U. S. ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, DC 20460 

OFFICE OF 

PREVENTION, PESTICIDES 

AND TOXIC SUBSTANCES 

PC Code No. 018301 

DP Barcodes: D235437 

D235434 

MEMORANDUM 

SUBJECT: Waiver Review on Generic DCI Regarding Chlorporpham for Use on Easter 

Lilies and Ginkgo Trees. 

TO: Gary Mullins, PM Team Reviewer 

Jim Tompkins, Product Manager 25 

Special Review and Re-registration Division 

PROM: Thomas M. Steeger, Ph.D., Senior Scientis 

Environmental Fate and Effects Division (7507C) / 

THROUGH: Betsy Behl, Branch Chief 

Environmental Risk Branch IV 

Environmental Fate and Effects Division \ 

The Environmental Fate and Effects Division (EFED) has reviewed the data waiver request 

submitted in response to the generic data call-in (DCI) regarding chlorpropham (PC Code 01 8301) 

use on Easter lilies and ginkgo trees. Based on the very limited use of chlorpropham on Easter lilies 

and ginkgo trees, the noncontiguous acreage (< 600 acres total) where it is applied, the existence of 

direct acute ecological effect data on chlorprofam, and the availability of data on a similarly 

structured compounds (propanil and propham), EFED is willing to waive all additional data 

requirements for the use of chlorprofam on 2,000 ginkgo trees in Washington DC, 400 acres of 

Easter lilies in Del Norte, California, and 150 acres of Easter lilies in Curry County, Oregon. 

According to the data package, approximately 300 pounds of active ingredient is applied for each 

use annually. EFEDYs willingness to concur with the current waiver requests should not be 

construed as a precedent for chemicals considered to be limited in use. The Special Review and Reregistration Division should recognize that waived data requirements introduce considerable 

uncertainty into characterizing the environmental fate and effects of any chemical. Furthermore, if 

additional uses are sought for chlorpropham, SRRD should report that EFED re-evaluate the need 

for additional data. Since rough calculations show that endangered species may be impacted by the 

proposed use of this chemical, any regulatory actions regarding chlorpropham use on Easter lilies 

and ginkgo trees should include the following language: 

The Agency has developed the Endangered Species Protection Program to identzfipesticides whose use may 

cause adverse impacts on endangered and threatened species, and to implement mitigation measures that 

address these impacts. The EndangeredSpecies Act requires federal agencies to ensure that their actions are 

Text Searchable Document
not likely to jeopardize listedspecies or adversely modzb designated critical habitat. To analyze the potential 

of registered pesticide uses to affect any particular species, EPA puts basic toxicity and exposure data 

developed for REDS into context for individual listed species and their locations by evaluating important 

ecologicalparameters, pesticide use information, the geographic relationship between speciJicpesticides uses 

and species locations, and biological requirements and behavioral aspects of the particular species. This 

analysis will include consideration of the regulatory changes recommended in this RED. A determination that 

there is a likelihood ofpotential impact to a listed species may result in limitations on use of the pesticide, 

other measures to mitigate anypotential impact, or consultations with the Fish and Wildlife Service and/or the 

National Marine Fisheries Service as necessary. 

Atpresent, the program is being implemented on an interim basis as described in a Federal Register 

notice (54 FR 27984-28008, July 3, 1989). Afinalprogram, which may be alteredfrom the interim program, 

will be proposed in a Federal Register notice scheduledforpublication in autumn of 2001. 

Attached please find a summary of the information used by EFED in deciding whether to 

waive outstanding data requirements for chlorpropham use on Easter lilies in California and Oregon 

and on ginkgo trees in Washington DC. 
Summary 

EFED has limited environmental fate data on chlorpropham (hydrolysis data only); ecological 

effect data are limited to acute toxicity data only for birds and aquatic animals; chronic toxicity data 

are available on mammals only. Ecological effect data indicate that chlorpropham is practically 

nontoxic to terrestrial animals and is moderately toxic to aquatic animals on an acute exposure basis. 

Data exist for two similarly structured herbicides, i. e., propanil and propharn. Based on the very 

limited use of chlorpropham on Easter lilies and ginkgo trees, the noncontiguous acreage (< 600 

acres total), the existence of direct acute ecological effect data on chlorprofam, and the availability 

of data on a similarly structured herbicides, i. e., propanil and propham, EFED is willing to waive all 

additional data requirements for the use of chlorprofam on 2,000 ginkgo trees in Washington DC, 

400 acres of Easter lilies in Del Norte, California, and 150 acres of Easter lilies in Curry County, 

Oregon. If additional uses are sought for chlorprofam, SRRD should report that EFED re-evaluate 

the need for additional environmental fate and ecological effects data particularly if the uses will be 

on food-crops or turf. Thus , decisions to waive data must remain on a case-by-case basis. EFED's 

willingness to concur with the current waiver requests should not be construed as a precedent for 

chemicals considered to be limited in use. 

Background 

Chlorpropham is a pre- and post-emergence herbicide that was originally registered in 1962 

for use on a variety of terrestrial food crops, nonfood crops, and ornamentals to control broadleaf 

weeds and grasses, and sprouting inpotatoes. Chlorpropham is a herbicide and plant growth inhibitor 

used to control mouseear chickweed in spinach and fi-uiting in ginkgo trees, reduce Botrytis infection 

in Easter lilies as well as assist in their floral bud removal, and inhibit sprouting in store potatoes. 

By 1990, the primary registrants had dropped all nationwide uses of chlorpropham except those for 

sprout control on post-harvest potatoes [indoor use]. However, an additional 1 1 registrations for use 

within a particular county or state [registered under FIFRA Section 24(c)] remained for use on 

spinach, Easter lilies, and ginkgo trees. 

The proposed label for chlorpropham (Sprout NipB) indicates the product contains 36% 

active ingredient by weight. For application to Easter lilies, chlorpropham is applied at a maximum 

single application rate of 4 lbs. active ingredient per acre by ground boom or two applications of 2 

lbs. a.i./A each separated by a 1-week interval.. For use on ginkgo tree in Washington DC, 

chlorpropham is applied at 0.02 lbs. a.i./gallon by mist blower and is applied to "near dripping 

point." 

Following publication of the 1996 re-registration eligibility document (RED), the Platte 

Chemical Company and the Easter Lily Research Foundation requested a waiver from all remaining 

environmental fate and ecological effects studies required to support the continued [outdoor use] of 

the plant growth inhibitor on lily bulbs on up to 400 acres in Del Norte California and 150 acres in 

Curry County, Oregon. Additionally, Platte Chemical requested a waiver from the same studies to 

support the continued use of chlorpropham on approximately 2,000 ginkgo trees in the Washington 

Page 3 of 11 
DC area. In both cases, the Environmental Fate and Effects Division concurred with the request to 

waive 6 environmental fate studies [photodegradation in water (Guideline 16 1 -2), photodegradation 

on soil (Guideline 16 1 -3), anaerobic soil metabolism (Guideline 162-2), laboratory volatility 

(Guideline 163-2), terrestrial field dissipation (Guideline 164-I), and bioaccumulation in fish 

(Guideline 165-4)]. The only environmental fate studies required were an aerobic soil metabolism 

(Guideline 162- 1) and an absorbtion/desorption study (Guideline 163- 1). EFED also agreed to waive 

8 ecological effect studies [seed germination /seedling emergence (Guideline 122- 1 a), vegetative 

vigor (Guideline 122- 1 b), aquatic plant growth (Guideline 122-2), avian reproduction (Guidelines 

71 -4 a and b), fish early life stage (Guideline 72-4a), aquatic invertebrate life cycle (Guideline 72- 

4b), and fish full life cycle (Guideline 72-5). The only ecological effect studies required by EFED 

were an avian acute oral (Guideline 7 1 - 1 a) and a subacute dietary study (Guideline 7 1 -2b). The 

registrant has rejected EFED's request for any additional data based on their belief that the limited 

use of chlorpropham in a very limited geographical area does not warrant any additional 

environmental fate or ecological effect data and in 1997, the registrant formally requested a waiver 

from the generic data call-in ((DB Barcodes D235437 and D235434). 

The only environmental fate data available for chlorpropham focus on hydrolysis; these data 

indicate that chlorpropham is stable to hydrolysis. The study concluded that chlorpropham does not 

hydrolyze or degrade in water at pH 4,7,9. 

Acute toxicity testing (Table 1) indicates that chlorpropham is practically nontoxic to 

mammals (LD50 = 4,100 mglkg) and birds (LD50 > 2,000 mglkg) on an acute exposure basis and 

is also practically nontoxic to birds on an acute dietary exposure basis (LC50 > 5,620 mglkg of diet. 

Chlorpropham is moderately toxic to freshwater fish (LC50 range 3.0 - 6.8 ma) and invertebrates 

(EC50 = 3.7 ma). 

No ecological risk assessment was conducted for the 1996 re-registration eligibility document 

since the plant growth regulator was being re-registered for indoor use only and since no 

environmental fate data were available for estimating environmental concentrations using available 

screening-level models. 

In the absence of data on a particular compound, EFED will attempt to address data gaps 

(uncertainty) using information from similarly structured chemicals. Figure 1 shows the structure 

of chlorpropham and the similarly structured herbicides propanil (Figure 2) and propham (Figure 

3). Environmental fate data on propanil indicate that the herbicide will not persist in the field as the 

compound is rapidly metabolized under aerobic or anaerobic conditions in a waterlsediment milieu 

(laboratory t,,, = 2-3 days). Propanil metabolized rapidly in aerobic soil with a half-life of 0.5 days. 

However, similar to chlorpropham, propanil is stable to hydrolysis at pHs 5, 7, and 9 in the 

laboratory. A soil photolysis study also suggests that propanil is stable to photodegradation. 

Propanil is susceptible to biodegradation, yet stable to chemical degradative processes. 

Environmental fate data on propham is not as detailed as that for propanil; however, the compound 

is stable to hydrolysis but is not likely to persist due to biotic degradation (aerobic soil metabolism 

tl,, < 14 days). 

Page 4 of 1 1 
Additionally, based on mobility criteria (highly soluble, medium KO, and K, values), propanil 

could possibly reach groundwater but due to its rapid metaboli,sm in a waterlsoil matrix, it is not 

likely to persist for a significant amount of time to leach in measurable quantities. Propham is also 

likely to be mobile (K, range 0.27 - 2.7). 

Comparison of ecological effect data on propanil (Table 1) indicates the herbicide is 

practically nontoxic to birds (LC50 = range 2,311 - 5,627 mglkg of diet) on a subacute dietary 

exposure basis but is slightly toxic mammals (LD50 = 1,080 mglkg) and moderately toxic to birds 

(LD50 = 20 1 mglkg) on an acute exposure basis. Similarly, propham is practically nontoxic to birds 

on an acute exposure basis (LD50 > 2,000 mglkg). Aquatic toxicity of propanil is roughly similar 

to that of chlorpropham for both freshwater fish (LC50 range: 2.3 - 5.4 mglL) and invertebrates 

(EC50 = 1.2 mgh,); propham is roughly an order of magnitude less toxic with freshwater fish LC50 

values of approximately 29 mgh,.. Chronic toxicity data are available for propanil and indicate acute 

to chronic ratios for freshwater fish and invertebrates of 258 (LC50,,, = 2.3 mgL divided by 

NOEC,,,,,, = 0.009 mg/L) and 13,953 (EC50,,,,,, = 1,200 mg/L divided by NOEC,,,,,, = 0.086 

mg/L), respectively. Additionally, data suggest that similar to the degradation products of propanil 

(dichloroaniline), a likely degradation product of chlorpropham (monochloroanaline) is also toxic. 

Exposure to monochloroaniline (Fujitani et al. 2001) has resulted in hematoxic effects similar to 

those observed in chronic toxicity tests with chlorpropham in rats (Fujitani et al. 1997; Fujitani et 

al. 2000). 

There are no plant toxicity data available on either chlorpropham or propham. Terrestrial 

plant testing of propanil showed monocots (onions) to be the most sensitive (EC25 = 1.4 lbs 

a.i./Acre) plant group tested based on seedling emergence studies. Aquatic plant toxicity testing 

indicated that exposure levels of propanil at 0.1 1 mglL or greater may cause detrimental effects to 

the growth and reproduction of vascular aquatic plant species and that algae and diatoms may be 

affected from propanil exposure levels of 0.016 mg/L or greater. 

Estimated environmental concentrations (EEC) (Appendix A) using the Generic Estimated 

Environmental Concentration (GENEEC2) model were derived for applications to Easter lilies 

based on the following input parameters: Kd = 0.27, solubility = 89 mglL, aerobic soil metabolism 

= 14 days, aerobic aquatic metabolism = 2 days. The estimated peak concentration in surface water 

is 197 ugh,. Based on this estimated concentration, the acute risk quotient (RQ = 0.066) for 

freshwater fish (EEC = 0.197 mglL divided by LC50,,, = 3 mglL) exceeds the acute endangered 

species level of concern (LOC). Additionally, the acute endangered species LOC is exceeded for 

freshwater invertebrates (RQ = 0.05). Thus, based on a rough screening-level assessment of RQ 

values and the absence of chemical-specific environmental fate data, EFED concludes that the 

proposed use of chlorpropham on Easter lilies may impact endangered species of freshwater fish and 

invertebrates. 

Chronic RQ values for aquatic animals were derived by comparing the 21-day EEC (0.053 

mg/L) to estimated no-observed effect concentrations (NOEC) for chlorpropham. Since no chronic 

toxicity data are available on chlorpropham, NOEC values were estimated using the acute to chronic 

Page 5 of 11 
ratio (ACR) for propanil. Thus, the NOEC for fish is estimated to be 0.012 mg/L (LC50 = 3 mg/L 

divided by ACR = 258); the NOEC for freshwater invertebrates is estimated to be 0.27 ug/L (EC50 

= 3.7 mg/L divided by ACR = 13,953). Based on these estimated chronic toxicity values, the chronic 

RQ values for fish and invertebrates are 4.4 and 196, respectively, and exceed chronic levels of 

concern. 

Appendix B lists threatened and/or endangered species located in Curray County, Oregon, 

and Madera County (Del Norte), California. There are three species of fish listed for the use sites: 

Lahontan cutthroat trout (Oncorhynchus clarki henshawi), Paiute cutthroat trout (0. clarki seleniris), 

and coho salmon (0. kisutch). Based on the suspected environmental fate properties of 

chlorpropham and the available acute toxicity data for freshwater fish, the use of chlorporpham may 

result in some mortality to these fish on an acute exposure basis. Additionally, chronic effects on 

these species are also likely. 

Because of the existence of environmental fate data on a similarly structured chemicals, the 

existence of acute toxicity data on chlorpropham which is similar to that for propanil and the limited 

use of chlorpropham on noncontiguous acreage of Easter lilies and ginkgo trees, EFED is willing to 

reserve many of the required data for conducting an ecological risk assessment of chlorpropham. 

However, this action should not be construed as setting a precedent for deminimous use compounds. 

Had a number of factors not have been in place (e.g. alternate data not or if the proposed use had 

been for a food-crop) EFED would likely have required the sorption/desorption study and the aerobic 

soil metabolism study. Additionally, had alternate chronic ecotoxicity data not been available, EFED 

would likely have required the chronic aquatic toxicity data identified in EFED's response to the 

1996 waiver request. 

Uncertainties 1 

Within the past year, EPA has been requested to provide both environmental fate and 

ecological effects data on two chemicals spilt in the DC metro area and which resulted in incidents 

along Rock Creek Parkway. While the pesticides might have had limited use, spills require that 

sufficient data are available to address unusual exposure/toxicity circumstances. Bridging data 

should never be considered an ideal substitute for chemical specific data. Thus, the decision to 

waive data introduces significant uncertainty into EFED's ability to provide accurate environmental 

fate and ecological effect data should the need arise. Additionally, lily bulbs in Del Norte, 

California, have in the past been a use site resulting in groundwater contamination from aldicarb, a 

persistent, mobile pesticide. Although monochloroaniline is a degradate of chlorpropham and there 

are data to indicate the degradate is toxic, the persistence and mobility of the degradate(s) are 

uncertain. EFED is uncertain to the degree to which the likely mobility of chlorprofam and its 

potential transformation to toxic degradates will impact groundwater. EFED has no direct plant data 

on chlorpropham and has had to rely on plant toxicity data for propanil. The proposed application 

rate for Easter lilies (4 lbs. a.i./A) is roughly 2.8 times the EC25 of propanil for terrestrial plants. 

The potential effects of chlorpropham to nontarget terrestrial and aquatic plants are unknown. 

Finally, rough estimates of aquatic risk quotients indicate that acute endangered species and chronic 

Page 6 of 11 
levels of concern are exceeded by the proposed use of chlorporpham on Easter lilies. Although the 

range of acute RQ values (0.53 to 0.66) is relatively low compared to the trigger value (RQ = 0.5), 

chronic RQ values exceed LOCs by factors ranging from 4 to 196. EFED believes that the limited 

use of chlorpropham in Madera County, California, and Curry County, Oregon, mitigates effects to 

endangered species; however, any regulatory document regarding the use of chlorpropham should 

contain language developed by the Field and External Affairs Division regarding endangered species. 

Table 1. Summary of acute and chronic toxicity data for chlorpropham and propanil (na = data not available). 

Bobwhite quail LD50 = na 

LC50 > 5,620 mglkg diet 

LD50 = 201 mgkg 

LC50 = 2,3 11 mgkg diet 

Mallard duck LD50 > 2,000 mgkg LD50 > 2,000 mglkg LD50 = na 

LC50 = na LC50 = 5,000 mgkg diet 

Laboratory rat LD50 > 5,620 mgkg 

NOEL > 1,000 mgkg diet 

LD50 = 1,080 mgkg 

NOEL = 300 mgkg diet 

Rainbow trout LC50 = 3.0 mg/L LC50 = 28 ma LC50 = 2.3 mg/L 

Bluegill sunfish LC50 = 6.8 mg/L LC50 > 29 mg/L LC50 = 5.4 mg/L 

Fathead minnow LC50 = na 

NOEC = na 

Water flea EC50 = 3.7 mg/L 

NOEC = na 

LC50 = na 

NOEC = 0.009 mg/L 

EC50 = 1,200 ma 

NOEC = 0.086 mdL 

Page 7 of 1 1 
Figure 1. Chlorpropham [(3-chlorophenyl) 

carbamic acid 1 -methylethyl ester] 

Figure 2. Propanil [N-(3,4- 

-. 

dichlorophenyl) propanamide] 

0 

I I 

C-O- C-H 

Figure 3. Propham [phenylcarbamic acid 

1 -methylethyl ester] 

Page 8 of 11 
References 

Fujitani, T. Y. Tada, A. T. Noguchi, M, Yoneyama. 1997. Hematoxicity of chlorpropham (CIPC) 

in F344 rats. Toxicology 123: 1 1 1 - 124. 

Fujitani, T. Y. Tada, A. Fujii, M. Kimura, and M. Yoneyama. 2000. Subchronic toxicity of 

chlorpropham (CIPC) in ICR Mice. Food and Chemical Toxicology 38: 617 - 625. 

Fujitani, T. Y. Tada, A. T. Noguchi, M, Yoneyama. 2001. Effects of chlorpropham (CIPC) on the 

hemopoietic system of rats. Food and Chemical Toxicology 39: 253 - 259. 

Page 9 of 1 1 
APPENDIX A GENEEC OUTPUT FILE 

RUN No. 1 FOR chlorpropham ON Easter lil * INPUT VALUES * .................................................................... 

RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE NO-SPRAY INCORP 

ONE (MULT) INTERVAL Kd (PPM) (%DRIFT) ZONE (FT) (IN) 

FIELD AND STANDARD POND HALFLIFE VALUES (DAYS) .................................................................... 

METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED 

(FIELD) RAIN/RUNOFF (POND) ( POND-EFF) ( POND) ( POND) 

GENERIC EECs (IN MICROGRAMS/LITER (PPB)) Version 2.0 May 1, 2001 .................................................................... 

PEAK MAX 4 DAY MAX 21 DAY MAX 60 DAY MAX 90 DAY 

GEEC AVG GEEC AVG GEEC AVG GEEC AVG GEEC 

Page 10 of 11 
APPENDIX B ENDANGERED SPECIES LISTED FOR CURRY COUNTY (OREGON) 

AND MADERA COUNTY(CALIFORN1A). 

CURRY OR 

............................................................................ ............................................................................ 

SPECIES GROUP STATUS KNOWN ............................................................................ 

EAGLE, BALD BIRD T KNOWN 

GOOSE, ALEUTIAN CANADA BIRD T KNOWN 

MURRELET, MARBLED BIRD T/CH KNOWN 

OWL, NORTHERN SPOTTED BIRD TI CH KNOWN 

PELICAN, BROWN BIRD E KNOWN 

PLOVER, WESTERN SNOWY BIRD T KNOWN 

SALMON, COHO (SOUTHERN OR/NORTHERN CA COAST)FISH T KNOWN 

SPECIES GROUP STATUS KNOWN ............................................................................ 

BEETLE, VALLEY ELDERBERRY LONGHORN INSECT TI CH KNOWN 

BIRD'S-BEAK, PALMATE-BRACTED PLANT E POSSIBLE 

EAGLE, BALD BIRD T KNOWN 

FOX, SAN JOAQUIN KIT MAMMAL E KNOWN 

GOLDEN SUNBURST, HARTWEG'S PLANT E KNOWN 

GRASS, HAIRY ORCUTT PLANT E KNOWN 

KANGAROO RAT, FRESNO MAMMAL El CH POSSIBLE 

LIZARD, BLUNT-NOSED LEOPARD REPTILE E KNOWN 

LUPINE, CLOVER PLANT E KNOWN 

OWL' S-CLOVER, FLESHY PLANT E KNOWN 

PUSSYPAWS, MARIPOSA PLANT T KNOWN 

ADOBE SUNBURST, SAN JOAQUIN PLANT E KNOWN 

TROUT, LAHONTAN CUTTHROAT FISH T KNOWN 

TROUT, PAIUTE CUTTHROAT FISH T KNOWN 

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