MEMORANDUM							June 27, 2007

SUBJECT:	Dietary Risk Assessment (Indirect Food Contact) from Indoor
Uses of Bromonitrostyrene (BNS)

From:	A. Najm Shamim, PhD., Chemist

	Regulatory Management Branch II

	Antimicrobials Division (7510P)

To:	Jenny Tao, Risk Assessor for BNS

	Risk Assessment and Science Support Branch

	Antimicrobials Division (7510P)

			And

	ShaRon Carlisle, CRM for BNS RED Process

	Regulatory Management Branch II

	Antimicrobials Division (7510P)

Thru:	Diane Isbell, Acting Team leader,

	Regulatory Management Branch II

	Antimicrobials Division (7510P)

		And				

		

	

	Mark Hartman, Chief

	Regulatory Management Branch II

	Antimicrobials Division (7510P)

DP Barcode:	

			EXECUTIVE SUMMARY

	As required by the RED process, Antimicrobials Division has assessed
the risks involved in the indoor use of Bromonitrostyrene for the
indirect food contact scenarios.

There are no risk concerns from the use of BNS on: paper/paperboard,
paper coatings and adhesives. The aPADs and cPADs for these uses fall
well below Agency’s level of concerns.

DIETARY RISK ASSESSMENT OF  BNS FROM INDRIECT FOOD CONTACT SURFACES

Background:

AD’s label search has shown that Bromonitrostyrene(BNS) is used in the
following table use patterns  trigger indirect food contact scenarios
and a dietary risk assessment becomes necessary.  

					Table I

Product Name/EPA REG#	Use Scenario	Application Rate

Canguard 777/464-686	Paper mill/pulp	0.3 lbs./ton paper of 25%
formulation

Canguard 777/464-686	Paperboard	8 lbs/ton  of 25% formulation

Canguard 777/464-686	Paper coatings	2.0 lbs/ 1000 lbs of product

Canguard 777/464-686	Adhesives/sealants	2.0  lbs/1000 lbs of product

Canguard 777/464-686	Printing inks	2.0 lbs/1000 lbs of product

Canguard 777/464-686	Coatings/ mineral slurries	2.0 lbs/1000 lbs of
product



	RESIDUE CHEMISTRY

	All uses of BNS are nonagricultural, and no residue chemistry data
based on Agency’s Residue Chemistry Guidelines (OPPTS GLN 860.xxx)
were submitted nor the Agency asked for it.  Therefore, The Agency has
used available methods to estimate BNS residues on food due to migration
of this chemical, when this chemical comes in to contact with
food-contact paper. In this regard Food and Drug Administration has
developed guidelines to estimate residues in food due to migration into
food.

Detailed Discussion:

FDA METHODOLOGY FOR DETERMINING ESTIMATED DAILY INTAKE (EDI) OF A
PESTICIDE USE IN A FOOD CONTACT PAPER

1)	Paper/ Paperboard Use

	FDA1,2, Method makes a number of assumptions for calculating migration
of active (in this case BIT) from food contact surfaces (paper): 1. Food
contact surface (paper) can be a one time use/day or a repeat use
material; 2. Consumption factor (CF) or fraction of daily food which
comes in to contact with the packaging surface (paper). CF represents
the actual weight of food that comes into contact with the paper to the
weight of all food packaged with paper; 3. The CF varies from one type
of packaging (type of paper) to the other (type of paper). FDA
methodology of migration of active assumes a 100% migration to the food
commodities(This represents a worst case scenario).

Note:	According to the label (Reg#: 777/464-686)  8 lbs of BNS is used
for 2000 lbs of product (in this case paper, paperboards). Since 25% of
the active is used,  2 lbs of BNS will be used for 2000 lbs of paper
products.

 Assume 2000 lbs paper ~ 1 ton paper. 

2 lb active /2000 lb of finished paper = 908 ppm active  mg/kg of 
finished paper

 But the paper slurry is 1% ; 908 mg x 01 = 9.08  active mg/kg of
finished paper = ~ 10 ppm of active in the paper slurry= Application
Rate

Application rate x % water / % pulp = 10 ppm = 5µg/g pulp slurry x
0.67g water/0.33.g pulp = 20 µ g of active/g pulp.

Consumption Factor (CF) = 0.10

	Likely amount of BNS  migrating into food:

 ⁄ mass of pulp x 0.92 g pulp∕ g of paper x 0.05 g ∕ in2 x 1 in2
∕ 10 g food = 0.092µ g of BNS ∕ g food

Since the Consumption factor for paper, based on FDA’s methodology is
0.10

The  actual amount of BNS in daily diet will be:

0.092µg of BNS∕ g food x 0.10 = 0.0092 µg ∕ g food

Estimated Daily Intake (EDI) of BNS for an adult:

0.0092µg of BNS ∕ g food x 3000 g food =27.6µg of BNS/person/day

Estimated Daily Intake (EDI) of BNS for a child:

0.0092µg of BNS ∕ g food x 1500 g food = 13.8 µg of BNS /person/ day

AD’s End Points Selection Committee (An AD Memo by Tim McMahon to
Jenny Tao, 2006  determined both the Acute dietary and chronic dietary
end points and based on the selection, the aRfD and cRfD respectively
are: 0.37 mg/kg/day and 0.037 mg/kg/day 

In Table II estimations are given for % aPAD and % cPAD.

				Table II

		Dietary Exposure from Paper/Pulp/ Paperboard

		

Dietary Conc. of  BNS	Estimated Daily Intake (EDI)	Daily Dietary Dose
(DDD): mg/kg/day	% aPAD

(aPAD = 0.37 mg/kg/day)	% cPAD (cPAD = 0.037 mg/kg/day)

20.0 µ g	Adult: 27.6 µg

	Adult: 27.6 µg/70 kg/day = 0.00039 mg/kg/day

	Adult: 0.00039 mg/kg/day ∕ 0.37 mg/kg/day x 100

= 0.105%	Adult: 0.00039 mg/kg/day/0.037 mg/kg/day x 100 = 0.0105 %

	Child: 13.8  µg 	Child: 13.8µg/ 15 kg/day = 0.00092 mg/kg/day	Child:
0.00092 mg/kg/day ∕ 0.37 mg/kg/day = 0.24% 	Child: 0.00092 mg/kg/day /
0.037 mg/kg/day = 0.024%



The calculations of % aPAD and cPAD show that there are no acute dietary
concerns from the migration of BNS from paper to food. 

Adhesive Use

As a matter of policy, AD has assessed adhesive use as an indirect food
use.  Since it is likely that adhesives may end up in the food packaging
materials, and this may result in the migration of the pesticide into
the food indirectly.  For the indirect food dietary assessment, AD has
adopted Food & Drug Administration (FDA) methodology.  For adhesive use,
FDA has provided guidance for dietary estimation that a maximum of 7 ppb
of a pesticide is likely to migrate from the food packaging materials
into the food. The quantity of 7 ppb can be used to calculate the
Estimated Daily Intake (EDI), Daily Dietary Dose (DDD), and using the
acute and dietary end points from toxicity data, one calculates the
overall risks to general and subgroups of populations ( % aPAD, and %
cPAD).

For the present case: FDA’s assumptions are: 1) Maximum migration of
BNS  into food from adhesive use = 7 ppb = 7µg/g; 2) Maximum adult food
intake = 3000 g; 3) Maximum food intake for a child = 1500 g.

In general, % PAD = DDD/% a PAD or % cPAD.

Table III gives estimates of % cPAD for adhesive use of BNS

. 

					Table III					

			Dietary Exposure from Adhesive Use

Use	Dietary Conc. (ppb)	Estimated Daily Intake (EDI) µg/p/day	Daily
Dietary Dose (DDD) mg/kg/day

 

	% aPAD

(aPAD= 0.37 mg/kg/d)	% cPAD

( cPAD = 0.037 mg/kg/d)

Adhesive	7	Adult: 7µg/g x 3000g = 21 µg/p/day

Child: 7 µg/g x 1500 g = 10.5 µg/p/day	Adult: 21 µg/70 kg/day =
0.0003 mg/kg/day

Child: 10.5 µg/15kg/day = 0.0007 mg/kg/day	Adult: 0.0003/0.37 x 100) =
0.081%

Child: 0.0007/0.37 x100 = 0.019%	Adult:  0.0003 mg/kg/day ∕ 0.037
mg/kg/day x100 = 0.81%

Child: 0.0007 mg/kg/day ∕ 0.037 mg/kg/day x 100  = 0.19 %

	

These calculations assume that the adhesive use is 100% of the chemical
produced, which is not a likely scenario. The actual % cPAD is going to
be much lower than the estimated one The Agency has no chronic dietary
concerns from the use of BNS in adhesives.

3)	BNS Used for Paper Coatings:

					Table IV

Max. Rate of Applications	Paper Coating Mass to Wt. of paper	Standard
Basis of Paper	Food Mass: Surface Area of Treated Paper	Migration
Consumption Factor

2 lbs/1000lbs product = 2000 ppm	10%	50 mg/in2 	10 g/in2	100%	10%



Dietary Conc of BNS for Paper coatings:

Appl. Rate x % Paper Coating x Basis of Wt. of Paper x Food Mass:
Surface Area x % Migration:

a.i. µg/g  x 0.1 g coating/g paper x 0.05 g/in2 x  1 in2/10 g food 

1 µg a.i. /g food; Since consumption factor is 10%:, actual dietary
conc. of BNS in food is:

1.0  µg x 0.1 = 0. 1 µg of BNS/g food

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$Daily Dietary Dose: 300 µg/70 kg/day = 4.3 µg of BNS/kg/day for an
adult

Dailey Dietary Dose: 150 µg/15 kg/day = 10 µg of BNS/kg/day for a
child

					Table V

			Dietary Exposure from Paper Coatings

Daily Dietary Dose (mg/kg/day)	% aPAD ( a PAD) = 0.37 mg/kg/day)	% cPAD
(cPAD = 0.037 mg/kg/day)

4.3 µ g/kg/day	 Adult: 4.3 =0.0043 mg/kg/day/0.37 x 100 = 1.16%

Child: 10/1000 = 0.001 mg/kg/day/ 0.37 x 100 = 0.27%	Adult: 0.0043
mg/kgday/0.037 mg x 100= 11.6%

Child: 0.001/0.037 x100 = 2.7% 



	

					BIBLIOGRAPHY

FDA, 2003, A Guidance For Industry: Preparations of food Contact
Notifications and Food Additive Petitions for Food Contact Substances,
Chemistry Recommendations. Final Guidance, April 2003.   HYPERLINK
"http://www.cfsan.fda.gov"  http://www.cfsan.fda.gov 

FDA, 2003.  Sanitizing Solutions: Chemistry Guidance for Food Additive
Petitions, January 2003.   HYPERLINK "Http://www.cfsan.fda.gov" 
Http://www.cfsan.fda.gov 

					

3.	AD’s End Points Selection Committee (An AD Memo by Tim McMahon to
Jenny Tao, 2006					

			

				

 

