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**UNITED STATES ENVIRONMENTAL PROTECTION AGENCY**

**WASHINGTON, D.C. 20460**

OFFICE OF PREVENTION, PESTICIDES AND

TOXIC SUBSTANCES

**[MEMORANDUM]{.underline}**

**SUBJECT:** EFED Drinking Water and Ecological Risk Review for
Coumaphos (036501) IR-4 Use on Beehives DP Barcode D315770

**TO:** Shaja Brothers, Risk Manager Reviewer

Daniel Rosenblatt, Risk Manager

Registration Division ()

**FROM:** Edward Odenkirchen, Ph.D., Senior Biologist

Environmental Risk Branch I

Environmental Fate and Effects Division (7507P)

**THROUGH:** Nancy Andrews, Ph.D., Chief

> Environmental Risk Branch I

Environmental Fate and Effects Division (7507P)

The Registration Division has requested the Environmental Fate and
Effects Division to review an IR-4 petition for the use of coumaphos
impregnated strips CheckMite+^®^ Pest Control Strip in beehives for the
control of varroa mites and small hive beetles within the honeybee
colony. The labeling for the IR-4 petition differs from previous Section
18 emergency exemptions for the use of coumaphos in only two ways. The
labeling would allow use of the coumaphos product during periods of
honey production. The labeling also has been revised for first aid
statements in compliance with PR Notice 2001-1.

EFED has reviewed the proposed label use and found a number of key
aspects of this use as it relates to both ecological risks and drinking
water assessment. First the material is impregnated on a solid substrate
which is placed inside the commercial beehive structure. Once in the
beehive, the material is sheltered from the elements so that no runoff
or drift of coumaphos to surrounding environments would likely occur
even during precipitation events. Secondly, the pesticide impregnated
strips are placed on the floor of the beehive or between center-most
combs of the beehive to eliminate or reduce bee contact with the strips.

Based on this understanding of the use of the product, EFED believes
that no drinking water concerns exist for the product used in accordance
with the label. The use of the material within a beehive structure
effectively eliminates pathways of exposure to surface and ground
waters. EFED believes that a previous drinking water assessment provides
the most comprehensive and conservative drinking water estimates for
coumaphos. The assessment entitled Revised Tier 1 Drinking Water
Assessment for Coumaphos (June, 2000, DP Barcode: D26651) provides an
analysis of potential drinking water contamination for other coumaphos
uses that would not be expected to be exceeded by any estimate for the
beehive use of the pesticide. In that June 2006 assessment GENEEC
modeling predicted that the total coumaphos residue concentration
(coumaphos + coumaphoxon) in surface water used as drinking water are
not likely to exceed 1.86 μg coumaphos equivalents/L for the maximum
annual concentration (acute) and 1.22 μg coumaphos equivalents/L for the
56 day average concentration (chronic). SCI-GROW modeling predicted that
the total coumaphos residue concentration in groundwater used as
drinking water is not likely to exceed 0.17 μg coumaphos equivalents/L.

With respect to ecological risks, the indoor use of the pesticide and
the placement of coumaphos-treated strips to avoid contact of bees
suggest that there are no complete routes of exposure to surface waters
or to the surrounding non-target terrestrial environment. Therefore,
without evident complete exposure routes to aquatic and non-target
terrestrial organisms, there are no acute or chronic risk concerns and
no concerns for effects to federally listed threatened or endangered
species.