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Administrative data

Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study was conducted in accordance with a recognised guideline and to GLP, and the validity criteria were fulfilled. However, the report omits some details of the characterisation of the test substance and of the test procedure.
Cross-reference
Reason / purpose for cross-reference:
reference to same study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1988
Report date:
1988

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
ISO 7346-1 (Determination of the Acute Lethal Toxicity of Substances to a Freshwater Fish [Brachydanio rerio Hamilton-Buchanan (Teleostei, Cyprinidae)] - Part 1: Static Method)
Version / remarks:
. The report cites a method of the German Umweltbundesamt (UBA), Berlin (1984)
Deviations:
no
Principles of method if other than guideline:
Not relevant.
GLP compliance:
yes

Test material

Constituent 1
Reference substance name:
proprietary name: chromium hydroxide sulphate
IUPAC Name:
proprietary name: chromium hydroxide sulphate
Details on test material:
- Name of test material (as cited in study report): 'Chromosal B'.
- Molecular formula (if other than submission substance): Cr2(OH)2(SO4)2*Na2SO4
- Molecular weight (if other than submission substance): 472.
- Physical state: solid.
- Analytical purity: not stated.
- Impurities (identity and concentrations): not stated.
- Composition of test material, percentage of components: 26% Cr2O3, 23-24% Na2SO4, balance water.
- Lot/batch No.: not stated.
- Expiration date of the lot/batch: not stated
- Stability under test conditions: not stated.
- Storage condition of test material: not stated.
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
Not relevant.

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Samples were taken of the 0-h (fresh) and 24-h (expired) media of each of the 'Chromosal B' treatments to determine concentrations of total and dissolved Cr. Samples were taken from the control vessel at the same times and analysed for total Cr only.

Test solutions

Vehicle:
no
Details on test solutions:
Freshly prepared test media containing 'Chromosal B' were neutralised in two steps, with the addition of an unspecified alkali to raise the initial pH. A second adjustment to pH 7.0 +/- 0.2 followed 2 h after the first. Samples for the analysis of concentrations of Cr in fresh media were taken 4 h after the second pH adjustment.

Absence of mortality or other observed effects on the test organisms implies that the neutralisation and pH-stabilisation steps were completed before introducing the fish to the test media, however this is not documented in the report.

Test organisms

Test organisms (species):
Danio rerio (previous name: Brachydanio rerio)
Details on test organisms:
TEST ORGANISM
- Common name: zebra fish
- Species: Brachydanio rerio Hamilton-Buchanan.
- Source: commercial supplier 'West Aquarium', Bad Lauterberg, Germany.
- Age at study initiation: ca. 14 to 17 weeks.
- Length at study termination (range): 2.5 to 3.2 cm in the control, 2.5 to 3.5 cm in all treatments.
- Wet weight at termination (mean): 0.23 g per fish in the control, 0.22 g per fish in all treatments.
- Feeding during test: not stated.


ACCLIMATION
- Acclimation period: ca. 3 to 6 weeks.
- Acclimation conditions (same as test or not): not stated.
- Type and amount of food: not stated.
- Feeding frequency: not stated.
- Health during acclimation (any mortality observed): no medication or mortalities prior to test initiation.

Study design

Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Post exposure observation period:
Not relevant.

Test conditions

Hardness:
Not stated.
Test temperature:
21.2 to 23.9 degrees C.
pH:
0 mg 'Chromosal B'/L (control): pH 6.8 in all fresh media, pH 6.3 to 6.7 in expired media.
4526 mg 'Chromosal B'/L: pH 2.8 to 3.6 in fresh media before neutralisation, pH 6.9 to 7.1 in fresh media after neutralisation, pH 5.9 to 7.1 in expired media.
6400 mg 'Chromosal B'/L: pH 2.9 to 3.7 in fresh media before netralisation, pH 6.8 to 7.1 in fresh media after neutralisation, pH 5.8 to 6.4 in expired media.
9051 mg 'Chromosal B'/L: pH 2.9 to 3.4 in fresh media before netralisation, pH 6.9 to 7.2 in fresh media after neutralisation, pH 5.8 to 7.2 in expired media.
10000 mg 'Chromosal B'/L: pH 2.9 to 3.3 in fresh media before netralisation, pH 6.9 to 7.2 in fresh media after neutralisation, pH 5.6 to 6.3 in expired media.





Dissolved oxygen:
8.9 to 9.6 mg O2/L in fresh media (all treatments).
7.7 to 8.6 mg O2/L in expired media (all treatments).
Salinity:
Not relevant.
Nominal and measured concentrations:
See results table below.
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): aquaria.
- Material, size, fill volume: 300 x 135 x 200 mm, 5 L medium.
- Aeration: yes.
- Renewal rate of test solution (frequency): 24 h semi-static.
- No. of organisms per vessel: 10.
- No. of vessels per concentration (replicates): one.
- No. of vessels per control (replicates): one.
- Biomass loading rate: 0.39 to 0.51 g wet weight/L.


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: not stated.
- Total organic carbon: not stated.
- Particulate matter: not stated.
- Metals: not stated, with the exception of total Cr (0.003 to 0.022 mg/L in the control).
- Pesticides: not stated.
- Chlorine: not stated.
- Alkalinity: not stated.
- Ca/mg ratio: not stated.
- Conductivity: not stated.
- Culture medium different from test medium: not stated.
- Intervals of water quality measurement: 0 h (fresh), 24 h (expired & fresh), 48 h (expired & fresh), 72 h (expired & fresh) and 96 h (expired).


OTHER TEST CONDITIONS
- Adjustment of pH: test media containing 'Chromosal B', initially pH 2.8 to 3.6, were adjusted twice to pH 7.0 +/- 0.2 before taking analytical samples (presumably also before exposure of fish). Identity of reagent used for pH adjustment not stated.
- Photoperiod: not stated.
- Light intensity: not stated.


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mortality and sub-lethal effects (2, 24, 48, 72 and 96 h).


TEST CONCENTRATIONS
- Spacing factor for test concentrations: variable, x 1.4 to x 1.1.
- Justification for using less concentrations than requested by guideline: not relevant: all concentrations exceded solubility limit and all concentratiions resulted in 0% mortality.
- Range finding study
- Test concentrations: Analysis results are given for two tests that preceded the definitive study: concentration range for test I: 4525, 6400, 9051 and 10000 mg/L, concentration range for test II: 1600, 2262, 3200 and 4526 mg/L.
- Results used to determine the conditions for the definitive study: not stated.
Reference substance (positive control):
no
Remarks:
Not required.

Results and discussion

Effect concentrationsopen allclose all
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
> 10 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
'Chromosal B'
Basis for effect:
mortality (fish)
Remarks on result:
other: none
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
10 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
'Chromosal B'
Basis for effect:
behaviour
Remarks:
(swimming)
Remarks on result:
other: none
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
> 3.21 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
dissolved
Remarks:
chromium
Basis for effect:
mortality (fish)
Remarks on result:
other: Mean of 4.96 and 1.46 mg Cr/L measured in fresh and expired media at top test substance concentration.
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
3.21 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
dissolved
Remarks:
chromium
Basis for effect:
behaviour
Remarks:
(swimming)
Remarks on result:
other: Mean of 4.96 and 1.46 mg Cr/L measured in fresh and expired media at top test substance concentration.
Details on results:
- Behavioural abnormalities: None.
- Observations on body length and weight: No evidence of treatment-related effects, relative to the control, following exposure to 'Chromosal B'.
- Other biological observations: No evidence of adverse sub-lethal effects in the control or the 'Chromosal B' treatments.
- Mortality of control: 0% after 96 h.
- Other adverse effects control: None.
- Abnormal responses: None.
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: Implied by filtration of analysis samples to distinguish between total and dissolved Cr, but observations not stated in report.
- Effect concentrations exceeding solubility of substance in test medium: Yes: nominal 'Chromosal B' concentrations exceed solubility limit.
Results with reference substance (positive control):
Not relevant.
Reported statistics and error estimates:
Not relevant.

Any other information on results incl. tables

Sublethal observations / clinical signs:

Measured concentrations of total and dissolved Cr and observations of fish mortality and sublethal effects following exposure to 'Chromosal B' are presented in the table below:

‘Chromosal B’ nominal concentration (mg/L)

Measured total Cr
(mg/L)

Measured dissolved Cr
(mg/L)

Mortality
(%)
after 96 hours

Sublethal effectsa

0 h
fresh

24 h
expired

0 h
fresh

24 h
expired

0 (control)

0.003

0.022

nd

nd

0

none

4526

823

801

0.010

0.005

0

none

6400

1131

1143

0.36

0.093

0

none

9051

1658

1654

1.19

0.25

0

none

10000

1859

1854

4.96

1.46

0

none

a           Based on observations of swimming behaviour after 2, 24, 48, 72 and 96 h exposure.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
Control mortality <10%, dissolved oxygen concentration >60%.
Conclusions:
The 96 hour LC50 of 'Chromosal B' (chromium hydroxide sulphate) to the zebra fish (B. rerio), under semi-static conditions with 24-h renewal of pH-adjusted media, was >10000 mg/L, based on nominal concentrations applied in the test. Based on the absence of abnormal swimming behaviour, the 96 h NOEC was 10000 mg/L (nominal).

The solubility of 'Chromosal B' was low under the conditions of the test. Based on the mean measured concentration of dissolved chromium at the highest concentration of 'Chromosal B' applied in the test, the 96 hour LC50 was >3.21 mg Cr/L.
Executive summary:

A study of the acute toxicity of 'Chromosal B' (chromium hydroxide sulphate) to fish was conducted with zebra fish (B. danio) exposed to nominal concentrations of 'Chromosal B' ranging from 4526 to 10000 mg/L for 96 hours under semi-static conditions, with renewal of pH-adjusted media at 24 -h intervals. The 96 hour LC50 of 'Chromosal B' was >10000 mg/L, based on the highest nominal concentration applied in the test. Based on the absence of abnormal swimming behaviour, the 96 h NOEC was 10000 mg/L (nominal). The solubility of 'Chromosal B' was low under the conditions of the test. Based on the mean measured concentration of dissolved chromium at the maximum concentration of 'Chromosal B', the 96 hour LC50 was >3.21 mg Cr/L.

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