Environmental Engineering Reference
In-Depth Information
a wide variety of fi eld and row crops under the trade name Lorsban
®
15G.
Consumption of granular pesticides is a route of exposure that is specifi c to birds.
Grit is dietary requirement of many birds to aid in digestion of hard dietary items
such as seeds and insects. Because granules of CPY are in the same size range as
natural grit particles that are consumed by birds, there is a potential for birds to
mistakenly ingest granular CPY instead of natural grit. The GranPARAM model
accounts for the proportion of time that birds forage for grit in treated fi elds, relative
proportions of natural grit versus pesticide granules on the surface of treated fi elds,
rates of ingestion of grit, attractiveness of pesticide granules relative to natural grit,
variability in rates of ingestion of grit, foraging behavior between birds within a
focal species, and variability in soil composition between fi elds for the selected use
pattern. Analysis of a wide variety of use patterns of the granular formulation found
that CPY posed little risk to bird species that frequent treated fi elds immediately
after application. The predictions of the model were consistent with the results of
several avian fi eld studies conducted with Lorsban 15G at application rates similar
to or exceeding maximum application rates on the label.
7
Risks to Pollinators
The seventh and last paper in this series used a tiered approach to assess risks posed
by CPY to insects that serve as pollinators (Cutler et al.
2014
). The assessment
focused on bees, although other groups of insects were also considered. Because
there have been recent reports of adverse effects of some pesticides on pollinators,
assessing risks of pesticides to pollinators is an important topic. A recent SETAC
workshop (Fischer and Moriarty
2011
) proposed changes to the assessment process
(USEPA
2011b
), and these served as guidance for this assessment.
Pollinators are important for both natural and agricultural ecosystems (Cutler
et al.
2014
). In the U.S., production of crops that require or benefi t from pollination
by the European honey bee,
Apis mellifera
L. (Apidae) has been estimated to have
a monetary value greater than $15 billion annually, while the value of non-
Apis
pol-
linators to crop production is estimated to be more than $11 billion.
CPY is considered to be highly toxic to honey bees by direct contact exposure.
However, label precautions and good agricultural practices prohibit application of
CPY when bees are fl ying and/or when fl owering crops or weeds are present in the
treatment area. Therefore, the risk of CPY to pollinators through direct contact
exposure should be small. The primary routes of exposure for honey bees are dietary
and contact with fl owers that were sprayed during application and remain available
to bees after application.
The main pathways for secondary exposure to CPY are through pollen and nec-
tar brought to the hive by forager bees and the sublethal body burden of CPY carried
on forager bees. Foraging for other materials, including water or propolis, are not
important routes of exposure. Because adult forager honey bees are most exposed,
they are expected to be most at risk compared to other life stages and castes of
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