Registration Dossier

Administrative data

Endpoint:
toxicity to other aquatic vertebrates
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Non-GLP, non-guideline data, no analytical follow-up (issue when considering the long exposure time), lacking details on design (media characteristics)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1976

Materials and methods

Test guideline
Qualifier:
no guideline available
Principles of method if other than guideline:
Teratogenicity towards Xenopus (amphibian) embryos:
Test using embryonic and larval stages of frogs, aimed at assaying the effects on the development of frogs and determining EC50 and no-effect levels.
- Greenhouse, G. (1976). A method for evaluating the toxic effects of pollutants on fresh water systems using embryos and larvae of Xenopus laevis, the South African clawed toad. Environ. Pollut.
- Nieuwkoop, P. and Faber, J. (1956). Normal Table of Xenopus Laevis (Daudin). North Holland, Amsterdam.
GLP compliance:
no
Remarks:
prior to GLP

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
source: Aldrich Chemical Company

Sampling and analysis

Analytical monitoring:
no

Test solutions

Details on test solutions:
Each glass bowl contained one liter of water and 100 embryos.

Test organisms

Test organisms (species):
Xenopus laevis
Details on test organisms:
Xenopus laevis embryos/larvae:
embryos (obtained by injection of frogs with human chorionic gonadotropin) were dejellied in 3% cystein, 0.1% papain, pH 8.0, and then cultured in aged dechlorinated tap water in glass bowls.
Only clutches of eggs which proved to be at least 95% fertile were used.

, source: wild-caught (drainage ditches in Costa Mesa, California) or commercial (South African Snake Farm, South Africa).
maintained in glass aquaria
fed Purina Trout Chow twice weekly

Study design

Test type:
static
Water media type:
not specified
Limit test:
no
Remarks on exposure duration:
from blastula to hatching
Post exposure observation period:
no data

Test conditions

Hardness:
no data
Test temperature:
no data
pH:
no data
Dissolved oxygen:
no data
Salinity:
no data
Nominal and measured concentrations:
Nominal test concentrations of <5, 5, 7.5, 10 and 15 mg/L.
Details on test conditions:
no data
Reference substance (positive control):
no

Results and discussion

Effect concentrations
Dose descriptor:
EC50
Effect conc.:
> 5 - < 7.5 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
morphology
Remarks:
teratogenicity
Details on results:
=< 5% embryos malformed at =< 5 mg/L
>= 97% embryos malformed at >= 7.5 mg/L
very steep dose-effect curve, so no precise EC50 value could be derived statistically
Reported statistics and error estimates:
not applicable

Applicant's summary and conclusion

Validity criteria fulfilled:
not applicable
Remarks:
non-guideline
Executive summary:

MMH was teratogenic to Xenopus laevis frog embryos. The EC50 for malformations lied between 5 and 7.5 mg/L, with an extremely steep dose-effect curve.