Bentazon - Pesticide Petition Filing 10/01
ENVIRONMENTAL PROTECTION AGENCY
Notice of Filing a Pesticide Petition to Establish a Tolerance
for a Certain Pesticide Chemical in or on Food
AGENCY: Environmental Protection Agency (EPA).
SUMMARY: This notice announces the initial filing of a pesticide
petition proposing the establishment of regulations for residues of a
certain pesticide chemical in or on various food commodities.
DATES: Comments, identified by docket control number PF-1047, must be
received on or before December 3, 2001.
ADDRESSES: Comments may be submitted by mail, electronically, or in
person. Please follow the detailed instructions for each method as
provided in Unit I.C. of the SUPPLEMENTARY INFORMATION. To ensure
proper receipt by EPA, it is imperative that you identify docket
control number PF-1047 in the subject line on the first page of your
FOR FURTHER INFORMATION CONTACT: By mail: Sidney Jackson, Registration
Division (7505C), Office of Pesticide Programs, Environmental
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460;
telephone number: (703) 305-7610; e-mail address:
I. General Information
A. Does this Action Apply to Me?
You may be affected by this action if you are an agricultural
producer, food manufacturer or pesticide manufacturer. Potentially
affected categories and entities may include, but are not limited to:
Categories NAICS potentially
Industry 111 Crop production
112 Animal production
311 Food manufacturing
This listing is not intended to be exhaustive, but rather provides
a guide for readers regarding entities likely to be affected by this
action. Other types of entities not listed in the table could also be
affected. The North American Industrial Classification System (NAICS)
codes have been provided to assist you and others in determining
whether or not this action might apply to certain entities. If you have
questions regarding the applicability of this action to a particular
entity, consult the person listed under FOR FURTHER INFORMATION
B. How Can I Get Additional Information, Including Copies of this
Document and Other Related Documents?
1. Electronically. You may obtain electronic copies of this
document, and certain other related documents that might be available
electronically, from the EPA Internet Home Page at http://www.epa.gov/.
To access this document, on the Home Page select "Laws and
Regulations" and then look up the entry for this document under the
"Federal Register--Environmental Documents." You can also go directly
to the Federal Register listings at http://www.epa.gov/fedrgstr/.
2. In person. The Agency has established an official record for
this action under docket control number PF-1047. The official record
consists of the documents specifically referenced in this action, any
public comments received during an applicable comment period, and other
information related to this action, including any information claimed
as confidential business information (CBI). This official record
includes the documents that are physically located in the docket, as
well as the documents that are referenced in those documents. The
public version of the official record does not include any information
claimed as CBI. The public version of the official record, which
includes printed, paper versions of any electronic comments submitted
during an applicable comment period, is available for inspection in the
Public Information and Records Integrity Branch (PIRIB), Rm. 119,
Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA, from 8:30
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The
PIRIB telephone number is (703) 305-5805.
C. How and to Whom Do I Submit Comments?
You may submit comments through the mail, in person, or
electronically. To ensure proper receipt by EPA, it is imperative that
you identify docket control number PF-1047 in the subject line on the
first page of your response.
1. By mail. Submit your comments to: Public Information and Records
Integrity Branch (PIRIB), Information Resources and Services Division
(7502C), Office of Pesticide Programs (OPP), Environmental Protection
Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
2. In person or by courier. Deliver your comments to: Public
Information and Records Integrity Branch (PIRIB), Information Resources
and Services Division (7502C), Office of Pesticide Programs (OPP),
Environmental Protection Agency, Rm. 119, Crystal Mall #2, 1921
Jefferson Davis Highway, Arlington, VA. The PIRIB is open from 8:30
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The
PIRIB telephone number is (703) 305-5805.
3. Electronically. You may submit your comments electronically by
e-mail to: email@example.com, or you can submit a computer disk as
described above. Do not submit any information electronically that you
consider to be CBI. Avoid the use of special characters and any form of
encryption. Electronic submissions will be accepted in Wordperfect 6.1/
8.0 or ASCII file format. All comments in electronic form must be
identified by docket control number PF-1047. Electronic comments may
also be filed online at many Federal Depository Libraries.
D. How Should I Handle CBI That I Want to Submit to the Agency?
Do not submit any information electronically that you consider to
be CBI. You may claim information that you submit to EPA in response to
this document as CBI by marking any part or all of that information as
CBI. Information so marked will not be disclosed except in accordance
with procedures set forth in 40 CFR part 2. In addition to one complete
version of the comment that includes any information claimed as CBI, a
copy of the comment that does not contain the information claimed as
CBI must be submitted for inclusion in the public version of the
official record. Information not marked confidential will be included
in the public version of the official record without prior notice. If
you have any questions about CBI or the procedures for claiming CBI,
please consult the person identified under FOR FURTHER INFORMATION
E. What Should I Consider as I Prepare My Comments for EPA?
You may find the following suggestions helpful for preparing your
1. Explain your views as clearly as possible.
2. Describe any assumptions that you used.
3. Provide copies of any technical information and/or data you used
that support your views.
4. If you estimate potential burden or costs, explain how you
arrived at the estimate that you provide.
5. Provide specific examples to illustrate your concerns.
6. Make sure to submit your comments by the deadline in this
7. To ensure proper receipt by EPA, be sure to identify the docket
control number assigned to this action in the subject line on the first
page of your response. You may also provide the name, date, and Federal
II. What Action is the Agency Taking?
EPA has received a pesticide petition as follows proposing the
establishment and/or amendment of regulations for residues of a certain
pesticide chemical in or on various food commodities under section 408
of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a.
EPA has determined that this petition contains data or information
regarding the elements set forth in section 408(d)(2); however, EPA has
not fully evaluated the sufficiency of the submitted data at this time
or whether the data support granting of the petition. Additional data
may be needed before EPA rules on the petition.
List of Subjects
Environmental protection, Agricultural commodities, Feed
additives, Food additives, Pesticides and pests, Reporting and
Dated: October 24, 2001.
Acting Director, Registration Division, Office of Pesticide Programs.
Summary of Petition
The petitioner summary of the pesticide petition is printed below
as required by section 408(d)(3) of the FFDCA. The summary of the
petition was prepared by the petitioner and represents the view of the
petitioners. EPA is publishing the petition summary verbatim without
editing it in any way. The petition summary announces the availability
of a description of the analytical methods available to EPA for the
detection and measurement of the pesticide chemical residues or an
explanation of why no such method is needed.
Interregional Research Project Number 4
EPA has received a pesticide petition 6E4703 from the Interregional
Research Project Number 4 (IR-4), 681 U.S. Highway #1 South, North
Brunswick, NJ 08902-3390 proposing, pursuant to section 408(d) of the
FFDCA, 21 U.S.C. 346a(d), to amend 40 CFR part 180 by establishing a
tolerance for combined residues of the herbicide, bentazon (3-
isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide) and its 6-
and 8-hydroxy metabolites in or on the raw agricultural commodities
clover forage at 1.0 part per million (ppm) and clover hay at 2.0 ppm.
EPA has determined that the petition contains data or information
regarding the elements set forth in section 408(d)(2) of the FFDCA;
however, EPA has not fully evaluated the sufficiency of the submitted
data at this time or whether the data support granting of the petition.
Additional data may be needed before EPA rules on the petition.
Bentazon is manufactured by the BASF Corporation, Agricultural Products
A. Residue Chemistry
1. Plant metabolism. The qualitative nature of the residue in
plants is adequately understood. Bentazon is rapidly metabolized,
conjugated and incorporated into natural plant constituents. Metabolism
involves the hydroxylation of bentazon at the 6- and 8-position. The
terminal residues of regulatory concern are bentazon, 6-hydroxy
bentazon, and 8-hydroxy bentazon (as specified in 40 CFR 180.355(a)).
2. Analytical method. Adequate enforcement methods are available
for the determination of residues of bentazon and its 6- and 8-hydroxy
metabolites in/on plant commodities. The Pesticide Analytical Manual
(PAM) Vol. II lists Method II, a GLC method with flame photometric
detection for the determination of bentazon and its hydroxy metabolites
in/on corn, rice, and soybeans; the limit of detection for each
compound is 0.05 ppm. Method III, modified from Method II, is available
for the determination of bentazon and its hydroxy metabolites in/on
peanuts and seed and pod vegetables with a limit of detection of 0.05
ppm for each compound.
3. Magnitude of residues. A total of 2 field residue trials were
conducted on red clover in 1993 in Oregon. A single application of
Basagran herbicide was made to clover at a rate of either 1.0 lb.
active ingredient per acre (a.i./acre) (0.5X) or 2.0 lb/a.i./acre (1X).
The spray volume was 20 gal/acre. An adjuvant (R-11) was included in
all treatments at 2 oz./acre. Samples of forage and hay were harvested
from each treated plot 36 days after treatment. Samples were analyzed
for the combined residues of bentazon and its 6- and 8-hydroxy
metabolites. Analysis of the treated samples showed that the maximum
total residue was 0.77 ppm in forage and 1.19 ppm in hay.
B. Toxicological Profile
1. Acute toxicity. Acute toxicity data for bentazon show that this
chemical is not acutely toxic by the oral, inhalation, or dermal routes
of exposure (Toxicity Categories III and IV). It is moderately
irritating to the eye (Toxicity Category II) and slightly irritating to
the skin (Toxicity Category IV). Bentazon is also a dermal sensitizer.
2. Genotoxicty. Bentazon was not mutagenic in the tests for gene
mutations, which were reverse mutation assays in S. typhimurium and in
E. coli WP2 uvrA as well as forward mutation assays with in vitro
Chinese hamster ovary cell (HGPRT) cultures. Bentazon was also negative
in the mouse micronucleus test for assessing structural chromosomal
aberrations and the unscheduled DNA synthesis assay with primary mouse
hepatocytes for detecting DNA damage.
3. Reproductive and developmental toxicity. A developmental study
in rats was conducted at doses of 0, 40, 100, or 250 milligrams per
kilogram per day (mg/kg/day). The maternal NOAEL (no observed adverse
effect level) is 250 mg/kg/day, HDT (highest dose tested). The maternal
LOAEL (lowest observed adverse effect level) is greater than 250 mg/kg/
day. The developmental NOAEL is 100 mg/kg/day. The developmental LOAEL
is 250 mg/kg/day, based on increased postimplantation loss, skeletal
variations (incomplete or absent ossification in the phalangeal nucleii
of the extremities, the sternebrae and cervical vertebrae), and reduced
body weights or fetuses surviving to day 21.
A developmental study in rabbits was conducted at doses of 0, 75,
150, or 375 mg/kg/day. The maternal/developmental NOAEL is 150 mg/kg/
day. The maternal/developmental LOAEL is 375 mg/kg/day (HDT), based
on doe with partial abortion, embryonic resorptions, and no living
fetuses. A 2-generation reproduction toxicity study in rats was
conducted at doses of 0, 200, 800, or 3,200 ppm; equivalent to 0, 15,
62, or 249 mg/kg/day. The parental systemic NOAEL is 62 mg/kg/day. The
parental systemic LOAEL is 249 mg/kg/day, based on increased incidences
of kidney mineralization and liver microgranuloma. The reproductive
NOAEL is 15 mg/kg/day. The reproductive LOAEL is 62 mg/kg/day, based on
reduced pup growth (body weight gain) during lactation.
4. Subchronic toxicity. A 21-day dermal toxicity study in rabbits
was conducted at doses of 0, 250, 500, or 1,000 mg/kg/day. The NOAEL is
1,000 mg/kg/day (HDT). The LOAEL is greater than 1,000 mg/kg/day. A 13-
week feeding study in rats was conducted at doses of 0, 400, 1,200, or
3,600 ppm; equivalent to 0, 25.3, 77.8, or 243.3 mg/kg/day for males
and 0, 28.9, 86.1, or 258.3 mg/kg/day for females. The NOAEL is 77.8
mg/kg/day. The LOAEL is 243.3 mg/kg/day for males and 258.3 mg/kg/day
for females based on depressed mean body weights in females, a slight
increase in food consumption in males, increased thromboplastin and
prothrombin times (males only), and increased kidney and liver weights.
5. Chronic toxicity. A chronic feeding study in dogs was conducted
at doses of 0, 100, 400, or 1,600 ppm; equivalent to 0, 3.2, 13.1, or
52.3 mg/kg/day. The NOAEL is 3.2 mg/kg/day. The LOAEL is 13.1 mg/kg/day
based on a dose-dependent presence of feces with red areas in dogs at
13.1 mg/kg/day (400 ppm) and 52.3 mg/kg/day (1,600 ppm) and slight to
severe anemia at the high dose. A chronic feeding/carcinogenicity study
in rats was conducted at doses of 0, 200, 800, or 4,000 ppm; equivalent
to 0, 9, 35, or 180 mg/kg/day in males and 0, 11, 45, or 244 mg/kg/day
in females. The NOAEL is 9/11 mg/kg/day, in males/females. The LOAEL is
35/45 mg/kg/day, in males/females, based on increased water
consumption, changes in urinalysis and hematology/coagulation
parameters, and decreased absolute and relative thyroid weight. No
evidence of carcinogenicity was observed. An oncogenicity study in mice
was conducted at doses of 0, 100, 400, or 2,000 ppm; equivalent to 0,
12, 47, or 242 mg/kg/day in males and 0, 12, 48, or 275 mg/kg/day in
females. The NOAEL is 12 mg/kg/day. The LOAEL is 47/48 mg/kg/day in
males/females, based on increased prothrombin time, increased liver and
kidney weights, calcification of the tunica albuginea, and islet cell
hyperplasia of the pancreas. No evidence of carcinogenicity was
6. Animal metabolism. A rat metabolism study with oral dosing
showed that parent bentazon was the major metabolite found in urine,
amounting to 77.37-91.02% of the dose. Another metabolism study
demonstrated that the absorption and excretion of bentazon or its
sodium salt in male rats after oral administration is rapid and
essentially equivalent. No sex differences in the absorption,
metabolism or excretion of sodium bentazon are apparent based on
equivalent excretion half-lives (4 hours), pattern of excretion greater
than 90% in urine or urinary metabolite identification greater than 80%
as free acid. A dermal penetration study in rats was conducted at doses
of 0.12, 1.2, 12, or 120 mg/kg. Single topical application of
radioactive sodium bentazon did not appear to significantly penetrate
the skin since a maximum of only 1-2% of the radioactivity was
recovered primarily in the urine at 72 hours. Negligible amounts of
dermally applied radioactivity were retained in the liver, kidneys,
G.I. tract and carcass. For risk assessment purposes, dermal
penetration is estimated to be 1-2%.
7. Metabolite toxicology. There are no metabolites of toxicological
significance to mammals.
8. Endocrine disruption. No special studies investigating potential
estrogenic or endocrine effects of bentazon have been conducted.
However, the standard battery of required studies has been completed.
These studies include an evaluation of the potential effects on
reproduction and development, and an evaluation of the pathology
exposure. These studies are generally considered to be sufficient to
detect any endocrine effects but no such effects of the endocrine
organs following repeated or long-term were noted in any of the
C. Aggregate Exposure
1. Dietary exposure--i. Food. In 1999, EPA evaluated the hazard and
exposure data for bentazon and recommended that the FQPA safety factor
be retained at 10X in assessing the risk posed by this chemical because
there was evidence of increased susceptibility in the developmental
toxicity study in rats and in the 2-generation reproduction toxicity
study in rats. The 10X FQPA Safety Factor is applicable to females 13-
50 years old for acute dietary and residential exposure assessments and
to all population subgroups for chronic dietary and residential
exposure assessments. The acute and chronic Population Adjusted Doses
(aPAD and cPAD, respectively) are modification of the acute and chronic
Reference Doses (RfDs) to include the FQPA safety factor. The acute or
chronic PAD is equal to the acute or chronic RfD divided by the FQPA
Acute and chronic dietary exposure analyses for bentazon were
performed using the Dietary Exposure Evaluation Model (DEEM) which
incorporates data generated in the USDA 1989-1992 nationwide Continuing
Surveys of Food Intake by Individuals (CSFII). For the acute analysis,
tolerance level residues were used and 100% crop treated (CT) was
assumed for all commodities (Tier I) for the females 13-50 years old
subgroup (the subpopulation of concern). For all the females 13-50
years old subgroup, 5% or less of the aPAD is occupied by dietary
exposure from food. Results of the acute analysis indicate that the
acute dietary risk residues in food associated with existing and
proposed uses of bentazon do not exceed EPA's level of concern.
A refined chronic dietary exposure analysis (Tier 3) was performed
using anticipated and tolerance level residues for commodities for the
general U.S. population and all population subgroups. For the chronic
analysis, percent crop treated information was used for several
commodities. The percent chronic population adjusted dose (%cPADs) for
all subgroups were less than 100%, with the highest being 28% for the
children 1-6 years subgroup. Results of the chronic analysis indicate
that the chronic dietary risk from residues in food associated with the
existing and proposed uses of bentazon do not exceed EPA's level of
ii. Drinking water. SCI-GROW (Screening Concentration in Ground
Water) modeling indicates that bentazon residue (bentazon + its
metabolite, 2-amino-N-isopropyl benzamide (AIBA) concentrations in
ground water used as drinking water are not likely to exceed 4.25 parts
per billion (ppb). The other regulated bentazon metabolites (6-hydroxy
and 8-hydroxy bentazon) have not been found in environmental fate
studies. Limited monitoring data indicated a range of bentazon
concentrations (excluding degradation products) in ground water of 20
to 120 ppb. Because monitoring data indicate a higher concentration
than the SCI-GROW screening model, EPA used the 20 ppb as the
environmental exposure concentration (EEC) for both acute and chronic
scenarios. The EEC for surface water (from EPA's Pesticide Root Zone
Model-EXAMS modeling) is 41 ppb for the peak (acute) and 8 ppb for the
36-year annual mean (chronic). The surface
and ground water estimates were used to compare against back-calculated
drinking water levels of comparison (DWLOCs) for aggregate risk
assessments. For the acute exposure scenario, the DWLOC is 2800 ppb for
females (13+/nursing). For the chronic exposure scenario, the DWLOCs
are 95, 82, 22, 94, and 95 ppb for the U.S. population, females (13+/
nursing), children (1-6 years), Hispanics and males (13-19 years),
2. Non-dietary exposure. Because bentazon is registered for
consumer use on turf and ornamentals, there is potential for
residential exposure to adult applicators and adults and children
entering recreational and residential areas treated with bentazon.
The handler exposure is expected to be short-term while the post-
application exposure is expected for both the short- and intermediate-
term. However, since there is no short-term dermal endpoint, the
residential post-application exposure cannot be aggregated with the
handler exposure. Short-term, non-dietary ingestion exposure for
toddlers is not a concern because it was determined that there is no
acute dietary or oral endpoint applicable to infants and children.
However, intermediate-term, non-dietary ingestion exposure to toddlers
playing on treated turf is possible and was assessed using the
intermediate-term endpoint identified from the 1 year dog feeding
study. Intermediate-term exposure is not expected for the ornamental
use. The level of concern for residential exposures to bentazon is for
MOE's less than 1,000.
There are no chemical-specific or site-specific data available to
determine the potential risks associated with residential exposures
from handling bentazon. Therefore, the exposure estimates are based on
assumptions and generic data as specified by the December 18, 1997
Draft HED Standard Operating Procedures (SOPs) for Residential Exposure
Assessments. Because bentazon is applied no more than twice per year,
only short-term exposure is expected for the residential handler.
Because a dermal endpoint of concern for the short-term duration was
not identified, only inhalation exposure estimates are relevant.
Assuming that a homeowner treats his lawn and ornamental plants on the
same day, the aggregate inhalation short-term MOE is 500,000 for the
residential handler. This estimate indicates that the potential handler
risks from residential uses of bentazon do not exceed EPA's level of
Environmental fate data indicate that bentazon is moderately
resistant to degradation (t1/2 = 24-65 days). Due to the length of time
bentazon is expected to remain in the environment, both short- and
intermediate-term residential post-application exposures are expected.
For toddlers playing on treated turf, the oral intermediate-term
endpoint was used to assess toddler incidental ingestion exposures.
Based on the residential use pattern, no long-term post-application
residential exposure is expected. Short-term, non-dietary oral
exposures to the toddler were not assessed because the subgroup of
concern was identified as females 13-50 years old. This endpoint is not
applicable to the infant and children population subgroups.
Intermediate-term, post-application exposure is not expected from the
ornamental use of bentazon.
Changes to the residential SOPs have been proposed that alter the
residential post-application scenario assumptions. The proposed
assumptions are expected to better represent residential exposure and
are still considered to be high-end, screening level assumptions.
Therefore, the proposed assumptions are used to calculate exposure
The dermal post-application exposure from the turfgrass use for
the adult results in an MOE of 9,100. The MOEs for post-application
exposures for the toddler are calculated as 6,400 and 3,500 for dermal
and hand-to-mouth exposures, respectively. The aggregate intermediate
MOE for post-application residential exposure to toddlers is 2,200.
Therefore, all residential post-application exposure estimates are well
below EPA's level of concern. Because these estimates were calculated
using screening-level assumptions, it is believed that the actual risks
will be lower. For the intermediate-term, typical lawn maintenance
practices such as mowing and watering are expected to expedite the
dissipation of bentazon on turfgrass. Therefore, with less residue
available, potential incidental hand-to-mouth exposures are expected to
be substantially lower.
D. Cumulative Effects
There is no available data to determine whether bentazon has a
common mechanism of toxicity with other substances or how to include
this pesticide in a cumulative risk assessment. Unlike other pesticides
for which EPA has followed a cumulative risk approach based on a common
mechanism of toxicity, bentazon does not appear to produce a toxic
metabolite produced by other substances. For the purposes of this
notice of filing, therefore, it is assumed that bentazon does not have
a common mechanism of toxicity with other substances.
E. Safety Determination
1. U.S. population. Acute risk estimates from aggregate exposure to
bentazon in food and water are below EPA's level of concern. For Tier 1
acute dietary exposure analysis, it was assumed that 100% of the crops
treated with bentazon and that residues equaled the tolerance level.
For all females 13-50 years old subgroups, less than or equal to 5% of
the aPAD is occupied by dietary exposure from food. The acute dietary
risk from food associated with the existing and proposed uses of
bentazon is below EPA's level of concern. The estimated average
concentrations of bentazon in surface and ground water are less than
EPA's levels of comparison for bentazon in drinking water as a
contribution to acute aggregate exposure.
Chronic (non-cancer) aggregate risk estimates are below EPA's
level of concern. The chronic dietary exposure analysis for residues in
food incorporated anticipated and tolerance level residues for
commodities. Percent crop treated information was used for several
commodities. The %cPADs for all subgroups were less than 100%, with the
highest being 28% for the children 1-6 years old subgroup. Thus, the
chronic dietary risk estimates from food associated with existing and
proposed uses of bentazon do not exceed EPA's level of concern. For
ground and surface water, the estimated average concentrations of
bentazon are less than EPA's levels of comparison for bentazon in
drinking water as a contribution to chronic aggregate exposure.
Aggregate short-term risk estimates are below EPA's level of
concern. In aggregating short-term risk, the background chronic dietary
exposure (food + drinking water) and short-term inhalation exposures
from residential uses are considered. Because a dermal endpoint of
concern for the short-term duration was not identified, only inhalation
exposure estimates are relevant for the adult handler. Short-term
inhalation exposure may occur for a homeowner treating turf and
ornamentals on the same day. The total short-term food and residential
aggregate MOE value is 220,000. As this MOE is greater than 1,000, the
short-term food and residential aggregate risk estimate is below EPA's
level of concern. For surface and ground water, the estimated average
concentrations of bentazon are less than EPA's levels of comparison for
bentazon in drinking water contribution to short-term aggregate
Aggregate intermediate-term risk estimates are below EPA's level
of concern for adults. In aggregating intermediate-term risk, the
background chronic dietary exposure (food + drinking water) and
intermediate-term dermal exposures from residential uses are
considered. For adults, dermal post-application exposures may result
from dermal contact with treated turf. For adults, the total food and
residential intermediate-term aggregate MOE is 7,600. As this value is
greater than 1,000, the intermediate-term aggregate risk estimate is
below EPA's level of concern. For surface and ground water, the
estimated average concentrations of bentazon are less than EPA's levels
of comparison for bentazon in drinking water as a contribution to
intermediate-term aggregate exposure.
A cancer risk assessment was not done. Bentazon is classified as a
Group E chemical (evidence of non-carcinogenicity for humans) based
upon lack of evidence of carcinogenicity in rats and mice. Based on
these risk assessments, it is concluded that there is a reasonable
certainty that no harm will result from aggregate exposure to bentazon
2. Infants and children. In assessing the potential for additional
sensitivity of infants and children to residues of bentazon, data from
developmental toxicity studies in the rat and rabbit and a 2-generation
reproduction study in the rat are considered. The developmental
toxicity studies are designed to evaluate adverse effects on the
developing organism resulting from maternal pesticide exposure during
gestation. Reproduction studies provide information relating to effects
from exposure to the pesticide on the reproductive capability of mating
animals and data on systemic toxicity.
FFDCA section 408 provides that EPA shall apply an additional
tenfold margin of safety for infants and children in the case of
threshold effects to account for prenatal and postnatal toxicity and
the completeness of the data base unless EPA determines that a
different margin of safety will be safe for infants and children.
Margins of safety are incorporated into EPA risk assessments
either directly through use of a margin of exposure (MOE) analysis or
through using uncertainty (safety) factors in calculating a dose level
that poses no appreciable risk to humans. EPA believes that reliable
data support using the standard uncertainty factor (usually 100 for
combined interspecies and intraspecies variability) and not the
additional tenfold MOE/uncertainty factor when EPA has a complete data
base under existing guidelines and when the severity of the effect in
infants or children or the potency or unusual toxic properties of a
compound do not raise concerns regarding the adequacy of the standard
The toxicological data base for evaluating prenatal and postnatal
toxicity of bentazon is complete with respect to current data
requirements. There was evidence of increased susceptibility following
in utero exposure to bentazon in the prenatal developmental toxicity
study in rats and there was quantitative evidence of increased
susceptibility following prenatal/postnatal exposure to bentazon in the
2-generation reproduction study in rats.
There is a complete toxicity data base for bentazon and exposure
data are complete or are estimated based on data that reasonably
accounts for potential exposures. The FQPA Safety Factor for protection
of infants and children will be retained at 10x for bentazon due to the
increased prenatal/postnatal susceptibility. The FQPA Safety Factor for
bentazon is applicable to females 13-50 years old only for acute
dietary and residential exposure assessments because increased
susceptibility was demonstrated in the developmental study in rats
which is designed to evaluate chemical effects on the mother and fetus
from the time of implantation of the fertilized egg in the uterus
through the end of gestation. The safety factor is also applicable to
all population subgroups for chronic dietary and residential exposure
assessments because increased susceptibility was demonstrated in the 2-
generation reproduction study (which is designed to assess the effects
of the pesticide on male and female reproductive processes, from egg
and sperm production and mating through pregnancy, birth, nursing,
growth and development, and maturation). An acute endpoint was not
identified and this risk assessment was not required.
Using the exposure assumptions described in this unit, it was
concluded that aggregate exposure to bentazon from food will utilize
28% of the chronic PAD for children 1-6 years old. EPA generally has no
concern for exposures below 100% of the chronic PAD because the chronic
PAD represents the level at or below which daily aggregate dietary
exposure over a lifetime will not pose appreciable risks to human
health. Despite the potential for exposure to bentazon in drinking
water and from non-dietary, non-occupational exposure, the aggregate
exposure is not expected to exceed 100% of the chronic PAD.
Although bentazon is a registered herbicide for use on turf and
ornamentals, short-term non-dietary ingestion exposure for toddlers is
not assessed because EPA determined that there is no acute dietary or
oral endpoint applicable to infants and children. Aggregate
intermediate-term risk estimates are below EPA's level of concern for
infants and children. In aggregating intermediate-term risk, background
chronic dietary exposure (food + drinking water) and intermediate-term,
non-dietary oral and dermal exposures from residential uses are
considered. For toddlers, dermal and non-dietary oral postapplication
exposures may result from dermal contact with treated turf as well as
hand-to-mouth transfer of residues from turfgrass. For infants and
children, the total food and residential intermediate-term aggregate
MOE is 2,000. As this value is greater than 1,000, the intermediate-
term aggregate risk estimate is below EPA's level of concern. For
surface and ground water, the estimated average concentrations of
bentazon are less than EPA's levels of comparison for bentazon in
drinking water as a contribution to intermediate-term aggregate
Based on these risk assessments, BASF concludes that there is a
reasonable certainty that no harm will result to infants and children
from aggregate exposure to bentazon residues.
F. International Tolerances
There is neither a Codex proposal, nor Canadian or Mexican limits
for residues of bentazon in clover. Therefore, a compatibility issue is
not relevant to the proposed tolerance.
[FR Doc. 01-27600 Filed 11-1-01; 8:45 am]