Pesticide residues in food — 2006: Toxicological ... - ipcs inchem

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2. Toxicological studies
2.1 Acute toxicity
The acute oral toxicity of boscalid (batch No. N 26, purity 95.3% was evaluated in groups of five
male and five female fasted Wistar rats given boscalid as a single dose at 2000 or 5000 mg/kg bw by
gavage in 0.5% aqueous Tylose CB 30.000, using dose volumes of 10 and 20 ml/kg bw r espectively.
The rats were then observed for up to 14 days. The stability of boscalid and the h omogeneity and
concentrations of the dosing solutions were confirmed by analysis.
There was no mortality in either males or females. Signs of toxicity noted at 5000 mg/kg bw
i ncluded impaired general condition, dyspnoea, excitation, erythema and piloerection in males and
females. These signs were observed on day 1 in two males and in one female. All rats appeared
n ormal within 2 days after dosing. Body-weight development was normal. There were no m acroscopic
p athological findings in rats killed at the end of the observation period (Wiemann & Hellwig, 1998c;
Wiemann, 2000e). The oral LD 50
was > 5000 mg/kg bw in male and female rats.
The acute percutaneous (dermal) toxicity of boscalid (batch No. N 26, purity, 95.3%) was
investigated in five male and five female Wistar rats given the test material at a dose of 2000 mg/kg
bw as a 0.5% aqueous Tylose CB 30.000 preparation under a semi-occlusive dressing for 24 h. The
application area was about 50 cm². The stability of boscalid, its homogeneity and concentration in the
vehicle was confirmed by analysis.
No mortality occurred during the 14 days of observation after application.
No clinical signs of toxicity were observed and body-weight development was normal. One
day after application, a well-defined erythema was observed in a single female on the first day
a fter a pplication. Body-weight development appeared to be normal. There were no macroscopic
p athological findings in rats killed at the end of the observation period (Wiemann & Hellwig, 1998b;
Wiemann, 2000a). The dermal LD 50
for boscalid in male and female rats was > 2000 mg/kg bw.
A test for the acute toxicity of boscalid (batch No. N 26, purity 95.3%) was conducted in a
group of five male and five female Wistar rats exposed by inhalation via a head/nose inhalation s ystem
for 4 h to boscalid at a mean analysed atmospheric concentration of 6700 μg/l. The observation time
was 14 days. Boscalid was demonstrated to be stable and homogeneously distributed in the exposure
atmospheres. Particle size analysis of the boscalid sample used revealed a mass median a erodynamic
diameter (MMAD) of 3.4 μm, which is within the respirable range. No mortalities occurred in the
test group. Clinical observations included attempted escape behaviour, irregular r espiration and
r espiratory sounds, as well as urine-smeared fur, piloerection and squatting posture. No unusual
clinical observations were made from day 3 after exposure onward. Body-weight d evelopment was
not adversely affected by the test substance exposure. No macroscopic pathological findings were
noted in exposed animals at the end of the study. The inhalation LC 50
of boscalid in male and female
rats was > 6700 mg/m 3 (Gamer & Hoffmann, 1998).
Boscalid (batch No. N 26, purity, 95.3%) was evaluated for acute dermal irritation potential
in two male and four female New Zealand White rabbits. Boscalid (0.5 g) was applied to the
intact skin for 4 h on a 2.5 cm × 2.5 cm test patch under a semi-occlusive dressing. After the
patches were r emoved, the treated area was rinsed with Lutrol and Lutrol/water (1:1). The skin
irritation was scored at 1, 24, 48 and 72 h after removal of the test material. The stability of the
test substance over the study period was confirmed. Results from the individual animals are shown
in Table 20.
BOSCALID X-X JMPR 2006