N-hexyllithium

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:

key study

Study period:

2010-04-26 to 2010-08-09

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Deviations:

yes

Principles of method if other than guideline:

Deviations to the guideline: No major deviations. A minor deviation was observed for the test temperature in the test vessels which ranged from 19.7 to 21.9 degree C throughout the test. The guideline recommends that the temperature variation should be within 2 degree C. This deviation of 0.2 degree C occurred only on one day and was considered to have no effect on the results and interpretation of the study.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1310-66-3

EC Number:

603-454-3

Cas Number:

1310-66-3

IUPAC Name:

1310-66-3

Constituent 2

Reference substance name:

Lithium hydroxide monohydrate

IUPAC Name:

Lithium hydroxide monohydrate

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

In order to confirm correct dosage and stability of exposure concentrations, samples (about 100 mL) of the control and all test concentrations of the Definitive Test were taken from separate vessels without daphnia including culturing medium (controls) or test solutions. These samples were collected at start and end of one exposure period per week.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
For the Range-Finding Test and the Definitive Test the test solutions were prepared in a dilution series from a stock solution of 100 mg/L of the test item in culturing medium. The test solutions were prepared using a mixing device (Ultra-Turrax, Janke & Kunkel; 8000 rpm, 2 minutes). In the Range-Finding Test the test solution of 50 mg/L showed slight turbidity, followed by a whitish precipitation. In the Definitive Test turbidity and precipitation could not be observed at test concentrations of 0.25 to 16.0 mg/L. The controls were kept in culturing medium.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
Daphnia magna (Crustacea, Daphniidae), Clone 5
Origin: German Environmental Ministry, Berlin
Age: At start of exposure: < 24 h, the offspring was not from first brood progeny
Pre-treatment: The animals were cultivated in an air-conditioned room (light/dark = 14 h/10 h; illumination: fluorescent tubes).
The animals were fed with algae (Desmodesmus subspicatus).
The daphnids were kept in culturing water (see below).
The environmental parameters for the culture were similar to the test conditions.

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Test conditions

Hardness:

c(CACO3)= 246 mg/L

Test temperature:

19.7 – 21.9 degree C

Nominal and measured concentrations:

Nominal: 0.25 mg/L, 0.5 mg/L, 1.0 mg/L, 2.0 mg/L, 4.0 mg/L, 8.0 mg/L and 16.0 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 150 mL glass beakers, test volume 100 mL
- Aeration: None
- Renewal rate of test solution: Every 48 h
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10


TEST MEDIUM / WATER PARAMETERS
- Alkalinity: 0.8 mmol/L
- Ca/mg ratio: 4:1
- Culture medium different from test medium: Daphnia medium according to DIN 38412-L11/ISO 6341 was used in the controls and as dilution water in the Daphnia Reproduction Test. In contrast to the Elendt M4 medium recommended in the guideline, this medium does not contain lithium and EDTA and was therefore considered as suitable for this test.

OTHER TEST CONDITIONS
- Adjustment of pH: Based on the outcome of the preliminary study the Range-Finding Test and Definitive Test were performed without adjustment of the pH.
- Photoperiod: Fluorescent tubes (16 h light, 8 h dark)
- Light intensity: 1200 Lux

EFFECT PARAMETERS MEASURED: Number of living and dead animals of the Parental generation (P), Measurements of body length (in mm) of the surviving animals of the Parental generation (P) were performed.

VEHICLE CONTROL PERFORMED: no

RANGE-FINDING STUDY
- Test concentrations: 1.0 mg/L, 10.0 mg/L and 50.0 mg/L

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

LiOH monohydrate

Basis for effect:

reproduction

Effect concentrations 2

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

LiOH monohydrate

Basis for effect:

reproduction

Effect concentrations 3

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

9 mg/L

Nominal / measured:

nominal

Conc. based on:

other: calculated for n-Hexyllithium

Basis for effect:

reproduction

Details on results:

- Mortality of parent animals: Growth and development of the animals of the Parental generation (P) in the control and at test concentrations of 0.25 to 4.0 mg/L were normal and no adverse effects were observed. Growth and development of the animals of the Parental generation (P) were affected at test concentration of 8.0 mg/L. Activity was slightly reduced compared to the control and as a tendency the daphnia were found in the lower parts of the test vessels. Survival of the animals of the Parental generation (P) were affected at test concentration of 16.0 mg/L. Activity was reduced compared to the control and as a tendency the daphnia were found in the lower parts of the test vessels. All daphnia died during 10 days. Reproduction did not occur.
Dead offspring and aborted eggs were observed only occasionally during the test in the control (7 dead juveniles / 10 aborted eggs), at test concentration of 0.25 mg/L (5 dead juveniles / 12 aborted eggs), at test concentration of 0.5 mg/L (4 dead juveniles / 7 aborted eggs), at test concentration of 1.0 mg/L (8 dead juveniles / 6 aborted eggs), at test concentration of 2.0 mg/L (10 dead juveniles / 8 aborted eggs), at test concentration of 4.0 mg/L (9 dead juveniles /4 aborted eggs) and were not concentration response related at these test concentrations. The number of dead offspring and aborted eggs was slightly increased at test concentration of 8.0 mg/L (17 dead juveniles / 15 aborted eggs).
Males and ephippia were not observed in the control and at test concentrations of 0.25 to 16.0 mg/L.

Results with reference substance (positive control):

No positive control tested.

Reported statistics and error estimates:

The Kolmogorov-Smirnov-test determined normality of the data (α = 0.05).
The results of a one-way ANOVA showed a significant effect on offspring in the presence of Lithium hydroxide monohydrate [F = 5.46; Fcritical (6, 57, α = 0.05) = 2.26].
The results of a one-way ANOVA showed a significant effect on body length in the presence of Lithium hydroxide monohydrate [F = 6.21; Fcritical (6, 57, α = 0.05) = 2.26].
Bartlett`s test detected homogeneity of variances of offspring in the presence of Lithium hydroxide monohydrate (α = 0.05).
Bartlett`s test did not detect homogeneity of variances of body length in the presence of Lithium hydroxide monohydrate (α = 0.05). However results were still regarded to be adaptable to perform the ANOVA analysis.
Dunnett`s test for comparison of the treatment groups with the control with reference to offspring and body length showed significant differences between the control and the effective concentration of 8.0 mg/L (α = 0.05).

Any other information on results incl. tables

Number of live offspring of the Filial generation (F1) derived from parent animals alive at the end of the test of the control and test concentrations of 0.25 to 16.0 mg/L; mean-value, standard deviation (SD) and variation coefficient (Vc):

	Control	0.25 mg/L *	0.5 mg/L *	1.0 mg/L *	2.0 mg/L *	4.0 mg/L *	8.0 mg/L *	16.0 mg/L *
Total	1001	991	917	837	794	854	147**	0**
Mean-value	100	99.1	91.7	83.7	79.4	85.4	36.8**	0**
SD	12.8	26.6	27.8	19.3	21.8	12.1	18.0	0
Vc	12.8	26.8	30.3	23.1	27.4	14.2	48.9	0

* nominal concentration of Lithium hydroxide monohydrate

** Significant difference compared to the control according to Dunnett`s test (p = 0.05).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The Test item Lithium hydroxide monohydrate caused a statistically significant effect on live offspring of the Filial generation (F1) derived from the parent animals surviving at the end of the test at nominal test concentration of 8.0 mg Lithium hydroxide monohydrate/L according to Dunnett`s test (p = 0.05). Therefore, the NOEC determined on reproduction for Lithium hydroxide monohydrate was 4.0 mg/L and the LOEC was 8.0 mg/L.
Based on read across approach, the calculated NOEC for n-Hexyllithium was 9 mg/L.

Executive summary:

A semi-static Daphnia magna reproduction test was performed according to OECD Guideline 211. At this method Daphnia magna, aged lower or equal 24 h at the beginning of the test, are exposed to a range of Lithium hydroxide monohydrate under defined conditions over a period of 21 days. The test item is a solid that is soluble in water and therefore, no solvent was used. The test solutions were prepared in a dilution series from a stock solution of 100 mg/L of the test item in culturing medium. In the definitive test the nominal concentrations were as follows: 0.25, 0.5, 1.0, 2.0, 4.0, 8.0 and 16.0 mg/L. Analysis of the test solutions for lithium confirmed that the test solutions were correctly dosed and stable during the exposure period (recoveries ranging from 95.5 to 102 % of nominal concentrations for the freshly prepared and aged test solutions). Therefore, the concentrations were reported as nominal concentrations. The Test item Lithium hydroxide monohydrate caused a statistically significant effect on live offspring of the Filial generation (F1) derived from the parent animals surviving at the end of the test at nominal test concentration of 8.0 mg Lithium hydroxide monohydrate/L according to Dunnett`s test (p = 0.05).

Therefore, the NOEC determined on reproduction for Lithium hydroxide monohydrate was 4.0 mg/L and the LOEC was 8.0 mg/L.

Based on read across approach, the calculated NOEC for n-Hexyllithium was 9 mg/L.