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Return to
Flocoumafen Index Page
Activity:
Rodenticide
(coumarin)
Structure:
Adverse Effects:
Ataxia
Embryotoxic
Liver
Teratogen
Environmental
•
WHO: Extremely hazardous (Class
1a)
•
In the mid to late 1970s, a group of compounds known as the
"second generation" anticoagulants were developed.
These compounds include bromadiolone, difenacoum, brodifacoum,
flocoumafen and difethialone,
and are considerably more toxic, killing
rodents that are resistant to the first generation
anticoagulants. With these compounds rodents may eat enough
to kill them in a single day or in some cases in a single
feeding, but they still will take several days to die. While
very successful and widely used, these compounds and particularly
the latter three have quite a high toxicity
to non-target animals and pose a significant secondary hazard
threat. In a sense, they lack some of the advantages
of the first-generation anticoagulants. Some resistance has
also been documented to second-generation anticoagulants in
a few areas.
Ref: Advances in IPM Rodent Control
in Agriculture. CISSE W. SPRAGINS, Rockwell Laboratories Ltd.,
Minneapolis, MN, USA. http://www.sustdev.org/journals/edition.01/download/01.135.pdf |
Ataxia
(click on for all fluorinated pesticides)
Sub-acute Toxicity.
...In a five-day range-finding study, male and female Fischer
344 rats received 0, 0.2, 0.4 or 0.8 ppm of flocoumafen in the
diet together with vitamin K3 at 3 ppm. Four out of five males
and four out of five females receiving 0.8 pm died after 9-12
days after the initial dose. Clinical signs reported in rats receiving
0.8 ppm included abnormal posture, ataxia,
paralysis of the hind legs, swelling, bruising and bleeding from
the nose. Body weight gain was reduced in both sexes receiving
the top dose and temporarily in some males receiving 0.4 and 0.2
ppm...
Ref:
Evaluation
on Flocoumafen. April 1987. UK Department
for Environment, Food and Rural Affairs, Pesticides Safety Directorate,
Mallard House, Kings Pool 3 Peasholme Green, York YO1 7PX. Also
available at
http://www.pesticides.gov.uk/citizen/evaluations/evallist.htm
Embryotoxic
and Teratogenic
(click on for all fluorinated pesticides)
Abstract: Embryotoxic
and teratogenic effects of flocoumafen (new anticoagulant rodenticide)
in chick embryos and white rats were studied. Flocoumafen was
injected (2 ug/egg) to the yolk sac of Fayuomi fertile eggs on
the 5th and 9th day of incubation. It was orally administered
to pregnant female rats (2.5 and 5 ug/kg B. Wt.) on the 8th, 10th
and 12th day of gestation. The study revealed
that flocoumafen was more embryotoxic than teratogenic in both
chick embryos and white rats.
Ref:
Khalifa BA et al. (1992). Embryotoxic and teratogenic effects
of flocoumafen in chick embryos and white rats. Journal of Applied
Animal Research;2(2):81-5
Liver
(click on for all fluorinated pesticides)
Sub-acute Toxicity.
... Male and female Fischer 344 rats received 0, 0.01, 0.05, 0.1
or 0.2 ppm flocoumafen (cis:trans ration - 55:44) in the diet
for 28 days. (3 ppm vitamin K3 was also incorporated into the
diet.) There were no deaths and no clinical signs of toxicity
were reported. small increases were observed in the prothrombin
and activated partial thromboplastin times in both sexes receiving
0.2 ppm and total protein was decreased in females receiving 0.1
and 0.2 ppm and in males receiving 0.2 ppm.
The majority of males receiving 0.2 ppm had treatment-related
histopathological changes in the liver (reduced periportal glycogenic
vacuolation and increased histiocytic foci). 0.05 ppm (equivalent
to 0.0025 mg/kg bw per day) was the no-effect level.
Ref:
Evaluation
on Flocoumafen. April 1987. UK Department
for Environment, Food and Rural Affairs, Pesticides Safety Directorate,
Mallard House, Kings Pool 3 Peasholme Green, York YO1 7PX. Also
available at http://www.pesticides.gov.uk/citizen/evaluations/evallist.htm
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Environmental
(click on for all
fluorinated pesticides)
In
a laboratory study, radiolabelled flocoumafen was applied
at a nominal rate of 50 mg/kg to 3 different soil types.
After 217 days, 84 to 89% of the applied
activity remained as unchanged flocoumafen, 2-4%
was recovered as carbon dioxide and 3-5% remained as unextractable
residue... Hydrolysis was only studied at 50C, at which
temperature flocoumafen was not readily broken down. The
half-life at pH5 was 30-31 days, pH7 447 days and pH9 445
days...
Toxicity
to Aquatic Organisms.
Technical flocoumafen was highly toxic
to fish when dispersed in acetone with 96 h LC values
of 0.091 mg/l (daily water change) and 0.32 mg/l (static)
in rainbow trout and 0.22 mg/l (static) in carp... Flocoumafen
was highly toxic to the water flea
(Daphnia magna), the 49 h EC 50 for technical
in acetone being 0.66 mg/l, and 280 mg formulation/1 (equivalent
to 1.4 mg ai/l). The 96 h EC 50 for technical flocoumafen
to Selenastrum capricornutum (planktonic algae) was
1.1 mg/l.
Effect
on Non-target species:
The following trials have been carrid out by MAFF using
0.005% flocoumafen on medium oatmeal and/or whole wheat
base prepared from 0.1% concentrate.
(a)
Surplus baiting technique, Welshpool
area, R-norvegious infestations - 6 sites.
3 non-target casualties were recorded during these trials
including a grey squirrel, a rabbit and a robin).
(b)
Minimal baiting technique, Welshpool
area, R-norvegious
infestations - 6 sites. These have not yet been reported.
(C)
Surplus baiting technique, Hampshire,
suspected Difenacoum resistant R-norvegious infestations
- 6 sites. Two of these farm sites were frequented by larged
mixed flocks of finches and these were observed to enter
bait boxes and to feed on bait. More than 30 bird casualties
were recorded, these included 4 pheasants, 1 partridge,
1 moorhen and numerous passerine birds. Post-mortem of these
birds revealed severe hemorrhaging or blue colouration of
the bill. No residues data for these casualties were supplied.
(D)
Surplus baiting technique, West Sussex,
Mus musculus infestations - 10 sites (granaries,
feed stores, utility barm). Mice died from 3 to 10 days
after start of baiting. This was an efficacy trial only
and so non-target casualties were not reported.
Three
further trials were carried out at Kent
farms by Shell Research Limited in December 1984
using a bait formulation of 0.005% flocoumafen on a cut
wheat base. Surplus baiting was carried out for 3 weeks
using an agreed wildlife monitoring protocol. A total of
67 dead non-target birds and 17 dead non-target mammals
(mice, voles and 1 grey squirrel) were found around farm
buildings. Of these, 28 were judged to have resulted from
flocoumafen poisoning based on haemorrhaging found at post-mortem.
These 28 deaths comprised small passerine birds. Residue
analysis of these carcases has not yet been reported. Few
birds were found during the baiting and early post-baiting
period other than 21 house sparrows at 1 site. The majority
of dead birds were not found until 2 to 4 weeks after baiting
finished, a period which also had more severe weather conditions.
One dead robin was found during the third week of baiting
lying beside a bait tray underneath the protective cover.
Flocoumafen residues in 25 dead rats found above ground
indicated whole body residues varied generally between 0.5
and 4.3 mg/kg bw. Between 20 and 40% of the total body burden
of flocoumafen was found in the rat livers.
Ref: Evaluation
on Flocoumafen. April 1987. UK
Department for Environment, Food and Rural Affairs, Pesticides
Safety Directorate, Mallard House, Kings Pool 3 Peasholme
Green, York YO1 7PX. Also available at http://www.pesticides.gov.uk/citizen/evaluations/evallist.htm
•
In the mid to late 1970s, a group of compounds known as
the "second generation" anticoagulants were developed.
These compounds include bromadiolone, difenacoum, brodifacoum,
flocoumafen and difethialone,
and are considerably more toxic, killing
rodents that are resistant to the first generation
anticoagulants. With these compounds rodents may eat enough
to kill them in a single day or in some cases in a single
feeding, but they still will take several days to die. While
very successful and widely used, these compounds and particularly
the latter three have quite a high
toxicity to non-target animals and pose a significant secondary
hazard threat. In a sense, they lack some of the
advantages of the first-generation anticoagulants. Some
resistance has also been documented to second-generation
anticoagulants in a few areas.
Ref: Advances in IPM Rodent Control
in Agriculture. CISSE W. SPRAGINS, Rockwell Laboratories
Ltd., Minneapolis, MN, USA. http://www.sustdev.org/journals/edition.01/download/01.135.pdf
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