Document ID: EPA-HQ-OPP-2005-0163-0167
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2006-11-15T05:00Z

Note to Reader

Request for Additional Information and Risk Management Suggestions for
the

Reregistration of Aldicarb

Phase 5 Public Comment Period

November 8, 2006

Dear Reader:

The purpose of this document is to summarize the current human health
and ecological risk picture for aldicarb and solicit risk management
suggestions.  The revised human health and ecological risk assessments
will be released for a 60-day public comment period, running from
November 15, 2006 to January 16, 2007.

Dietary Risks

Under the Food Quality Protection Act of 1996 (FQPA), EPA is required to
ensure that all food and drinking water risks for a given pesticide fit
within the pesticide’s “risk cup”.  The risk cup can be simply
defined as the “acceptable level of exposure” to an individual from
a pesticide, on an acute (i.e., one day) or chronic (i.e., long term)
basis.  When dietary risks are of concern, EPA takes steps to address
the risks to ensure food safety.

The Agency has determined that the estimated acute dietary exposure and
risk from food only does not exceed EPA’s level of concern (i.e., less
than 100 % of the acute population adjusted dose (aPAD)) for the general
U.S. population or any population subgroup.  The estimated dietary risk
for the highest exposed population subgroup, children 1-2 years of age,
at the 99.9th percentile of exposure is 78% of the aPAD. For the general
U.S. population, the dietary risk is 37% of the aPAD.  EPA conducted
additional analyses to determine which food or food forms made the
greatest contribution to dietary risk.  For all population subgroups,
aldicarb residues in potatoes were the most significant source of
dietary exposure.

While the dietary exposure and risk from aldicarb residues in food alone
is not of concern, the aggregate exposures and risks from food and
drinking water from rural well ground water sources suggest a risk
concern (139-147% aPAD) for infants less than one year of age only in
peanut/ cotton growing regions in the southern coastal plain (Alabama,
Georgia, South Carolina).  However, these risks diminish as the distance
increases between aldicarb-treated fields and drinking water wells.  The
concerns for drinking water exposure are confined to areas where high
leaching potential soils occur over shallow, acidic ground water.  The
acute risk assessment takes into account that the
cholinesterase-inhibition effects for aldicarb decrease as a function of
the amount of time elapsed after the food or water is consumed, and that
people eat food at various times throughout the day allowing for
recovery of cholinesterase activity between eating events.  

While the aggregate exposure and risk from food and drinking water from
private, rural well ground water sources is a concern for vulnerable
subpopulations, the Agency has determined that aggregate exposure and
risk from food and drinking water from community surface and ground
water sources is not a risk concern for any population subgroup. 

Residential Risks

As there are no residential uses of aldicarb, the Agency did not include
residential risks in its aggregate assessment of this chemical.

Occupational Risks

The occupational risk assessment for aldicarb is based on potential
exposure to agricultural workers during loading and application of
granular products.  Aldicarb is applied early in the growing season, and
labels require immediate soil incorporation of granules. 
Postapplication exposures are not expected for workers, so a
quantitative postapplication risk assessment has not been conducted.

Unlike with some pesticides, there is aldicarb-specific worker exposure
data that mirrors how aldicarb is packaged, handled, and used in
agriculture.  This data was used along with an additional study to
conduct the occupational risk assessment for aldicarb. For the
occupational assessment using the various worker exposure data, risks
were not of concern for loader or applicator exposure scenarios.

Human Studies Review Board

As required by EPA’s Human Subjects Protections Rule of 2006, the
Agency’s Human Studies Review Board (HSRB) reviewed the aldicarb human
oral study used in the human health risk assessment.  For additional
information relating to the HSRB’s determination for the
aldicarb-specific study, please refer to EPA’s website at   HYPERLINK
"http://www.epa.gov/osa/hsrb/"  http://www.epa.gov/osa/hsrb/ .

Ecological Risks

The ecological risk assessment is based on maximum rates and average
usage rates of aldicarb.  Using multiple lines of evidence (such as use
scenarios, average or “typical” application rates, registrant
submitted toxicity studies, open literature data, and field monitoring
data), aldicarb labeled uses pose acute risk (mortality) concerns to
birds, mammals, and aquatic organisms, as well as acute and chronic
reproductive concerns in fish and aquatic invertebrates.  The Agency is
currently working with the U.S. Fish and Wildlife Service and National
Marine Fisheries Service to gather information on listed species and
their habitats, to support endangered species effect determinations
associated with registered aldicarb uses.

Terrestrial Organisms

For terrestrial organisms, acute risk and acute endangered species
levels of concern for birds and mammals are exceeded for all target
crops at both maximum allowed label rates and average use rates.  Acute
levels of concern are consistently exceeded by a factor of greater than
100x and are frequently exceeded by more than 1000x.  Although aldicarb
labels require immediate soil incorporation, granules left exposed on
the surface appear to be the main source of exposure.  In addition,
other sources such as residues taken up by plants and contaminated
earthworms may also serve as a means of exposure.

Aquatic Organisms

For aquatic organisms there are acute risks for freshwater and
estuarine/marine fish and invertebrates for all of the registered uses
except the use on potatoes.  The chronic level of concern is exceeded
for freshwater invertebrates (reproductive effects) and estuarine/marine
invertebrates (average number of offspring) for all of the registered
uses.  Based on reproductive effects, the chronic level of concern is
also exceeded for freshwater fish (larval and juvenile survival) for
soybean, cotton, and pecan use patterns and for estuarine/marine fish
for all crop scenarios.  

Cumulative Risk

The Agency has determined that N-methyl carbamate pesticides, such as
aldicarb, should be considered as a Common Mechanism Group due to their
ability to inhibit acetylcholinesterase.  A cumulative risk assessment
for this Common Mechanism Group, including aldicarb, will be finalized
once the individual assessment of aldicarb is complete.  This more
comprehensive assessment of the N-methyl carbamate group may result in
additional measures to mitigate potential risk from the use of aldicarb.
   

Solicitation for Benefits Information and Risk Management Suggestions

At this time, the dietary (food only) and occupational risks from
aldicarb are not of concern for the registered uses.  However, there are
aggregate food and water dietary risks of concern in peanut/cotton
growing regions in the southern coastal plain, as well as nationwide
ecological risks of concern.  

The Agency has performed preliminary impact analyses to identify
available alternatives for the uses of aldicarb that appear to pose the
highest risks (see “Preliminary Impact Analysis for Aldicarb on
Potatoes”, “Preliminary Impact Analysis for Aldicarb on Major Citrus
Crops”, and “Impact Analysis for Aldicarb on Cotton”).  Additional
alternatives analyses have also been performed for crops with the
highest use of aldicarb (see “Alternatives Analysis for Sugar
Beets”, “Analysis for Aldicarb on Peanuts”, and “Alternatives
Assessment for Aldicarb”).  

It is important to note that FQPA does not allow for the consideration
of benefits when conducting dietary assessments; therefore, benefits
analyses play an important role in only non-dietary considerations, such
as ecological and worker risks.  For the crops cited above, impact and
alternative analyses are available in the aldicarb docket.  These
analyses show that there are not adequate alternatives available for
aldicarb use on potatoes and citrus.  Furthermore, though there are
effective alternatives for cotton, peanuts, and sugar beets, these
alternatives may have considerably higher costs since multiple chemicals
may be needed to control multiple pests currently controlled by aldicarb
alone.  

At this time, the Agency has begun to identify some viable options for
effectively mitigating the ground water and ecological risks from
aldicarb.  In part, the questions below seek feedback from the public on
potential mitigation options in areas where the risk assessments show
concerns; however, EPA is also soliciting input from interested
stakeholders on benefits information 

(i.e., critical uses of aldicarb and impacts to growers from the loss of
aldicarb). If you would like to provide this type of input, please
submit your comments directly to the aldicarb docket.

The Agency is providing the following questions to help the public in
preparing comments:

(1) Results of the drinking water dietary assessment suggest that there
are risks to infants less than one year of age for the aldicarb use on
peanuts/cotton in the southern coastal plain with 300 ft. setbacks from
drinking water wells.  In order to make the FQPA safety finding, OPP
believes one option is to extend setbacks to 500 feet.   What effect
would this have on peanut and cotton farmers, and are there other
options? 

(2) What pests do you feel aldicarb is critical in controlling on the
following crops: sweet potato, dry beans, sorghum, soybeans, sugarcane,
seed alfalfa, field grown ornamentals, tobacco, and coffee?

(3) What alternatives, if any, do you believe are available to replace
aldicarb use on sweet potato, dry beans, sorghum, soybeans, sugarcane,
seed alfalfa, field grown ornamentals, tobacco, and coffee?

(4) What percentage of the use are the aldicarb post-emergence
applications, and is aldicarb only applied post emergence as a side
dress application?  

(5) Against which pests and on which crops is the aldicarb
post-emergence side dress application used, and how critical is this
use?

(6) What alternatives, if any, do you believe are available for the
post-emergence side-dress use and how effective do you believe these
alternatives to be?

(7) What percentage of the use, if at all, are the broadcast and/or
banded applications?

(8) Against which pests and on which crops, if any, are broadcast and/or
banded applications being used?

(9) It is the Agency’s understanding that positive displacement
application equipment is used in the majority of aldicarb applications
to potatoes.  What percentage of aldicarb applications involves use of
positive displacement equipment on other crops?

(10) Is positive displacement application equipment readily available
and affordable for use on all crops?

11) What are the mitigation options that best address the risks of
concern identified in the risk assessments?

Please provide as much detail and documentation in your comments as
possible so that the Agency is fully informed in its decision-making.

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