EBDCs (General Information) EBDC Regulatory Update 6/91
June 14, 1991
Dear Ag Professional:
Subject: EBDC Regulatory Update
We want to thank you for your continued support of DITHANE Agricultural
Fungicide and we want to bring you up-to-date on some of the current
activities and regulatory events involving DITHANE and other EBDCs relative to
the EBDC Special Review. An update of pertinent issues follows. Additionally,
a summary of the market basket survey information is attached.
Dietary Risk Assessment
EPA's dietary risk assessment for PD 2/3 was a preliminary assessment
based on field trial data for estimating exposure to residues and a
preliminary toxicity factor called Q*. The registrants have provided
information to enable the EPA to refine the risk assessment for the conclusion
of Special Review, which is referred to as PD 4.
Market Basket survey data will be used for the residue exposure
assessment in PD 4. The EBDC/ETU market basket survey was submitted to EPA on
October 1, 1990. In this survey, foods were collected from grocery stores
across the United States to measure actual consumer exposure to EBDC and ETU
residues. This was the largest survey of its kind ever conducted. Overall,
the survey showed that consumer exposure to EBDCs and ETU is very low. Eighty
percent of approximately 6,000 samples had no measurable residues of EBDCs or
ETU. Where residues were present, they were only at trace levels. The
samples were analyzed with extremely sensitive analytical methods. In
general, residues were ten to a hundred times lower than those seen in field
Almonds, bananas, apples, and grape samples collected in the market
basket survey had been analyzed at Craven Laboratories. Because of
allegations regarding some of Craven Laboratories procedures used to develop
the data, the EBDC/ETU Task Force told EPA they would not be relying on those
data until the Agency had conducted its own review of the matter and any
concerns had been addressed. Subsequent to completion of the market basket
survey, new residue data have been submitted to EPA. Almonds will be
regulated by field trial data previously submitted to EPA.
The market basket survey data will be used to refine the risk assessment.
Likewise, the EBDC/ETU Task Force has provided data on the toxicity factor, Q*
to allow a refinement in the toxicity portion of the risk equation.
Specifically, the Task Force assembled an Independent Panel of noted
statisticians to review all available toxicology data, including data which
the Agency did not have available to it when it performed its preliminary Q*
analysis. The opinion of the Independent Panel was that the data strongly
indicated that a lowering of the Q* is appropriate. The Task Force presented
the views and analysis of the Independent Panel to the EPA. The Agency is
currently reviewing these data.
EPA issued its regulatory proposal, or PD 2/3, in December, 1989. In PD
2/3, EPA proposed cancelling potatoes, tomatoes, and bananas based on residues
developed in controlled field trials. This is only a proposal, and it is
legal to use EBDCs on these three crops while Special Review continues. The
crops are still on the EBDC labels. There is no restriction on the use of
EBDCs or the sale of these crops treated with EBDCs while we are in Special
The EPA will conclude the Special Review with the issuance of PD 4. EPA
is now estimating late fall or early winter for issuance of PD 4.
Tolerance Revocation Proposal
On May 16, 1990 EPA proposed revoking EBDC tolerances for some
commodities. However, it indicated that such action would be held pending
completion of the Special Review process. Further, if any uses were cancelled
through the Special Review, any related tolerances would be eliminated over an
extended period of time to permit lawfully treated produce and processed
product to clear trade channels. According to the proposal, most tolerances
would remain in effect until December, 1993 or until December, 1994 for apples
and potatoes, assuming a conclusion of Special Review in spring, 1991. These
dates would be extended if the conclusions of Special Review were delayed.
Therefore, no action to eliminate tolerances is expected until and unless the
Agency determines that final cancellation of a particular use is appropriate.
Thank you again for your continued support of EBDC fungicides. We look
forward to a successful conclusion of Special Review. Please call me at (215)
592-3627 if you have any questions.
F. W. Belledin
Rohm and Haas Company
EBDC/ETU Market Basket Survey
In a report submitted to the EPA on October 1, 1990, the EBDC/ETU Task
Force(1) confirmed that consumer exposure to ethylenebisdithiocarbamate (EBDC)
fungicides and ethylenethiourea (ETU) was very low. In general, the residues
found in foods purchased from grocery stores nation wide as part of the year
long Market Basket Survey were 10 to 100 times lower than those seen in
previously conducted field trials. These results corroborate earlier market
basket surveys conducted by registrants and Federal and State agencies showing
that residues of EBDCs and ETU occur only rarely in the marketplace.
(1)Atochem North America, Inc., BASF Corporation, E.l du Pont de Nemours and
Company, and Rohm and Haas Company.
- Largest food survey of its kind ever conducted.
- Approximately 300 samples of each food item were collected.
- Samples were collected from urban, rural, small and large stores across the
United States, generally every two weeks.
- Food items, in varying forms, included: dry beans, broccoli, corn,
cucumbers, lettuce, meat, milk, onions, potatoes, tomatoes.
- Additional data will be used to support almonds for the future.
Number of % of Food Samples Where
Analyzed Food Samples Residues Were Not Found(1)
EBDC 5,888 81%
ETU 5,890 82%
(1) Based on limit of quantitation.
(2) Excludes broccoli and onion residues that were not truly EBDCs.
SENSITIVITY OF ANALYSES
Meat, Milk 0.005 ppm 0.005 ppm
Crop Items 0.02 ppm 0.005-0.02 ppm
Meat, Milk 0.001 ppm 0.001 ppm
Crop Items 0.01 ppm 0.002-0.005ppm
ADDITIONAL DATA SUPPORTS FRESH GRAPES, APPLES AND BANANAS
In the six months following the initial report submitted to the EPA by the
EBDC/ETU Task Force, additional data were collected from monitoring studies of
fresh grapes, apples and bananas. The following is a summary of the studies
and the results submitted to the EPA:
- Seven samples of grapes, grown for commercial use, were collected in
California in 1990.
- The crop received one to three commercial applications of DITHANE
fungicide applied through bloom. The pre-harvest interval was 113 to 150
- No detectable ETU residues were found at an analytical sensitivity of 0.005
ppm. (EPA required analytical sensitivity of analyses for crop items is 0.01
- Only trace residues of mancozeb were found, and these residues were far
below the EPA tolerance of 7 ppm.
- Trials took place in six states, using DITHANE fungicide applications (four
in most cases) up to bloom, or seven applications through second cover.
(These early season use patterns have a reduced seasonal application rate
and a longer pre-harvest interval than the previous full season use pattern,
so the theoretical dietary risk will be lower.)
- There were no detectable mancozeb residues, or only trace residues of
mancozeb with an analytical sensitivity of 0.02 ppm. These residues were
far below the EPA tolerance of 7 ppm.
- At a limit of detection of 0.005 ppm, no detectable ETU residues were found
in eleven of twelve trials. In one trial, a trace residue of 0.005 ppm was
- Samples were collected from ships delivering bananas for commercial sale
arriving in ports across the United States. They came from all of the
banana producing countries that currently export to the U.S.
- All samples, except those from Ecuador, were known to have been treated with
EBDCs. Altogether, 169 samples of edible banana pulp were analyzed for
EBDCs, and 125 of them had been treated. Only one sample had a trace
residue-0.05 ppm-of EBDC, which was most likely due to contamination
from peeling the banana.
- Altogether, 98 samples were analyzed for ETU, and 75 of them had been
treated. None of the samples had measurable residues of ETU, with an
analytical sensitivity of 0.005 ppm.
The data from this survey provide a sound basis for which EPA will make a
regulatory decision regarding the future of these important fungicides
sometime in 1991. The results of the studies support the continued
registration of DITHANE agricultural fungicide, marketed by Rohm and Haas