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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Administrative data

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1991-06-25 to 1991-08-22
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP-Guideline study. According to the ECHA guidance document "Practical guide 6: How to report read-across and categories (March 2010)", the reliability was changed from RL1 to RL2.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Wessalith P, Natrium-Aluminium silikat
- Framework: monoclinic
- Related CAS number: 1318-02-1
- Physical state: white flocky powder
- Analytical purity: 80.6% active ingredient, 19.4% crystal water (79.8% active ingredient, source Degussa, respectively - two information sheets are given in the study, both supplied by the sponsor)

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
For preparing the test solutions 1000, 1800, 3200, 5600 and 10000 mg/L Wessalith P were weighed out and added to 1 L dilution water. The suspensions were stirred at 20°C for 1 h and then filtered through a paper filter (S&S 595 1/2).

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
ca. 24 h old, cultured in the laboratory according to guideline NPR, Nederlandse Praktijkrichtlijn, 6503

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
24 h

Test conditions

Hardness:
204 mg/L expressed as CaCO3
Test temperature:
20 +/- 1°C
pH:
8.0-8.2
Dissolved oxygen:
> 7.0 mg/L
Details on test conditions:
Daphnids were exposed for 24 hours to a series of solutions of Wessalith P in 150 mL vessels each containing 100 mL test suspension or control medium (5 daphnids per vessel; four test vessels per test suspension or control; no aeration, no feeding).

Results and discussion

Effect concentrationsopen allclose all
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
2 808 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
24 h
Dose descriptor:
EC100
Effect conc.:
5 600 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
24 h
Dose descriptor:
NOEC
Effect conc.:
1 800 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
24 h
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
behaviour

Any other information on results incl. tables

The initial pH value of the control and test solutions was determined to be 8.2 (control), 8.2, 9.1, 9.6, 9.9, 10.2 and 10.5 (highest concentration). The measured pH after 24 h was reported as 8.0 (control), 8.0, 8.6, 9.0, 9.4, 9.6 and 9.8 (highest concentration).
Observations on the test solution: At the start of the test, all suspensions were slightly turbid, turbidity increased with dosed amount. After 24 h all aqueous phases were clear, but undissolving material was sticking on the bottom of the test vessels.
The EC50 for mobility after 24 h was calculated as 2808 mg/L, EC100 5600 mg/L and NOEC 1800 mg/L. The NOEC for condition of the daphnids (swimming behavior: slower movements, irregular movements) was determined as 1000 mg/L.
During the study, a series of previous or further experiments were performed:
- Pre-test with nominal concentrations between 56 and 1000 mg/L (spaced by a factor of 1.8) plus 10000 mg/L. Only the highest treatment showed an effect of the test substance on mobility and swimming behavior of daphnids.
- Unfiltered versus filtered test suspensions in a limit test (1000 and 10000 mg/L): This test was carried out because it was shown in the first test that the daphnids were physically hampered by undissolved material. Unfiltered test suspensions resulted in increased immobilization and affected swimming behavior of daphnids compared to filtered suspensions (for the highest concentration of 10000 mg/L).
- Main test (results see above)
- ph test: dilution water adjusted to various high pH values because it was likely that the mobility of daphnids in the tests with Wessalith P was affected by the rather high pH values of the test suspensions. After 24 h, pH values of 10.5 and 11.0 and after 48 h, additionally pH 10.0 resulted in an increased immobility. Besides, swimming behavior was affected in the respective treatments, and animals were paler than control animals.

Applicant's summary and conclusion