Registration Dossier

Administrative data

Endpoint:
long-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Data is from peer reviewed journal

Data source

Reference
Reference Type:
publication
Title:
LIFE-CYCLE TOXICITY OF 4-NONYLPHENOL TO MEDAKA (ORYZIAS LATIPES)
Author:
HIROFUMI YOKOTA, MASANORI SEKI, MASANOBU MAEDA, YUJI OSHIMA,HIROSHI TADOKORO, TSUNEO HONJO,and KUNIO KOBAYASHI
Year:
2001
Bibliographic source:
Environmental Toxicology and Chemistry, Vol. 20, No. 11, pp. 2552–2560, 2001

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: refer below principle
Principles of method if other than guideline:
The chronic effects of 4-NP on the life cycle of medaka (ORYZIAS LATIPES) over two generations in continuous exposures.
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid: viscous
Details on test material:
- Name of test material (as cited in study report): 4-Nonylphenol (104-40-5)
- Molecular formula (if other than submission substance): C15-H24-O
- Molecular weight (if other than submission substance): 220.354 g/mol
- Smiles notation (if other than submission substance): c1(ccc(O)cc1)CCCCCCCCC
- InChl (if other than submission substance): IGFHQQFPSIBGKE-UHFFFAOYSA-N
- Structural formula attached as image file (if other than submission substance): No data available
- Substance type: Organic
- Physical state: Liquid
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
No data available

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
No data available

Test solutions

Vehicle:
yes
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
A 4-NP stock solution of 1,500 mg/L was prepared by dissolving in ethanol.

Test organisms

Test organisms (species):
Oryzias latipes
Details on test organisms:
TEST ORGANISM
- Common name: Japanese rice fish
- Strain: No data available
- Source: local fish farm in Kumamoto, Japan
- Age at study initiation (mean and range, SD): No data available
- Length at study initiation (length definition, mean, range and SD): mean ± standard deviation : 29.9 ± 1.8
mm
-Weight at study initiation (mean and range, SD): mean ± standard deviation : 233 ± 50 mg
- Method of breeding: No data available
- Feeding during test: Yes
- Food type: Artemia nauplii
- Amount: No data available
- Frequency: Twice a day

ACCLIMATION
- Acclimation period: breeding stock of this medaka has been maintained for several years in our laboratory.
- Acclimation conditions (same as test or not): No data available
- Type and amount of food: No data available
- Feeding frequency: No data available
- Health during acclimation (any mortality observed): No data available

QUARANTINE (wild caught)
- Duration: No data available
- Health/mortality: No data available

Study design

Test type:
flow-through
Water media type:
freshwater
Remarks on exposure duration:
Two generation duration (F0 and F1)
Post exposure observation period:
60 d posthatch

Test conditions

Hardness:
44.0–73.5 mg CaCO3/L
Test temperature:
24 ± 18°C.
pH:
7.4– 7.5
Dissolved oxygen:
No data available
Salinity:
No data available
Nominal and measured concentrations:
1.85, 5.56, 16.7, 50, and 150 µg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: cylindrical glass test chamber
- Material, size, headspace, fill volume: diameter, 15.0 cm; depth, 17.5 cm
- Aeration: No data available
- Type of flow-through (e.g. peristaltic or proportional diluter): Continuous flow system
- Renewal rate of test solution (frequency/flow rate): in each chamber was 14 times a day
- No. of organisms per vessel: 15/vessels
- No. of vessels per concentration (replicates): quadruplicate
- No. of vessels per control (replicates): No data available
- No. of vessels per vehicle control (replicates): No data available
- Biomass loading rate: No data available

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: designed to contain about 1.8 L of the test solution by maintaining an overflow level of 10 cm.
- Total organic carbon: No data available
- Particulate matter: No data available
- Metals: No data available
- Pesticides: No data available
- Chlorine: No data available
- Alkalinity: No data available
- Ca/mg ratio: No data available
- Conductivity: No data available
- Culture medium different from test medium: No data available
- Intervals of water quality measurement: No data available

OTHER TEST CONDITIONS
- Adjustment of pH: No data available
- Photoperiod: 16 h light: 8 h dark.
- Light intensity: No data available

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Embryological development, hatching, posthatch survival, growth, sexual differentiation, and reproduction under flow-through exposures.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: No data available
- Justification for using less concentrations than requested by guideline:
This three 4.2, 8.2, 17.7 µg/L concentrations were used and upper two concentrations were discarded because mortality found was higher than control mortality.

- Range finding study: study based on a 7-d preliminary exposure with newly hatched larvae.
- Test concentrations: 4.2, 8.2, 17.7, 51.5, and 183 µg/L
- Results used to determine the conditions for the definitive study: No data available
Reference substance (positive control):
not specified

Results and discussion

Effect concentrationsopen allclose all
Dose descriptor:
LOEC
Effect conc.:
17.7 µg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: Growth, external secondary sex characteristics, and gonadal histology
Dose descriptor:
NOEC
Effect conc.:
8.2 µg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: Growth, external secondary sex characteristics, and gonadal histology.
Dose descriptor:
LOEC
Effect conc.:
17.7 µg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: hatching success, posthatch mortality, or growth
Details on results:
- Mortality/survival at embryo and larval stages: No embryological abnormalities or hatching failures of fertilized eggs (F1 embryos) were observed in any treatment.

- Overall mortality/survival: Mortalities in the 17.7- and 51.5-µg/L treatments increased after 20 d posthatch, and the cumulative mortalities at 60 d posthatch were significantly different from those of the pooled controls (p = 0.031 and 0.002, respectively).

- Days to hatch and numbers hatched: The hatchabilities in all treatments were ≥70%, and the time to hatch in most embryos was 10 to 12 d in every treatment, with no significant differences between the treatments and the pooled controls.

- Data for length and weight of surviving fish: No significant differences were observed in either mean total length or body weight of the F0 fish at 60 d posthatch in any treatments.

- Type of and number with morphological abnormalities: Morphological examination of secondary sex characteristics showed that the sex ratios were approximately 1:1 in the control and ≤8.2 mg/L in the 4-NP treatment. In the 17.7-µg/ L treatment, however, more females than males were identified, and the sex ratio of males to females was about 1:2.

- Type of and number with behavioural abnormalities:
Induction of testis–ova in the gonads of the F1 generation was observed at lower 4-NP concentrations than at those in the F0 generation. In the 8.2- and 17.7-µg/L treatments, testis– ova were observed in two (10%) and five (25%) among 20 fish examined, respectively.

- Other biological observations: No data available
- Effect concentrations exceeding solubility of substance in test medium: No data available
- Incidents in the course of the test which might have influenced the results: No data available
Results with reference substance (positive control):
No data available
Reported statistics and error estimates:
chi-square test, Student’s t test (parametric data), or Bonferroni’s U test (nonparametric data) were used prior to data analysis to determine whether differences existed between the solvent control and control groups.

Any other information on results incl. tables

No histological abnormalities were observed in the ovaries of medaka in the 17.7- and 51.5-µg/L.

 

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Conclusions:
In F0 generation the end point for developmental toxicity test was found to be LOEC and NOEC at 17.7 and 8.2µg/L after treatment with p-nonylphenol (104-40-5).
Executive summary:

Developmental toxicity test was performed on MEDAKA (ORYZIAS LATIPES) for two generations.

 

The exposure study of the parental (F0) medaka was begun on embryos within 24 h post fertilization and continued with monitoring through embryological development, hatching, post hatch survival, growth, sexual differentiation, and reproduction under flow-through exposures to mean measured 4-NP concentrations of 4.2, 8.2, 17.7, 51.5, and 183 µg/L for up to 104 d. Exposure was initiated at less than 24 h post fertilization.

 

After hatching, the larvae were fed an adequate amount of Artemia nauplii (24 h after hatching) twice a day. Daily observation was made to examine mortality and abnormal behavior and appearance until 60 d post hatch, and dead fish were removed as soon as possible.

 

Larval–juvenile phase:At 60 d post hatch, five individuals from each of the four test chambers were randomly removed and observed for external secondary sex characteristics.

The fish were euthanized embedded in paraffin wax were sectioned longitudinally at 3 mm in thickness providing at least five sections per gonad. The sections were stained with hematoxylin and eosin, mounted with malinol and then examined under a light microscope.

 

Reproductive phase:At 70 d post hatch, the sex of the surviving fish was distinguished by their external appearances, and six mating pairs from each of the two low treatments (4.2 and 8.2 mg/L) and the controls and solvent controls were selected to examine fecundity and fertility.

 

F1 embryo phase:The eggs spawned on the last 2 d of the reproductive phase (102 and 103 d post hatch) were subjected to the following semi static 4-NP exposure until hatching.

 

F1 larvae–juvenile phase:The newly hatched larvae in the two low treatments (4.2 and 8.2 mg/L) and the controls and solvent controls were randomly transferred to four test chambers in each treatment and kept in the chambers until the last hatching.

 

Embryo development and hatching of medaka eggs were affected by 4-NP exposure. Hatchability was significantly decreased in the highest treatment (183 mg/L) relative to the pooled controls but most hatch abilities in the lower treatments were >90%, with no significant difference from the controls.

No significant differences were observed in either mean total length or body weight of the F0 fish at 60 d post hatch in any treatments.

 

Observation of external secondary sex characteristics the sex ratios of males to females in the controls were about 1:1.3, and those in the three groups treated with 4-NP at ≤17.7 mg/L were slightly different from each other, whereas no males were distinguished in the 51.5-mg/L treatment.

 

The fecundity of paired medaka during the reproductive phase from 71 to 103 d post hatch was not affected by 4-NP treatment; however, mean fertility was decreased in the 17.7-mg/L treatment. No embryological

abnormalities or hatching failures of fertilized eggs

(F1 embryos) were observed in any treatment.

 

Morphological examination of secondary sex characteristics showed that the sex ratios were approximately 1:1 in the control and ≤8.2 mg/L in the 4-NP treatment. In the 17.7-mg/ L treatment, however, more females than males were identified, and the sex ratio of males to females was about 1:2.

 

Therefore, it was found that In F0 generation the end point for developmental toxicity test was found to be LOEC and NOEC at 17.7 and 8.2µg/L after treatment with p-nonylphenol (104-40-5).