 0.610 1.7 0.014 5.5 0.044 6.6 0.055 <1 <0.01

The radioactive residues of quinclorac found in sorghum following typical agricultural practices 

consist predominantly of parent compound. A minor metabolite, the methyl ester of quinclorac, 

is found in all tissues, but always at less than 10% TRR. A lower percentage of the residue in 

sorghum fodder was found to be quinclorac, but the majority of the residue was soluble polar 

compounds. The current analytical methodology (BASF Method No. A8902) employs a similar 

acetone extraction step as used in the above extractions. Therefore, the accountability of the 

residues is high. 

Metabolism in Wheat: (MRID #44322207). The test substance used in this study was 

quinclorac (labeled at the 3 position) at two application rates (0.112 lb ai/A (0.45X the proposed 

rate) and 0.446 lb ai/A (1.8X the proposed rate)). Only the higher application rate is presented in 

the table below. Plants were grown in greenhouse conditions and sprayed 22 days after planting, 

when they were in the 3 to 5 leaf stage. Forage samples were collected at a 37-day PHI, straw 

and grain at a PHI of 92 days. 

TABLE 5. Distribution and Identification of Residues from Wheat RACs Treated at 0.446 

lb ai/A Quinclorac. 

RAC

Radioactive Residues

Identified Unidentified Unextracted Marc

quinclorac quinclorac methyl ester aqueous acetone soluble hydrolyzable non-hydrolyzable

%TRR ppm %TRR ppm %TRR ppm %TRR ppm %TRR ppm
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ppm

forage 13.1 45.1 5.9 6.4 0.84 38.4 5.1 10.3 0.34 1.9 0.06

straw 8.2 22.4 1.8 12.6 1.0 45.1 3.7 12.4 0.23 3.3 0.06

grain 3.9 68 2.7 3.7 0.15 17.2 0.68 3.3 0.04 0.3 <0.01

The primary path by which plants metabolize quinclorac is through the hydroxylation of the 

quinoline ring of the parent, followed by the conjugation of glucose and other biologically

available compounds at the hydroxlated site. Ultimately, some radioactive residues are 

incorporated into the high molecular weight natural products.

The petitioner, IR-4, requests a waiver from the requirement of another metabolism study based 

on the following. In the studies to date it has been shown that in plants the primary path by

which quinclorac is metabolized is through hydroxylation of the quinolone ring of the parent, 

followed by the conjugation of glucose and other biologically available compounds at the 

hydroxylated site. These results were similar for all quinclorac metabolism studies submitted to 

date.

Rhubarb and cranberry are very low acreage crops. Cranberry is commercially grown on just 

over 40,000 acres, and Rhubarb is commercially grown on approximately 2,000 acres in the US 

(based on 2002 census of Agriculture).

In addition, other related quinoline compounds, such as quinoxyfen have shown similar 

metabolism results in that the parent is the primary residue component (D276835, 3/26/2003, G. 

Kramer) when conducted on a wide variety of plant matrices (cucumber, grape, sugarbeet, and 

tomato). In these studies, quinoxyfen was the primary residue component and other remaining 

compounds were incorporated into natural plant constituents. In cucumber and tomato, 

unchanged quinoxyfen remained largely on the surface of treated plants. The presence of 

multiple unidentified polar residues suggests that metabolism of quinoxyfen does occur to some 

extent to form more polar soluble components with the incorporation into insoluble material. 

TABLE 1. Test Compound Nomenclature for the similar pesticide Quinoxyfen

Common name Quinoxyfen

Company name DE-795

Chemical Class Quinoline fungicide

IUPAC name 5,7-dichloro-4-quinolyl 4-fluorophenyl ether

CAS name 5,7-dichloro-4-(4-fluorophenoxy)quinoline

CAS # 124495-18-7

End-use product/EP Quintec®

Chemical Structure N

O F

Cl

Cl
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Conclusions. While the metabolism of quinclorac is adequately understood with regard to the 

currently registered uses, there are no plant metabolism data for quinclorac on commodities 

similar to cranberry. These data are not being required at this time. However, any further 

expansion of the use of quinclorac to other commodities grown on larger acreages than rhubarb 

and cranberry, will trigger a requirement of additional metabolism data.

The methyl ester of quinclorac was reported in some grain commodities at <15% of the TRR. 

The methyl ester is measured by the enforcement method, which includes a methylation step.

860.1300 Nature of the Residue - Livestock

D241204, J. Stokes, 11/6/1998

D325790, M. Doherty, 9/13/2007

The qualitative nature of quinclorac residues in livestock is understood based upon the adequate 

goat and poultry metabolism studies (MRIDs 41076104 and 41063535, respectively). In both 

studies, quinclorac was the principal residue identified in each commodity. HED concluded that 

parent is the only residue of concern for risk assessment and tolerance expression for livestock. 

However, the enforcement method includes a methylation step and determines the methyl ester of 

quinclorac. 

In a rat metabolism study (MRID 41063533), quinclorac was the primary metabolite reported. 

Elimination was primarily in the urine (91-98%) with small amounts in the feces (1-4%) 

eliminated by day 5 after dosing.

Conclusions. No further livestock metabolism data are required at the present time.

860.1340 Residue Analytical Methods

D241204, J. Stokes, 11/6/1998

DEB 5554, J. Garbus, PP#9F3755/9H5583, 8/7/90

Adequate analytical methods (GC/ECD) are available to enforcing quinclorac tolerances on plant 

(BASF Method A8902; MRID# 41063537) and livestock (BASF Method 268/1; MRID# 

41063536) commodities. Both methods have undergone successful agency method validation 

trials and have been submitted to FDA for publication in PAM II as the tolerance enforcement 

methods. The LOQ of both methods is 0.05 ppm for all matrices. 

In BASF Method 268/1, used for both plant and animal matrices, samples are soaked in 0.1 N 

NaOH for 1 hour and then extracted with acetone, pH adjusted with sodium bicarbonate, and 

then the extract is extracted several times with dichloromethane. Organic extracts are combined, 

redissolved in ether and methanol, treated with diazomethane, and taken to dryness. (No suitable 

substitute was found for the diazomethane.) The methylated residue is dissolved in 75% 

dichloromethane/hexane and cleaned up with silica gel. The eluant fraction containing the 

methylated quinclorac is evaporated to dryness and redissolved in acetone/hexane. An aliquot is 

subjected to GC chromatography using a DB-5 column and electron capture detection. 

Methylated standard is used for quantitation. The LOD was reportedly 0.05 ppm, but this was 
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also the lowest level validated.

In the current field trials, residues of quinclorac in/on rice, wheat, and sorghum plant parts were 

determined using a LC/MS/MS method (BASF Method A9708/1). This method was adequately

validated in conjunction with the analysis of field trial samples.

Crop samples were soaked in 0.1 N NaOH for 1 hour and then extracted with acetone. The 

extract was concentrated to remove the acetone, and then acidified. Residues were next 

partitioned into dichloromethane, concentrated to dryness, redissolved in 0.0025 N NaOH, and 

adjusted to pH 8-11. Residues were then cleaned up using a quaternary amine SPE column, and 

analyzed by LC/MS/MS using external standards. The 240→196 m/z ion transition was used to 

detect and quantify residues. The validated LOQ for quinclorac is 0.05 ppm in both matrices, 

and the LOD was not reported. With only one ion transition monitored, the LC/MS/MS method 

cannot be considered suitable for enforcement, but it is suitable for data collection.

Conclusions. An adequate GC/ECD method is available for enforcing the proposed tolerances, 

and the field trial data were collected using an LC/MS/MS method adequate for determining 

quinclorac, per se. If LC/MS/MS is tobe used, a method is needed for the methyl ester of 

quinclorac and any other metabolites found in the required metabolism study.

860.1360 Multiresidue Methods

PP#9F3755, J. Garbus, 08/07/90

Adequate data are available evaluating quinclorac through the FDA Multi-Residue Methods Test 

guidelines, and quinclorac is detected by Protocol B. Quinclorac is not detected by the other 

FDA MRM protocols.

860.1380 Storage Stability

D241204, J. Stokes, 11/6/1998

PP#9F3755, J. Garbus, 08/07/90

Adequate data are available indicating that quinclorac (and the methyl ester) is stable under 

frozen storage conditions for up to 37-40 months in rice grain and straw, corn grain, forage, 

silage, and fodder, soybean grain and fodder, sugar beet roots and tops, alfalfa hay, sorghum 

forage, hay, silage, and fodder. 

Storage stability of quinclorac residues in livestock tissues was assessed by reanalyzing tissue 

samples after a period of time equal to their storage prior to the initial analysis. Stability in 

animal and plant tissues has been demonstrated in accountability studies where plant and animal 

tissues were stored for 3 years between radiochemcial and chromatography analyses (See J. 

Garbus, 08/02/90).

In addition, IR-4 provided concurrent storage stability data for rhubarb and cranberry, 

demonstrating stability for the time and conditions the samples were stored.

Conclusions. The available storage stability data are adequate and support the storage conditions 

and durations incurred in the existing field trials, for currently registered uses. The IR-4 
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concurrent storage stability data for rhubarb and cranberry are adequate for residues of 

quinclorac, demonstrating stability for the time and conditions the samples were stored. Storage 

stability data are needed for residues of the methyl ester of quinclorac and other residues of 

concern found in any future metabolism study.

860.1400 Water, Fish, and Irrigated Crops

For existing use on rice and the proposed use on cranberry, a label restriction is needed regarding 

the use of treated rice and cranberry fields for aquaculture. Alternatively, the petitioner can 

determine residues in catfish and crayfish raised in treated fields and propose tolerances for these 

commodities if necessary. The label provided for Quinclorac/QuinStar 4-L does not contain any

restriction against aquaculture.

Conclusions. Data on catfish and crayfish are required, or the label must prohibit use of treated 

water from rice and cranberry fields for aquaculture.

For registration review, the PM must ensure that all quinclorac labels with uses on rice and 

cranberry contain such a restriction.

860.1460 Food Handling

This guideline topic is not relevant to the proposed use.

860.1480 Meat, Milk, Poultry, and Eggs

DP# D241204, J. Stokes, 11/6/1998

DP# D358151, G. Oatkie, 04/30/2009

Adequate cattle and poultry feeding studies are available. The uses proposed in this petition do 

not involve livestock feeds, and will not affect the existing tolerances on meat, milk, poultry and 

eggs. 

For registration review, we are recommending that the tolerance on Grain, aspirated fractions be 

revoked, since data have been received demonstrating that the tolerance is not needed, as residues

on aspirated grain fractions (AGF) are no higher than the tolerances on the grains. AGF were the 

highest contributor to the livestock dietary burden, but tolerances have since been established for 

grass commodities, which is now the highest contributor to the livestock dietary burden.

Dietary burdens for livestock were recalculated in connection with the petition for residues of 

quinclorac on pasture and rangeland grasses. (D358151, 04/30/2009, G. Otakie, MRID 

45066302). In the review of that petition we concluded:

As the use on grasses does not substantially alter the calculated MDB for cattle (275 vs 290 

ppm), no changes are necessary in the existing tolerances for milk and meat, fat and meat 

byproducts of cattle, goats, horses and sheep. However, the recalculated MDBs for poultry and 

swine indicate that the existing tolerances for poultry and hog commodities should be reassessed.

These data support the current 0.05 ppm tolerances (LOQ) for eggs and poultry fat and meat, and 

indicate that the current 0.1 ppm tolerance for poultry meat byproducts should be lowered to 0.05 
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

Page 13 of 32

ppm. HED notes that lowering the tolerance for poultry meat byproducts to 0.05 ppm will also 

harmonize this tolerance with the existing Canadian MRL for poultry meat byproducts.

These data support the current 0.05 ppm tolerance (LOQ) for hog meat, and indicate that the 

current tolerances for hog fat (0.7 ppm) and hog meat byproducts (1.5 ppm) should also be 

lowered to 0.05 ppm. Lowering the tolerances for these commodities will also harmonize the 

U.S. tolerances with the existing Canadian MRLs for hog fat and meat byproducts.

Conclusions. Tolerances in livestock commodities will be changed in connection with 

Registration Review.

860.1500 Crop Field Trials

48697501.der.doc Rhubarb

48697502.der.doc Cranberry

Cranberry (for Low Growing Berries except strawberry, subgroup 13-07. Five cranberry field 

trials were conducted in the United States during the 2009 growing season, in North American 

Free Trade Agreement (NAFTA) Growing Zones 1 (MA; 2 trials), 5 (WI; 2 trial), and 12 (OR; 1 

trial). The two MA trials (MA01 and MA03) and the two WI trials (WI01 and WI02) were each 

conducted using the same Field Research Director (FRD). Careful examination of the field trial 

records indicates that the only difference between each pair of trials was the use of different 

varieties of cranberry, and distance between MA trials of > 20 miles, and different soil 

characterics for the MA trials. HED has concluded that there are insufficient distinguishing 

characteristics to classify the WI pair as separate trials; however, the trials were conducted prior 

to development of the guidance on field trial differentiation.

Following two foliar broadcast applications of the 3.8 lb ai/gal SC formulation of quinclorac at 

0.484-0.528 lb ai/A, residues of quinclorac (and per trial averages) in/on cranberry harvested at a 

57- to 62-day PHI were 0.15-0.68 (0.16-0.67) ppm. Applications were made at a 28- to 32-day

retreatment interval (RTI) using ground equipment in spray volumes of 29.7-35.3 gal/A. A crop

oil concentrate (COC) was added to the spray mixture for each of the applications at 2 pints/A. 

Rhubarb. Four field trials were conducted in the United States during the 2009 growing season 

in the North American Free Trade Agreement (NAFTA) Growing Zones 5 (MI; 1 trial) and 12 

(OR; 3 trials). The two rhubarb trials in Canby, OR (OR11 and OR12) and the trial in Hillsboro, 

OR (OR10) were conducted by the same Field Research Director (FRD). Careful examination of 

the field trial records indicates there are sufficient distinguishing characteristics to classify the 

Hillsboro, OR trial as a separate trial from the Canby, OR trials, based on location (>20 miles 

apart) and spray volume (>25% higher at the Hillsboro site). There are insufficient 

distinguishing characteristics to classify the two Canby, OR trials as separate trials; therefore, the 

Canby, OR trials constitute a single trial with replicate samples for purposes of 860.1500 data 

requirements. The adjustment in trial numbers results in a total of three field trials, with one trial 

in Zone 5 and two trials in Zone 12.

Following two foliar broadcast applications of the 3.8 lb ai/gal SC formulation of quinclorac at 

0.736-0.798 lb ai/A, residues (and per trial averages) of quinclorac in/on rhubarb harvested at a 

29- to 33-day PHI were 0.05-0.231 (0.082-0.205) ppm. The method LOQ was 0.05 ppm. 
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

Page 14 of 32

Applications were made at a 28- to 31-day retreatment interval (RTI) using ground equipment in 

spray volumes of 19.9-36.7 gal/A. A crop oil concentrate (COC) was added to the spray mixture 

for each of the applications at a rate of 1-2 pints/A. 

Conclusions. Field trial data are adequate to determine residues of quinclorac, per se. 

IR-4 should note the current guidance for differentiating field trial sites.

Existing Uses of Remaining Crops

Existing uses of Quiclorac include use on rice, wheat, soybeans, barley (import), grass forage and 

hay. Each is discussed below, followed by a summary of available data for the dimethylamine 

salt of quinclorac (quinclorac DMA).

Rice. (D241198, 10/01/98, J. Stokes, MRID 44323101) Field trial data were submitted from 

fifteen sites in five states [(MS (3), AR (4), LA (5), MO (1), and TX (2)]. Data from CA were 

not included since the DF formulation is not registered in CA. Rice was treated at 0.5 lb a.i./A 

with the DF formulation, with a 40-day PHI (time before flooding the field). Residue decline 

samples from a plots in MS and AR at -6, -3, +3, and +6 before and after the targeted growth 

stage harvest per RAC. The residues of quinclorac on rice grain ranged from 0.346 ppm to 4.35 

ppm, and averaged 0.987 ppm. The residues of quinclorac on rice straw ranged from 0.120 ppm 

to 2.74 ppm, and averaged 1.07 ppm. The established 5.0 ppm and 12.0 ppm tolerances are 

adequate to cover residues of quinclorac in harvested rice grain and straw, respectively, with a 

40-day PHI. 

Grain sorghum and wheat D241204; D248880; D248881, 11/06/98; PP#9F3755, J. Stokes

Grain Sorghum (MRID#’s 44322212, 44583102).

MRID#44322212: Four grain sorghum field trials with quinclorac 75% DF were conducted in 

KS, NE, OK, and TX. A single postemergence broadcast spray application was made with 

FACET 75 DF Herbicide (EPA Reg. No. 7969-113, 75% a.i. quinclorac) at a rate of 0.25 lb 

a.i./A at the six leaf stage. Samples were collected at two stages of crop maturity, i.e., at the late 

dough stage for forage (54 to 83 DAT), and at grain/stover harvest (81 to 108 DAT). Residues of 

quinclorac ranged from <0.05 ppm to 0.15 ppm in sorghum forage, <0.05 ppm to 0.26 ppm in 

sorghum grain, and all samples were <0.05 ppm in sorghum stover. At the KS plot additional 

samples were collected for a residue decline study; samples were collected at -10, -5, +5, and +10 

days in addition to the target stage samples. All of the samples of sorghum grain and 

forage/stover had residues <0.05 ppm.

MRID#44583102: Twelve field trials trials with quinclorac 75% DF were conducted in nine 

states. Grain sorghum was treated with one preemergence and one post emergence application of 

FACET DF at the rate of 0.5 lb a.i./A per application. (0.84X maximum seasonal application 

rate (preergemence + postemergence: 0.25 lb a.i./A + 0.38 lb a.i./A = 0.63 lb a.i./A)). The 

maximum seasonal rate is 0.75 lb a.i./A. The preemergence application was timed prior to 

planting and the postemergence allocation was 60 to 65 days before harvest of grain and stover. 

Plants were harvested for forage and hay immediately after flowering or 30 days after the last 
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

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treatment. Silage was targeted to be harvested at the soft dough stage of the plant growth. 

Maximum residues were reported as 3.67, 6.68, 4.50, 3.13, and 1.08 ppm in grain sorghum 

forage, grain, hay, silage, and stover, respectively. Tolerances for residues on quinclorac were 

set at 6.0 ppm for sorghum grain, 3.0 for sorghum forage, and 1.0 for sorghum fodder. 

Wheat MRID#44322208: Twelve winter wheat field trials were conducted in 12 states. A single 

broadcast preplant application of FACET 75DF was made at a rate of 0.25 lb a.i./A. Three 

additional plots in KS, OK, and TX received a single broadcast application at twice the label 

maximum rate, i.e., 0.5 lb a.i./A.. Samples were harvested according to normal crop maturity as 

follows: forage, 46 to 224 DAT, dried hay, 162 to 268 DAT, and grain and straw, 194 to 324 DAT. 

Maximum residues in wheat commodities from the 0.25 lb ai/A rate were reported as 0.88, 0.32, 

0.24, and 0.08 ppm quinclorac in forage, hay, grain, and straw, respectively; and 1.55, 0.54, 0.56, and 

0.12 ppm quinclorac in forage, hay, grain, and straw, respectively, from the 0.50 lb ai/A rate. 

Tolerances for residues of quinclorac were set on wheat forage (1.0 ppm), hay (0.5 ppm), grain (0.5 

ppm), and straw (0.1 ppm).

Barley (imported). Data for residues of quinclorac DF formulation were reviewed by PMRA. 

Twelve field trials with spring barley, grown in the prairie provinces, were conducted. The 

barley was treated with one ground application of Facet 75 DF at a target rate of 0.200 kg a.i./ha

[0.18 lbs a.i./A] (2x rate or Canadian GAP). A surfactant was added to the tank mix. Forage 

samples were harvested 16-30 days following application, while grain and straw were harvested 

63-97 days following application. Residues in forage ranged from <0.05-2.01 ppm. The highest

average field trial residue (HAFT) found in forage was 1.78 ppm. In the grain, individual 

residues ranged from <0.05-1.25 ppm. The HAFT in the grain was 1.165 ppm. In the straw, the 

residues ranged from <0.05-0.484 ppm, with the HAFT being 0.299 ppm. A tolerance of 2 ppm 

was established for residues of quinclorac on barley grain.

Aspirated Grain Fractions(AGF): Data for quinclorac aspirated grain fractions were not submitted 

for the original grain petitions. The needed tolerance for AGF was estimated at 200X the 6.0 ppm 

tolerance for sorghum grain (200 X 6.0 = 1200 ppm). Data were later provided.

(D344496, 09/25/08; GOtakie: Quinclorac. Magnitude of the Residue in Wheat and Sorghum 

Aspirated Grain Fractions. MRIDs 45598703 and 45598704.)

Two field trials were conducted for quinclorac (BAS 514 H) on wheat aspirated grain fractions 

and sorghum aspirated grain fractions. The studies were conducted in the United States in Zone 

5 (York County, Nebraska) during the 1999 growing season. Residues of quinclorac were 

quantitated at 0.453 and 0.516 ppm in/on wheat AGFs following two applications of BAS 514 H 

at 0.25 lb ai/A/application (0.50 lb ai/A/season). Residues of quinclorac were quantitated at 

0.147 and 0.145 ppm in/on sorghum AGFs following two applications of BAS 514 H at 0.25 and 

0.50 lb ai/A/application (0.75 lb ai/A/season). Ash content was between 12.0 and 17.5% in all 

wheat AGF samples and between 5.5 and 9.0% in all sorghum AGF samples.

Tolerances for quinclorac established under 40 CFR 180.463 are 0.5 ppm and 6.0 ppm on wheat 

and sorghum grain, respectively. Average residues at the maximum application rate in aspirated 

grain fractions were 0.48 and 0.15 ppm, in wheat and sorghum respectively. Accordingly, 

separate tolerances on aspirated grain fractions are not required, pending submission of detailed 

weather data, throughout the residue trial period. The existing tolerance for residues of 
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

Page 16 of 32

quinclorac on AGF should be revoked.

Pasture and Rangeland Grasses. (D358151, 04/23/2009, G. Otakie, MRID 45066302). Thirteen 

field trials conducted in the United States in Zones 2, 4, 5, 6, 7, 8, 9, 10, and 11 during 1999, 

quinclorac (75% DF) was applied to representative grass species as a single broadcast foliar 

application during vegetative development at rates of 0.746-0.780 lb ai/A (1x rate). All 

applications were made using ground equipment in volumes of 9-41 gal/A, and include both 

MSO (0.5-3.3% v/v) and aqueous UAN (0.7-5.6% v/v) as adjuvants.

Following a single foliar application of quinclorac (DF) to grasses at ~1x the proposed rate, 

residues were 36.3-105.9 ppm in/on 26 samples of forage harvested at 0 DAT and 3.6-70.1 ppm 

in/on 26 samples of hay harvested at 7-8 DAT. Average quinclorac residues were 68.3 ppm for 

forage and 24.3 ppm for hay, and the HAFT residues were 105.7 ppm for forage and 58.5 ppm 

for hay. The residue decline data indicate that residues in/on forage declined steadily from an 

average of 43.1 ppm at 0 DAT to 7.1 ppm by 15 DAT. For hay, residues initially increased from 

70 ppm at 0 DAT to 83.5 ppm at 3 DAT, but then declined steadily to 24.3 ppm by 15 DAT. 

Tolerances for residues of quinclorac were set at 150 ppm for grass forage and 130 ppm for grass 

hay based on these data.

Comparison of Quinclorac with Quinclorac DMA in rice, wheat, and sorghum. Six field trials, 

each consisting of side-by-side trials comparing the dry flowable (DF) and the soluble liquid (SL) 

formulations of the dimethylamine salt (DMA) of active ingredient, were conducted in 

geographically diverse locations.

The results from these trials indicated that there was no discernable difference between the 

residues SL DMA salt in rice, wheat, and grain sorghum obtained using the dry flowable (DF) or 

soluble liquid (SL DMA) formulations of quinclorac.

Conclusions. Field trial data are adequate to support the existing uses of quinclorac on rice, grain 

sorghum, barley (imported), and pasture and range grasses. In decline studies on grains, when 

detectable residues were initially reported, residues generally degraded substantially within 14 

days.

The established tolerance on aspirated grain fractions should be revoked as it is not needed. The 

tolerance on rice straw may be revoked, as rice straw is no longer considered a livestock 

feedstuff.

860.1520 Processed Food and Feed

There are no processed commodities in connection with the current petition.

For registration review, processing studies submitted to support existing tolerances are adequate. 

Processing studies were submitted for Rice (MRID 41063543), Sorghum (MRID 44322213), and

Wheat (MRID 44322209).
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Table 6. Average Processing Factors for Sorghum

Commodity Processing Factor (x)

Rice, hulls 1.1

Rice, bran 3.5

Rice, milled 0.76

Grain sorghum flour (dry milling) 0.90

Grain sorghum starch (wet milling) 0.04

Wheat, bran 1.8

Wheat, middlings 0.79

Wheat, shorts 1.24

Wheat, flour 0.66

Wheat, germ 2.8

Tolerances for residue of quinclorac of 1.0 ppm, 1.5 ppm, and 0.75 ppm, were set for wheat bran, 

wheat germ, and wheat shorts, respectively.

Conclusions. Available processing data are adequate to support the currently registered uses of 

quinclorac. Residues concentrate on hulls and some milling fractions.

860.1650 Submittal of Analytical Reference Standards

Analytical standards for quinclorac and the quinclorac methyl ester are available from BASF, but 

not from Albaugh, Inc. The methyl ester of quinclorac is used as an analytical standard for the 

quinclorac enforcement method. Albaugh must supply the Pesticide Repository with analytical 

standards for quinclorac and the quinclorac methyl ester.

An analytical standard for the quinclorac DMA salt must be submitted to the EPA National 

Pesticide Standards Repository.

860.1850/1900 Confined and Field Accumulation in Rotational Crops

DP# D241204, J.Stokes, 11/6/1998 

Adequate rotational crop studies are available to support the use of quinclorac. (MRID 

42294108, 42294109 – confined rotational crop; MRID 41781428 – field rotational crop)

The confined rotational crop studies are summarized in the tables below. No quantifiable 

residues (<0.05 ppm for the current enforcement method) were reported in chard, or beet tops or 

roots 10 months (309 days) after treatment at the 1x application rate of 0.5 lb ai/A. Detectable 

residues were reported in chard 1 months after a 2x application rate of 1.0 lb ai/A.
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

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Field rotational crop (MRID 41781428). Rotational crop studies were conducted in LA and MS 

following the application o f 0.5 1b ai/A of quinclorac to rice that was harvested in the fall of 

1987. No residues greater than the limit of detection of 0.05 ppm quinclorac were found in 

mustard leaves and turnip leaves and roots when planted 4 months or 9 months (20 and/or 270 

days) after a quinclorac application to rice. (The analytical method was validated down to 0.05 

ppm, so 0.05 ppm may be called the limit of quantitation (LOQ) or the lower limit of method 

validation (LLMV).
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

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860.1550 Proposed Tolerances

The current tolerance expression for quinclorac is:

“Tolerances are established for residues of the herbicide quinclorac, including its metabolites and 

degradates, in or on the commodities in the table in this paragraph. Compliance with the 

tolerance levels specified in this paragraph is to be determined by measuring only quinclorac, 

3,7-dichloro-8-quinolinecarboxylic acid, in or on the commodity.”

The tolerance expression is in accord with our current guidance on tolerance expressions.

Permanent tolerances have been established for residues of quinclorac in/on small cereal grain 

commodities at levels ranging from 0.1 ppm in wheat straw to 15 ppm in rice bran [40 CFR 

§180.463(a)], and for grass forage at 150 ppm and grass hay at 130 ppm. There is also a 1200 

ppm tolerance for AGF; however, recently reviewed data indicate that a tolerance on AGF is not 

necessary (DP# 344496, G. Otakie, 9/25/08). Permanent tolerances have also been established 

for residues of quinclorac per se in/on livestock commodities at levels ranging from 0.05 to 1.5 

ppm. The tolerances being proposed by IR-4 for the current petition are listed in Table 7, along 

the HED’s recommended tolerances.

An adequate number of field trials at ~1x the proposed use rate are available for rhubarb and 

cranberry to support permanent tolerances. The Agency’s SOP “Guidelines for Setting Pesticide 

Tolerances Based on Field Trial Data” were utilized for determining the appropriate tolerance 

level for each commodity (Appendix II). The recommended tolerance for rhubarb is 0.5 ppm, 

and the recommended tolerance for Low growing berries, except strawberries, subgroup 13-07H

is 1.5 ppm.

Based on the recalculated dietary burdens for livestock and the data from the available cattle and 

poultry feeding studies, the current tolerances for livestock commodities are adequate, with the 

exceptions of the tolerances on poultry meat byproducts and hog fat and meat byproducts. Based 

on the recalculated MDBs for swine (6.0 ppm) and poultry (5.4 ppm) and the data from the 

poultry and cattle feeding studies, the existing tolerances for poultry meat byproducts and hog fat 

and meat byproducts are too high as quinclorac residues in these commodities are expected to be 

<0.05 ppm at 1x the MDB. Therefore, the tolerances for these livestock commodities should be 

lowered to 0.05 ppm. Lowering the tolerances on these commodities will also harmonize the 

U.S. tolerances with the existing Canadian MRLs for poultry meat byproducts and hog fat and 

meat byproducts.

In addition, HED notes that the Agency no longer considers rice straw to be a significant 

livestock feedstuff (OPPTS 860.1000, Table I, ChemSAC memo 6/30/08). Therefore, the 

current tolerance for residues of quinclorac on rice straw may be revoked.

CODEX has not established any established maximum residue limits (MRLs) for quinclorac. 

Canada has established maximum residue limits (MRLs) for quinclorac on selected agricultural 

commodities. An International Residue Limit Status Sheet is attached in Appendix I.
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

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The use of the DMA salt of quinclorac will not affect the established tolerances for quinclorac on 

rice, grain sorghum, and wheat.

Table 7. Tolerance Summary for Quinclorac. § 180.463

Commodity Current/Proposed 

Tolerance (ppm)

Recommended 

Tolerance (ppm)

Comments; Correct Commodity 

Definition

Low growing berries, 

except strawberries, 

subgroup 13-07H

1.1 1.5 Revised level based on OECD tolerance 

calculation procedures. At the time of 

publication of this tolerance, the 

tolerance for residues quinclorac on 

cranberry in § 180.463(b) should be 

revoked.

Rhubarb 0.4 0.5 Revised level based on OECD tolerance 

calculation procedures. 

Currently Established Tolerances Reevaluated for Registration Review

Barley, grain 2.0 2.0 The tolerance needs a footnote to 

indicate that there are no U. S. 

Registrations.

Cattle, fat 0.7 0.7

Cattle, meat byproducts 1.5 1.5

Cattle, meat 0.05 0.05

Egg 0.05 0.05

Goat, fat 0.7 0.7

Goat, meat byproducts 1.5 1.5

Goat, meat 0.05 0.05

Grain, aspirated fractions 1200 revoke Data submitted demonstrate that the 

tolerance is not needed. Current 

tolerance was based on a theoretical 

calculation.

Grass, forage 150 150

Grass, hay 130 130

Hog, fat 0.7 0.05 Based on the residue data from the cattle 

feeding and the calculated MDB of 6.0 

ppm for swine, the tolerances can be 

lowered to the method LOQ (0.05 ppm). 

This level is harmonized with Canada. 

Hog, meat byproducts 1.5 0.05 Based on the residue data from the cattle 

feeding and the calculated MDB of 6.0 

ppm for swine, the tolerances can be 

lowered to the method LOQ (0.05 ppm). 

This level is harmonized with Canada. 
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

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Table 7. Tolerance Summary for Quinclorac. § 180.463

Commodity Current/Proposed 

Tolerance (ppm)

Recommended 

Tolerance (ppm)

Comments; Correct Commodity 

Definition

Hog, meat 0.05 0.05

Horse, fat 0.7 0.7

Horse, meat byproducts 1.5 1.5

Horse, meat 0.05 0.05

Milk 0.05 0.05

Poultry, fat 0.05 0.05

Poultry, meat byproducts 0.1 0.05 Based on the residue data from the 

poultry feeding and the calculated MDB 

of 5.4 ppm for poultry, the tolerance can 

be lowered to the method LOQ (0.05 

ppm). This level is harmonized with 

Canada.

Poultry, meat 0.05 0.05

Rice, bran 15.0 15.0

Rice, grain 5.0 5.0

Rice, straw 12.0 Revoke Rice straw is no longer a regulated 

livestock feedstuff.

Sheep, fat 0.7 0.7

Sheep, meat byproducts 1.5 1.5

Sheep, meat 0.05 0.05

Sorghum, grain, forage 3.0 3.0

Sorghum, grain, grain 6.0 6.0

Sorghum, grain, stover 1.0 1.0

Wheat, forage 1.0 1.0

Wheat, germ 0.75 0.75

Wheat, grain 0.5 0.5

Wheat, hay 0.5 0.5

Wheat, straw 0.1 0.1
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References

DP Barcode: None. CB 6228, 6229, 6230

Subject: PP#9G3797, FAP#0H5594, EUP# 7969-EUP-25. Quinclorac (New Chemical on Rice with 

Temporary Tolerances).

From: A. Aikins

To: R. Taylor/V. Walters

Dated: 7/26/1990

MRID(s): 41063501 through -03, 41063534 through -46, 41076101 and 41076104

DP Barcode: None. CB 5554

Subject: New Chemical Review: PP#9F3755/9H5583: Quinclorac (FACET) in or on Rice Grain and Straw. 

Evaluation of Analytical Method and Residue Data.

From: J. Garbus

To: R. Taylor/J. Miller

Dated: 8/7/1990

MRID(s): 41063501 through -03, 41063534 through -46, 41076101 and 41076104

DP Barcode: None. EFED DER

Subject: DER for Paulick, R.C. January 1991. Magnitude of the residues of quinclorac (BAS 514H) in 

rotational crops (mustard and turnips) following rice culture in Louisiana (RCN 87096) and 

Mississippi (RCN 87098). BASF Report No. A9104. BASF Registration Document No. 91/5022.

From: RJ. Mahler

To: R. Taylor/V. Walters

Dated: 11/5/1991

MRID(s): 41781428

DP Barcode: None. EFED DER

Subject: DER for Nelson, DM. 1992. Accumulation study of 14C-BAS 514H in fall planted confined 

rotational crops. BASF Protocol No. M8909. BASF Report No. M9125. BASF Registration 

Document No. 92/5044. Unpublished study performed and submitted by BASF Corp. Agricultural 

Products, Research Triangle Park, NC. 107 pp

From: RJ. Mahler

To: R. Taylor/V. Walters

Dated: 9/15/1992

MRID(s): 42294109

DP Barcode: None. EFED DER

Subject: DER for Uinkler, V and JM Nelson. 1991. Accumulation of 14C-BAS 514H in annual confined 

rotational crops. BASF Protocol No. M8910. BASF Report No. M9123. BASF Registration 

Document No. 91/5170. Unpublished study performed and submitted by BASF Corp. Agricultural 

Products, Research Triangle Park, NC. 104 pp.

From: RJ. Mahler

To: R. Taylor/V. Walters

Dated: 9/17/1992

MRID(s): 42294108

DP Barcode: D241198

Subject: Quinclorac. ID#007969-00113. Revised Section B. Reduction In PHI For Use On Rice.

From: JStokes

To: MJ Nelson

Dated: 10/01/98 

MRID(s): 44323101
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

Page 24 of 32

DP Barcode: D241204; D248880; D248881

Subject: PP#7F4870. Quinclorac. In/On Grain Sorghum and Wheat. Evaluation of Analytical Method and 

Residue Data.

From: JStokes

To: MJ Nelson

Dated: 11/06/98

MRID(s): 44322206, 44322207, 44322208, 44322209, 44322211, 44322212, 44322213, 44322214, 

44322216, 44583101, 44583102, and 44583103

DP Barcode: D342446

Subject: Quinclorac – Request for Establishment of Tolerances on Barley Grain without a U.S. 

Registration. Summary of Analytical Chemistry and Residue Data. Petition Number 0E6114.

From: M. Doherty

To: H. Johnson/J. Tompkins

Dated: 9/11/2007

MRID(s): 44817507, 45088301

DP Barcode: D344496

Subject: Quinclorac. Magnitude of the Residue in Wheat and Sorghum Aspirated Grain Fractions.

From: G. Otakie

To: J Schnackenbeck

Dated: 9/25/2008

MRID(s): 45598703 & 45598704

.

DP Barcode: D358151

Subject: Quinclorac; Petition for Tolerances and Use on Pasture and Rangeland Grasses. Summary of 

Analytical Chemistry and Residue Data.

From: G. Otakie

To: James Tompkins

Dated: 04/30/2009

MRID(s): 45066302

F. DOCUMENT TRACKING

RDI: S. Hummel 08/11/12;RAB4chemists

Petition Number: 1E7957

DP#: D397719 and 

PC Code: 128974, 028974
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

Page 25 of 32

Attachment 1. Residue Chemistry Data Requirements

Residue Chemistry Data Requirements for Quinclorac

GLN Data Requirements

Current 

Tolerances 

(ppm) [§180.463]

Additional 

Data 

Needed?

MRID Nos.

860.1200: Directions for Use NA

860.1300: Nature of the Residue - Plants NA No

41063534, 44322207, 

44322211, 44817502

860.1300: Nature of the Residue -

Livestock NA No 41076104, 41063535

860.1340: Residue Analytical Method 

Plant and Livestock Commodities NA No 41063537, 44583103

41063536

860.1360: Multiresidue Method 41063541

860.1380: Storage Stability Data

Plant Commodities NA No 41063544, 44322214

Livestock Commodities NA No

860.1400: Magnitude of the Residue -

Water, Fish and Irrigated Crops NA NA None

860.1460: Magnitude of the Residue - Food 

Handling NA NA None

860.1480: Magnitude of the Residue - Meat, Milk, Poultry, Eggs 

Cattle fat, meat, and meat byproducts 0.7/1.5/0.05 No 41063545

Hog fat, meat and meat byproducts 0.7/1.5/0.05 No None

Milk 0.05 No 41063545

Eggs and the Fat, Meat and Meat Byproducts 

of Poultry

0.05/0.05/0.1/0.05 No 41063546

860.1500: Crop Field Trials

Rhubarb 0.5 proposed No 48697501

Cranberry 1.5 proposed No 48697502

Grains

Barley grain (imported) No 44817507, 45088301

Rice grain, straw 5.0/12.0 No 41063542, 44323101

Sorghum forage, grain, stover 3.0/6.0/1.0 No 44322212

Wheat forage, grain, hay, straw 1.0/0.5/0.5/0.1 No 44322208, 44322209, 

45066301

Grain, aspirated fractions No 45598703, 45598704

Pasture/rangeland grasses No 45066302

Comparison of DF formulation of quinclorac 

to quinclorac DMA salt in rice, sorghum, 

wheat

No 48051901

860.1520: Processed Food/Feed

Barley No

Rice No 41063543

Sorghum No 44322213, 44583102, 

44583104

Wheat No 44322210, 44817501, 

860.1650: Submittal of Analytical 

Reference Standards NA No None

860.1850: Confined Accumulation in 

Rotational Crops NA No 42294108, 42294109

860.1900: Field Accumulation in 

Rotational Crops NA No 41781428
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

Page 26 of 32

Attachment 2

Additional information on metabolism from EFED reviews

From 3/8//99 review by R. Mahler and E. Odenkirchen, Quinclorac Herbicide, Environmental 

Fate and Effects Assessment and Characterization for a Section 3 Use on Wheat and Sorghum

Hvdrolysis (161 - 1)

.

Fifty ppm [3-14C] quinclorac was hydrolytically stable in aqueous buffered pH 5, 7, and 9

solutions. After 737 hours, quinclorac comprised >98% of the applied in the three buffer

solutions and was the only [14C]compound detected. This study is acceptable. (MRID

40320816)

P&Q degradation in Water (161-2)

[3-'4C]Quinclorac (radio chemical purity 99.6%), at 5.4 ppm, degraded slightly (-40% of

the applied) in a sterile aqueous pH 7 buffer solution that was irradiated for 697 hours

using a xenon arc lamp at 25 C. After 697 hours of irradiation, quinclorac comprised 92%

Iof the recovered radioactivity, an unidentified degradate comprised 1.6%, and 2.7%

remained near the origin of the TLC plate. The extrapolated half-life was 100 days (note

extrapolations beyond the study duration are uncertain). The sensitized half-life using

acetone was 52 days. This study is acceptable. (MRID 41063560)

Conversely, the photolytic half-lives of non-radiolabled quinclorac in non-sterile natural

river water and solutions containing activated sewage sludge were, respectively, 5 and 10

days (not corrected for dark control results, which suggest that between 8- 12% of

degradation would be accounted for processes other than photolysis over a 47-day

incubation). The authors concluded that photolysis was the main route of degradation in

these two studies; however, they did not identify any degradates. Furthermore, the length

of exposure was only 6 hours/day. Had a longer daily sunlight exposure regime been

used, the half-lives, as determined, may have differed from that reported and may have

been less by at least one-half, based on a typical 12-hour daylight exposure period. This

study is supplemental. (MRID 41063564)

From Y Donovan, “Quinclorac: Section 3 Registrations for New Use on Pasture/ Rangeland:

Drinking Water Exposure Assessment, D362085, June 3, 2009.

For persistence, laboratory data indicate that quinclorac is stable to hydrolysis, photolysis in 

sterile water, as well as aerobic and anaerobic metabolism in soil. Conversely, quinclorac 

undergoes rapid photolysis in non-sterile rice paddy, natural river waters, and solutions 

containing activated sewage sludge (half-lives of 5-10 days). Photolysis on soil surface is also a 

route of dissipation with a mean half life of 141 days. Field studies reviewed to date indicate 

that quinclorac is moderately persistent (18-176 days half-lives) in terrestrial environment. 
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

Page 27 of 32

According to the aerobic soil metabolism and field dissipation studies and the research cited in 

the literature reviews, the fate of quinclorac can be described as such:

1. Quinclorac is initially metabolized to the primary degradate, 3-chloro-8-quinoline 

carboxylic acid (BH 514-1). This degradate undergoes further degradation to 5-chloro-2-

hydroxy-nicotinic acid, which in turn is metabolized to 5-chloro-2,6-dihydroxy-nicotinic 

acid, 2 hydroxy-3-chloro-8-quinoline carboxylic acid (BH 514 2-OH), 7-chloro-8-

quinoline carboxylic acid, 8-quinoline carboxylic acid, and other small fragments. These 

compounds can then bind with or become incorporated into the soil or humic material of 

the soil as a part of natural soil components (i.e., carbon pool of the soil), and/or can 

degrade to CO2, a major terminal product. 

2. The only volatile compound detected in the aerobic soil metabolism study (MRID 

44084503) was CO2 at a maximum concentration of 7.1% TRR. Other than parent, 

residues identified at maximum concentrations were: BH 514 2-OH (14.9% TRR), BH 

514-Me ester (7.8% TRR). Parent was found at maximum concentrations of 58.1% 

TRR.

3. BH 541-1 was also reported in the aerobic aquatic metabolism (MRID 42294102), at 

maximum of 55.7% of the initial radioactivity after 6 months and 30.8% after 12 

months. Adsorption/desorption studies determine that this degradate is less mobile than 

its parent, with Kd’s ranging from 1.56 in sand soil, 1.97 in sandy loam soil, 11.4 in loam 

soil, 13.3 in clay loam soil, and 30.2 in silty clay soil. This degradate was not reported in 

any of the terrestrial field dissipation studies, at any soil depth. 

For mobility in aquatic environment, aquatic field dissipations studies with rice indicate that the 

compound is less stable than predicted by the laboratory and is probably not mobile under normal 

use conditions.

For volatility, both vapor pressure (7.5 x 10-8 mm Hg at 20o C) and Henry's Law Constant (1.22 

to 24.3 x 10-15 atm.m3 mol-1 ) indicate a low possibility of volatilization from soil and water. 

Bioaccumulation in fish is not expected according to the acceptable fish accumulation study, 

which showed that after 28 days of exposure, quinclorac did not accumulate in channel catfish. 

No BCF value was reported (MRID 40320819 and 41063559). Furthermore, the octanol/water 

partition coefficient (KOW) of 0.266 also suggests that quinclorac has low potential to 

bioaccumulate. 

A detailed assessment of the environmental fate of Quinclorac could be found in the 

“Environmental Fate and Ecological Effects Assessment and Characterization for a Section 3 for 

Use on Wheat and Sorghum” report dated March 05, 1999 (DP Barcodes: 250179, 248882, 

248884, 192866, 231399, and 238400). The chemical structures of quinclorac and its 2 major 

metabolites (BH 514-1 and BH 514 2-OH) are shown in Table III.
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

Page 28 of 32

Table III - Chemical Structures of quinclorac and its major metabolites

Cl N

Cl

CO2H

Quinclorac

N

BH514-1

CO2H

N

BH 514 2-OH

CO2H

OH

Cl
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

Page 29 of 32

Appendix I: International Residue Limits 

Quinclorac (PC Code 128974; Date of Request 7/26/12)

Summary of US and International Tolerances and Maximum Residue Limits 

Residue Definition:

US Canada Mexico1 Codex

40 CFR 180.463

Plant/Livestock: quinclorac, 3,7-dichloro-8-

quinolinecarboxylic acid

3,7-dichloro8-

quinolinecarb

oxylic acid

None

Commodity Tolerance (ppm) /Maximum Residue Limit (mg/kg)

US Canada Mexico1 Codex

Barley, grain 2.0 2.0

Cattle, fat 0.7 0.05

Cattle, meat byproducts 1.5 0.05

Cattle, meat 0.05 0.05

Egg 0.05 0.05

Goat, fat 0.7 0.05

Goat, meat byproducts 1.5 0.05

Goat, meat 0.05 0.05

Grass, forage 150

Grass, hay 130

Hog, fat 0.7 0.05

Hog, meat byproducts 0.05 0.05

Hog, meat 0.05 0.05

Horse, fat 0.05 0.05

Horse, meat byproducts 1.5 0.05

Horse, meat 0.05 0.05

Milk 0.05 0.05

Poultry, fat 0.05 0.05

Poultry, meat byproducts 0.05 0.05

Poultry, meat 0.05 0.05

Rice, bran 15.0

Rice, grain 5.0 5.0

Sheep, fat 0.7 0.05

Sheep, meat byproducts 1.5 0.05

Sheep, meat 0.05 0.05

Sorghum, grain, forage 3.0

Sorghum, grain, grain 6.0

Sorghum, grain, stover 1.0

Wheat, forage 1.0

Wheat, germ 0.75

Wheat, grain 0.5 0.5

Wheat, hay 0.5

Wheat, straw 0.1
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

Page 30 of 32

Summary of US and International Tolerances and Maximum Residue Limits 

Residue Definition:

US Canada Mexico1 Codex

Proposed MRLs 

Low growing berries, except 

strawberries, subgroup 13-07H

1.5

Rhubarb 0.5

MRLs With No US Equivalent

Barley, bran 3.5

Completed by: M. Negussie; 07/31/2012

1 Mexico adopts US tolerances and/or Codex MRLs for its export purposes.

(b) Section 18 emergency exemptions . Time-limited tolerances are established for residues of 

the herbicide quinclorac, including its metabolites and degradates, in or on the commodity in the 

table in this paragraph. Compliance with the tolerance level specified in this paragraph is to be 

determined by measuring only quinclorac, 3,7-dichloro-8-quinolinecarboxylic acid, in or on the 

commodity. The tolerance expires and is revoked on the date specified in the table in this 

paragraph.

Commodity Parts per million Expiration/revocation date

Cranberry 15.0 12/31/12
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

Page 31 of 32

Appendix II

OECD MRL CALCULATOR 

Quinclorac 

Cranberry 

US 

2 x 0.25 lb ai, 60 PHI 

Quinclorac 

Residues (mg/kg) Cranberry 

0.550 US 

0.180 2 x 0.25 lb ai, 60 PHI 

0.165 

0.155 Total number of data (n) 5 

0.670 Percentage of censored 

data 

0% 

Number of non-censored data 5 

Lowest residue 0.155 

Highest residue 0.670 

Median residue 0.180 

Mean 0.344 

Standard deviation (SD) 0.247 

Correction factor for censoring (CF) 1.000 

Proposed MRL estimate 

- Highest residue 0.670 

- Mean + 4 SD 1.331 

- CF x 3 Mean 1.032 

Unrounded MRL 1.331 

Rounded MRL 1.5 

High uncertainty of MRL estimate. 

[Small dataset] 
Quinclorac 128974 Summary of Analytical Chemistry and Residue Data DP#: D397719

Page 32 of 32

OECD MRL CALCULATOR 

Quinclorac

Rhubarb 

US 

2 X 0.375 lb ai 

Quinclorac 

Residues (mg/kg) Rhubarb 

0.205 US 

0.173 2 X 0.375 lb ai 

0.108 

0.067 Total number of data 

(n) 

4 

Percentage of censored data 0% 

Number of non-censored data 4 

Lowest residue 0.067 

Highest residue 0.205 

Median residue 0.141 

Mean 0.138 

Standard deviation (SD) 0.062 

Correction factor for censoring (CF) 1.000 

Proposed MRL estimate 

- Highest residue 0.205 

- Mean + 4 SD 0.388 

- CF x 3 Mean 0.415 

Unrounded MRL 0.415 

Rounded MRL 0.5 

High uncertainty of MRL estimate. 

[Small dataset]