Picloram; Time-Limited Pesticide Tolerances

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-300748; FRL-6039-4]

RIN 2070-AB78

Picloram; Time-Limited Pesticide Tolerances

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes time-limited tolerances for the

indirect or inadvertent residues of the herbicide, picloram, 4-amino-

3,5,6-trichloropicolinic acid and its potassium salt in or on certain

raw agricultural commodities. Dow AgroSciences requested this tolerance

under the Federal Food, Drug and Cosmetic Act (FFDCA), as amended by

the Food Quality Protection Act of 1996 (Pub. L. 104-170).

DATES: The effective date of this rule is December 31, 1998. Objections

and requests for hearings must be received by EPA on or before March 8,

1999.

ADDRESSES: Written objections and hearing requests, identified by the

docket control number, [OPP-300748], must be submitted to: Hearing

Clerk (1900), Environmental Protection Agency, Rm. M3708, 401 M St.,

SW., Washington, DC 20460. Fees accompanying objections and hearing

requests shall be labeled ``Tolerance Petition Fees'' and forwarded to:

EPA Headquarters Accounting Operations Branch, OPP (Tolerance Fees),

P.O. Box 360277M, Pittsburgh, PA 15251. A copy of any objections and

hearing requests filed with the Hearing Clerk identified by the docket

control number, [OPP-300748], must also be submitted to: Public

Information and Records Integrity Branch, Information Resources and

Services Division (7506C), Office of Pesticide Programs, Environmental

Protection Agency, 401 M St., SW., Washington, DC 20460. In person,

bring a copy of objections and hearing requests to Rm. 119, CM #2, 1921

Jefferson Davis Hwy., Arlington, VA.

A copy of objections and hearing requests filed with the Hearing

Clerk may also be submitted electronically by sending electronic mail

(e-mail) to: [email protected]. Copies of objections and

hearing requests must be submitted as an ASCII file avoiding the use of

special characters and any form of encryption. Copies of objections and

hearing requests will also be accepted on disks in WordPerfect 5.1/6.1

file format or ASCII file format. All copies of objections and hearing

requests in electronic form must be identified by the docket control

number [OPP-300748]. No Confidential Business Information (CBI) should

be submitted through e-mail. Electronic copies of objections and

hearing requests on this rule may be filed online at many Federal

Depository Libraries.

FOR FURTHER INFORMATION CONTACT: By mail: James A. Tompkins,

Registration Division 7505C, Office of Pesticide Programs,

Environmental Protection Agency, 401 M St., SW., Washington, DC 20460.

Office location, telephone number, and e-mail address: Crystal Mall #2,

1921 Jefferson Davis Hwy., Arlington, VA, (703) 305-5697, e-mail:

[email protected].

SUPPLEMENTARY INFORMATION:In the Federal Register of May 13, 1997 (62

FR 26305), EPA issued a notice pursuant to section 408 of the Federal

Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(e) announcing the

filing of a pesticide petition (PP 4F4412) for tolerances by DowElanco,

9330 Zionsville Road, Indianapolis, IN 46254. This notice included a

summary of the petition prepared by DowElanco, the registrant. The

petition requested that 40 CFR 180 be amended by establishing

tolerances for inadvertent residues of the herbicide, picloram, 4-

amino-3,5,6-trichloropicolinic acid, in or on sorghum grain at 0.3

parts per million (ppm), sorghum grain forage at 0.2 ppm, and sorghum

stover at 0.5 ppm.

In the Federal Register of November 20,1998 (63 FR 64494), EPA

issued a notice announcing that Dow AgroSciences amended the petition

by also proposing to established a tolerance for residues of the

herbicide picloram in or on the raw agricultural commodity aspirated

grain fractions at 4 ppm. There were no comments received in response

to the notices of filing. The tolerances will expire and will be

revoked on December 31, 2000.

I. Risk Assessment and Statutory Findings

Section 408(b)(2)(A)(i) of the FFDCA allows EPA to establish a

tolerance (the legal limit for a pesticide chemical residue in or on a

food) only if EPA determines that the tolerance is ``safe.'' Section

408(b)(2)(A)(ii) defines ``safe'' to mean that ``there is a reasonable

certainty that no harm will result from aggregate exposure to the

pesticide chemical residue, including all anticipated dietary exposures

and all other exposures for which there is reliable information.'' This

includes exposure through drinking water and in residential settings,

but does not include occupational exposure. Section 408(b)(2)(C)

requires EPA to give special consideration to exposure of infants and

children to the pesticide chemical residue in establishing a tolerance

and to ``ensure that there is a reasonable certainty that no harm will

result to infants and children from aggregate exposure to the pesticide

chemical residue***.''

EPA performs a number of analyses to determine the risks from

aggregate exposure to pesticide residues. For further discussion of the

regulatory requirements of section 408 and a complete description of

the risk assessment process, see the Final Rule on Bifenthrin Pesticide

Tolerances (62 FR 62961, November 26, 1997) (FRL-5754-7).

A. Toxicity

1. Threshold and non-threshold effects. For many animal studies, a

dose response relationship can be determined, which provides a dose

that causes adverse effects (threshold effects) and doses causing no

observed effects (the ``no-observed adverse effect level'' or

``NOAEL'').

Once a study has been evaluated and the observed effects have been

determined to be threshold effects, EPA generally divides the NOAEL

from the study with the lowest NOAEL by an uncertainty factor (usually

100 or more) to determine the Reference Dose (RfD). The RfD is a level

at or below which daily aggregate exposure over a lifetime will not

pose appreciable risks to human health. An uncertainty factor

(sometimes called a ``safety factor'') of 100 is commonly used since it

is assumed that people may be up to 10 times more sensitive to

pesticides than the test animals, and that one person or subgroup of

the population (such as infants and children) could be up to 10 times

more sensitive to a pesticide than another. In addition, EPA assesses

the potential risks to infants and children based on the weight of the

evidence of the toxicology studies and determines whether an additional

uncertainty factor is warranted. Thus, an aggregate daily exposure to a

pesticide residue at or below the RfD (expressed as 100 percent or less

of the RfD) is generally considered acceptable by EPA. EPA generally

uses the RfD to evaluate the chronic risks posed by pesticide exposure.

For shorter term risks, EPA calculates a margin of exposure (MOE) by

dividing the estimated human

[[Page 419]]

exposure into the NOAEL from the appropriate animal study. Commonly,

EPA finds MOEs lower than 100 to be unacceptable. This 100-fold MOE is

based on the same rationale as the 100-fold uncertainty factor.

Lifetime feeding studies in two species of laboratory animals are

conducted to screen pesticides for cancer effects. When evidence of

increased cancer is noted in these studies, the Agency conducts a

weight of the evidence review of all relevant toxicological data

including short-term and mutagenicity studies and structure activity

relationship. Once a pesticide has been classified as a potential human

carcinogen, different types of risk assessments (e.g., linear low dose

extrapolations or MOE calculation based on the appropriate NOAEL) will

be carried out based on the nature of the carcinogenic response and the

Agency's knowledge of its mode of action.

2. Differences in toxic effect due to exposure duration. The

toxicological effects of a pesticide can vary with different exposure

durations. EPA considers the entire toxicity data base, and based on

the effects seen for different durations and routes of exposure,

determines which risk assessments should be done to assure that the

public is adequately protected from any pesticide exposure scenario.

Both short and long durations of exposure are always considered.

Typically, risk assessments include ``acute'', ``short-term'',

``intermediate term'', and ``chronic'' risks. These assessments are

defined by the Agency as follows.

Acute risk, by the Agency's definition, results from 1-day

consumption of food and water, and reflects toxicity which could be

expressed following a single oral exposure to the pesticide residues.

High end exposure to food and water residues are typically assumed.

Short-term risk results from exposure to the pesticide for a period

of 1-7 days, and therefore overlaps with the acute risk assessment.

Historically, this risk assessment was intended to address primarily

dermal and inhalation exposure which could result, for example, from

residential pesticide applications. However, since enaction of FQPA,

this assessment has been expanded to include both dietary and non-

dietary sources of exposure, and will typically consider exposure from

food, water, and residential uses when reliable data are available. In

this assessment, risks from average food and water exposure, and high-

end residential exposure, are aggregated. High-end exposures from all

three sources are not typically added because of the very low

probability of this occurring in most cases, and because the other

conservative assumptions built into the assessment assure adequate

protection of public health. However, for cases in which high-end

exposure can reasonably be expected from multiple sources (e.g.

frequent and widespread homeowner use in a specific geographical area),

multiple high-end risks will be aggregated and presented as part of the

comprehensive risk assessment/characterization. Since the toxicological

endpoint considered in this assessment reflects exposure over a period

of at least 7 days, an additional degree of conservatism is built into

the assessment; i.e., the risk assessment nominally covers 1-7 days

exposure, and the toxicological endpoint/NOAEL is selected to be

adequate for at least 7 days of exposure. (Toxicity results at lower

levels when the dosing duration is increased.)

Intermediate-term risk results from exposure for 7 days to several

months. This assessment is handled in a manner similar to the short-

term risk assessment.

Chronic risk assessment describes risk which could result from

several months to a lifetime of exposure. For this assessment, risks

are aggregated considering average exposure from all sources for

representative population subgroups including infants and children.

B. Aggregate Exposure

In examining aggregate exposure, FFDCA section 408 requires that

EPA take into account available and reliable information concerning

exposure from the pesticide residue in the food in question, residues

in other foods for which there are tolerances, residues in groundwater

or surface water that is consumed as drinking water, and other non-

occupational exposures through pesticide use in gardens, lawns, or

buildings (residential and other indoor uses). Dietary exposure to

residues of a pesticide in a food commodity are estimated by

multiplying the average daily consumption of the food forms of that

commodity by the tolerance level or the anticipated pesticide residue

level. The Theoretical Maximum Residue Contribution (TMRC) is an

estimate of the level of residues consumed daily if each food item

contained pesticide residues equal to the tolerance. In evaluating food

exposures, EPA takes into account varying consumption patterns of major

identifiable subgroups of consumers, including infants and children.

The TMRC is a ``worst case'' estimate since it is based on the

assumptions that food contains pesticide residues at the tolerance

level and that 100% of the crop is treated by pesticides that have

established tolerances. If the TMRC exceeds the RfD or poses a lifetime

cancer risk that is greater than approximately one in a million, EPA

attempts to derive a more accurate exposure estimate for the pesticide

by evaluating additional types of information (anticipated residue data

and/or percent of crop treated data) which show, generally, that

pesticide residues in most foods when they are eaten are well below

established tolerances.

Percent of crop treated estimates are derived from Federal and

private market survey data. Typically, a range of estimates are

supplied and the upper end of this range is assumed for the exposure

assessment. By using this upper end estimate of percent of crop

treated, the Agency is reasonably certain that exposure is not

understated for any significant subpopulation group. Further, regional

consumption information is taken into account through EPA's computer-

based model for evaluating the exposure of significant subpopulations

including several regional groups, to pesticide residues. For this

pesticide, the most highly exposed population subgroup non-nursing

infants was not regionally based.

II. Aggregate Risk Assessment and Determination of Safety

Consistent with section 408(b)(2)(D), EPA has reviewed the

available scientific data and other relevant information in support of

this action, EPA has sufficient data to assess the hazards of picloram

and to make a determination on aggregate exposure, consistent with

section 408(b)(2), for a time-limited tolerance for indirect or

inadvertent residues of picloram and its potassium salt in certain raw

agricultural commodities when present therein as a result of the

application of picloram as a herbicide. EPA's assessment of the dietary

exposures and risks associated with establishing the tolerances

follows:

A. Toxicological Profile

EPA has evaluated the available toxicity data and considered its

validity, completeness, and reliability as well as the relationship of

the results of the studies to human risk. EPA has also considered

available information concerning the variability of the sensitivities

of major identifiable subgroups of consumers, including infants and

children. The nature of the toxic effects caused by picloram acid

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and its salts and esters are discussed below:

1. Rat acute oral studies with LD50s greater than 5,000

milligrams (mg)/kilogram (kg) (males) and 4,012 mg/kg (females) with

picloram acid and greater than 5,000 mg/kg (males) and 3,536 mg/kg

(females) with the potassium salt of picloram

2. A 13-week rat feeding study with picloram acid with a No

Observed Adverse Effect Level (NOAEL) 50 mg/kg/day and with a Lowest

Observed Adverse Effect Level (LOAEL) of 150 mg/kg/day based on liver

weight increases and minimal microscopic changes in the liver.

3. A 13-week rat feeding study with the isooctyl ester of picloram

with a NOAEL 73 mg/kg/day and with a LOAEL of 220 mg/kg/day based on

increased liver weights accompanied by slight/very slight

hepatocellular hypertrophy and increased kidney weights in males only.

4. A 13-week rat feeding study with the triisopropanolamine salt of

picloram with a NOAEL 90 mg/kg/day and with a LOAEL of 550 mg/kg/day

based on hepatocellular hypertrophy; decreased body weight gain and

increased liver and kidney weights (females only) at 1,800 mg/kg/day.

5. A 6 month dog feeding study with picloram acid with a NOAEL of

35 mg/kg/day and a LOAEL of 175 mg/kg/day based on decreased mean body

weight gain and food consumption.

6. A 21-day dermal study with potassium salt of picloram in rabbits

with a NOAEL for systemic effects greater than 753 mg/kg/day, the

maximum amount of test material that could be practically maintained at

the test site - limit of test.

7. A 21-day dermal study with triisopropanolamine salt of picloram

in rabbits with a NOAEL for systemic effects greater than 1,320 mg/kg/

day - limit of test.

8. A dog chronic feeding study with picloram acid with a NOAEL of

35 mg/kg/day and a LOAEL of 175 mg/kg/day based on increased absolute

and relative liver weights.

9. A rat chronic feeding/carcinogenicity study with picloram acid

with a systemic NOAEL of 20 mg/kg/day and a systemic LOAEL of 60 mg/kg/

day based on increased size and altered staining properties of

centrilobular hepatocytes and increased absolute and/or relative liver

weights in both sexes. Negative for carcinogenicity.

10. A second rat chronic feeding/carcinogenicity study with

picloram acid with a systemic NOAEL less than 250 mg/kg/day and a

systemic LOAEL of 250 mg/kg/day based on increases in the incidence and

severity of glomerulonephritis, blood in the urine, decreased specific

gravity of the urine, increased size of hepatocytes that often had

altered staining properties, increase in the incidence of unilateral or

bilateral renal papillary necrosis and increases in absolute and

relative kidney weights. There was no evidence of increased tumor

incidence.

11. A mouse carcinogenicity study with picloram acid with a NOAEL

was 500 mg/kg/day and the LOAEL was 1,000 mg/kg/day based on increased

absolute and relative kidney weights in males. There was no evidence of

carcinogenicity.

12. A two-generation rat reproduction study with picloram acid with

a parental systemic NOAEL of 200 mg/kg/day and a reproductive NOAEL of

1,000 mg/kg/day [Highest Dose Tested (HDT)] and a Parental Systemic

LOAEL of 1,000 mg/kg/day based on microscopic lesions in male (and some

female) kidneys, blood in urine, decreased urine specific gravity,

increased absolute and relative kidney weights.

13. A rat developmental study (picloram acid) with a maternal NOAEL

of 500 mg/kg/day and a developmental LOAEL of 500 mg/kg/day [Lowest

Dose Tested] based on transient delayed ossification of 5th sternebrae

(fetuses but not litters) and with a maternal LOAEL of 750 mg/kg/day

based on hyperactivity and mild diarrhea and deaths.

14. A rat developmental study with the potassium salt of picloram

with a maternal NOAEL of 174 mg/kg/day and a developmental NOAEL of 347

mg/kg/day [HDT] and with a maternal LOAEL of 347 mg/kg/day based on

excessive salivation.

15. A rabbit developmental study with the potassium salt of

picloram with a maternal NOAEL of 40 mg/kg/day and a developmental

NOAEL of 400 mg/kg/day [HDT] and with a maternal LOAEL of 200 mg/kg/day

based on reduced maternal weight gain during gestation.

16. A rat developmental study with the isooctyl ester of picloram

with a maternal NOAEL of 100 mg/kg/day and a developmental NOAEL of

1,000 mg/kg/day [HDT] and with a maternal LOAEL of 500 mg/kg/day based

on decreased body weight gain during early gestation.

17. A rabbit developmental study with the isooctyl ester of

picloram with a maternal NOAEL of 20 mg/kg/day and a developmental

NOAEL of 500 mg/kg/day [HDT] and with a maternal LOAEL of 100 mg/kg/day

based on an increase in incidence of clinical signs (decreased feces at

500 and decreased body weight gain at 100 mg/kg/day and above).

18. A rat developmental study with the triisopropanolamine salt of

picloram with a maternal NOAEL of 500 mg/kg/day and a developmental

NOAEL of 1,000 mg/kg/day [HDT] and with a maternal LOAEL of 1,000 mg/

kg/day based on excessive salivation, decreased body weight gain and

food consumption.

19. A rabbit developmental study with the triisopropanolamine salt

of picloram with a maternal NOAEL of 54 mg/kg/day and a developmental

NOAEL of 1,000 mg/kg/day [HDT] and with a maternal LOAEL of 180 mg/kg/

day based on increased rate of abortions at 1,000 mg/kg/day, increased

clinical signs at 538 mg/kg/day and above and decreased food

consumption and body weight gain at 180 mg/kg/day and above.

20. In a gene mutation assay (Ames assay) picloram acid did not

produce a mutagenic response either in the presence or absence of

activation. In a gene mutation assay in Chinese hamster ovary (CHO)

cells picloram acid was found to be negative for inducing forward

mutation with and without metabolic activation. In gene mutation assay

with CHO/HGPRT+ cells picloram acid did not induce a mutagenic response

at doses up to and including those generally associated with severe

cytotoxicity. In a cytogenetics in vivo study picloram acid did not

produce cytogenetic effects. In an other genotoxic effects study

picloram acid was negative for unscheduled DNA synthesis treated up to

cytotoxic levels. In a gene mutation assay (Ames test) the isooctyl

ester of picloram did not induce a mutagenic response in the presence

or absence of metabolic activation. In a gene mutation assay (mammalian

CHO cells) isooctyl ester of picloram there was no evidence of a

mutagenic response at any dosage level in either the S9 activated

trials or the non-activated trials. In a structural chromosomal

aberration assay isooctyl ester of picloram demonstrated no potential

for inducing chromosomal aberrations. In a micronucleus test in mice

the isooctyl ester was found not to be clastogenic. In a gene mutation

assay (Ames test) the triisopropanolamine salt of picloram did not

produce a mutagenic response either in the presence or absence of

activation. In a cytogenetics assay the triisopropanolamine salt of

picloram was non-clastogenic in mice, as determined by lack of

mutagenic effect at doses up to lethality. In another genotoxic effects

assay the triisopropanolamine salt of picloram was negative for

inducing unscheduled

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DNA synthesis at doses up to toxic levels.

21. A rat metabolism study showed that radio-labeled

14C-picloram acid is rapidly absorbed, distributed and

excreted following oral and intra-venous (i.v.) administration. A rat

metabolism study demonstrated that isooctyl ester of picloram is

hydrolyzed rapidly to picloram (free acid) and 2-ethyl hexanol, and

that picloram isooctyl ester does not influence the excretion of

picloram in the rat. For the triisopropanolamine salt of picloram, the

metabolism study showed that the conversion of the salt to picloram was

not affected by the presence of triisopropanolamine.

B. Toxicological Endpoints

1. Acute toxicity. EPA could not identify any toxicological effects

that could be attributable to a single oral exposure (dose) in any of

the available toxicological studies.

2. Short- and intermediate-term toxicity. EPA could not identify

any toxicological effects that could be attributable to short- or

intermediate-term dermal or inhalation exposure. No systemic effects

were observed in available dermal studies. In addition, no endpoints

for short- or intermediate-term exposure could be identified from

available oral studies.

3. Chronic toxicity. EPA has established the RfD for picloram at

0.2 mg/kg/day. This RfD is based on NOAEL of 20 mg/kg/day in the

combined chronic toxicity/carcinogenicity study in rats with a 100-fold

safety factor to account for inter-species extrapolation (10x) and

intra-species variability (10x).

4. Carcinogenicity. The Health Effects Division Carcinogenicity

Peer Review Committee has classified picloram acid and its potassium

salt as Group E ``no evidence of carcinogenicity'' to humans based on

the lack of carcinogenicity in rats and mice. A carcinogenicity risk

assessment is required for hexachlorobenzene (HCB) a process impurity

in picloram.

C. Exposures and Risks

1. From food and feed uses. Tolerances have been established (40

CFR 180.292) previously for the residues of picloram, and its salts in

or on raw agricultural commodities from use on barley, grasses, oats

and wheat. Appropriate tolerances are established for secondary

residues of picloram and its salts occurring in meat, milk, poultry, or

eggs. Risk assessments were conducted by EPA to assess dietary

exposures and risks from picloram from the proposed and registered uses

as follows:

i. Acute exposure and risk. Acute dietary risk assessments are

performed for a food-use pesticide if a toxicological study has

indicated the possibility of an effect of concern occurring as a result

of a 1 day or single exposure. No toxicological effect that could be

attributable to a single oral exposure was identified, and therefore

picloram is not expected to present an acute dietary risk.

ii. Picloram chronic exposure and risk. The Reference Dose (RfD)

for picloram is 0.02 mg/kg/day. This value is based on the systemic

LOAEL of 200 mg/kg/day in the rat chronic feeding/carcinogenicity study

with a 100-fold safety factor to account for interspecies extrapolation

(10x) and intraspecies variability (10x). start

A Dietary Risk Evaluation System (DRES) chronic exposure analysis

was conducted using established tolerance levels for proposed

tolerances, meat, milk and eggs, and percent crop treated information

for cereal grains to estimate dietary for the general population and 22

subgroups. The chronic analysis showed that dietary exposure for non-

nursing infants (the subgroup with the highest exposure) would be 2% of

the Reference Dose (RfD). The exposure for the general U.S. population

would be less than 1% of the RfD.

Section 408(b)(2)(F) states that the Agency may use data on the

actual percent of food treated for assessing chronic dietary risk only

if the Agency can make the following findings: (1) That the data used

are reliable and provide a valid basis to show what percentage of the

food derived from such crop is likely to contain such pesticide

residue; (2) that the exposure estimate does not underestimate exposure

for any significant subpopulation group; and (3) if data are available

on pesticide use and food consumption in a particular area, the

exposure estimate does not understate exposure for the population in

such area. In addition, the Agency must provide for periodic evaluation

of any estimates used.

The Agency used percent crop treated (PCT) information as follows.

A routine chronic dietary exposure analysis for picloram was based on

2% of cereal grain crop treated. The Agency believes that the three

conditions listed above have been met. With respect to (1), EPA finds

that the (PCT) information described above for picloram used on cereal

grains is reliable and has a valid basis based on past pesticide use

surveys. Approval of crop rotation of the minor use corp sorghum after

treatment with picloram is not likely to significant increase the

percentage of the total U.S. cereal grains treated with picloram. As to

(2) and (3), regional consumption information and consumption

information for significant subpopulations is taken into account

through EPA's computer-based model for evaluating the exposure of

significant subpopulations including several regional groups. Use of

this consumption information in EPA's risk assessment process ensures

that EPA's exposure estimate does not understate exposure for any

significant subpopulation group and allows the Agency to be reasonably

certain that no regional population is exposed to residue levels higher

than those estimated by the Agency. Other than the data available

through national food consumption surveys, EPA does not have available

information on the regional consumption of food to which picloram may

be applied in a particular area.

iii. HCB (hexachlorobenzene) chronic exposure and risk. EPA

calculated the chronic dietary carcinogenic risk from all known

pesticidal sources of HCB, including picloram. Eight pesticides were

included in the calculations, three of which were major contributors to

HCB levels in the diet: chlorothalonil, pentachloronitrobenzene and

picloram. The estimated dietary carcinogenic risk for HCB from all

known pesticidal sources is 6.3 x 10-7 which is less than

the 1 x 10-6 point which is generally considered to be

negligible.

2. From drinking water- i. Acute risk. Because no acute dietary

endpoint was determined, no acute risk is expected.

ii. Chronic risk. Based on the chronic dietary (food) exposure and

using default body weights and water consumption figures [70 kg weight/

2L water consumed (adult male), 60 kg/2L (adult female), and 10 kg/1L

(child)], the chronic drinking water levels of concern (DWLOC) for

drinking water were calculated. To calculate the DWLOC, the chronic

dietary food exposure was subtracted from the RfD.

DWLOCchronic = [chronic water exposure (mg/kg/day) x

(body weight)]/[consumption (L) x 10-3 mg/g]

where chronic water exposure (mg/kg/day) = [RfD - (chronic food +

residential exposure) (mg/kg/day)]

The results are summarized in the following Table:

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Chronic Scenario

--------------------------------------------------------------------------------

Maximum SCI-GROW2

Population Subgroup\1\ RfD mg/kg/ Food Water DWLOC EEC (g/ m>g/L)\3\ (g/

kg/day kg/day\2\ L) L)\3\

----------------------------------------------------------------------------------------------------------------

U.S. Population................ 0.20 0.0011 0.20 7000 379 103.1

Females (13-19 years old, not

pregnant or nursing).......... 0.20 0.00090 0.20 6000 379 103.1

Non-Nursing Infants (g/L (ppb). The

GENEEC model predicted that with the present use pattern, the 56-day

average picloram surface water concentration for the highest

application rate (2 lbs/A) would be 103.1 g/L (ppb). The SCI-

GROW2 model estimated that the ground water concentration from the

current uses of picloram for the highest application rate would be 379

g/L (ppb). Therefore, exposure from water is below DWLOC for

chronic dietary exposure for any of the populations examined.

iii. Dietary cancer risk for hexachlorobenzene (HCB) - (combined

food and water). HCB is persistent and relatively immobile in the

environment. Based on the high binding potentials of HCB, contamination

of ground water resources is relatively unlikely. The dietary cancer

risk for HCB from all pesticidal uses is 6.3 x 10-7. In

order to calculate a DWLOC for HCB, the Anticipated Residue

Contribution (ARC's) for each of the pesticides included in the risk

calculation are needed. Although a few significant figures are lost

with this calculation, an estimate of the overall dietary exposure can

be made by dividing the risk value by the Q*. The

calculation is as follows: (6.3 x 10-7/1.02 = 6.2 x

10-7). Based on summaries of monitoring data and fate

properties, long term concentrations of HCB in filtered surface water

are not likely to exceed 10 ppt or 0.01 ppb. The amount of HCB in water

is also estimated from uses of other chemicals with HCB as an impurity,

not just picloram. The chronic water exposure is calculated by dividing

the negligible risk (1.0 x 10-6) by the Q* and subtracting

from that the chronic food plus residential exposure. 1.0 x

10-6/1.02 mg/kg/day-1 = 9.8 x 10-7 mg/

kg/day. Using the equation for calculating the DWLOC (ppb), the DWLOC

for the general population for dietary cancer risk for HCB from all

pesticidal uses is calculated as follows:

9.8 x 10-7 mg/kg/day x 70kg/2L x 10-3 mg/

g = 0.034 g/L (ppb)

The DWLOC of 0.034 ppb is greater than 0.01 ppb, the maximum

concentration of HCB estimated in surface water.

3. From non-dietary exposure. Picloram is a Restricted Use

Pesticide that has no residential uses. For uses currently registered

under the Federal Insecticide, Fungicide and Rodenticide Act, rights-

of-way, forestry, pastures, range lands, and small grains; entry into a

treated area soon after the application of picloram is limited by the

re-entry restrictions on the picloram labels. Non-dietary exposure to

picloram will be minimal for the general population.

4. Cumulative exposure to substances with common mechanism of

toxicity. Section 408(b)(2)(D)(v) requires that, when considering

whether to establish, modify, or revoke a tolerance, the Agency

consider ``available information'' concerning the cumulative effects of

a particular pesticide's residues and ``other substances that have a

common mechanism of toxicity.'' Picloram is a pyridine carboxylic acid

herbicide. Other herbicides in this class include clopyralid,

quinclorac and thiazopyr.

EPA does not have, at this time, available data to determine

whether picloram 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,

picloram does not appear to produce a toxic metabolite produced by

other substances. For the purposes of this tolerance action, therefore,

EPA has not assumed that picloram has a common mechanism of toxicity

with other substances. For information regarding EPA's efforts to

determine which chemicals have a common mechanism of toxicity and to

evaluate the cumulative effects of such chemicals, see the Final Rule

for Bifenthrin Pesticide Tolerances (62 FR 62961, November 26, 1997).

D. Aggregate Risks and Determination of Safety for U.S. Population

1. Acute risk. Picloram is not expected to pose an acute risk.

2. Chronic risk. The Reference Dose (RfD) for picloram is 0.02 mg/

kg/day. This value is based on the systemic LOAEL of 200 mg/kg/day in

the rat chronic feeding/carcinogenicity study with a 100-fold safety

factor to account for interspecies extrapolation (10x) and intraspecies

variability (10x). The dietary exposure for non-nursing infants (the

subgroup with the highest exposure) is 2% of the Reference Dose (RfD).

The exposure for the general U.S. population would be less than 1% of

the RfD.

The drinking water level of concerns (DWLOCs) for chronic exposure

to picloram in drinking water calculated for U.S. population was 7,000

parts per billion (ppb) assuming that an adult weighs 70 kg and

consumes a maximum of 2 liters of water per day, for females 13-19

years old (not pregnant or nursing) the DWLOC was 6,000 assuming that

an adult female weighs 60 kg and consumes a maximum of 2 liters of

water per day, and for children (1 - 6 years old) the DWLOC was 2,000

ppb assuming that a child weighs 10 kg and consumes a maximum of 1

liter of water per day.

The drinking water estimated concentration (DWECs) for groundwater

(picloram acid) calculated from the highest application rate for the 56

day average is 379 ppb which does not exceed DWLOC of 2,000 ppb for

children (1-6 years old). The DWEC for surface water based on the

computer model Generic Expected Environmental Concentration (GENEEC)

was calculated to be 103.1 ppb for chronic concentration (parent

picloram and degradate thiadone) which does not exceed the DWLOC of

2,000 ppb for children (1-6 years old). From

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groundwater monitoring the maximum concentration reported was 4.6 ppb.

Picloram is regulated under the Safe Drinking Water Act (SDWA). Water

supply systems are required to sample for it. A Maximum Contaminate

Level (MCL) of 500 ppb and a 1-10 day health advisory of 20,000 ppb

have been established.

EPA concludes that there is a reasonable certainty that no harm

will result from aggregate exposure to picloram residues.

E. Aggregate Risks and Determination of Safety for Infants and

Children

In assessing the potential for additional sensitivity of infants

and children to residues of picloram, EPA considered data from

developmental toxicity studies in the rat and rabbit and a two-

generation reproduction study in the rat. The developmental toxicity

studies are designed to evaluate adverse effects on the developing

organism resulting from pesticide exposure during prenatal development

to one or both parents. 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 pre- and post-natal toxicity and the

completeness of the database unless EPA determines that a different

margin of safety will be safe for infants and children. There is no

indication of increased sensitivity to young rats or rabbits following

pre- and/or post-natal exposure to picloram in the standard

developmental and reproductive toxicity studies, there was no

indication that picloram is a neurotoxic herbicide. Therefore, a 10-

fold safety factor for children and infants is not required to be used

in the aggregate dietary acute and chronic risk assessments.

III. Other Considerations

A. Metabolism In Plants and Animals

The nature of the residue in rotated sorghum is adequately

understood. The residues of concern for the tolerance expression are

picloram and its salts. Appropriate tolerances are established to cover

any secondary residues which would occur in animal commodities from the

proposed and registered uses.

B. Analytical Enforcement Methodology

An adequate analytical method, gas chromatography/mass spectrometry

with selected ion monitoring, is available for enforcement purposes.

Because of the long lead time from establishing these tolerances to

publication of the enforcement methodology in the Pesticide Analytical

Manual, Vol. II, the analytical methodology is being made available in

the interim to anyone interested in pesticide enforcement when

requested from: Calvin Furlow, Public Information and Records Integrity

Branch, Information Resources and Services Division (7502C), Office of

Pesticide Programs, Environmental Protection Agency, 401 M St., SW.,

Washington, DC 20460. Office location and telephone number: Room 101FF,

CM #2, 1921 Jefferson Davis Highway, Arlington, VA 22202, (703-305-

5229).

C. Endocrine Effects

EPA is required to develop a screening program to determine whether

certain substances (including all pesticides and inerts) ``may have an

effect in humans that is similar to an effect produced by a naturally

occurring estrogen, or such other effect***.'' The Agency is currently

working with interested stakeholders, including other government

agencies, public interest groups, industry and research scientists in

developing a screening and testing program and a priority setting

scheme to implement this program. Congress has allowed 3 years from the

passage of FQPA (August 3, 1999) to implement this program. At that

time, EPA may require further testing of this active ingredient and end

use products for endocrine disrupter effects.

D. Magnitude of Residues

Due to the data gap, an aspirated grain fraction study; EPA

believes it is inappropriate to establish permanent tolerances for the

proposed use of picloram at this time. EPA believes that the existing

data support tolerances to December 31, 2000. The nature of the residue

in plants is adequately understood for the purposes of these

tolerances.

E. International Residue Limits

There are no Codex Alimentarius Commission (Codex) Maximum Residue

Levels (MRLs) for picloram.

F. Rotational Crop Restrictions

Tolerances for indirect or inadvertent residues of picloram and its

potassium salt established by this regulation will cover any residues

in sorghum planted in treated fields in accordance with the

restrictions that appear on the labeling proposed for registration

under the Federal Insecticide Fungicide and Rodenticide Act (FIFRA), as

amended.

IV. Conclusion

The analysis for picloram and its salts using crop tolerances,

percentage of crop estimates, and estimated drinking water

concentrations for all population subgroups examined by EPA shows the

proposed rotation to sorghum from the registered uses of picloram will

not cause exposure at which the Agency believes there is an appreciable

risk during the period of time for the tolerance. Therefore EPA

concludes there is a reasonable certainty of no harm from aggregate

exposure to picloram. Based on the information cited above, EPA has

determined that establishing tolerances for the residues of the

herbicide, picloram in or on aspirated grain fractions at 4.0 ppm,

sorghum grain at 0.3 ppm, sorghum grain forage at 0.2 ppm and sorghum

grain stover at 0.5 ppm will be safe. These tolerances will expire and

be revoked on December 31, 2000. Therefore, the tolerances are

established as set forth below.

V. Objections and Hearing Requests

The new FFDCA section 408(g) provides essentially the same process

for persons to ``object'' to a tolerance regulation issued by EPA under

new section 408(e) and (l)(6) as was provided in the old section 408

and in section 409. However, the period for filing objections is 60

days, rather than 30 days. EPA currently has procedural regulations

which govern the submission of objections and hearing requests. These

regulations will require some modification to reflect the new law.

However, until those modifications can be made, EPA will continue to

use those procedural regulations with appropriate adjustments to

reflect the new law.

Any person may, by March 8, 1999, file written objections to any

aspect of this regulation and may also request a hearing on those

objections. Objections and hearing requests must be filed with the

Hearing Clerk, at the address given above (40 CFR 178.20). A copy of

the objections and/or hearing requests filed with the Hearing Clerk

should be submitted to the OPP docket for this rulemaking. The

objections submitted must specify the provisions of the regulation

deemed objectionable and the grounds for the objections (40 CFR

178.25). Each objection must be accompanied by the fee prescribed by 40

CFR 180.33(i) or a request for a fee waiver. If a hearing is requested,

the objections must include a statement of the factual issues on which

a hearing is requested, the requestor's contentions on such issues, and

a summary of any

[[Page 424]]

evidence relied upon by the requestor (40 CFR 178.27). A request for a

hearing will be granted if the Administrator determines that the

material submitted shows the following: There is genuine and

substantial issue of fact; there is a reasonable possibility that

available evidence identified by the requestor would, if established,

resolve one or more of such issues in favor of the requestor, taking

into account uncontested claims or facts to the contrary; and

resolution of the factual issues in the manner sought by the requestor

would be adequate to justify the action requested (40 CFR 178.32).

Information submitted in connection with an objection or hearing

request may be claimed confidential 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. A copy of the

information that does not contain CBI must be submitted for inclusion

in the public record. Information not marked confidential may be

disclosed publicly by EPA without prior notice.

VI. Public Record and Electronic Submissions

EPA has established a record for this rulemaking under docket

control number [OPP-300748]. A public version of this record, including

printed, paper versions of electronic comments, which does not include

any information claimed as CBI, is available for inspection from 8:30

a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The

public record is located in Room 119 of the Public Information and

Records Integrity Branch, Information Resources and Services Division

(7502C), Office of Pesticide Programs, Environmental Protection Agency,

Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA.

The official record for this rulemaking, as well as the public

version, as described above will be kept in paper form. Accordingly,

EPA will transfer any copies of objections and hearing requests

received electronically into printed, paper form as they are received

and will place the paper copies in the official rulemaking record which

will also include all comments submitted directly in writing. The

official rulemaking record is the paper record maintained at the

Virginia address in ``ADDRESSES'' at the beginning of this document.

VII. Regulatory Assessment Requirements

A. Certain Acts and Executive Orders

This final rule establishes tolerances under FFDCA section 408(d)

in response to a petition submitted to the Agency. The Office of

Management and Budget (OMB) has exempted these types of actions from

review under Executive Order 12866, entitled Regulatory Planning and

Review (58 FR 51735, October 4, 1993). This final rule does not contain

any information collections subject to OMB approval under the Paperwork

Reduction Act (PRA), 44 U.S.C. 3501 et seq., or impose any enforceable

duty or contain any unfunded mandate as described under Title II of the

Unfunded Mandates Reform Act of 1995 (UMRA) (Pub. L. 104-4). Nor does

it require any prior special considerations as required by Executive

Order 12898, entitled Federal Actions to Address Environmental Justice

in Minority Populations and Low-Income Populations (59 FR 7629,

February 16, 1994), or require OMB review in accordance with Executive

Order 13045, entitled Protection of Children from Environmental Health

Risks and Safety Risks (62 FR 19885, April 23, 1997).

In addition, since tolerances and exemptions that are established

on the basis of a petition under FFDCA section 408(d), such as the

tolerance in this final rule, do not require the issuance of a proposed

rule, the requirements of the Regulatory Flexibility Act (RFA) (5

U.S.C. 601 et seq.) do not apply. Nevertheless, the Agency has

previously assessed whether establishing tolerances, exemptions from

tolerances, raising tolerance levels or expanding exemptions might

adversely impact small entities and concluded, as a generic matter,

that there is no adverse economic impact. The factual basis for the

Agency's generic certification for tolerance actions published on May

4, 1981 (46 FR 24950) and was provided to the Chief Counsel for

Advocacy of the Small Business Administration.

B. Executive Order 12875

Under Executive Order 12875, entitled Enhancing the

Intergovernmental Partnership (58 FR 58093, October 28, 1993), EPA may

not issue a regulation that is not required by statute and that creates

a mandate upon a State, local, or tribal government, unless the Federal

government provides the funds necessary to pay the direct compliance

costs incurred by those governments. If the mandate is unfunded, EPA

must provide to OMB a description of the extent of EPA's prior

consultation with representatives of affected State, local, and tribal

governments, the nature of their concerns, copies of any written

communications from the governments, and a statement supporting the

need to issue the regulation. In addition, Executive Order 12875

requires EPA to develop an effective process permitting elected

officials and other representatives of State, local, and tribal

governments ``to provide meaningful and timely input in the development

of regulatory proposals containing significant unfunded mandates.''

Today's rule does not create an unfunded Federal mandate on State,

local, or tribal governments. The rule does not impose any enforceable

duties on these entities. Accordingly, the requirements of section 1(a)

of Executive Order 12875 do not apply to this rule.

C. Executive Order 13084

Under Executive Order 13084, entitled Consultation and Coordination

with Indian Tribal Governments (63 FR 27655, May 19, 1998), EPA may not

issue a regulation that is not required by statute, that significantly

or uniquely affects the communities of Indian tribal governments, and

that imposes substantial direct compliance costs on those communities,

unless the Federal government provides the funds necessary to pay the

direct compliance costs incurred by the tribal governments. If the

mandate is unfunded, EPA must provide OMB, in a separately identified

section of the preamble to the rule, a description of the extent of

EPA's prior consultation with representatives of affected tribal

governments, a summary of the nature of their concerns, and a statement

supporting the need to issue the regulation. In addition, Executive

Order 13084 requires EPA to develop an effective process permitting

elected officials and other representatives of Indian tribal

governments ``to provide meaningful and timely input in the development

of regulatory policies on matters that significantly or uniquely affect

their communities.''

Today's rule does not significantly or uniquely affect the

communities of Indian tribal governments. This action does not involve

or impose any requirements that affect Indian tribes. Accordingly, the

requirements of section 3(b) of Executive Order 13084 do not apply to

this rule.

VIII. Submission to Congress and the Comptroller General

The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the

Small

[[Page 425]]

Business Regulatory Enforcement Fairness Act of 1996, generally

provides that

before a rule may take effect, the Agency promulgating the rule must

submit a rule report, which includes a copy of the rule, to each House

of the Congress and the Comptroller General of the United States. EPA

will submit a report containing this rule and other required

information to the U.S. Senate, the U.S. House of Representatives and

the Comptroller General of the United States prior to publication of

the rule in the Federal Register. This rule is not a ``major rule'' as

defined by 5 U.S.C. 804(2).

List of Subjects in 40 CFR Part 180

Environmental protection, Administrative practice and procedure,

Agricultural commodities, Pesticides and pests, Reporting and

recordkeeping requirements.

Dated: December 22, 1998.

James Jones,

Director, Registration Division, Office of Pesticide Programs.

Therefore, 40 CFR chapter I is amended as follows:

PART 180-[AMENDED]

1. In Part 180:

a. The authority citation for part 180 continues to read as

follows:

Authority: 21 U.S.C. 346a and 371.

b. Section 180.292 is amended by designating the existing text as

paragraph (a), adding a paragraph heading and designating the text

following the paragraph heading as paragraph (a)(1); by adding and

reserving with headings paragraphs (b) and (c); and by adding paragraph

(d) to read as follows:

Sec. 180.292 Picloram; tolerances for residues.

(a) General. (1) * * *

(b) Section 18 emergency exemptions. [Reserved]

(c) Tolerances with regional registrations. [Reserved]

(d) Indirect or inadvertent residues. Tolerances are established

for indirect or indadvertent residues of the herbicide picloram, 4-

amino-3,5,6-trichloropicolinic acid, from application of its potassium

form on barley, fallow cropland, oats, and wheat in or on the following

raw agricultural commodities:

------------------------------------------------------------------------

Expiration/

Commodity Parts per Revocation

million Date

------------------------------------------------------------------------

Aspirated grain fractions..................... 4.0 12/31/00

Sorghum grain................................. 0.3 12/31/00

Sorghum grain, forage......................... 0.2 12/31/00

Sorghum grain, stover......................... 0.5 12/31/00

------------------------------------------------------------------------

PART 185-[AMENDED]

2. In Part 185:

a. The authority citation continues to read as follows:

Authority: 21 U.S.C. 346a and 348.

Sec. 185.4850--[Partially Redesignated and Removed]

b. The text of Sec. 185.4850, including the table, is redesignated

as paragraph (a)(2) of Sec. 180.292. The remainder of Sec. 185.4850 is

removed.

PART 186-[AMENDED]

3. In Part 186:

a. The authority citation continues to read as follows:

Authority: 21 U.S.C. 342, 348, and 371.

Sec. 186.4850 [Partially Redesignated and Removed]

b. The text of Sec. 186.4850, including the table, is redesignated

as paragraph (a)(3) of Sec. 180.292. The remainder of Sec. 186.4850 is

removed.

[FR Doc. 98-34830 Filed 12-31-98; 8:45 am]

BILLING CODE 6560-50-F