Environmental Engineering Reference
In-Depth Information
fi ndings of the FMC study. A study by Overgaard, Walsh, Hertel et al. (1983) deals with a non-
agricultural use pattern but nevertheless offers some useful insight. These reports contain substantial
information that we briefl y outline below.
Although investigators conducted most of these studies in cornfi elds, results are representative of
other types of crops. As farmers typically apply granular carbofuran to bare fi elds, there is little to
distinguish a cornfi eld from a potato fi eld or any other type of fi eld immediately after planting. Thus,
the remaining variables are the number of granules accessible to birds and the presence of birds
in the fi eld. Data reviewed by Mineau and Clark (2008), as well as the kill record, indicate that the
exact soil incorporation rate of granular carbofuran may be largely inconsequential. This is due
to the extreme toxicity of carbofuran (see Chapter 2) and the fact that there seem to be surplus sur-
face granules in and around treated fi elds, regardless of the crop or cropping conditions. The data
consistently indicate that the principal determinant of a bird kill is the presence of birds in treated
fi elds rather than the number of granules applied.
8.2.1.2 FMC 1983: corn, Utah, incorporated band application
The applicators banded Furadan 10G and 15G in cornfi elds (maize) at 340 g/100 m of row (FMC
1983). This application rate in corn, although registered in the United States at the time, was higher
than the average rate used by farmers. The applicators then incorporated the banded granules into
the soil following label recommendations, taking care to avoid spillage while loading or exposure
of granules at row-ends during turning. Applicators planted three plots totalling 45 hectares with
Furadan 10G. Field personnel picked up 373 dead birds of eight species during the 60-day moni-
toring period. Personnel picked up 504 more carcasses on nearby plots (57 hectares) treated with
Furadan 15G. Personnel also collected 35 more birds that moved to control plots before dying.
The overall kill rate was not statistically different between the 10G and 15G plots, but the spatial
proximity of the plots meant that birds could readily move among plots before dying. Most of the
dead birds were horned larks (
Eremophila alpestris
) (799 individuals killed), which were fl edging
from nearby fi elds. Investigators found dead birds representing 14 species, including the northern
harrier (
Circus cyaneus
) and short-eared owl (
Asio fl ammeus
), two bird of prey species.
8.2.1.3 FMC 1986a: corn, Iowa and Illinois, incorporated band application
Investigators monitored three plots treated with Furadan 10G and three plots treated with Furadan
15G in Illinois and in Iowa at 1.5 kg ai/ha (FMC 1986a). Again, the applicators took care to avoid
spillage or surface exposure of granules and incorporated the granules into the soil. At the Iowa sites,
investigators and company personnel took additional measures to reduce the avian hazard, even
though these efforts do not refl ect normal farming practices because of the extreme time and effort
required. In the authors' words:
FMC personnel witnessed the planting operations and assisted in covering spills
of Furadan granules. In general, these efforts consisted of walking along end rows
(where the planter was raised and lowered when turning around) and kicking soil over
any spills observed. At one site, the FMC representative systematically searched all
end rows for exposed granules. As instructed by the FMC representative, the farmer
disked [note from the authors: a tillage implement] the end rows after planting the
long rows and then planted the end rows. In addition, he was asked to place a plastic
fl ag at locations where he stopped in mid fi eld during planting. These sites were sub-
sequently inspected by the FMC representative.
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