Magnesium perchlorate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Remarks:

in silico, (Q)SAR performed with OECD QSAR Toolbox, Read Across analysis

Type of information:

other: (Q)SAR from supporting substances (structural analogues or surrogates) for which an experimental result is available

Adequacy of study:

key study

Study period:

2019-03-29

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification, with an experimental result (as provided by the OECD QSAR Toolbox)

Justification for type of information:

1. SOFTWARE
OECD QSAR Toolbox v4.3.1

2. MODEL (incl. version number)
Read Across analysis

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
[Mg+2].[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
Please refer to 'Attached justification'

5. APPLICABILITY DOMAIN
Please refer to 'Attached justification'

Guideline:

other: ECHA Guidance R.6

Principles of method if other than guideline:

- Software tool(s) used including version: OECD QSAR Toolbox v4.3.1
- Model(s) used: Read Across analysis
- Model description: see field 'Justification for non-standard information' and 'Attached justification'
- Justification of QSAR prediction: see field 'Justification for type of information' and 'Attached justification'

GLP compliance:

no

Remarks:

Not applicable (QSAR calculation)

Specific details on test material used for the study:

[Mg+2].[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Water media type:

freshwater

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

110 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Validity criteria fulfilled:

not applicable

Conclusions:

The toxicity of Magnesium perchlorate to aquatic algae and cyanobacteria was predicted with OECD QSAR Toolbox v4.3.1 using experimental results of the analogues Potassium perchlorate (CAS 7778-74-7) and Lithium perchlorate (CAS 7791-03-9). Since the perchlorate is considered to trigger the toxicity, this approach is justified. The predicted ErC50 (72 h) for the freshwater green-algae Pseudokirchneriella subcapitata is 110 mg/L (nominal).

In water, Magnesium perchlorate will rapidly dissolve and completely dissociate into the perchlorate anion and the corresponding cation. Toxicity is determined only by the perchlorate moiety of the salt, as magnesium is known to be non-toxic. Based on that fact, it is considered entirely appropriate to use data of related perchlorate salts dissociating in water.

The EC50 > 100 mg/L is above the limit value for classification as aquatic chronic Cat. 3, so Magnesium perchlorate does not need to be classified according to Regulation 1272/2008 and amendments.

Executive summary:

The toxicity of Magnesium perchlorate to aquatic algae and cyanobacteria was predicted with OECD QSAR Toolbox v4.3.1 using experimental results of the analogues Potassium perchlorate (CAS 7778-74-7) and Lithium perchlorate (CAS 7791-03-9). Since the perchlorate is considered to trigger the toxicity, this approach is justified. The predicted E_rC₅₀ (72 h) for the freshwater green-algae Pseudokirchneriella subcapitata is 110 mg/L (nominal).

In water, Magnesium perchlorate will rapidly dissolve and completely dissociate into the perchlorate anion and the corresponding cation. Toxicity is determined only by the perchlorate moiety of the salt, as magnesium is known to be non-toxic. Based on that fact, it is considered entirely appropriate to use data of related perchlorate salts dissociating in water.

Description of key information

E_rC₅₀ (72 h) = 110 mg/L for Pseudokirchneriella subcapitata (prediction by OECD QSAR Toolbox v4.3.1, 2019; based on experimental results of closely related analogues Potassium perchlorate and Lithium perchlorate)

Key value for chemical safety assessment

EC50 for freshwater algae:

110 mg/L

Additional information

The toxicity of Magnesium perchlorate to aquatic algae was predicted with OECD QSAR Toolbox v4.3.1 using experimental results of the closely analogue substances Potassium perchlorate (CAS 7778-74-7) and Lithium perchlorate (CAS 7791-03-9). These analogue substances were tested for their toxicity to the freshwater green-algae Pseudokirchneriella subcapitata according to OECD TG 201 (GLP). Since the perchlorate is considered to trigger the toxicity, this approach is justified.

In water, Magnesium perchlorate will rapidly dissolve and completely dissociate into the perchlorate anion and the corresponding cation. Toxicity is determined only by the perchlorate moiety of the salt, as magnesium is known to be non-toxic. Based on that fact, it is considered entirely appropriate to use data of related perchlorate salts dissociating in water. However, the registrant is prepared to conduct an experimental study but considered it as not necessary at first instance taking into account the available results.

The EC₅₀> 100 mg/L is above the limit value for classification as aquatic chronic Cat. 3, so Magnesium perchlorate does not need to be classified according to Regulation (EC) No 1272/2008 and amendments.