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Toxicological information

Genetic toxicity: in vivo

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Administrative data

Endpoint:
in vivo mammalian germ cell study: cytogenicity / chromosome aberration
Type of information:
experimental study
Adequacy of study:
disregarded due to major methodological deficiencies
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
significant methodological deficiencies
Remarks:
- The dose applied is extremely high (if body weight mouse is 25 g: 20,000 mg/kg bw/d). This is 10 times the maximum dose allowed according to OECD 475. - The number of animals used is not mentioned and individual data are not given (it could be possible that 3 animals have been used and the deviation was only in one animal). - The number of metaphases is 300, while 100 per animal on a group of 5 animals per dose are required according to OECD 475. - No positive control used.

Data source

Reference
Reference Type:
publication
Title:
Induction of mitotic-chromosome anomalies in mice by single super phosphate.
Author:
Chaurasia, O.P. and Sinha, S.P.
Year:
1988
Bibliographic source:
Cytologia 53:485-489.

Materials and methods

Test guideline
Qualifier:
no guideline followed
GLP compliance:
not specified
Type of assay:
mammalian bone marrow chromosome aberration test

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
No additional data available.

Test animals

Species:
mouse
Strain:
Swiss
Sex:
not specified
Details on test animals and environmental conditions:
7-10 weeks old

Administration / exposure

Route of administration:
oral: feed
Details on exposure:
Single superphosphate was fed to 7-10 week old mice for seven days at a rate of 500 mg/day after mixing with basic food.
Duration of treatment / exposure:
7 d
Doses / concentrations
Dose / conc.:
500 mg/kg bw/day (nominal)
No. of animals per sex per dose:
No data
Control animals:
no
Positive control(s):
No data

Examinations

Tissues and cell types examined:
Their bone marrow was separated from both femura and slides were prepared. Screening of any chromosomal abnormalities was made in 300 well spread metaphase plates.
Details of tissue and slide preparation:
Of the 300 metaphase plates, 90 abnormal ones were found in treated animals in contrast to 15 among the controls, a six-fold increase in chromosomal abnormalities. Among the gross types, clumping and stickiness of chromosomes as well as pulverization were observed.

Results and discussion

Additional information on results:
Among the individual types, the breaks were in the form of subchromatidal and chromatidal nature. Translocations, gaps, and constrictions were also observed. The frequency of chromosomal abnormality relative to controls increased by 40% whereas that of gross and individual types was by 5 and 35%, respectively. The breaking-points of the affected chromosomes were somewhat localized in the distal region. According to the authors, single superphosphate, when administered to mammals, is clastogenic and appears to be mutagenic.

Applicant's summary and conclusion

Conclusions:
Due to major methodological deficiencies the study cannot be used for classification.