Pesticide residues in food — 2007: Toxicological ... - ipcs inchem

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Table 5. Cholinesterase activity in mice fed diets containing azinphos-methyl for 104 weeks
Time-point
Cholinesterase activity a
Dietary concentration (ppm)
0 5 20 40
Males Females Males Females Males Females Males Females
Plasma
(μmol/ml per min):
6 months 3.11 5.76 3.33 5.45 2.57 3.08 1.62 1.48
1 year 3.88 6.51 4.81 5.44 2.63 3.27 1.32 1.50
2 years 4.33 4.98 3.95 4.93 2.97 3.86 1.89 1.65
Erythrocytes
(μmol/ml per min):
6 months 1.33 1.16 1.11 1.03 0.88 0.67 0.67 0.63
1 year 1.04 0.87 0.99 0.81 0.45 0.39 0.20 0.20
2 year 0.95 0.79 0.80 0.62 0.54 0.40 0.35 0.32
Brain
(μmol/g per min):
2 years 14.7/ 14.4 12.9/ 13.6 12.3 10.6 5.4 4.7
From Hayes (1985); Annex 1, reference 64, amended with reference to original data.
a
Results of statistical analysis not specified in the report.
2.4 Genotoxicity
The results of studies of genotoxicity with azinphos-methyl are summarized in Table 7.
An effort was made to evaluate the genotoxicity of a variety of pesticides, with the specific objectives
of comparing different assays in vivo and in vitro, examining the spectrum of genetic activity
displayed by the selected pesticides and examining the test results in relation to other biological and
chemical features of the pesticides. In this research programme, azinphos-methyl was used in 14 teats
for mutagenicity, examining point or gene mutations, DNA damage and chromosomal effects. Positive
results for azinphos-methyl were seen in only two tests: an assay for forward mutation in mouse
lymphoma L5178Y cells (only in the presence of metabolic activation) and an assay for mitotic recombination
in Saccharomyces cerevisiae strain D3. Azinphos-methyl gave negative results in tests
for point/gene mutation and DNA damage in prokaryotes and showed no positive results in tests for
chromosomal effects (Waters et al., 1982; Annex 1, reference 64).
2.4 Reproductive toxicity
(a)
Multigeneration studies
Rats
In a two-generation (two litters per generation) study of reproduction, groups of 12 male and
24 female Wistar rats were given diets containing azinphos-methyl (purity, 87.2%) at a concentration
of 0 (control), 5, 15 or 45 ppm (equal to 0, 0.33–0.42, 1.02–1.22 and 3.46–7.37 mg/kg bw per
day in males and 0, 0.48–0.67, 1.48–2.02 and 4.84–10.27 mg/kg bw per day in females). At 45 ppm,
AZINPHOS-METHYL 139–172 JMPR 2007