N-methylaniline

Long-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Abstract only.

Data source

Reference

Reference Type:

publication

Title:

Embryonic development assay with Daphnia magna: application to toxicity of aniline derivatives

Author:

Abe T, Saito H, Niikura Y, Shigeoka T, Nakano Y

Year:

2001

Bibliographic source:

Chemosphere. 2001 Nov;45(4-5):487-95.

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

A specific embryo assay was performed on Daphnia magna species. This assay provided useful information to evaluate the toxicity of chemicals and the differences in sensitivity between the life stages. The effects of 15 aniline derivatives on embryonic development of D. magna embryos were determined.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

3-methylaniline

IUPAC Name:

3-methylaniline

Constituent 2

Reference substance name:

4-methylaniline

IUPAC Name:

4-methylaniline

Constituent 3

Reference substance name:

4-ethylaniline

EC Number:

209-637-0

EC Name:

4-ethylaniline

Cas Number:

589-16-2

IUPAC Name:

4-ethylaniline

Details on test material:

In total 15 aniline derivatives were tested.

Sampling and analysis

Analytical monitoring:

no

Test organisms

Test organisms (species):

Daphnia magna

Study design

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 d

Results and discussion

Any other information on results incl. tables

Ratios of 48-h EC50 (juvenile)/3-day EC50 (embryo) for eight anilines were greater than 5.0. Particularly, the ratios of 4-methyl-, 4-ethyl- and 3-methylaniline were 77, 23 and 11, respectively. EC50s for embryos and juveniles were poorly correlated (r = 0.41).

EC50s also poorly correlated (r = -0.097) with the log Kow (1-octanol/water partition coefficient).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

In control and solvent control groups, embryonic development from an egg to a free-swimming animal proceeded completely within 3 days with more than 90% hatchability.

Conclusions:

Embryonic stages of D. magna are significantly more sensitive to methylated anilines than juveniles tested normally in 48-h acute toxicity tests. It should be noted however, that this may be at least be partly due to the longer exposure period.

Executive summary:

An assay system using Daphnia magna embryos was applied to investigate the adverse effects of aniline derivatives. The data were compared with our previous data for chlorophenols. This new assay provides useful information to evaluate the toxicity of chemicals and the differences in sensitivity between the life stages. The effects of 15 aniline derivatives on embryonic development of D. magna embryos were determined. At the start of exposure, 2-6-h old eggs (between stages 1 and 2, round in shape, diameter approx. 400 microm), were used. In control and solvent control groups, embryonic development from an egg to a free-swimming animal proceeded completely within 3 days with more than 90% hatchability. Median effective concentrations (EC50s) to reduce the numbers hatched were determined and gross morphological abnormalities of hatched animals recorded. Anilines induced no obvious morphological abnormalities and no developmental delay although premature deaths occurred. However, they affected the number of embryos hatching in a dose-dependent manner. In addition, this embryo assay was more sensitive to aniline derivatives (except for aniline) than acute juveniles immobilization assay. Ratios of 48-h EC50 (juvenile)/3-day EC50 (embryo) for eight anilines were greater than 5.0. Particularly, the ratios of 4-methyl-, 4-ethyl- and 3-methylaniline were 77, 23 and 11, respectively. EC50s for embryos and juveniles were poorly correlated (r = 0.41). This indicated that the sensitivities of the two life stages were different to the effects of anilines. EC50s were poorly correlated (r = -0.097) with the log Kow (1-octanol/water partition coefficient).