Superphosphates

Genetic toxicity: in vivo

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

Test material information

Constituent 1

Reference substance name:

Superphosphates

EC Number:

232-379-5

EC Name:

Superphosphates

Cas Number:

8011-76-5

Molecular formula:

not applicable

IUPAC Name:

Superphosphates

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 or test system 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.