Registration Dossier

Administrative data

Endpoint:
toxicity to other aquatic vertebrates
Remarks:
Experimental information for endocrine activity discussion.
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Justification for type of information:
Experimental information for endocrine activity discussion.

Data source

Reference
Reference Type:
publication
Title:
Assessment of hormonal activity of UV filters in tadpoles of frog Xenopus laevis at environmental concentrations
Author:
Kunz PY, Galicia HF, Fent K
Year:
2004
Bibliographic source:
Marine Environmental Research 58 (2004) 431–435

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
other: OECD Guideline 231 (Amphibian Metamorphosis Assay)
Version / remarks:
2009
Deviations:
yes
Remarks:
Longer exposure duration, fewer replicates and number of tadpoles per test vessel than recommended and no iodide concentrations and feeding reported.
GLP compliance:
not specified
Remarks:
Published study from a peer-reviewed journal.

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: All exposure groups were sampled at the start of exposure and the 1 μg/L exposure group was sampled at 72 hours.

Test solutions

Vehicle:
yes

Test organisms

Aquatic vertebrate type (other than fish):
frog
Test organisms (species):
Xenopus laevis
Details on test organisms:
TEST ORGANISM
- Age at study initiation: NF stage 52

Study design

Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
35 d
Remarks on exposure duration:
From NF stage 52 to 66

Test conditions

Test temperature:
22 ± 1°C
Nominal and measured concentrations:
1, 5 and 50 μg/L (nominal)
Actual concentrations were 93-115% of nominal concentrations at 0 h for all exposure groups and was 39% for the 1 μg/L exposure group at 72 hours.
Details on test conditions:
TEST SYSTEM
- Test vessel: 10 L stainless steel tanks
- Aeration: Test water was well-aerated.
- Renewal rate of test solution: Every 48 hours on weekdays and 72 hours on weekends.
- No. of organisms per vessel: 15
- No. of vessels per concentration: 2
- No. of vessels per control: 2
- No. of vessels per vehicle control: 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Artificial tap water

OTHER TEST CONDITIONS
- Photoperiod: 12 h/12 h light/dark cycle

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Developmental stage, whole body and tail length of the tadpoles were determined on day 0, 7, 14, 21, 28 and 35 of exposure. At the end of the experiment, visual inspection of gonads was conducted to assess sex ratio and gross gonad morphology.
Reference substance (positive control):
yes
Remarks:
1 μg/L thyroxin (T4)

Results and discussion

Effect concentrations
Key result
Duration:
35 d
Dose descriptor:
NOEC
Effect conc.:
> 50 µg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: developmental stage, body length, tail length, sex ratio
Details on results:
Mortality was less than 3% in all treatment groups and no apparent behavioural differences were observed between treatments. No significant effects on the metamorphosis rate, developmental stages, body and tail lengths, sex ratio or gross gonad morphology were observed compared to the controls.
Results with reference substance (positive control):
The positive control accelerated metamorphosis and differed significantly (p < 0.001) from all other treatment groups in developmental stage, as well as body and tail length.
Reported statistics and error estimates:
Statistical comparisons were performed using Kruskal–Wallis one-way ANOVA (on ranks, Dunn’s test) for development stages, body and tail length on day 0–28 and the Chi-square test for sex ratio.

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Conclusions:
Mortality was less than 3% in all treatment groups and no apparent behavioural differences were observed between treatments. No significant effects on the metamorphosis rate, developmental stages, body and tail lengths, sex ratio or gross gonad morphology were observed compared to the controls.
Executive summary:

The activity of 4-methylbenzylidene camphor on the thyroid and sex hormone system of frogs was investigated in Xenopus laevis tadpoles. Tadpoles were exposed to nominal concentrations of 1, 5 and 50 μg/L, alongside a control, solvent control and positive control, in an aqueous static-renewal system for 35 days from NF stage 52 to 66. Actual concentrations were 93-115% of nominal concentrations at 0 h for all exposure groups and was 39% for the 1 μg/L exposure group at 72 hours. Developmental stage, whole body and tail length of the tadpoles were determined on day 0, 7, 14, 21, 28 and 35 of exposure. At the end of the experiment, visual inspection of gonads was conducted to assess sex ratio and gross gonad morphology. Mortality was less than 3% in all treatment groups and no apparent behavioural differences were observed between treatments. No significant effects on the metamorphosis rate, developmental stages, body and tail lengths, sex ratio or gross gonad morphology were observed compared to the controls. This study is reliable with restrictions (Klimisch 2) as it was similar to OECD Guideline 231, with minor limitations in experimental design and reporting.