3,5-xylidine

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Test period 24.12.1997 - 31.03.1998

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1992

GLP compliance:

yes

Analytical monitoring:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
The test solution was prepared by diluting 1000 mg of the test substance in 1000 mL of pure water (concentration of test substance: 1000 mg/L). For the test solution, the following volume of the test substance stock solution was taken and diluted to 5.0 g/L with dilution water.

Test organisms (species):

Oryzias latipes

Details on test organisms:

TEST ORGANISM
- Common name: killifish
- Source: Sankyo Suisan Corporation (Tokyo)
- Length at study initiation (length definition, mean, range and SD): 1.7 cm (1.56 - 1.83 cm), n=10
- Weight at study initiation (mean and range, SD): 0.085 g (0.056 - 0.108g), n=10

ACCLIMATION
- Acclimation period: January 8, 1998 - January 26, 1998
- Acclimation conditions: same as test
- Type and amount of food during acclimation: commercial food (Tetramin O)
- Feeding frequency during acclimation: 24 hours prior to test no food
- Health during acclimation (any mortality observed): Mortality was less than 5% during the 7 days prior to exposure.


FEEDING DURING TEST (as applicable)
No feeding

Test type:

semi-static

Water media type:

freshwater

Remarks:

change every 24 hours

Limit test:

no

Total exposure duration:

96 h

Hardness:

63 mg/L (CaCO3 equivalent)

Test temperature:

24±1 °C

pH:

7.8

Conductivity:

180 μS/cm

Nominal and measured concentrations:

Control, 6.00, 12.0, 24.0, 48.0 and 96.0 mg/L (ratio 2)

Details on test conditions:

TEST SYSTEM
- Test vessel: Beaker
- Type (delete if not applicable): closed (with Teflon sheet)
- Material, size, headspace, fill volume: glass, 5L
- Aeration: no
- Renewal rate of test solution (frequency/flow rate): 24h
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: dechlorinated water, well aerated


OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod: 16 hours light/8 hours dark

OBSERVATIONS
- After measuring the water temperature, dissolved oxygen concentration, and pH of the test solution in each test tank, 10 test fish per concentration ten fish per test tank were placed in the test tank. Water temperature, dissolved oxygen concentration, and pH were measured at the beginning of the test and before and after water changes every 24 hours. Mortalities were recorded at 24, 48, 72, and 96 hours after the start of exposure, and any signs of toxicity or abnormality observed were recorded.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study
- Test concentrations: 1st run: 1, 10, 100 mg/L (one series of 5 fish/concentration)
2nd run: 3, 10, 30 mg/L
- Results used to determine the conditions for the definitive study: 96-hour mortality rate was 20% in 1 and 10 mg/L, 100% in 100 mg/L and 3% in 3 mg/L and 10 and 30 mg/L
Based on the results of the preliminary study, the concentrations in this study were 6.0, 12.0, 24.0, 48.0 and 96.0 mg/L.

Reference substance (positive control):

yes

Remarks:

Copper (II) sulfate pentahydrate, Reagent Special Grade, Wako Pure Chemical Industries, Ltd. LC50(96h) 0.73 mg/L (95% confidence interval: 0.53 mg/L to 1.0 mg/L)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

33.9 mg/L

95% CI:

>= 25.5 - <= 45.2

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

96 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

(1) Concentration of the test substance in the test solution: All measured concentrations were within ±20% of the set concentration. Therefore, the calculation of the results was based on the set concentrations.
(2) 96-hour half lethal concentration (LC50): 33.9 mg/L (95% confidence interval: 25.5 g/L to 45.0 g/L)


Concentration of the test substance in the test solution
　The concentration of the test substance in the test solution was measured at the beginning and after 24 hours. The concentrations at the beginning of the study were
The concentration at the start of the test was 5.71-91.3 mg/L (set value: 6.00-96.0 mg/L), and the concentration after 24 hours was 5.67-92.0 mg/L (set value: 6.00-96.0 mg/L).
The concentration after 24 hours was 5.67 to 92.0 mg/L (set value: 6.00 to 96.0 mg/L). The geometric mean concentrations at the beginning and after 24 hours ranged from 5.69 to 91.6 mg/L.
The geometric mean concentrations at the beginning and after 24 hours ranged from 5.69 to 91.6 mg/L. All measured concentrations were within ±20% of the set concentration. Therefore, the calculation of the results was based on the set concentrations.

Reported statistics and error estimates:

The mortality rate (%) was calculated from the number of deaths in each concentration zone and the number of specimens (10 fish), and the half lethal concentration (LC50) was calculated by the Probit method.

Sublethal observations / clinical signs:

Toxicological symptoms
　Abnormal swimming and inability to swim were observed at concentrations of 24.5 mg/L and above. No abnormal symptoms were observed in the control group during the study period.
The mortality rate in the control group was 5.4%.

Validity criteria fulfilled:

yes

Conclusions:

The median lethal concentration (LC50) after 96 hours was determined to be 33.9 mg/L.

Executive summary:

A GLP compliant 96-hour acute toxicity test of 3,5-xylidine on Oryzias latipes has been conducted in accordance with the acute toxicity test described in "Methods of Tests pertaining to New Chemical Substances, Etc" and comparable to OECD Guideline 203.

Ten fish per test concentration (control, 6.00, 12.00. 24.00. 48.00 and 96.0 mg/L) were evaluated in a semi-static 96 -hour acute toxicity test. Mortalities as well as symptoms of abnormal mobility has been evaluated. No symptoms of abnormal mobility, etc. were observed in the concentration area of 12.00 mg/L or lower. Abnormal swimming and inability to swim were observed at concentrations of 24.5 mg/L and above. All specimens died after 72 hours at 96.00 mg/L.

Since the variations to the set concentration of the measured concentration of the test substance were all less than ± 20%, the set concentration was used as the concentration of the test substance in the test solution. The median lethal concentration (LC₅₀), the highest concentration producing 0 percent death and the lowest concentration producing 100 percent deaths 24, 48, 72, and 96 hours after exposure were shown below.

Exposure period	LC50* (95% confidence limit) (mg/L)	Highest concentration producing 0 % mortality (mg/L)	Lowest concentration producing 100% mortality (mg/L)
24 hours	>96	48.00	>96.0
48 hours	65.3*	24.00	>96.0
72 hours	36.3*	12.00	96.0
96 hours	33.9*	12.00	96.0

*Probit analysis

Description of key information

OECD 203, GLP, Oryzias latipes, 96h, semi-static: LC50(96h) 33.9 mg/L (nominal)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

33.9 mg/L