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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
Study period:
1972
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH
Further information in a detailed justification report is included as attachment to the same iuclid record point.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
For the determination of analogue in this read-across approach, the following points have been considered:
- Chemical speciation and valency (common barium cation: Ba2+).
- The water solubility, as it provides a first indication of the availability of the metal ion in the different compartments of interest. The most simplistic approach to hazard evaluation is to assume that the specific metal-containing compound to be evaluated shows the same hazards as the most water-soluble compounds.
- In fluids of organisms and in in aqueous media, dissociation of barium peroxide takes place immediately, resulting in formation of barium cations (Ba2+) and oxygen. Thus, any ingestion or absorption of barium peroxide by living organisms, in case of systemic consideration, will inevitably result of exposure to the dissociation products.
- Oxygen (formed during the dissociation of barium peroxide) is of low (eco)toxicological relevance when ingested and taken up systemically. Thus, any possible toxicological or ecotoxicological effect triggered by barium peroxide exposure can be attributed to barium.
- Counter ions: the assumption that the metal ion is responsible for the common property or effect implies that the toxicity or ecotoxicity of the counter ion present in the compound will be largely irrelevant in producing the effects to be assessed.
- Likely common breakdown products via physical and/or biological processes for the targeted substance (barium peroxide) and the analogues identified cannot present strong differences since the structures are very simple and very similar (formation of Ba2+ ion).

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source chemical information is provided in the “source” endpoint. No impurity affecting the classification is reported for the source chemical.
Information on the impurities of the target chemical are detailed in the attached report.

3. ANALOGUE APPROACH JUSTIFICATION
The main hypothesis are presented in the detailed report attached. The experimental data performed on the substance (tests performed in this REACH registration dossier on strontium peroxide) consolidates the approach performed.

4. DATA MATRIX
A data matrix is presented in the detailed report attached.
Reason / purpose:
read-across source
Related information:
Composition 1
Reference:
Composition 0
Test material information:
Composition 1
Key result
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
14 500 µg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
mortality
Remarks:
including immobility
Reported statistics and error estimates:
Results were statistically evaluated with the method of Litchfield and Wilcoxon (1949). LC50 was used for survival and represents an interpolation from three or more partial-effect concentrations.

Chemical characteristics of Lake Superior water were monitored during the testing period according to procedures outlined by the American Public Health Association and procedures employing atomic absorption spectroscopy.

Validity criteria fulfilled:
yes
Conclusions:
Results are based on nominal values, and test did not exacty follow existing guidance (1972-study), but followed test method well described and test conditions (eg. test medium composition) were properly identified. The resulting 48h-EC50 of 14,500 µg Ba/L (endpoint= immobility) is an acceptable value for this endpoint, and can be used for classification purposes.
Executive summary:

BaCl2.2H2O toxicity was investigated on Daphnia magna in a static test during 48h. The relevant effect observed was complete immobilisation or death.

Results are based on nominal values, and test did not exacty follow existing guidance (1972-study), but followed test method well described and test conditions (eg. test medium composition) were properly identified. The resulting 48h-EC50 of 14,500 µg Ba/L (endpoint= immobility) is an acceptable value for this endpoint, and can be used for classification purposes.

Description of key information

BaCl2.2H2O toxicity was investigated on Daphnia magna in a static test during 48h. The relevant effect observed was complete immobilisation or death.

This study was used in a read-across approach.

Results are based on nominal values, and test did not exacty follow existing guidance (1972-study), but followed test method well described and test conditions (eg. test medium composition) were properly identified. The resulting 48h-EC50 of 14,500 µg Ba/L (endpoint= immobility) is an acceptable value for this endpoint, and can be used for classification purposes.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
14.5 mg/L

Additional information