[Federal Register Volume 74, Number 110 (Wednesday, June 10, 2009)]
[Rules and Regulations]
[Pages 27447-27454]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-13476]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[EPA-HQ-OPP-2007-0395; FRL-8412-1]
Residues of Silver in Foods from Food Contact Surface Sanitizing
Solutions; Exemption from the Requirement of a Tolerance
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: This regulation amends the exemption from the requirement of a
tolerance for residues of silver (excludes silver salts) in or on all
foods when applied or used in public eating places, dairy processing
equipment, and food-processing equipment. ETO H2O, Inc., submitted a
petition to EPA under the Federal Food, Drug, and Cosmetic Act
requesting to establish concentration limits for silver in end-use
solutions eligible for tolerance exemption. The regulation being
established will exempt all foods from the requirement of a tolerance
for residues of silver resulting from contact with surfaces treated
with solutions in which the end-use concentration of silver is not to
exceed 50 parts per million (ppm).
DATES: This regulation is effective June 10, 2009. Objections and
requests for hearings must be received on or before August 10, 2009 and
must be filed in accordance with the itructions provided in 40 CFR part
178 (see also Unit I.C. of the SUPPLEMENTARY INFORMATION).
ADDRESSES: EPA has established a docket for this action under docket
identification (ID) number EPA-HQ-OPP-2007-0395. To access the
electronic docket, go to http://www.regulations.gov, select ``Advanced
Search,'' then ``Docket Search.'' Insert the docket ID number where
indicated and select the ``Submit'' button. Follow the instructions on
the regulations.gov web site to view the docket index or access
available documents. All documents in the docket are listed in the
docket index available in regulations.gov. Although listed in the
index, some information is not publicly available, e.g., Confidential
Business Information (CBI) or other information whose disclosure is
restricted by statute. Certain other material, such as copyrighted
material, is not placed on the Internet and will be publicly available
only in hard copy form. Publicly available docket materials are
available either in the electronic docket at http://www.regulations.gov, or, if only available in hard copy, at the Office
of Pesticide Programs (OPP) Regulatory Public Docket in Rm. S-4400, One
Potomac Yard (South Building), 2777 S. Crystal Drive Arlington, VA. The
hours of operation of this Docket Facility are from 8:30 a.m. to 4
p.m., Monday through Friday, excluding legal holidays. The Docket
telephone number is (703) 305-5805.
FOR FURTHER INFORMATION CONTACT: Marshall Swindell, Antimicrobials
Division (7510P), Office of Pesticide Programs, Environmental
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-
0001; telephone number: (703) 308-6341; e-mail address:
[email protected].
SUPPLEMENTARY INFORMATION:
I. General Information
A. Does this Action Apply to Me?
You may be potentially affected by this action if you are a dairy
cattle milk producer, food manufacturer, or beverage manufacturer.
Potentially affected entities may include, but are not limited to:
Food Manufacturing (NAICS code 311).
Beverage Manufacturing (NAICS code 3121).
Dairy Cattle Milk Production (NAICS code 11212).
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 this unit could also be
affected. The North American Industrial Classification System (NAICS)
codes have been provided to assist you and others in determining
whether this action might apply to certain entities. To determine
whether you or your business may be affected by this action, you should
carefully examine the applicability provisions in 40 CFR 180.940 (a)
Tolerance exemptions for active and inert ingredients for use in
antimicrobial formulations (Food-contact surface sanitizing solutions).
If you have any questions regarding the applicability of this action to
a particular entity, consult the person listed under FOR FURTHER
INFORMATION CONTACT.
B. How Can I Access Electronic Copies of this Document?
In addition to accessing an electronic copy of this Federal
Register document through the electronic docket at http://
[[Page 27448]]
www.regulations.gov, you may access this Federal Register document
electronically through the EPA Internet under the ``Federal Register''
listings at http://www.epa.gov/fedrgstr. You may also access a
frequently updated electronic version of 40 CFR part 180 through the
Government Printing Office's pilot e-CFR site at http://www.gpoaccess.gov/ecfr.
C. Can I File an Objection or Hearing Request?
Under section 408(g) of the FFDCA, as amended by the FQPA, any
person may file an objection to any aspect of this regulation and may
also request a hearing on those objections. The EPA procedural
regulations which govern the submission of objections and requests for
hearings appear in 40 CFR part 178. You must file your objection or
request a hearing on this regulation in accordance with the
instructions provided in 40 CFR part 178. To ensure proper receipt by
EPA, you must identify docket ID number EPA-HQ-OPP-2007-0395 in the
subject line on the first page of your submission. All requests must be
in writing, and must be mailed or delivered to the Hearing Clerk on or
before August 10, 2009.
In addition to filing an objection or hearing request with the
Hearing Clerk as described in 40 CFR part 178, please submit a copy of
the filing that does not contain any CBI for inclusion in the public
docket that is described in ADDRESSES. Information not marked
confidential pursuant to 40 CFR part 2 may be disclosed publicly by EPA
without prior notice. Submit your copies, identified by docket ID
number EPA-HQ-OPP-2007-0395, by one of the following methods:
Federal eRulemaking Portal: http://www.regulations.gov.
Follow the on-line instructions for submitting comments.
Mail: Office of Pesticide Programs (OPP) Regulatory Public
Docket (7502P), Environmental Protection Agency, 1200 Pennsylvania
Ave., NW.,Washington, DC 20460-0001.
Delivery: OPP Regulatory Public Docket (7502P),
Environmental Protection Agency, Rm. S-4400, One Potomac Yard (South
Building), 2777 S. Crystal Drive, Arlington, VA. Deliveries are only
accepted during the Docket's normal hours of operation (8:30 a.m. to 4
p.m., Monday through Friday, excluding legal holidays). Special
arrangements should be made for deliveries of boxed information. The
docket telephone number is (703) 305-5805.
II. Background and Statutory Findings
In the Federal Register of July 11, 2007 (72 FR 37779) (FRL-8136-
1), EPA issued a notice pursuant to section 408(d)(3) of the FFDCA, 21
U.S.C. 346a(d)(3), announcing the filing of an pesticide tolerance
petition (PP 7F7178) by ETO H20, Inc, 1725 Gillespie Way, El Cajon, CA
92020. The petition requested that 40 CFR 180.940(a) be amended by
establishing concentration limits for Silver in end-use solutions
eligible for the tolerance exemption in all foods from treatment of
food contact surfaces in public eating establishments, dairy processing
equipment, and food processing equipment and utensils not to exceed
silver at 50 ppm. The notice referenced a summary of the petition
prepared by ETO H20, Inc., 90 Boroline Rd Allendale, NJ 07401, the
registrant, which is available to the public in the docket at
www.regulations.gov, Docket ID Number EPA-HQ-OPP-2007-0395. There were
no comments received in response to the notice of filing.
In drafting the regulatory language for this exemption, EPA has
adopted more restrictive language than suggested in the petition to
ensure that the scope of the exemption does not exceed the form of
silver evaluated in the risk assessment supporting this action. As
revised, the tolerance expression would now read:
Silver ions resulting from the use of electrolytically-generated
silver ions stabilized in citric acid as silver dihydrogen citrate
(does not include metallic silver).
This revised tolerance expression excludes any other silver-containing
compounds whether they are other silver salts, complexes with inorganic
polymers such as zeolites, or metallic silver in any form or dimension
including nanoscale.
EPA understands that this petition was not intended to extend to
silver salts accordingly EPA has modified the regulatory language to
make this clear.
Section 408(c)(2)(A)(i) of the FFDCA allows EPA to establish an
exemption from the requirement for 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(c)(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. Pursuant to section 408(c)(2)(B), in
establishing or maintaining in effect an exemption from the requirement
of a tolerance, EPA must take into account the factors set forth in
section 408(b)(2)(C), which 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. First, EPA determines the
toxicity of pesticides. Second, EPA examines exposure to the pesticide
through food, drinking water, and through other exposures that occur as
a result of pesticide use in residential settings.
III. Toxicological Profile
A. Toxic Effects
Consistent with section 408(b)(2)(D) of FFDCA, EPA has reviewed the
available scientific data and other relevant information in support of
this action and considered its validity, completeness and reliability
and the relationship of this information 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 silver
are discussed in this unit.
Silver ions and preparations containing silver in an ionic state
have been used for over a century for medicinal and bactericidal
purposes. Because of its bactericidal properties, silver has been used
as a topical treatment for burns, as a treatment for venereal diseases,
as an ingredient in cosmetic formulations and in the sanitation of
swimming pools and hot tubs/spas. Silver has also been used in
dentistry (as amalgams and as an ingredient in mouth washes), in
acupuncture, jewelry making, and photography. Silver can be found in
electroplating as well as in paints and in water purification systems.
The toxicity of silver is well understood based on epidemiological
data from humans, toxicology data in animals, and documented
information on the metabolism of silver in mammalian species. Unlike
for other pesticides, EPA does not have a conventional check-list of
guideline laboratory animal studies to assess human risk from exposure
to silver. Based on the extensive past uses of
[[Page 27449]]
silver and EPA's knowledge and experience about those uses of the
compound, however, it is apparent that humans and laboratory animals do
not handle elevated doses of silver in the same manner. For this
reason, additional conventional laboratory animal toxicity studies
would not provide a better understanding of the effects of silver in
humans. Further, the Agency has determined that silver and several of
its salts (chloride, sulfate nitrate and acetate) can be reviewed
together because these silver salts react similarly in aqueous media
and the major active ion is the silver ion.
A human biomonitoring study conducted in 1935, as reported in the
Journal of the American Medical Association by L.E. Gaul and H.E.
Staud, has served as the basis for establishing regulatory limits for
silver in drinking water and in the diet. The results from this study
were further supported by the results from an inhalation study
conducted by Pillsbury and Hill in 1939, which established inhalation
limits for silver in humans. In both studies, the effect of concern was
argyria, a bluish discoloration of the skin. Argyria, while a permanent
condition, is a cosmetic condition. The function of the skin as an
organ is not compromised and the resulting discoloration is not
associated with systemic toxicity. In the 1935 study by Gaul and Staud,
silver was administered for medicinal purposes to 70 patients for
periods from 2 to 9 years. Of the 70 patients receiving medicinal
silver, 1/70 developed argyria after receiving an intravenous dose of 1
gram. This intravenous dose was converted to an oral dose of 0.014
milligram/kilogram/day (mg/kg/day) and was considered a lowest observed
effect level. Other patients did not develop argyria until doses five
times higher were administered. This study and an inhalation
biomonitoring study by Pillsbury, et al, clearly determined the
endpoint of concern for humans. Interestingly, the skin form of argyria
has not been reported in laboratory animals when doses that are
approximately 4 orders of magnitude higher (100 mg/kg) are
administered.
Further support for not requiring additional laboratory animal
studies for silver is provided from the results of the developmental
toxicity study in rats, conducted by the National Toxicology Program
(NTP). In a developmental study conducted in 2002, silver acetate was
administered by gavage on days 6 - 19 of gestation. No developmental
effects were reported at doses up to 100 mg/kg; maternal animals were
observed to have piloerection and rooting behavior at 30 mg/kg. The
observed effects in maternal animals would not be expected to occur in
humans and are frequently observed in animal studies. These
observations, when made in the absence of other clinical findings are
not considered adverse when establishing a ``no adverse effect level.''
More importantly, the results from this study did not demonstrate an
increased susceptibility of offspring, nor did it demonstrate systemic
toxicity. This study corroborates the use of the information provided
by the human biomonitoring study in determining dietary limits for
silver and further supports our decision to not rely on animal data
when assessing the health effects of silver in humans.
In addition to the information gleaned from the biomonitoring
studies and the developmental toxicity study, the reviews of the
literature by other EPA offices and national and inter-national
organizations provide supplemental support that argyria is the primary
effect in humans (e.g. EPA's Integrated Risk Management System, Agency
for Toxic Substances and Disease Registry, the World Health
Organization). Also the acute oral toxicity studies that have been
provided to support the registration of silver as an antimicrobial
agent establish LD50s between 2,000 and 5,000 mg/kg. These
values are above the limit dose for acute toxicity. For other silver
salts, such as silver cyanide, the LD50 values may be
significantly lower based on the molecules to which the silver ions are
attached. For the antimicrobial silver covered by this exemption, the
LD50 ranges are very high because the silver ions have very
low acute toxicity.
Finally, the pharmacokinetics of silver is understood and may
explain the low systemic toxicity potential of the compound.
Pharmacokinetics describes what the body does to a chemical when it is
introduced into the body including how it is metabolized, distributed,
and eliminated. When silver is introduced into the body by the oral or
dietary route, it is absorbed by the digestive system and then enters
the liver before it reaches the rest of the body (referred to as first-
pass metabolism). This first pass through the liver greatly reduces the
bioavailability of silver in that about 90% of the orally administered
dose is eliminated in the feces. The remaining 10% that is not
eliminated in the feces, reacts with proteins by binding to a specific
chemical group contained in the structure of the protein. By forming
silver-protein complexes through this binding action, the remaining
silver is removed from circulation. This remaining fraction accounts
for the background levels of silver that are found within the body. At
excessive doses, the pathways of elimination become saturated and
deposition of these complexes in the tissues is increased. The
formation of these complexes and deposition in the skin, mucous
membranes, and conjunctiva is the primary mechanism which results in
the development of argyria. Based on information from biomonitoring
studies, the lowest observed effect level for the formation of argyria
was 1 gram (total dose), which was converted to an oral dose of 0.014
mg/kg/day.
B. Regulatory Levels
Safe exposure levels for silver have been established by several
regulatory Agencies including the Food and Drug Administration,
Occupational Safety and Health Administration and other offices within
EPA based on the common endpoint argyria and using the same human
studies. Argyria is a blue-gray discoloration of the skin and is not
considered as being of toxicological concern. Argyria is cosmetically
disfiguring and permanent in nature; however, the occurrence of this
condition does not adversely affect organ function or threaten human
health. EPA believes that by regulating for argyria, it is protecting
the public from this permanent cosmetic effect as well as any potential
toxic manifestations of silver that may occur at much higher doses.
There is no animal condition that would mimic the dermatologic form of
argyria found in humans following exposure to silver by various routes.
This may be due in part to the protection imparted by the presence of
the fur or by the fact that laboratory animal species are not routinely
exposed to direct sunlight. Argyrosis, a form of argyria which involves
silver deposition in organs, has been documented. In laboratory
species, the effects of silver toxicity have been reported to involve
pathology to the liver (necrosis) and kidney (thickening of the
basement membranes of the glomeruli), and, at elevated levels, death.
The effect on which silver is regulated (argyria) occurs only after
chronic exposure. Both the Secondary Maximum Contamination Level (SMCL)
reported by the EPA's Office of Water and the oral reference dose (RfD)
reported under the EPA's Integrated Risk Information System (IRIS) were
determined based on the previously-mentioned human biomonitoring by
Gaul and Staud. For the SMCL, additional mathematical derivations were
applied to the oral equivalent dose
[[Page 27450]]
to the study Lowest Observed Adverse Effect Level (LOAEL) of 0.014 mg/
kg/day to obtain a 0.1 milligram/Liter (mg/L) dose level. The factors
applied for changing volume to mass account for the slight difference
in the values reported for the SMCL (0.003 mg/kg/day) and for the RfD
(0.005 mg/kg/day).
In deriving the chronic dietary regulatory level (RfD) and the
SMCL, a safety factor of 3X was applied based on the following
rationale as reported by the Office of Water and IRIS. First, the
critical effect was cosmetic and not of toxicological significance.
Second, the derivation of the LOAEL included the most sensitive
individual since other patients did not present with argyria unless
dose levels five times higher were administered. Finally, in the human
biomonitoring study, silver was administered to these individuals over
a period of time that is in excess of chronic exposure and that
approaches a level that would be considered a life time exposure
duration. Therefore, the dose that was administered was determined as
being one that would mimic lifetime exposure.
For the oral exposure route, the Agency is relying on the drinking
water Secondary Maximum Contaminant Level (SMCL) of 0.1 mg/L (0.003 mg/
kg/day) based on skin discoloration and graying of the whites of eyes
(argyria). The Agency applied an additional 3X uncertainty factor to
further address the lack of a NOAEL in the study on which this
assessment and all regulatory advisories are set. This additional 3X
factor was not imposed due to the lack or need for additional standard
animal toxicity testing. Thus, a composite database factor of 10X is
being applied to account for a lack of NOAEL in the Gaul and Staud
(1935) study. This composite factor of 10 should be sufficient for
providing protection from the non-toxic effects which may result from
chronic oral exposure to silver.
Chronic Dietary Reference Dose (RFD) = 0.003 mg/kg/day / 3 =
0.001 mg/kg/day
Alternatively, a roughly equivalent chronic RfD can be derived by
dividing the oral equivalent dose from the Gaul and Staud study (0.014
mg/kg/day) by a factor of 10X.
Following dermal exposure, silver ions tend to bind to the skin and
do not penetrate the skin to cause systemic effects. Rather, skin
discoloration is the only effect induced by silver exposure through the
dermal route. Although this discoloration appears to be the same effect
that results from oral and inhalation exposure, the mechanism by which
discoloration occurs following dermal exposure is not the same as the
mechanism leading to argyria following other routes of exposure.
Systemic uptake and distribution of silver following dermal exposure
does not occur, and the discoloration is the result of a localized
reaction. Again, the effect is not adverse and there is no reason to
believe that there would be an increase in susceptibility based on age
to the nontoxic discoloration. Susceptibility to this cosmetic event is
a function of dose and not age.
IV. Aggregate Exposures
To establish a tolerance, it must be shown ``that there is
reasonable certainty that no harm will result from aggregate exposure
to pesticide chemical residue, including all anticipated dietary
exposures and other exposures for which there are reliable
information.'' Aggregate exposure is the total exposure to a single
chemical (or its residues) that may occur from dietary (i.e., food and
drinking water), residential, and other non-occupational sources, and
from all known or plausible exposure routes (oral, dermal, and
inhalation).
Silver is commonly used for a variety of non-pesticidal industrial
uses, which include but are not limited to photography, cosmetics,
sunscreens, manufacture of inks and dyes, mirror production, and in
jewelry. These sources result in primary exposures being via the dermal
route. As previously mentioned, the consequence of silver exposures via
the dermal route is dermal argyria, which does not contribute to the
systemic argyria induced by oral and inhalation routes of exposures.
Silver has also been used in dentistry (as amalgams) and as an
ingredient in mouth washes. However, there is no documented evidence of
argyria developing from dental or mouth wash uses of silver despite its
widespread and frequent use in dentistry for over a century;
consequently, EPA concludes that the level of exposure from the dental
and mouthwash uses is negligible. Therefore, EPA did not aggregate the
exposures resulting from these various uses with pesticidal exposure
sources.
A. Dietary Exposure
Under the current proposal (PP 7F7178), silver will be used as a
sanitizer for food contact surfaces, resulting in dietary, drinking
water, and residential exposures. The use sites include but are not
limited to: Food service facilities, cafeterias, households, kitchens,
food preparation areas, food processing equipment and treated surfaces,
such as countertops, equipment, and appliances. The sanitizing solution
is applied to these various surfaces by spraying (trigger, spraying,
coarse pump), wiping with a cloth or sponge, mopping, or by full
immersion. As a result of these uses, residues are expected to transfer
to the food that comes into contact with these treated surfaces and
subsequently to be ingested by humans.
1. Food. The Agency assessed chronic dietary exposure from the use
of silver as a food contact sanitizer. The dietary assessment was only
completed for chronic routes because the regulatory effect that has
been identified is based on argyria, one that occurs only after chronic
exposure. For dietary exposures from this product being used on
countertops, the Incidental Dietary Residential Exposure Assessment
Model, IDREAMTM incorporates consumption data from USDA's
Continuing Surveys of Food Intakes by Individuals (CSFII), 1994-1996
and 1998. The 1994-1996, and 1998 data are based on the reported
consumption of more than 20,000 individuals over two non-consecutive
survey days. The maximum rate for silver is 50 ppm active ingredient.
The use on utensils, dishes and glass was assessed. Based on
conservative calculations, risk concerns were identified. At this time,
a label restriction will be required that prohibits the use on
utensils, dishes and glassware until a residue transfer study has been
conducted and accepted by the Agency.
Agricultural Premises-Dairy Facilities. Dietary exposures from
these general premise uses are expected to be much lower than the
dietary exposure resulting from the surface disinfectant and sanitizing
uses considered for this tolerance exemption: therefore, the
agricultural uses were not assessed separately. However, the
sanitization of food processing equipment permits product contact with
the interior of equipment. The milk-truck model (described in the FDA
document, ``Sanitizing Solutions: Chemistry Guidelines for Food
Additive Petitions'', pages 9-10)(FDA 2003) for these types of uses was
executed in order to estimate residues that could transfer from treated
surfaces to food. From this guidance, it was conservatively assumed
that a child will consume 320 grams of milk per day (90th percentile
value) and an adult will consume 125 grams milk per day (mean value).
Because EPA has utilized this maximized value for children along with a
child's body weight in this assessment, EPA has confidence that the
calculations are conservative and representative of any potential risks
to any population.
[[Page 27451]]
The Agency assumes that the sanitized tank truck which transports
the milk is a conservative estimate of residue that is available in
food processing facilities.
Milk undergoes no additional dilution prior to reaching the
consumer and it is also assumed that 100% of the residues available
post sanitation is transferred to the food.
Additionally, the dietary contribution as a result of food
processing equipment sanitization is so extremely small that it is
considered negligible and not included in the combined or aggregate
assessments.
2. Drinking water exposure. There are no outdoor or potable human
drinking water system uses for the use of silver proposed in pesticide
petition (PP) 7F7178. In addition, the uses identified as indoor hard
surface applications will result in minimal, if any, runoff of silver
into the surface water. The use of silver as a food contact surface
sanitizer will result in minimal, if any, runoff of silver into the
surface water. This use will result in an insignificant contribution to
drinking water exposures. In addition to sanitization, silver is
registered as an active ingredient in water filters. The bacteriostatic
water filters are impregnated with silver and may result in residues in
the drinking water supply. However, the levels of available residues
resulting from impregnated water filters are much less when in
comparison to the amount of residues that will be available for intake
when silver-containing liquid concentrates are used. As a result, any
drinking water exposures from the new use of silver are assumed to be
negligible. Additionally, any drinking water risks from impregnated
filters are assumed to be represented by the dietary risks resulting
from hard surface sanitization. The Agency believes that an assessment
of any potential risks resulting from silver in drinking water is not
warranted at this time.
Therefore, based on the uses of silver outlined in the pesticide
petition, the Agency believes that risks resulting from silver in
drinking water will be negligible and that an assessment is not
warranted at this time.
Table 1 provides a comprehensive summary of all of the use patterns
potentially resulting in dietary exposure that were considered for this
tolerance exemption.
Table 1.--Potential Use Scenarios
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Use Site Category Example Use Sites Scenarios
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Use Site Category I: Dairy farms, hog Application to
Agricultural Premises and farms, equine hard surface
Equipment farms (feeding dishes,
bottling
equipment,
floors, etc)
through coarse
spraying (low
pressure spray),
trigger pump
spray, wipe/
sponge, mop, and
immersion
------------------------------------------------------------------------
Use Site Categories II, III, and Food processing Application to
V: Food Handling, Commercial/ plants; hard surfaces
Institutional/Industrial, Hospitals; Public through coarse
Medical places (e.g., spraying (low
restaurants, pressure spray),
hotel/motel trigger pump
rooms); Medical/ spray, wipe/
Dental offices; sponge, mop, and
Nursing home; immersion.
Schools, Cruise Some examples of
ships, Dining surfaces include:
Halls. sinks, cutting
boards, counter
tops, kitchen
appliances,
breast pumps and
parts, baby
bottles, ice
chests, and
various others
that are
summarized on the
proposed label.
------------------------------------------------------------------------
Use Site Category IV: Homes, kitchens Application to
Residential and Public Access hard surfaces
Premises through coarse
spraying (low
pressure spray),
trigger pump
spray, wipe/
sponge, mop, and
immersion.
Examples of the
hard surfaces
include those
identified for
Use Site
Categories II,
III, and V.
------------------------------------------------------------------------
B. Other Non-Occupational Exposure
The residential exposure assessment considers all potential non-
occupational pesticide exposure, other than exposure due to residues in
food or in drinking water. Exposures may occur during and after
application on hard surfaces (e.g., floors). Each route of exposure
(incidental oral, dermal, inhalation) is considered where appropriate.
The risks to handlers are quantitatively assessed based on the nature
of the chemical. As previously stated, there are no adverse
toxicological consequences (systemic or irritation) resulting from
contact with silver other than skin discoloration. Residential
exposures are short-term (< 30 days) and intermediate-term (1 to 6
months) in nature. As supported in the toxicological discussion,
however, silver ion produces only cosmetic effects and only as a result
of chronic exposures. In addition, incidental ingestion (hand to mouth
behavior of a child on a treated floor) as well as dermal exposures
resulting from a child contacting a freshly cleaned floor are
considered short-term in duration.
Based on the fact that silver will exist in the ionic form, which
does not volatilize, any post-application inhalation exposures to
vapors are expected to be negligible. Essentially, there are no
toxicological consequences (systematic or irritation) resulting from
contact with silver other than discoloration. Table 2 outlines the use
patterns and routes of exposure that were considered for purposes of a
non dietary residential assessment. The Agency will request that label
claim be placed on the label to advise users that prolonged contact
with the product may cause skin discoloration.
Other non-pesticidal industrial uses of silver include, but are not
limited to, photography, cosmetics, sunscreens, manufacture of inks and
dyes, mirror production, and in jewelry. All these uses may result in
exposures via the dermal route, which over a chronic duration, may
cause skin discoloration. However, dermal exposures resulting from
these uses are not appropriate to include in this aggregate exposure
assessment. It has been previously concluded that systemic uptake and
distribution of silver does not occur via the dermal route. The
specific uses of silver that were considered for this aggregate
assessment include the cleansing of hard surfaces in various food
handling, institutional, medical and residential premises. Exposures
[[Page 27452]]
resulting from freshly cleaned surfaces are considered not to be of
concern to the Agency.
Table 2.--Representative Uses Associated with Residential Exposure
----------------------------------------------------------------------------------------------------------------
Representative Use Exposure Scenario Application Method Application Rate
----------------------------------------------------------------------------------------------------------------
Indoor Hard Surfaces ST Handler: Dermal and Liquid Pour 4.17 E-04 lb ai/gal
Inhalation; (0.005% ai x 8.34 lb/
gal)
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ST and IT Post-app\1\: Mopping 50 ppm silver ion
child incidental Wiping.................
ingestion and dermal Trigger Pump Spray.....
Low Pressure Spray
(coarse spray).
Immersion\2\...........
----------------------------------------------------------------------------------------------------------------
ST = Short-term exposure, IT = Intermediate-term exposure
\1\ IT post-application exposures to children were assessed because this product could be used in a commercial
day care facility.
\2\ The handler exposures associated with liquid pouring of this product are representative of those associated
with immersion (standing solution).
V. Cumulative Effects
Section 408(b)(2)(D)(v) of FFDCA 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.''
Unlike other pesticides for which EPA has followed a cumulative
risk approach based on a common mechanism of toxicity, EPA has not made
a common mechanism of toxicity finding between silver and any other
substances and silver does not appear to produce a toxic metabolite
produced by other substances. For the purposes of this tolerance
exemption action, therefore, EPA has not assumed that silver 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 policy statements released by EPA's Office of
Pesticide Programs concerning common mechanism on EPA's website at
http://www.epa.gov/pesticides/cumulative.
VI. Safety Factor for Infants and Children-
1. In general. Section 408(b)(2)(C) of FFDCA provides that EPA
shall apply an additional tenfold (10X) 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 database on toxicity
and exposure unless EPA determines based on reliable data that a
different margin of safety will be safe for infants and children. This
additional margin of safety is commonly referred to as the FQPA safety
factor (SF). In applying this provision, EPA either retains the default
value of 10X, or uses a different additional safety factor when
reliable data available to EPA support the choice of a different
factor.
2. Prenatal and postnatal sensitivity. There is extensive data and
analysis on silver's toxicity in the historical data/literature and the
regulatory advisories established by other Federal Agencies, which do
not indicate an increased susceptibility of children to the toxic
effects of silver. A NTP developmental toxicity study concluded that
the NOAEL recorded for developmental toxicity in rats receiving gavage
doses of silver acetate, was greater than 100 mg/kg when the test
material was administered on gestation days 6 through 19. No increase
in susceptibility was apparent in this study. Furthermore, silver
nitrate has been used for decades to treat neonatal conjunctivitis.
Finally, there is no reason to believe that the effects that are
observed following the administration of silver would warrant
additional safety factors for children. The skin is the target organ
and the deposition of silver should not be age dependent. Moreover,
because EPA believes that the Gaul and Staud study adequately
characterizes variability in human sensitivity, EPA is not applying an
intra-species uncertainty factor in deriving the chronic RfD for
silver.
3. Conclusion. Although EPA is not applying an inter-species
uncertainty factor (because of reliance on human data) or an intra-
species uncertainty factor (because human sensitivity has been
adequately characterized), EPA is retaining the 10X FQPA safety factor
in assessing oral risk to address the fact that the dose used to
determine the chronic RfD showed effects from silver (argyria). In
making this determination, EPA took into account that argyria is not a
toxic effect, there is no evidence of increased sensitivity in the
young, and the exposure assessment for silver is very conservative.
For dermal exposure, silver ions tend to bind to the skin and do
not penetrate the skin to cause systemic effects. Thus, systemic uptake
and distribution of silver does not occur following dermal exposure.
Skin discoloration is the only effect due to a localized reaction.
Based on the above findings, a FQPA safety factor of 1X should be
applied to the chronic dietary RfD for assessing dermal exposure. An
additional safety factor is not required for the protection of infants
and children because there would not be an increase in susceptibility
to this cosmetic nontoxic effect. This cosmetic event is a function of
the dermal contact dose not age. Furthermore, the approach taken to
assess risk from dermal exposure is very conservative in that the
Agency has based its dermal risk assessment on the systemic oral dose
that was used to establish the oral/dietary risks.
VII. Aggregate Risks and Determination of Safety
Safety is assessed for acute and chronic risks by comparing
aggregate exposure to the pesticide to the acute population adjusted
dose (aPAD) and chronic population adjusted dose (cPAD). The aPAD and
cPAD are calculated by dividing the LOC by all applicable uncertainty/
safety factors. For linear cancer risks, EPA calculates the probability
of additional cancer cases given aggregate exposure. Short-term,
intermediate-term, and long-term risks are evaluated by comparing
aggregate exposure to the LOC to ensure that the margin of exposure
(MOE) called for by the product of all applicable uncertainty/safety
factors is not exceeded.
For a tolerance to be found to be safe, it must be shown ``that
there is reasonable certainty that no harm will
[[Page 27453]]
result from aggregate exposure to pesticide chemical residue, including
all anticipated dietary exposures and other exposures for which there
are reliable information.'' Aggregate exposure is the total exposure to
a single chemical (or its residues) that may occur from dietary (i.e.,
food and drinking water), residential, and other non-occupational
sources, and from all known or plausible exposure routes (oral, dermal,
and inhalation).
1. Dietary risk. A summary of antimicrobial indirect food use
acute/chronic risk estimates from exposure to treated countertops are
shown below in Table 3. As explained above, EPA believes that exposures
resulting from silver in drinking water will be negligible. For adults,
chronic dietary exposure risk estimates are approximately 20% of the
chronic PAD. For children, the most highly exposed population subgroup,
the chronic dietary risk estimates are 62% of the chronic PAD.
Therefore, chronic dietary exposure estimates are below the Agency's
level of concern for all population subgroups.
Table 3.--Calculated Exposure and risk Resulting from Silver
Sanitization of Countertops
------------------------------------------------------------------------
Chronic
-----------------------
Exposure Group DDD(mg/kg/
d) \a\ %cPAD \b\
------------------------------------------------------------------------
Adult males (13+) 0.00022 22
------------------------------------------------------------------------
Adult females (13-69) 0.00021 21
------------------------------------------------------------------------
Children (1-2) 0.00062 62
------------------------------------------------------------------------
\a\ DDD (mg/kg/day) was provided from the IDREAM model.
\b\ % PAD = exposure (total dietary exposure)/ PAD) x 100. The cPAD is
equivalent to the chronic oral RfD value of 0.001mg/kg/day.
2. Aggregate non-cancer risk. Aggregate exposure takes into account
residential exposure plus chronic exposure to food and water
(considered to be a background exposure level). Because any oral
residential exposures will be short-term in nature, the chronic risk is
equal to the estimate for dietary risk.
3. Aggregate cancer risk for U.S. population. Available animal and
human experience through occupational and medicinal exposure scenarios
have not indicated a carcinogenic potential for silver. Therefore,
silver is not expected to be carcinogenic to humans particularly in
light of its low systemic toxicity potential and our understanding of
its metabolism.
4. Determination of safety. Based on these risk assessments, EPA
concludes that there is reasonable certainty that no harm will result
to the general population or to infants and children from aggregate
exposure to silver residues.
VIII. Other Considerations
A. Analytical Enforcement Methodology
An analytical method for food is not needed. Food contact
sanitizers are typically regulated by state health departments to
ensure that the food industry is using these products in compliance
with the regulations in 40 CFR 180.940. The end use solution that is
applied to the food contact surface is analyzed rather than food items
that may come into contact with the treated surface. An analytical
method is available to analyze the use dilution that is applied to food
contact surfaces. The following methods of analysis are used to analyze
the use dilution of silver being applied to food contact surfaces: Gas
chromatography (GC), infrared (IR), ultraviolet absorption (UV),
nuclear magnetic resonance (NMR).
B. International Residue Limits
There is not a Codex Maximum Residue Level established for silver.
IX. Statutory and Executive Order Reviews
This final rule establishes a tolerance under section 408(d) of
FFDCA 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). Because this rule has been
exempted from review under Executive Order 12866, this rule is not
subject to Executive Order 13211, Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use (66 FR 28355,
May 22, 2001) or Executive Order 13045, entitled Protection of Children
from Environmental Health Risks and Safety Risks (62 FR 19885, April
23, 1997). 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., nor does it require any special considerations
under Executive Order 12898, entitled Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations (59 FR 7629, February 16, 1994).
Since tolerances and exemptions that are established on the basis
of a petition under section 408(d) of FFDCA, 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.
This final rule directly regulates growers, food processors, food
handlers and food retailers, not States or tribes, nor does this action
alter the relationships or distribution of power and responsibilities
established by Congress in the preemption provisions of section
408(n)(4) of FFDCA. As such, the Agency has determined that this action
will not have a substantial direct effect on States or tribal
governments, on the relationship between the national government and
the States or tribal governments, or on the distribution of power and
responsibilities among the various levels of government or between the
Federal Government and Indian tribes. Thus, the Agency has determined
that Executive Order 13132, entitled Federalism (64 FR 43255, August
10, 1999) and Executive Order 13175, entitled Consultation and
Coordination with Indian Tribal Governments (65 FR 67249, November 6,
2000) do not apply to this rule. In addition, This rule does not impose
any enforceable duty or contain any unfunded mandate as described under
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA) (Public Law
104-4).
This action does not involve any technical standards that would
require Agency consideration of voluntary consensus standards pursuant
to section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (NTTAA), Public Law 104-113, section 12(d) (15 U.S.C. 272
note).
X. Congressional Review Act
The Congressional Review Act, 5 U.S.C. 801 et seq., generally
provides that before a rule may take effect, the agency promulgating
the rule must submit a rule report to each House of the Congress and to
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 this final rule in the Federal
Register. This final 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,
Food contact sanitizers, Silver, Food additives, Pesticides and pests,
[[Page 27454]]
Reporting and recordkeeping requirements.
Dated: May 26, 2009.
Joan Harrigan-Farrelly,
Director, Antimicrobials Division, Office of Pesticide Programs.
0
Therefore, 40 CFR chapter I is amended as follows:
PART 180--[AMENDED]
0
1. The authority citation for part 180 continues to read as follows:
Authority: 21 U.S.C. 321(q), 346a and 371.
0
2. Section 180.940 is amended by adding alphabetically the following
entry to the table in paragraph (a):
Sec. 180.940 Tolerance exemptions for active and inert ingredients
for use in antimicrobial formulations (Food-contact surface sanitizing
solutions).
* * * * *
(a) * * *
------------------------------------------------------------------------
Pesticide Chemical CAS Reg. No. Limits
------------------------------------------------------------------------
* * * * * * *
Silver ions resulting from the 14701-21-4 When ready for
use of electrolytically- use, the end-use
generated silver ions concentration of
stabilized in citric acid as silver ions is
silver dihydrogen citrate (does not to exceed 50
not include metallic silver) ppm of active
silver.
* * * * * * *
------------------------------------------------------------------------
* * * * *
[FR Doc. E9-13476 Filed 6-9-09; 8:45 am]
BILLING CODE 6560-50-S