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Short-term toxicity to fish

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Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Study period:
22 November 2015 - 5 October 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Analytical monitoring:
yes
Details on sampling:
- Samples for dissolved yttrium analysis were taken at the beginning of the study in fresh test media, in fresh and old test media at 48 h, and in old test media at 96 h.
- Samples were taken in duplicate.
- Sample storage conditions before analysis: stored in a closed vessel in the dark and under dry conditions at 10.1-25.8°C
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
A solution containing 139.3 (first experiment) resp. 139.2 mg/L and 139.3 mg/L (second experiment) test item (Y(NO3)3.6H2O) corresponding to 99.9 mg/L and 100.0 mg/L Y(NO3)3 (anhydrous form) in dilution water was prepared. This was done by weighing the nominal load, adding the corresponding amount of dilution water and stirring vigorously on a magnetic stirrer. No auxiliary solvent or emulsifier was used. To guarantee maximal dissolution of the test item, the pH of the dilution water was adjusted to pH 6.0 before adding the test substance. After initial stirring for dissolving the test substance, the pH was measured and adjusted again to pH 6.0. The solution was further stirred for 24 ± 1 hours. Then the pH of the solution was measured again and adjusted to pH 6.0, before filtration through a 0.45 µm nylon membrane filter. The undiluted filtrate was used as a stock solution for preparation of the concentrations to be tested by diluting the stock solution with dilution water at pH 6.0. In the control and in each test solution the pH of the final test media then was measured again and adjusted to pH 6.0 before addition of the test organism. The test media were prepared before the start of the test (= addition of test organisms) and before test medium renewal.
Test organisms (species):
Oncorhynchus mykiss (previous name: Salmo gairdneri)
Details on test organisms:
TEST ORGANISM
- Common name: Rainbow trout (Oncorhynchus mykiss)
- Source: Forellenzucht Schneider, 67734 Katzweiler
- Age at study initiation (mean and range, SD): sexually immature young fish
- Length at study initiation (length definition, mean, range and SD): 4.1-5.0 cm
- Weight at study initiation (mean and range, SD): not reported

ACCLIMATION
- Acclimation period: 12 days under test conditions
*Vessels: glass aquaria
*Medium: chlorine-free tap water
*Feeding: three times a day with trout food
*Medium renewal: flow-through conditions
*Photoperiod: 12/12 hours, using neon tubes
*Temperature: 13-14°C
- Health during acclimation (any mortality observed): no mortality was observed

FEEDING DURING TEST: no
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Hardness:
1.03 mmol/L (i.e. 103.09 mg CaCO3/L)
Test temperature:
15.0 – 16.5 °C (first experiment)
15.0 – 15.9 °C (second experiment)
pH:
First experiment:
0 h (fresh media): 6.0
24 h (old media): 7.0-7.3

Second experiment:
0 h (fresh media): 6.0
24 h (old media): 6.8-7.0
48 h (old media): 6.9-7.1
48 h (fresh media): 6.0
72 h (old media): 6.9-7.0
96 h (old media): 7.2-7.3
Dissolved oxygen:
First experiment: 8.4-10.2 mg/L
Second experiment: 8.0-10.8 mg/L
Salinity:
not applicable
Conductivity:
242 µS/cm
Nominal and measured concentrations:
First experiment:
- Nominal concentrations: control + 14, 7.8, 4.5, 2.5 and 1.4 mg/L yttrium trinitrate hexahydrate (Y(NO3)3.6H2O) (corresponding to 10.0, 5.6, 3.2, 1.8 and 1 mg/L yttrium trinitrate anhydrous (Y(NO3)3))
- Measured concentrations (t=0h): not detectable + 9.624, 5.456, 3.180, 1.776 and 0.996 mg Y(NO3)3/L (i.e. 96.2-99.6% of nominal)
- No measurements performed in old test media since the test was stopped after 24 h because mortality occurred in all treatments.

Second experiment:
- Nominal concentrations: control + 3.1, 1.4, 0.64, 0.28, 0.14 and 0.06 mg/L yttrium trinitrate hexahydrate (Y(NO3)3.6H2O) (corresponding to 2.2, 1.0, 0.46, 0.22, 0.1, 0.046 mg/L yttrium trinitrate anhydrous (Y(NO3)3))
- Measured concentrations (t=0h): not detectable + 2.200, 0.985, 0.450, 0.202, 0.102 and 0.059 mg Y(NO3)3/L (i.e. 97.7-129.2% of nominal)
- Measured concentrations (t=48h, old test media): not detectable + not measured (all fish dead), not measured (all fish dead), 0.373, 0.143, 0.073 and 0.028 mg Y(NO3)3/L (i.e. 61.2-81.1% of nominal)
- Measured concentrations (t=48h, fresh test media): not detectable + 0.442, 0.194, 0.097 and 0.050 mg Y(NO3)3/L (i.e. 96.0-108.4% of nominal)
- Measured concentrations (t=96h): not detectable + 0.318, 0.121, 0.059 and 0.018 mg Y(NO3)3/L (i.e. 39.0-69.2% of nominal)
Details on test conditions:
TEST SYSTEM
- Test vessel: aquaria
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: glass, max. volume 10 L, fill volume 7 L
- Aeration: accomplished with glass tubes, frequency of bubbles 1/s
- Renewal rate of test solution (frequency/flow rate): yes, after 48 hours (second experiment)
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): one
- No. of vessels per control (replicates): one
- Biomass loading rate: one fish/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: tap water (drinking water)
- Total organic carbon: 0.5 mg/L
- Particulate matter: not reported
- Metals:
antimony <0.001 mg/L
arsenic <0.001 mg/L
lead <0.001 mg/L
cadmium <0.0001 mg/L
chromium <0.001 mg/L
copper <0.001 mg/L
nickel <0.002 mg/L
mercury <0.0001 mg/L
selenium <0.001 mg/L
boron <0.02 mg/L
magnesium 4.3 mg/L
aluminium 0.010 mg/L
iron <0.002 mg/L
manganese <0.001 mg/L

- Pesticides: no
- Chloride: 12 mg/L
- Alkalinity: not reported
- Ca/mg ratio: 33.9 mg Ca/L / 4.3 mg Mg/L
- Culture medium different from test medium: no
- Intervals of water quality measurement:
*Tap water: yearly
*During test: Temperature, pH and dissolved oxygen were measured every 24 h. In the second experiment, at medium renewal (48 h), temperature, pH and dissolved oxygen were measured both in the old and new test solution.

OTHER TEST CONDITIONS
- Adjustment of pH: yes, to pH 6.0
- Photoperiod: 12/12 hours using neon tubes
- Light intensity: not reported

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): mortality

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8 (experiment 2), 2.2 (experiment 1)
- Justification for using less concentrations than requested by guideline: not relevant
- Range finding study: yes
- Test concentrations in range finder: 139 / 14 / 1.4 mg/L Y(NO3)3.6H2O (corresponding to 100 / 10 / 1 mg/L Y(NO3)3)
- Results used to determine the conditions for the definitive study: Yes - 100% mortality in the two highest test concentrations, but no mortality in the lowest test concentration (the latter deviating from the results of the main tests - this may however be due to the somewhat higher initial pH compared to the main tests (pH 6.2 instead of 6.0), which may have resulted in lower exposure to dissolved Y, however, this could not be verified as no analytics were performed in the range finder).
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
0.62 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
act. ingr. (dissolved fraction)
Remarks:
anhydrous yttrium trinitrate
Basis for effect:
mortality
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
0.2 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element (dissolved fraction)
Remarks:
dissolved Y
Basis for effect:
mortality
Details on results:
Effect concentrations:
- 96-h NOEC = 0.55 mg Y(NO3)3.6H2O/L (i.e. 0.39 mg Y(NO3)3/L, i.e. 0.13 mg Y/L)
- 96-h LC50 = 0.87 mg Y(NO3)3.6H2O/L (i.e. 0.62 mg Y(NO3)3/L, i.e. 0.20 mg Y/L)

Observations:
- In the first experiment, after 48 hours, significant mortality was observed at all concentrations. Therefore, the experiment was aborted and a second experiment using lower concentrations was conducted.
- In the second experiment, in the 2 highest concentrated treatments, 100% mortality was observed before the end of the first test period (48 hours). In the control and the other treatments no mortality was observed and the animals showed normal behaviour until the end of the experiment (96 hours).
Reported statistics and error estimates:
ToxRat® Professional, version 3.2.
Validity criteria fulfilled:
yes
Conclusions:
The 96-h acute toxicity of yttrium trinitrate to Oncorhynchus mykiss was studied under semi-static conditions, according to OECD Guideline 203. In a first experiment, mortality was observed in all treatments after 48 hours. Therefore, the experiment was aborted and a second experiment using lower concentrations was conducted. In the second experiment, fish were exposed to nominal concentrations of 3.1, 1.4, 0.64, 0.28, 0.14 and 0.06 mg/L Y(NO3)3.6H2O (corresponding to 2.2, 1.0, 0.46, 0.2, 0.1 and 0.046 mg/L Y(NO3)3). In the 2 highest concentrated treatments, 100% mortality was observed before the end of the first test period (48 hours). In the control and the other treatments, no mortality was observed and the animals showed normal behaviour until the end of the experiment (96 hours). The 96-h LC50 was 0.87 mg Y(NO3)3.6H2O/L, which is equivalent to 0.62 mg Y(NO3)3/L and 0.20 mg Y/L.
Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
22 April 1996 - 18 October 1996
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
significant methodological deficiencies
Remarks:
Because dissolved Y analysis indicates that Y precipitates and disappears from the test solution and because effect concentrations were based on nominal concentrations (no recalculation possible), the study cannot be considered reliable. However, as relatively important adverse effects were observed in this study underestimating toxicity, it may be used as supporting study.
Qualifier:
according to
Guideline:
EU Method C.1 (Acute Toxicity for Fish)
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
Test solution samples were analysed at 0 and 24 hours (from test solutions kept under the same conditions as the test without test animals present in it).
Vehicle:
no
Test organisms (species):
Oncorhynchus mykiss (previous name: Salmo gairdneri)
Details on test organisms:
TEST ORGANISM
- Common name: rainbow trout
- Strain: Walbaum
- Source: fish culture of Roger TEPPE, 01310 Polliat
- Age at study initiation (mean and range, SD): not reported
- Length at study initiation (length definition, mean, range and SD): 5.3 ± 0.6 cm
- Weight at study initiation (mean and range, SD): 1.6 ± 0.7 g
- Method of breeding: not reported

ACCLIMATION
- Acclimation period: 24 hours prior to start of test, selected fish were kept starved and placed in new aquaria
- Acclimation conditions (same as test or not): yes

Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Hardness:
150 ppm as CaCO3
Test temperature:
14.0 - 16.4°C
pH:
7.3 - 8.3
Dissolved oxygen:
76 - 98%
Salinity:
Not applicable.
Nominal and measured concentrations:
Nominal concentration: 0, 5.6, 10, 18, 32, 56, 100 mg/L
Measured concentration in 100 mg/L solution: initially ca. 23 mg Y/L, and 3 mg Y/L in solution after 24 h, precipitation at bottom of vessel contains Y
Details on test conditions:
TEST SYSTEM
- Test vessel: aquarium
- Material, size, headspace, fill volume: glass, 28 cm x 28 cm x 28 cm, 15 L fill volume
- Renewal rate of test solution (frequency/flow rate): after 24 h and 48 h living fish were transferred to fresh aquaria (with test solution or dilution water for the treatment and blanc fish respectively), while dead fish were removed
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: potable water, stabilised, dechlorinated by aeration
- pH and dissolved oxygen were measured before each renewal and at the end of the test

OTHER TEST CONDITIONS
- Adjustment of pH: not reported
- Photoperiod: 12:12 hours dark:light
- Light intensity: 1000 - 2000 lux at water surface

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): mortality and behaviour was checked after 3 h, 24 h, 48 h, 72 h and 96 h

Range finder test: Mortality was observed at two concentrations tested during the range-finder (10 mg/L: 20% mortality observed from 72 h, 100 mg/L: 100% mortality observed from 24 h).
Reference substance (positive control):
yes
Remarks:
lindane
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
2.3 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
other: CI could not be determined
Details on results:
LC50 (24h) = 70 mg/L (CI 18-100 mg/L)
LC50 (48h) = 33 mg/L (CI 22-50 mg/L)
LC50 (72h) = 17 mg/L (CI 7.2-30 mg/L)

Almost immediately after preparation of the test solutions, precipitates were formed. Consequently, undissolved test substance was observed at the bottom of the test vessels (confirmed by qualitative analysis). Only 3 mg Y/L was present in the water column after 24 h. No further measurements were performed.

Results with reference substance (positive control):
LC50 (96h) = 0.051 mg/L (ppm) with C.I. 0.044-0.065 mg/L
Validity criteria fulfilled:
yes
Conclusions:
This study reported an LC50 of 2.3 mg Y(NO3)3/L for Oncorynchus mykiss after a 96-hour exposure. However, within 24 hours, dissolved yttrium concentrations in the water column had decreased from 23 mg/L to 3 mg/L. No further measurements were performed. Due to precipitation, the results cannot be considered entirely reliable and could represent an underestimation of toxicity.

Description of key information

The key study from Muckle (2016, Klimisch 1) yielded a 96-h LC50 of 0.20 mg Y/L for rainbow trout, which is equivalent to 0.62 mg Y(NO3)3/L. Yttrium trinitrate is therefore considered to be very toxic to fish upon acute exposure.

Key value for chemical safety assessment

LC50 for freshwater fish:
0.62 mg/L

Additional information

Two relevant studies have been identified for this endpoint.

 

The study from Muckle (2016) investigated the acute toxicity of yttrium trinitrate to Oncorhynchus mykiss under semi-static conditions, according to OECD Guideline 203. In a first experiment, mortality was observed in all treatments after 48 hours. Therefore, the experiment was aborted and a second experiment using lower concentrations was conducted. In the second experiment, fish were exposed to nominal concentrations of 3.1, 1.4, 0.64, 0.28, 0.14 and 0.06 mg/L Y(NO3)3.6H2O (corresponding to 2.2, 1.0, 0.46, 0.2, 0.1 and 0.046 mg/L Y(NO3)3). In the two highest concentrated treatments, 100% mortality was observed before the end of the first test period (48 hours). In the control and the other treatments no mortality was observed and the animals showed normal behaviour until the end of the experiment (96 hours). The 96-h LC50 was 0.20 mg Y/L (which corresponds to 0.62 mg/L anhydrous yttrium trinitrate). This study was considered reliable without restrictions (Klimisch 1) and was assigned key status for endpoint coverage. Based on the results of this study, yttrium trinitrate is considered to be very toxic to fish.

A supporting study was the study of Bazin (1996). This study reported a 96-h LC50 of 2.3 mg Y(NO3)3/L for Oncorynchus mykiss after a 96-hour exposure. No analytical verification of the test concentrations was performed except in separate test solutions at the start of testing and after 24 hours. Dissolved yttrium concentrations decreased from 23 mg/L to 3 mg/L within 24 hours. Due to the observed precipitation, the results of this study cannot be considered entirely reliable (Klimisch 3) and may represent an underestimation of toxicity. The results of this study were therefore only used as supporting information.