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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
The rationale to read-across the data is attached in Section 13.
Reason / purpose for cross-reference:
read-across source
Test organisms (species):
Daphnia magna
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h
Nominal and measured concentrations:
Nominal loading rate: 100 mg/L
Key result
Duration:
48 h
Dose descriptor:
LL50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
No remarkable observations concerning the appearance of the test medium.

The analytically measured concentrations of yttrium oxide in the test medium samples taken at the start and at the end of the test were 528 and 519 µg/L respectively (arithmetic mean = 523 µg/L). The solubility limit reached during this test was thus slightly different from that obtained during the water solubility test (see IUCLID section 4.8). Such contrasting results could be explained by the different water media used in the water solubility test and ecotoxicological studies (media containing analytical grade salts).
Validity criteria fulfilled:
yes
Conclusions:
In a limit test at nominal loading rate of 100 mg/L, yttrium oxide has no acute toxic effect on Daphnia magna up to its solubility limit in the test water (solubility limit concentration determined as 523 µg/L).
This result is read-across to yttrium oxide, europium-doped.
Executive summary:

The 48hr-acute toxicity of yttrium oxide to Daphnia magna was studied under static conditions according to the EU Commission Directive 92/69/EEC, Part C.2 (1992) and the OECD Guideline for Testing of Chemicals, N°202 (2004). Daphnids were exposed to a control and the test chemical at a nominal loading rate of 100 mg /L for 48 hours. Mortality/immobilization were observed daily. No immobility was observed during the 48-h test period, neither in the control, nor at the loading rate of 100 mg/L. The 48 hour LL50 and NOELR were thus > 100 mg/L and >= 100 mg/L, respectively.

This result is read across to yttrium oxide, europium-doped.

Description of key information

The 48-h LL50 obtained on Daphnia magna for yttrium oxide is > 100 mg/L based on nominal loading rate corresponding to > 523 µg/L based on measured concentration (calculated from arithmetic mean of measured concentrations). Therefore, yttrium oxide is not harmful to aquatic invertebrates up to its solubility limit into water.

Key value for chemical safety assessment

Additional information

The toxicity of the substance itself to aquatic invertebrates was not tested, howver, an acute Daphnia study with the analogue yttrium oxide is available. The justification for read-across using the analogue approach is described in a report (see section 13 of IUCLID).

The 48hr-acute toxicity of yttrium oxide to Daphnia magna was studied under static conditions according to the EU Commission Directive 92/69/EEC, Part C.2 (1992) and the OECD Guideline for Testing of Chemicals, N°202 (2004). Daphnids were exposed to control and test chemical at a nominal loading rate of 100 mg /L for 48 hours. Mortality/immobilization were observed daily. No immobility was observed during the 48-h test period, neither in the control, nor at the nominal loading rate of 100 mg/L, corresponding to 523 µg/L based on measured concentration (calculated from arithmetic mean of measured concentrations). The 48 hour LL50 and NOELR were thus above the water solubility limit or > 100 mg/L and >= 100 mg/L, respectively.