N-methylaniline

Long-term toxicity to fish

Administrative data

Endpoint:

fish early-life stage toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From June 09 to July 14, 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 210 (Fish, Early-Life Stage Toxicity Test)

Version / remarks:

26 July 2013

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

N-methylaniline

EC Number:

202-870-9

EC Name:

N-methylaniline

Cas Number:

100-61-8

Molecular formula:

C7H9N

IUPAC Name:

N-methylaniline

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: Zebrafish
- Strain: Danio rerio
- Source: breeding of Hydrotox GmbH

POST-HATCH FEEDING
• From 2 d post hatch: ≥ 1×/d commercial dust food (Sera Micron, Sera GmbH, Heinsberg, Germany), infusoria
• From 8 d post fertilisation: ≥ 1 ×/d dust food, infusoria, Artemia salina larvae
• From 15 d post fertilisation: ≥ 1 ×/d dust food and Artemia salina

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

35 d

Test conditions

Test temperature:

25.4 – 26.6 °C

pH:

7.6 – 7.9

Dissolved oxygen:

6.5 – 8.2 mg/L

Conductivity:

674 – 1017 μS/cm

Nominal and measured concentrations:

0.02, 0.06, 0.21, 0.66 and 2.1 mg/L nominal concentration corresponding to
0.06, 0.03, 0.15, 0.32 and 0.82 mg/L geometric mean

Details on test conditions:

TEST SYSTEM
- Test vessel: beakers
- Material, size, headspace, fill volume: glass beakers of 250 mL from test start, 400 mL from 7 d post fertilisation, 600 mL from 16 d post fertilisation
- Renewal rate of test solution: three times per week
- No. of fertilized eggs/embryos per vessel: 10
- No. of vessels per concentration (replicates): 8
- No. of vessels per control (replicates): 8


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: ISO 7346 medium was prepared by mixing ISO 1, ISO 2, ISO 3 and ISO 4 (500 mL) with ultrapure water up to a final volume of 50L

OTHER TEST CONDITIONS
- Adjustment of pH: not specified
- Photoperiod: 14 h light : 10 h dark
- Light intensity:

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Vitality, hatching, development and behavior of the fish was assessed at least every working day as well as body length and weight at the end of the exposure period.

RANGE-FINDING STUDY
- Test concentrations: Nominal concentrations of 10 μg/L, 100 μg/L, 1000 μg/L
- Results used to determine the conditions for the definitive study: 7.5 %, 15.0 %, 27.5 %
mortality at the doses above listed, and 12.5 % for the negative control. The mean length at the end of the
exposure was 9.57 mm, 9.59 mm, 9.38 mm for 10 μg/L, 100 μg/L, 1000 μg/L test item treatment,
respectively, and 9.62 mm for the negative control. The chemical analysis of the test item
concentration at day 5 resulted in 7.75 μg/L, 82.9 μg/L, 863 μg/L test item before the renewal of
test solutions and 9.98 μg/L, 100 μg/L, 981 μg/L test item after the renewal, for nominal 10 μg/L,
100 μg/L, 1000 μg/L test item treatment, respectively.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

35 d

Dose descriptor:

NOEC

Effect conc.:

> 0.82 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

weight

Remarks:

Wet and dry

Effect concentrations 2

Duration:

35 d

Dose descriptor:

NOEC

Effect conc.:

> 0.82 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

length

Effect concentrations 3

Duration:

35 d

Dose descriptor:

NOEC

Effect conc.:

0.03 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: Post-hatch mortality

Effect concentrations 4

Duration:

5 d

Dose descriptor:

NOEC

Effect conc.:

> 0.82 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

time to hatch

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

NOEC for post-hatch mortality (35d) = 0.03 mg/L based on measured geom. mean

Executive summary:

The substance was tested for its potential to induce toxicity on fish after long-term exposure according to the OECD guideline 210.

The purpose of this study was to investigate the effects of the test item on early-life stage of Danio rerio. Zebrafish (eggs) < 2 h (8 – 32 cell stage) old were exposed to five concentrations of the test item in ISO 7346 medium for 35 d using a semi-static test design with renewal of the test solutions 3×/week. An accompanying substance specific chemical analysis was performed to determine the test item concentrations in the test vessels. Vitality, hatching, development and behavior of the fish was assessed at least every working day as well as body length and weight at the end of the exposure period. In the present study, nominal concentrations of 0.02. 0.06, 0.21, 0.66 and 2.1 mg/L test item were
applied, corresponding to 0.06, 0.03, 0.15, 0.32 and 0.82 mg/L measured geometric mean.

No effects on hatching, body lenght and weight were detected during the study at the highest concentration applied. Post hatch mortality was observed instead and the NOEC value was found to be 0.03 mg/L, based on geometric mean.