Yttrium

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:

19 Feb 2017 - 4 May 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: The OECD Series on Testing and Assessment No. 23: Guidance document on aquatic toxicity testing of difficult substances and mixtures.

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

purity: >99.8%
grey powder
Expiry date: 26 June 2018
storage conditions: room temperature in the dark

Analytical monitoring:

yes

Details on sampling:

- Water samples were taken from the control and 100% v/v saturated solution test group, from fresh and old media throughout the 96-Hour test period, for quantitative analysis.
- Duplicate sets of samples at 0 and 72 hours (fresh media) and 24 and 96 hours (old media) were taken for further analysis if necessary.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Due to the insolubility of the test item in test water, a saturated solution method of preparation was considered most appropriate.
- Stirring experiment: A nominal amount of test item (500 mg) was dispersed in 5 L of test water with the aid of vigorous magnetic stirring for 96 hours. After 3, 24 and 96 hours the stirring was stopped, the pH checked and adjusted to pH 6-8.5 if necessary. A sample was taken at each time point after any undissolved test item was removed by filtration through a 0.2 μm Sartorious Sartopore filter (first approximate 1 liter used to pre-condition the filter was discarded) to give a 100% v/v saturated solution.
- The nominal test concentrations in the combined range finder-limit test were 1.0, 10 and 100% v/v saturated solutions. The 100% v/v saturated solution was prepared in a similar way as described for the stirring experiment (2200 mg test item in 22 L test water, vigorous magnetic stiring for 24h, 0.2-µm filtered using a Sartorius Sartopore filter). The 1.0 and 10% v/v saturated solutions were then prepared through serial dilution of the 100% saturated solution.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Source: Brow Well Fisheries Limited, Hebden, near Skipton, Yorkshire, UK
- Length at the end of the combined range finder-limit test (length definition, mean, range and SD): mean: 4.5 cm; SD: 0.15
- Weight at study initiation (mean and range, SD): mean: 0.66 g; SD: 0.08
- Feeding during test: no

ACCLIMATION
- Acclimation period: 8 days before the test
- Acclimation conditions (same as test or not): yes, same as test
- Type and amount of food: commercial trout pellets (discontinued 25 h before start of the test)
- Feeding frequency: daily
- Health during acclimation (any mortality observed): no mortality in the seven days prior to the start of the test

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

140 mg CaCO3/L

Test temperature:

t=0h (fresh media): 14-15°C
t=24h (old media): 14°C
t=24h (fresh media): 14-15°C
t=48h (old media): 14°C
t=48h (fresh media): 14-15°C
t=72h (old media): 14°C
t=72h (fresh media): 14-15°C
t=96h (old media): 14°C

pH:

t=0h (fresh media): 7.5-8.3
t=24h (old media): 7.8-8.1
t=24h (fresh media): 7.7-8.4
t=48h (old media): 8.2-8.3
t=48h (fresh media): 7.6-8.3
t=72h (old media): 7.9-8.0
t=72h (fresh media): 7.6-8.4
t=96h (old media): 8.0-8.1

Dissolved oxygen:

t=0h (fresh media): 9.7-11.0
t=24h (old media): 9.9-10.0
t=24h (fresh media): 9.6-10.9
t=48h (old media): 9.9-10.0
t=48h (fresh media): 9.3-11.1
t=72h (old media): 9.9-10.3
t=72h (fresh media): 10.0-11.1
t=96h (old media): 9.9-10.1

Salinity:

not relevant

Conductivity:

345 µS/cm at 20°C

Nominal and measured concentrations:

Range finder test:
Nominal concentrations: 1.0, 10 and 100% of SS
Measured concentrations at t=0h (fresh): < LOQ, < LOQ, 0.317 mg/L test item
Measured concentrations at t=24h (old): < LOQ, < LOQ, 0.269mg/L test item

Limit test:
Nominal concentrations: Control and 100% of SS
Measured concentrations at t=0h (fresh): < LOQ, 0.794 mg/L Lu; < LOQ, 0.00395 mg/L test item
Measured concentrations at t=24h (old): < LOQ, 0.800 mg/L test item
Measured concentrations at t=72h (fresh): < LOQ, 0.488 mg/L test item
Measured concentrations at t=96h (old): < LOQ, 0.362 mg/L test item

Details on test conditions:

TEST SYSTEM
- Test vessel: aquaria
- Material, size, headspace, fill volume: 25-30-L glass aquaria, filled with 20 L test solution and covered to reduce evaporation
- Aeration: yes, via narrow bore glass tubes
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Laboratory tap water, dechlorinated by passage through an activated carbon filter (Purite Series 500) and partly softened (Elga Nimbus 1248D Duplex Water Softener) giving water with a total hardness of approximately 140 mg/L as CaCO3.
- Culture medium different from test medium: no
- Intervals of water quality measurement: water temperature, dissolved oxygen and pH were recorded daily in fresh and old test media

OTHER TEST CONDITIONS
- Photoperiod: 16 h light and 8 h dark, with 20-min transition periods to mimic dusk and dawn transition periods

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Fish were considered to be dead when no reaction was observed after touching the caudal peduncle and visible breathing movements were absent. Mortality checks were performed after 1, 3, 6, 24, 48, 72 and 96 h.

TEST CONCENTRATIONS
- Range finding study: yes, the study was a combined range finder-limit test as no (adverse) effects were expected
- Test concentrations: 1.0, 10 and 100% of a saturated solution with nominal loading rate of 100 mg/L (test item)
- Results used to determine the conditions for the definitive study: no (the test was a combined range finder-limit test)

Reference substance (positive control):

not specified

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0.61 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

element (dissolved fraction)

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

>= 100 other: % v/v saturated solution

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

No mortality was observed in any of the test solutions.
The 96-h LC50 was therefore > 100% v/v of a saturated solution with nominal loading rate 100 mg/L.
There were no sub-lethal effects of exposure observed in the test.

Reported statistics and error estimates:

No statistics applied.

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test item to juvenile rainbow trout was investigated in accordance with OECD guideline 203 and GLP. A semi-static combined range finder-limit test was performed, in which no adverse effects were observed up to and including at the highest concentration tested (i.e., a 100% v/v saturated solution with nominal loading rate 100 mg/L). The 96-h LC50 was therefore > 100% v/v of a saturated solution with nominal loading rate 100 mg/L. The mean measured test concentration the 96 hour LC50 was greater than 0.61 mg Ydissolved/L (equivalent to 100% v/v saturated solution). The NOEC was 0.61 mg Ydissolved/L (equivalent to 100% v/v saturated solution).
This study showed that there were no toxic effects at saturation. The results can be considered reliable with restrictions.

Description of key information

The acute toxicity of yttrium metal to rainbow trout was determined in a 96 hour static limit test according to the OECD guideline 203 (Abblitt, 2018, Klimisch 1). Under the conditions of the present study, no effects were seen up to a concentration of 100 % v/v saturated solution. The results of the test can be considered reliable without restriction. The 96h LC50 was therefore > 100% v/v of a saturated xsolution with a nominal loading rate of 100 mg/L. This study was assigned key status for endpoint coverage,

and based on its results it can be concluded that yttrium metal is not harmful to fish at its solubility limit into water.