Refined Avian Risk Assessment for Chlorpyrifos in the United States - Reviews of Environmental Contamination and Toxicology - page 197

no decrease in activity, indicating that mortality was not likely the result of exposure
to CPY. There were no indications of short-term negative impacts from CPY on birds
in the vineyard during the study. There were no signifi cant effects to birds in the grape
fi eld study, however the application rate in this fi eld study was well below that used in
the modeling exercise. Therefore, it was not possible to determine whether
LiquidPARAM overestimated risks to the blue grosbeak ( P. caerulea ) (Table 5 ).
Telemetry-based fi eld studies . Brassica, pome fruit and citrus crops were treated
with CPY to determine potential effects on wild birds (Wolf et al. 2010 ). Brassica
fi elds were located near Sochaczew, Poland, pome fi elds near Belfi ore, northern
Italy, and citrus groves in Valencia, Spain. Four or fi ve sites were used for each crop
type and fi elds averaged 4 ha (9.9 A) in size. Chlorpyrifos was applied to brassicas
using a tractor-mounted boom sprayer at a rate of 0.95 kg ha −1 (0.86 lb ai A −1 ).
Three brassica sites received two applications of Dursban 480 EC and two other
sites received an application of a formulation not relevant to this assessment
(Pyrinex ® 25 CS, a microencapsulated formulation). Chlorpyrifos was applied to
pome and citrus fruit crops using a tractor-mounted broadcast air-assisted sprayer.
Three citrus fi elds received two applications of Dursban 75 WG at a rate of
2.32 kg ha −1 (2.1 lb ai A −1 ), and the remaining fi eld received two applications of
Pyrinex 25 CS. One fi eld of pome fruit received applications of Pyrinex 25 CS and
one pome fruit fi eld received three applications of 0.95 kg ha −1 (0.86 lb ai A −1 )
Dursban 75 WG, whereas the other two plots received two applications of
0.95 kg ha −1 (0.86 lb ai A −1 ) Dursban 75 WG. All bird species regularly foraging in
the crops were monitored during the study.
Birds were trapped and radio-tagged before each application and tracked for 7-d
following each application. Those tagged for earlier applications were monitored
during subsequent applications if the radio-tags were still functional. Of the 242
radio-tagged birds, 194 were tracked for the full 7-d period following application.
No signs of toxicity or lethality were observed. Un-tagged birds were also observed
during the study period. No signs of toxicity were detected. Ten bird carcasses were
found during the study, six of which had detectable levels of CPY. Detectable con-
centrations of CPY on skin and feathers ranged from 0.3 to 14.0 mg ai kg −1 bwt.
CPY was only detected in the bodies of two birds (1.2 and 0.3 mg ai kg −1 bwt).
Similarly, core body concentrations of CPY were only detected in two birds at
levels of 0.1 and 1.2 mg ai kg −1 bwt.
Rates of application used in the pome (e.g., apple) and brassica plots were
less than the maximum rates listed on the Lorsban Advanced label for those crops.
The rate of application used in the citrus plots (2.32 kg ha −1 (2.1 lb ai A −1 )) was
similar to the maximum rate of application for grapefruit on the Lorsban Advanced
label (i.e., 2.76 kg ha −1 (2.5 lb ai A −1 )). LiquidPARAM predicted approximately
34% mortality to blue grosbeaks ( P. caerulea ) in grapefruit treated at the maximum
rate of application, assuming that this species was highly sensitive (Table 5 ).
All other bird species were predicted to experience little to no mortality. The results
for citrus groves indicate that LiquidPARAM might be over-estimating risk to blue
grosbeaks (Wolf et al. 2010 ).