		

DIDECYL DIMETHYL AMMONIUM CHLORIDE

DIETARY RISK ASSESSMENT 

(OPPTS 248.5000)

 Prepared by:

First Draft Versar, Inc.

6850 Versar Center

Springfield, VA 22151

For US EPA/OPP/AD

Amended  and Finalized by:

US EPA/AD/RMBII

MEMORANDUM								Jan 20, 2006

Subject: 	Dietary Risk  Assessment for  Didecyl Dimethyl Ammonium
Chloride (DDAC) for Reregistration Eligibility Decision (RED)

From:			A. Najm Shamim, Ph.D, Chemist and Risk Assessor for DDAC

			Regulatory Management Branch II

			Antimicrobials Division (7510P)

To:			Tracy Lantz, CRM for DDAC RED

			Regulatory Management Branch I

			Antimicrobials Division (7510P)

Thru:			Diane Isbell, Team Leader

			Regulatory Management Branch II

			Antimicrobials Division (7510P)

					And

			Mark Hartman, Chief

			Regulatory Management Branch II

			Antimicrobials Division (7510C)

Executive Summary

Didecyl Dimethyl Ammonium Chloride (DDAC) can be used as a disinfectant
or sanitizer on counter tops, utensils, appliances, tables,
refrigerators, on animal premises and/or farms, and in mushroom
premises.  The use of antimicrobials on food or feed contact surfaces,
agricultural commodities, in animal premises and poultry premises
including hatcheries and application to food-grade eggs may result in
pesticide residues in human food.  Residues from treated surfaces, such
as utensils, countertops, equipment, and appliances can migrate to food
coming into contact with the treated and rinsed surfaces and can be
ingested by humans.

  

	In the absence of data for residues of  DDAC on treated food contact
surfaces, the Agency estimated residue levels that may occur in food
from the application rates on food contact surfaces.  Dietary exposures
from general agricultural premise use, poultry hatcheries, mushroom
houses and hydroponic uses are expected to be much lower than the
dietary exposures resulting from the surface disinfectant and sanitizing
uses; therefore, these uses were not assessed.

	To estimate the Estimated Daily Intake (EDI) to treated food contact
surfaces and food utensils, an FDA (FDA, 2003) model was used in lieu of
residue data.  The maximum application rate for DDAC in food handling
establishments from the various labeled ready-to-use products is 0.0043 
a..i. pounds per gallon of treatment solution.  The EDI calculations
presented in this assessment assume that food can contact 2,000 cm2 or
4,000 cm2 (50% and 100% of the FDA worst case scenario) of treated
surfaces, and that 10% of the pesticide migrate to food, based on the
Agency Residential SOPs. The use of the 10% transfer rate, instead of
the use of a 100% transfer rate that is used in the FDA Sanitizer
Solution Guidelines, requires the submission of confirmatory data to
establish the reliability of the use of the10% transfer rate.  These
daily estimates were conservatively used to assess both acute and
chronic dietary risks.  None of the calculated % aPad or % cPad values
exceeded 100%.

The maximum application rate for DDAC for bottling/packing of food is
0.0020 lbs a.i per gallons of treatment solution.  EDI values were
calculated for these scenarios.  Exposure was assumed to occur through
the ingestion of three food products that might be packaged with treated
material: milk, egg products, and beverages (alcoholic and
non-alcoholic).  None of the calculated % aPad or % cPad values exceeded
100%.   

Dietary Toxicity

The acute or chronic Population Adjusted Dose (aPAD or cPAD) is
presented in Table 1.   The aPAD and cPAD were both 0.1 mg/kg/day
(Versar, 2006).    

Table 1: DDAC Dietary Toxicity

Exposure

Scenario	Dose Used in Risk Assessment

(mg/kg/day)	Target MOE/UF,

Special FQPA SF

for Risk Assessment	Study and Toxicological Effects

Acute Dietary

(Females 13-50)	NOAEL (developmental) = 10 mg/kg/day	FQPA SF = 1

UF = 100 (10x inter-species extrapolation, 10x intra-species variation)
Prenatal Developmental Toxicity - Rat

MRID 41886701

LOAEL = 20 mg/kg/day based on increased incidence of skeletal
variations.

	aPAD = 0.1 mg/kg/day (for Females age 13-50)

Chronic Dietary

(general population)	NOAEL = 10

mg/kg/day	FQPA SF = 1

UF = 100 (10x inter-species extrapolation, 10x intra-species variation
Chronic Toxicity Study - Dog

MRID 41970401

LOAEL = 20 mg/kg/day based on increased incidence  of clinical sign in
males and females and  decreased total cholesterol levels in females.

	cPAD = 0.1 mg/kg/day

a.	cPAD or aPAD= the RfD/FQPA SF (acute RFD and FQPA for aPAD and
chronic RFD and FQPA SF for the cPAD)

Use Information

Seven DDAC products were identified that have uses that could lead to
incidental ingestion.  These uses/products are presented in Table 2. 
The labels with the maximum-listed application rate for each use are
presented in bold.   

Table 2: Use Site Categories and Application Rates

Use Site	Product Label (Registration No.)	Method of Application	Range of
Application Rates (lb a.i./gal)

Egg handling equipment: Incubator and hatchers 	10324-80 

1839-173 

10324-81 

10324-108 

10324-117 	Fogger	0.0223-0.0563

Hatchery: hatchery, settlers, trays, racks, carts, sexing tables,
delivery trucks, and other hard surfaces	10324-80

1839-173

10324-81

10324-108

10324-117	Mop, cloth, sponge, hand pump trigger sprayer, or low pressure
coarse sprayer	0.0014-0.0043

Egg handling rooms: hatcheries	10324-80

1839-173

10324-81

10324-108

10324-117

10324-134	Fogger	0.0007-0.2193

Egg packing plants: food grade eggs	1839-173

10324-81

10324-117	Immersion, low pressure coarse sprayer, or swabs	0.0007-0.0020

Food handling establishments: utensils and equipment 	1839-173

10324-81

10324-117

	Immersion, low pressure coarse sprayer, or swabs	0.0020

Food handling establishments: countertops, appliances, and tables
10324-81

10324-108

10324-117

1839-173

10324-80	Mop, cloth, sponge, hand pump trigger sprayer, or low pressure
coarse sprayer	0.0023-0.0043

Food processing plants: (poultry, meat, fish, tobacco etc.): hard
surfaces and

equipment, including utensils, dishes, silverware, glasses, sink tops,
countertops, refrigerated storage, display equipment, storage shelves,
appliances, conveyers (fruits/vegetables or meat/poultry) etc.	10324-81

10324-108

10324-117

10324-80

1839-173

10324-134

	Mop, cloth, sponge, hand pump trigger sprayer, or low pressure coarse
sprayer, feeding equipment 	0.0020-0.0043

Bottling/packaging sanitizer: food contact surface sanitizer (i.e.
bottle sanitizing, beer storage tanks, and beverage dispensing unit)
1839-173

10324-81

10324-117	Towel, circulation, liquid pour - mechanical or automated
systems	0.0020

Mushroom facilities	10324-80

10324-81

10324-108

10324-117	Mop, cloth, sponge, hand trigger sprayer, or coarse spray
device	0.0023-0.0086

Farm (poultry, swine, dairy) premises, feed storage areas, and cows
(uters, flanks, and teats)	1839-173

10324-81

10324-80

10324-108

10324-117	Towel, mop, cloth, sponge, hand trigger sprayer, or coarse
spray device	0.0007-0.0043



3. Quantitative Dietary assessment 

3.1 Egg handling equipment, Agricultural Premise Use, and Poultry
Hatcheries 

	DDAC products may be used on egg shells in both poultry hatcheries and
food grade-eggs.   Although it is possible that some of
sanitizer/disinfectant chemicals may penetrate the egg shells, at this
time the Agency believes that the amount of the chemical transferred
into food is likely to be minimal.  Dietary exposures from general
agricultural premise use, poultry hatcheries, mushroom houses and
hydroponic uses are expected to be much lower than the dietary exposures
resulting from the surface disinfectant and sanitizing uses; therefore,
these uses were not assessed.

3.2 Food Handling Establishments and Food Processing Plants

To calculate the EDI associated with use of a DDAC product as a food
utensil sanitizer in food handling establishments, a number of
assumptions have been made based on the FDA guidelines (FDA, 2003). 

When a surface is treated with a disinfectant, a quantity of the
disinfectant remains on the surface (Residual Solution).  The FDA
recommended worst-case concentration for this quantity is 1 mg of
solution per square centimeter of treated surface area.  In the absence
of any other data, this value has been used.

The FDA suggests that, as a worst-case scenario, all food that an
individual consumes will come into contact with 4,000 cm2 of sanitized
non-porous food-contact surfaces.  This contact area represents all the
surface area from silverware, china, and glass used by a person who
regularly eats three meals per day at an institutional or public
facility.

It is assumed that 10% of the active material present on food contact
surfaces will migrate.  

The body weights used for this assessment are: adult man = 70 kg; adult
woman = 60 kg, and 3-yr old toddler = 15 kg (USEPA, 1997).  

For use of a DDAC product as a counter top disinfectant in food handling
establishments, the same assumptions as listed above were used, and one
additional assumption was added:

The amount of counter top surface area that comes in contact with food
should be much smaller than the amount of food utensil area that comes
into contact with food.  As a conservative estimate, it is assumed that
50% of the FDA value, or 2,000 cm2 of treated counter top surface area,
comes into contact with an individual’s food per day.   

The above assumptions and the following equations were used to calculate
EDI and Dietary Daily Dose (DDD):

EDI (mg/p/day) = AR x RS x SA x F x 10-6	 			(1)

DDD (mg/kg/day) = AR x RS x SA x F x 10-6/BW 			(2)

Where: 

AR 	=  	Application rate (ppm)

RS	=	Residual solution (mg/cm2)

SA	=	Surface area of the treated surface which comes into contact with
food (cm2)

F 	= 	Fraction of the pesticide transferred or migrated to food
(unitless)

BW 	= 	Body weight (kg)

The input parameters listed in Table 4 and equations 1 and 2 were used
to calculate the output parameters listed in Table 5.  

Table 4: Input Parameters for Food Handling Establishments and Food
Processing Plants Hard Surface Sanitizer

Parameter	Value	

Rationale

	Food Utensil	Countertop

	Residual Solution on Surface	1 mg/cm2	FDA worst-case assumption

Area of Treated Surface	4,000 cm2	2,000 cm2	100% and 50% of FDA
worst-case assumption for food utensils

DDAC concentration in diluted Solutiona	0.0020 lb a.i./gal    or        
                240 ppm        	0.0043 lb a.i./gal   or                 
      515 ppm                   	Diluted Solution concentration, based
on maximum concentration.

Fraction Transferred	10%	EPA Assumption

Body Weight (kg) 

Adult man =

Adult woman =

Child =	

70

60

      15	EPA, 1997

a.	Maximum application rates for food utensils were from product labels
1839-173, 10324-81, and 10324-117 for Utensils and product label
10324-80 for counter-tops.   

Table 5: Calculated EDIs, aPAD, and cPAD for Utensils and Countertops

Exposure Group	Utensils	Countertops	Aggregate

	EDI (mg/p/d)	DDD (mg/kg/d)	% PADa	EDI (mg/p/d)	DDD (mg/kg/d)	% PADa	EDI
(mg/p/d)	DDD (mg/kg/d)	% PADa (mg/kg/d)

Adult males	0.0959	0.00137	1.37	0.103	0.00147	1.47	0.199	0.00284	2.84

Adult females	0.0959	0.00160	1.60	0.103	0.00172	1.72	0.199	0.00332	3.32

Children	0.0959	0.00639	6.39	0.103	0.00687	6.87	0.199	0.0133	13.3

a.	% PAD = exposure (DDD) /(aPAD or cPAD) x 100. The acute and chronic
population average dose is the same; therefore the % PADs are the same. 
	

For DDAC treatments of food processing plants, the application rates are
similar to food handling establishments presented above, and hence the
exposure, EDIs, DDDs, and % aPAD and cPADs are also similar. 

Food Bottling/Packaging 

DDAC may also be used as a sanitizer or disinfectant in processing
equipments, utensils in dairies, breweries, canning operations, meat and
vegetable processing plants.  In assessing this use, the following
assumptions were made, based on USEPA (2005): 

The DDAC concentration in the treatment solution is 0.0020 lb a.i./gal,
or 240 ppm (0.00024 wt/wt)

When a surface is treated with a disinfectant, a quantity of the
disinfectant remains on the surface (Residual Solution).  The FDA
recommended worst-case concentration for this quantity is 1 mg of
solution per square centimeter of treated surface area.  In the absence
of any other data, this value has been used.

For the fraction of pesticide that migrates from the residue to the food
(F in equations 3 and 4), a transfer rate of 100% was used instead of
10% because the food is in contact with the treated surfaces for
potentially very long periods of time.  

For a given person, the grams of food per surface area of container were
as follows (g/cm2):

Milk (dairy): 				6.6 

Egg/mayonnaise:			64.0

Beer, beverages:			150

The daily intake rates for an adult (g/person/day) were as follows:

Beverages, alcoholic/beer:		182  

Beverages, non-alcoholic:		240  

Egg products:				9.0

Milk:					124

A child will consume a smaller quantity of calories in a given day.  To
account for differences between intake values among children and adults
a calorie intake modification factor of 0.64 was applied to the EDI for
a child.  Recommended energy allowances measured in kilocalories per
body weight for different age groups and genders were taken from the
National Research Counsil’s Recommended Energy Allowances.  The values
are based on the resting energy expenditure and the energy required for
light to moderate levels of activity, as determined by the World Health
Organization (USAID, 2005).  The calculation of the factor is presented
in Table 6 below.  

The above assumptions and the following equations were used to calculate
EDI and Dietary Daily Dose (DDD):

EDI (mg/p/day) = AR x RS x DIR x MSA-1 x F x 10-6 x CMF	 		(3)

DDD (mg/kg/day) = AR x RS x DIR x MSA-1 x F x 10-6 x CMF/BW 		(4)

Where: 

AR 	=  	Application rate (ppm)

RS	=	Residual solution (mg/cm2)

MSA	=	Mass-surface area ratio (the treated surface that comes into
contact with food) (g/cm2)

DIR	=	Daily intake rate of food in a given day (g/p/day)

F 	= 	Fraction of the pesticide transferred or migrated to food
(unitless)

BW 	= 	Body weight (kg)

CMF	=	Calorie intake modification factor (100% adults; 64.4% Children)

Assumptions 1-4, inputs from Table 6 and 7, and equations 3 and 4 were
used to calculate the dietary rates and doses presented in Table 8.  

Table 6: Toddler (3-yr old) and Adult Calorie Intake Comparison

Group (Age)	Body Weight (kg)	Kilocalories per kga	Kilocaloriesb

Child (1-3)	15.0	102	1,530

Female (25-50)	60.0	36.0	2,160

Male (25-50)	70.0	37.0	2,590

Output

Child Modification Factor (CMF)c 	0.644

USAID, 2005

Kilocalories = Kcal/Kg x BW 

CMF = Kcal-child ÷ [(Kcal-female + Kcal-male)/2]

Table 7: Input Parameters for Food Bottling/Packaging Hard Surface
Sanitizer

Parameter	Input	Rational

Food mass/surface (g/cm2)                                               
                                                                        
             	Milk 	6.6	USEPA, 2005

 

	Egg/Mayonnaise	64



Beer, beverages	150

	Intake rates (g/p/d)                                                   
                                                                        
         	Milk 	124	USEPA, 2005

 

 

 

	Egg products	9



Beer, beverages	182



Beverages/ nonalcoholic	240

	Fraction Transferred 	100%	FDA worst case assumption

Residual Solution on Surface	1 mg/cm2	FDA worst case Assumption

Quantity DDAC 	0.0020 lb ai  or 240 ppm	Diluted solution concentration,
based on maximum concentration.

Body Weight (kg)

Adult man =

Adult woman =

Child =	 

70

60

15	 

USEPA, 1997

 

 

a.	Maximum application rates for food utensils were from product labels
1839-173, 10324-81, and 10324-117.   

Table 8:  Calculated EDIs, aPAD, and cPAD for Representative Dairy and
Beverage Consumption

Food Type	Exposure Group	EDI (mg/p/d)	DDD (mg/kg/d)	% PAD

Milk 	Adult Male	0.00451	6.44x10-5	0.0644

	Adult Female

7.52x10-5	0.0752

	Childa	0.00290	1.94x10-4	0.194

Egg product	Adult Male	0.000034	4.8x10-7	4.8x10-4

	Adult Female

5.6x10-7	5.6x10-4

	Child a	0.000022	1.44x10-6	1.48x10-3

Beverages, non-alcoholic	Adult Male	0.00038	3.29x10-4	0.0055

	Adult Female

5.6x10-6	0.384

	Childa	0.00056	1.60x10-5	0.0064

Beverages, alcoholic, beer	Adult Male	2.91x10-4	4.16x10-6	0.00416

	Adult Female

4.85x10-6	0.00485

a.	Child EDI values are multiplied by a modification factor of 0.64	4.0
References

FDA. 2003.  “Sanitizing Solutions:	Chemistry Guidelines for Food
Additive Petitions.” 

  GOTOBUTTON BM_1_ http://www.cfsan.fda.gov/~dms/opa-cg3a.html.   Last
accessed June 9, 2003.

USAID. 2005. “ANNEX III: Recommended Energy Allowance Tables.”
November 2005.   HYPERLINK
"http://www.usaid.gov/our_work/humanitarian_assistance/ffp/crg/annex-3.h
tm" 
http://www.usaid.gov/our_work/humanitarian_assistance/ffp/crg/annex-3.ht
m .  Last viewed January 23, 2006. 

USEPA.  1997.  Exposure Factors Handbook. Volume I-II.  Office of
Research and Development.  Washington, D.C.  EPA/600/P-95/002Fa. August
1997.

USEPA. 2005. Dietary Assessment of Chlorine Dioxide, Sodium Chlorite
From Their Use As Indirect Food Contact Sanitizers/Disinfectants (Hard
Surface Sanitizers). Memorandum from Najm Shamim, USEPA to Melba Morrow
and Jennifer Slotnick, USEPA. Dates August 15, 2005.  

Versar. 2006. DDAC Occupational and Residential Exposure Assessment.
Memorandum from Adria Diaz/Karie Riley/Kelly McAloon, Versar, Inc., to
Laura Bailey, USEPA dated January 20, 2006.   

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