Advisory Committee on Pesticides Annual Report 2001

<strong>Advisory</strong> <strong>Committee</strong> on Pesticides Annual Report 2001
With a 100-fold assessment factor this gave an ADI of 0.013 mg/kg bw/day.
The <strong>Committee</strong> agreed that an acute reference dose (ARfD) should be set,
as it was possible that haemolysis could be caused after a single exposure.
It considered that the NOAEL of 11 mg/kg bw/day in a rat 28-day oral study
was the most appropriate starting point for setting an ARfD. Adverse effects
reported at higher doses were haemolysis as characterised by changes in
haematology accompanied by splenic and Kupffer cell haemosiderin and
haematopoiesis in bone spleen and liver. Use of a 100-fold assessment factor
gave an ARfD of 0.11 mg/kg bw/day. Calculated consumer exposures were
acceptable.
For derivation of the acceptable operator exposure level (AOEL) it was
considered appropriate to use the NOAEL of 1.8 mg/kg bw/day from the
90-day time point in a one-year dog study. This was based on reductions in
bodyweight, bodyweight gain and food efficiency in males at higher doses.
Applying a 100-fold assessment factor and a correction factor of 60 percent to
take account of incomplete oral absorption gave an AOEL of 0.01 mg/kg bw/day.
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It was concluded that dermal absorption appeared to be greater than 10 percent
as there seemed to be approximately equal levels of anaemia in rats dosed
orally and dermally at around 100 mg/kg bw/day The <strong>Committee</strong> agreed that
without further data, a conservative value of 25 percent dermal absorption
should be assumed. Operator, worker and bystander exposures were
acceptable when calculated using this dermal absorption value.
It was agreed that based on acute toxicity of the formulation to algae, ‘AC
900001’ required a classification of ‘Extremely dangerous to fish or aquatic
life’. Initial risk assessment had indicated unacceptable risks to aquatic life.
However, a microcosm study was presented which mimicked more realistic
conditions and indicated that effects on algae were transient with recovery
occurring within six weeks. No direct or indirect effects on zooplankton were
observed. Based on this study, and the fact that only one application per crop
was proposed and picolinafen did not persist in water, the <strong>Committee</strong>
concluded that the risks to aquatic life were acceptable without a buffer zone.
The <strong>Committee</strong> agreed that the long-term risks of the active substance to
earthworms were acceptable based on the low long-term persistence of
picolinafen in soil. The main soil metabolite, picolinafen acid, was more
persistent and its long-term risk to earthworms was considered. An outdoor
soil macro-organisms study indicated no adverse effect on the breakdown
of leaf material over a six-month period in plots treated with 100 g
picolinafen/ha. It was considered reasonable to assume that the main