Gadolinium trinitrate

Long-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Remarks:

Study was well performed, however, there was a high variation between the different measurements of dissolved Gd concentration (after centrifugation), for which no explanation was given. Although there was still an apparent concentration series when considering the mean measured dissolved Gd concentrations, the high variation between the different measurements results in a higher uncertainty around the results of the study. Much smaller variation was observed when considering total Gd concentrations, however, effect concentrations are preferentially expressed as/based on dissolved Gd concentrations and therefore the study is not considered reliable enough to serve as a key study.

Data source

Reference

Reference Type:

other: PhD thesis

Title:

Umweltverhalten und Ökotoxikologie von gadoliniumhaltigen Magnetresonanztomographie-Kontrastmitteln.

Author:

Neubert C

Year:

2008

Bibliographic source:

Fakultät III – Prozesswissenschaften Institut für Technischen Umweltschutz der Technischen Universität Berlin - Dissertation zur Erlangung des akademischen Grades Doktor der Ingenieurwissenschaften.

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.20 (Daphnia magna Reproduction Test)

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Gadolinium trichloride

EC Number:

233-386-6

EC Name:

Gadolinium trichloride

Cas Number:

10138-52-0

Molecular formula:

Cl3Gd

IUPAC Name:

gadolinium trichloride

Test material form:

solid: crystalline

Details on test material:

- Name of test material: GdCl3.6H2O (hexyhydrate was used)
- Source: Sigma-Aldrich
- Purity: 99.99%

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Samples were taken in fresh medium at t=0, t=8 and t=15 days.
- Samples were taken in old medium at t=8, t=15 and t=22 days. The replicates were pooled before sampling.
- 5 mL for determination of total Gd and 5 mL for determination of dissolved Gd were sampled. The latter samples were centrifuged before analysis to remove any precipitated material.
- Samples were acidified 1/100 with 1% HNO3.

Test solutions

Vehicle:

no

Details on test solutions:

No details reported.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Test species: Daphnia magna
Strain: Strauss
Source: Umweltbundesambt
Test animals: Third brood of the 3rd generation was used for the test.
Feeding was carried out daily with an algae suspension of Chlorella vulgaris.

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Test conditions

Test temperature:

20.7-21.9°C

pH:

Freshly prepared concentrations: 8.4-9.0
Old medium: 8.5-8.6

Dissolved oxygen:

8.1-12.5 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

Nominal concentrations: 0-0.2-2.0-10.0 mg Gd/L
Mean measured total Gd concentrations in fresh test solutions: < LOD and 0.07, 0.70, 3.46 mg Gd/L
Mean measured total Gd concentrations in old test solutions: < LOD and 0.05, 0.58, 2.79 mg Gd/L
Mean measured dissolved Gd concentrations (after centrifugation) in fresh test solutions: Mean measured dissolved Gd concentrations (after centrifugation) in old test solutions: Arithmetic means for the total Gd concentrations over the whole test period: < LOD, 0.06, 0.64, 3.13 mg Gd/L
Arithmetic means for the dissolved Gd concentrations over the whole test period: < LOD, 0.005, 0.09, 0.28 mg Gd/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100-mL glass bekaers
- Type (delete if not applicable): open
- Fill volume: 80 mL
- Renewal rate of test solution (frequency/flow rate): 3 times a week
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: not clearly reported
- Culture medium different from test medium: not clearly reported
- Intervals of water quality measurement: Once weekly, the pH, oxygen content and temperature were measured in the freshly prepared and old test media.

OTHER TEST CONDITIONS
- Adjustment of pH: not clearly reported
- Photoperiod: not clearly reported
- Light intensity: not clearly reported

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): mortality and reproduction (observations made after each medium renewal, i.e. 3 times per week)

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.64 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element (total fraction)

Remarks:

non-centrifuged samples

Basis for effect:

other:

Remarks:

reproduction and mortality

Effect concentrations 2

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

1.07 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat. (total fraction)

Remarks:

anhydrous GdCl3, non-centrifuged samples

Basis for effect:

other:

Remarks:

reproduction and mortality

Effect concentrations 3

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.09 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element (dissolved fraction)

Remarks:

centrifuged samples

Basis for effect:

other: reproduction and mortality

Effect concentrations 4

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.15 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat. (dissolved fraction)

Remarks:

anhydrous GdCl3, centrifuged samples

Basis for effect:

other: reproduction and mortality

Details on results:

21-d LOEC = 3.13 mg Gd/L (total, mean measured, non-centrifuged samples)
21-d LOEC = 5.25 mg GdCl3/L (total, mean measured, non-centrifuged samples)
21-d LOEC = 0.28 mg Gd/L (dissolved, mean measured, centrifuged samples)
21-d LOEC = 0.47 mg GdCl3/L (dissolved, mean measured, centrifuged samples)

SURVIVAL
Highest concentration: 50% mortality.
No mortality in other test solutions.

REPRODUCTION:
Total number of offspring: Between 615 and 668 offspring were produced in the control group and the groups exposed to the two lowest concentrations. 156 offspring were produced in the group exposed to the highest concentration.
Number of broods per parental daphnid: Between 3.9 and 4.3 broods were produced per parental daphnid in the control group and the groups exposed to the two lowest concentrations. 3.4 broods were produced per parental daphnid in the group exposed to the highest concentration.

Results with reference substance (positive control):

48-h EC50 = 1.63-2.53 mg/L during test period.

Reported statistics and error estimates:

ToxRat Professional software was used for calculation of the effect concentrations.

Any other information on results incl. tables

Measured Concentration anhydrous GdCl3 (mg/L) (calculated based on measured total Gd concentrations)	Surviving mother daphnids/number of offspring	Number of juveniles (mean +/- SD)	Number of juveniles per surviving mother
< LOD	10/657	65.7 +/- 11.2	4.3 +/- 0.5
0.09	10/615	61.5 +/- 9.0	3.9 +/- 0.3
1.08	10/668	66.8 +/- 5.4	4.0 +/- 0.0
5.24	5/156	31.2 +/- 4.5	3.4 +/- 0.8

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In a daphnid reproduction test performed according to OECD guideline 211, the 21-d NOEC was determined to be 0.64 mg Gd/L (1.07 mg GdCl3/L) based on mean measured total Gd concentrations in non-centrifuged samples and 0.09 mg Gd/L (0.15 mg GdCl3/L) based on mean measured dissolved Gd concentrations in centrifuged samples.