
                                                                                                                                                            


                 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                         WASHINGTON, D.C. 20460      

                                                    	OFFICE OF CHEMICAL SAFETY 
                                                       AND POLLUTION PREVENTION
	


MEMORANDUM

Date:  May 18, 2011

SUBJECT:	2,4-D: Petition for the Establishment of Tolerances on Teff; Request for Registration of Latigo (EPA Reg No. 5905-564) on Teff.  Consideration of Changes in Percent Crop Treated.

PC Codes:  030001
DP Barcode:  389865
Decision No.: 440785
Registration No.: 5905-564
Petition No.: 0E7796
Regulatory Action: Section 3 Registration
Risk Assessment Type: Human Health Risk Assessment
Case No.: NA
TXR No.: NA
CAS No.: 94-75-7
MRID No.: NA
40 CFR: §180.142
		              								
          	
FROM:	Christine Olinger, Risk Assessor
		Risk Assessment Branch VII
		Health Effects Division (7509P)
		
THROUGH:	Michael Metzger, Branch Chief
		Risk Assessment Branch VII
		Health Effects Division (7509P)

TO:		Laura Nollen
		RIMUERB, Registration Division (7505P)


This document provides an assessment of potential change in aggregate risk as a result of changes in the 2,4-D percent crop treated since the last comprehensive risk assessment (Timothy C. Dole, 5/12/05).  This assessment is being done to support the subject use of 2,4-D on teff.  

The Chronic dietary assessment will be used to screen for potential increase in dietary risk.  While this approach does not directly address acute risk, the major commodities likely to contribute to acute risk are single serving commodities such as pome, citrus, and stone fruit, which have mostly non-detectable residues (higher residues are generally found in field crops).  Furthermore, the changes in PCT observed are minor.  Also, changes in PCT will not affect residential or occupational risk estimates.  

HED has completed a screening level assessment of the change in chronic risk as follows:

   1. Complete a Commodity Contribution Analysis based on the last comprehensive risk assessment using a threshold for results presentation of > 0.1% cPAD.  
   2. For commodities < 0.1 % cPAD, assume 0.1% cPAD commodity contribution
   3. Multiply the commodity contribution (% cPAD) for each commodity by the factor by which the PCT has changed.
   4. Sum the total risk

The results are shown in the attached table.  The changes in risk from the 2005 assessment to 2011 for the general population and children (the most sensitive subpopulation) are 2.2% and 3.1% cPAD, respectively.  These differences are insignificant.  Therefore, HED concludes that changes in PCT between the 2005 risk assessment and 2011 will not result in significant changes in estimated aggregate risk.  

It should be noted that many conservative assumptions were incorporated into this screening level assessment to minimize unnecessary use of resources, and these estimates of changes in risk as a result of changes in PCT are therefore very conservative.

Changes in 2,4-D Chronic Risk Estimates Resulting From Changes in Percent Crop Treated Between 2005 and 2011.
Crop
                                % Crop Treated
                         Commodity Contribution (2005)
                         Commodity Contribution (2011)

New
Old
Proportional Change
%cPAD, Gen pop
%cPAD, Children 1-6
%cPAD, Gen pop
%cPAD, Children 1-6
Alfalfa
                                                                          <1
                                                                            0.6
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Almonds
                                                                             15
                                                                             10
                                                                           1.50
                                                                            0.1
                                                                            0.1
                                                                           0.15
                                                                           0.15
Apples
                                                                             20
                                                                             36
                                                                           0.56
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.06
Apricots
                                                                             15
                                                                              8
                                                                           1.88
                                                                            0.1
                                                                            0.1
                                                                           0.19
                                                                           0.19
Asparagus
                                                                             10
                                                                             15
                                                                           0.67
                                                                            1.2
                                                                           0.98
                                                                           0.80
                                                                           0.65
Avocados
                                                                              1
                                                                           NA 
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Barley
                                                                             30
                                                                             43
                                                                           0.70
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.07
Beans, green
                                                                          <1
                                                                              3
                                                                           0.30
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.03
Blueberries
                                                                          <1
                                                                            0.5
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Cane berries
                                                                        <2.5
                                                                           NA 
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Canola/rapeseed
                                                                        <2.5
                                                                              2
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Cherries
                                                                             15
                                                                             24
                                                                           0.63
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.06
Corn
                                                                              5
                                                                             12
                                                                           0.42
                                                                            1.9
                                                                           4.15
                                                                           0.79
                                                                           1.73
Cotton
                                                                              5
                                                                              3
                                                                           1.67
                                                                            0.1
                                                                            0.1
                                                                           0.17
                                                                           0.17
Cucumbers
                                                                          <1
                                                                           NA 
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Dry beans/peas
                                                                          <1
                                                                           NA 
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Fallow, summer
                                                                             20
                                                                             10
                                                                           2.00
                                                                            0.1
                                                                            0.1
                                                                           0.20
                                                                           0.20
Grapefruit
                                                                             15
                                                                             19
                                                                           0.79
                                                                            0.1
                                                                           0.02
                                                                           0.10
                                                                           0.02
Grapes
                                                                              5
                                                                              2
                                                                           2.50
                                                                            0.1
                                                                            0.1
                                                                           0.25
                                                                           0.25
Hazelnuts (filberts)
                                                                             55
                                                                             58
                                                                           0.95
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.09
Lemons
                                                                        <2.5
                                                                            1.5
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Nectarines
                                                                             15
                                                                             10
                                                                           1.50
                                                                            0.1
                                                                            0.1
                                                                           0.15
                                                                           0.15
Oats
                                                                             15
                                                                             19
                                                                           0.79
                                                                            0.1
                                                                           0.11
                                                                           0.10
                                                                           0.09
Onions
                                                                              5
                                                                           NA 
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Oranges
                                                                             15
                                                                              7
                                                                           2.14
                                                                           0.25
                                                                           0.49
                                                                           0.54
                                                                           1.05
Pastures
                                                                             10
                                                                              5
                                                                           2.00
                                                                            0.1
                                                                            0.1
                                                                           0.20
                                                                           0.20
Peaches
                                                                             15
                                                                             12
                                                                           1.25
                                                                            0.1
                                                                            0.1
                                                                           0.13
                                                                           0.13
Peanuts
                                                                              5
                                                                              4
                                                                           1.25
                                                                            0.1
                                                                            0.1
                                                                           0.13
                                                                           0.13
Pears
                                                                             15
                                                                             14
                                                                           1.07
                                                                            0.1
                                                                            0.1
                                                                           0.11
                                                                           0.11
Peas, green
                                                                          <1
                                                                            NA
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Pecans
                                                                              5
                                                                            NA
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Pistachios
                                                                              5
                                                                            NA
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Plums
                                                                             20
                                                                             17
                                                                           1.18
                                                                            0.1
                                                                            0.1
                                                                           0.12
                                                                           0.12
Potatoes
                                                                          <1
                                                                              2
                                                                           2.00
                                                                           0.71
                                                                           1.41
                                                                           1.42
                                                                           2.82
Prunes
                                                                             15
                                                                            NA
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Pumpkins
                                                                          <1
                                                                            NA
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Rice
                                                                             10
                                                                             17
                                                                           0.59
                                                                           2.85
                                                                            5.3
                                                                           1.68
                                                                           3.12
Sorghum
                                                                             20
                                                                             16
                                                                           1.25
                                                                            0.1
                                                                            0.1
                                                                           0.13
                                                                           0.13
Soybeans
                                                                              5
                                                                              7
                                                                           0.71
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.07
Squash
                                                                        <2.5
                                                                            NA
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Strawberries
                                                                              5
                                                                              7
                                                                           0.71
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.07
Sugarbeets
                                                                          <1
                                                                            NA
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Sugarcane
                                                                             40
                                                                             53
                                                                           0.75
                                                                            0.1
                                                                           0.08
                                                                           0.10
                                                                           0.06
Sunflowers
                                                                              5
                                                                              4
                                                                           1.25
                                                                            0.1
                                                                            0.1
                                                                           0.13
                                                                           0.13
Sweet corn
                                                                              5
                                                                            NA
                                                                           1.00
                                                                           0.19
                                                                           0.49
                                                                           0.19
                                                                           0.49
Tangelos
                                                                             15
                                                                            NA
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Tangerines
                                                                              5
                                                                            NA
                                                                           1.00
                                                                            0.1
                                                                           0.03
                                                                           0.10
                                                                           0.03
Tobacco
                                                                          <1
                                                                            NA
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Tomatoes
                                                                        <2.5
                                                                            NA
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Walnuts
                                                                             10
                                                                              9
                                                                           1.11
                                                                            0.1
                                                                            0.1
                                                                           0.11
                                                                           0.11
Watermelons
                                                                          <1
                                                                            NA
                                                                           1.00
                                                                            0.1
                                                                            0.1
                                                                           0.10
                                                                           0.10
Wheat
                                                                             25
                                                                   4  (Spring )
                                                                           6.00
                                                                            0.1
                                                                           0.16
                                                                           0.60
                                                                           0.96


                                                                   24  (Winter)
                                                                           1.00
                                                                            0.1
                                                                              0
                                                                           0.10
                                                                           0.00
Meat / fish / Milk
 
 
                                                                           2.00
                                                                           2.65
                                                                           4.83
                                                                           5.30
                                                                           9.66
                                                                   Total--->
 
                                                                          14.45
                                                                          22.15
                                                                          16.65
                                                                          25.27

