Impacts of carbofuran on birds in Canada and the United State - Carbofuran and Wildlife Poisoning: Global Perspectives and Forensic Approaches - page 220

8.2.2.2.2 November 1974 to January 1975, turnip, Ladner, British Columbia
Heavy rains fl ooded about a tenth of a fi eld near the river (Ladner is on the opposite shore of the
Fraser from Richmond). Field personnel found about 50 dead ducks of four species (mallards,
northern pintails, American wigeon ( Anas americana ), and green-winged teal ( Anas crecca )) in and
around the fl ooded area. In a later visit to the same site about one month later, fi eld personnel found
another 15 to 20 ducks and a glaucous-winged gull ( Larus glaucescens ). Personnel recovered ten
more ducks on a third visit, for a total of about 80 birds.
Although the site was a harvested potato fi eld, there was also a row of immature cabbage on one
side of the fi eld. The farmer stated that he had planted the fi eld to turnips the previous April or May
and he used carbofuran at that time, applying the pesticide in band (with a Gandy TM seeder). After
unseasonal spring rains caused crop failure, the farmer ploughed the entire fi eld and put in potatoes.
In September the farmer harvested the potatoes and planted the row of cabbage.
Field personnel found the second group of birds in a fl ooded section of the cabbage row. Water
samples taken from the main puddle contained 0.063 ppm carbofuran. Soil sample pH values ranged
from 5.3 to 5.6. Laboratory personnel found granules in the guts of one of the two birds submitted
for analysis. Two laboratories analysed combined organs (heart, liver, gizzard, and intestines) from
one bird. One laboratory reported a value of 60.9 ppm carbofuran, whereas another reported 8.2 ppm
for the same sample. (It is possible that some degradation could have taken place in transit from one
laboratory to the other but this does represent a large discrepancy.) A sample of granules taken from
the fi eld contained 4.3% carbofuran, or slightly less than half of the nominal 10% concentration, and
this following about seven to eight months of weathering.
There was some confusion as to the acreage actually planted to turnips, and certain questions
remained about the pesticide application rate. Also, investigators found some jugs of Furadan 4F on
site that may have been used on the potato crop. However, the presence of carbofuran granules in the
ducks and the residue levels left in the granules at the time of the kill suggest that the early summer
application of the granular formulation was a more likely cause of death, since this is when birds
would have fed on them (Whitehead 1975a; FMC 1975a; Bruns 1975).
8.2.2.2.3 October to December 1975, turnip, Ladner, British Columbia
This kill occurred in a fi eld next to (and owned by the same grower as) the fi eld in which the kill
reported above (Section 8.2.2.2.2) occurred. Here, approximately 60 green-winged teal found ini-
tially had granules in their gastrointestinal tracts. Field crews installed propane exploders to keep
other birds out of the fi eld. A month after discovery of the fi rst dead birds, the propane exploders
malfunctioned, and about 1 000 teal entered the fi eld and died within a few hours. Five teal examined
contained between 2 and 125 carbofuran granules in their guts.
The grower had applied granules to transplanted turnips in late May through early June. This
individual applied the granules around the plants by hand rather than with a calibrated applicator, as
he had in other fi elds. The farmer harvested the crop in mid-July and later disked part of the fi eld.
(Disking is a type of ploughing; it has the effect of covering surface soil). Puddles appeared in the
fi eld in October after heavy rains. Based on the number of granules still present in the fi eld and on
residue levels found in the leftover turnips, fi eld investigators determined that the grower had over-
applied the product by a factor of two to four (2:4). The grower had also applied the granules to a
nearby cabbage fi eld, where investigators found 40 more ducks and a hawk (species unspecifi ed).
Furadan 10G was (and is) not registered for cabbage. The grower had banded the granules as in a
turnip crop but, for all these reasons, pesticide regulatory authorities deemed the application a tech-
nical misuse and fi ned the grower under the Pest Control Products Act.
After this incident, FMC and Chemagro (the name of the Bayer Corporation in Canada at the time)
withdrew registrations of Furadan 10G from the lower mainland of British Columbia (Whitehead
1975b; FMC 1975b, 1976b). At the request of British Columbia's Department of Agriculture