Magnesium oxalate

Endpoint summary

Description of key information

A Local Lymphe Node Assay (LLNA, OECD 429) was conducted on oxalic acid. It is considered as a relevant study for magnesium oxalate in a read across approach. Considering the result of this study, magnesium oxalate has not to be considered as dermal sensitiser.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

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 record.

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 magnesium cation: Mg2+).
- 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 aqueous media, dissociation of magnesium oxalate takes place immediately, resulting in formation of magnesium cations (Mg2+) and oxalate anions. Thus, any ingestion or absorption of magnesium oxalate by living organisms, in case of systemic consideration, will inevitably result of exposure to the dissociation products.
- Magnesium is an abundant mineral naturally present in the body. It is a cofactor in more than 300 enzyme systems that regulate diverse biochemical reactions in the body, including protein synthesis, muscle and nerve function, blood glucose control, and blood pressure regulation (IOM 1997, Rude 2010, Rude 2012). Magnesium is required for the normal functioning of several biochemical and physiological reactions and pay an essential role in the human body (Rude 2012). An adult body contains approximately 25 g magnesium, with 50% to 60% present in the bones and most of the rest in soft tissues (Volpe 2012). Human Recommended Dietary Allowances (RDA) for magnesium is up to 420mg per day (IOM 1997). For the same reasons (involvement in biochemical and physiological functions), magnesium is also naturally present in various organisms of the environment such as fish, crustacea or vegetables. Besides they are identified as food sources of magnesium (US 2012). Consequently, it can be concluded that magnesium is of low (eco)toxicological relevance when ingested and taken up systemically. Thus, any possible toxicological or ecotoxicological effect triggered by magnesium oxalate exposure can be attributed to oxalate anion.
- Counter ions: the assumption that the oxalate 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 (magnesium oxalate) and the analogues identified cannot present strong differences since the structures are very simple and very similar (formation of Mg2+ or oxalate 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 for the analogue approach are verified. They are presented in the detailed report attached. The experimental data performed on the substance (tests performed in this REACH registration dossier on strontium peroxide) confirms the analogue approach performed (same results on analogues).

4. DATA MATRIX
A data matrix is presented in the detailed report attached.

Reason / purpose for cross-reference:

read-across source

Parameter:

SI

Remarks on result:

other: see Remark

Remarks:

None of the 3 concentrations tested reached the stimulation index of 3: The stimulation index at a concentration of 12.5% was of 2.6 The stimulation index at a concentration of 25% was of 1.9 The stimulation index at a concentration of 50% was of 2.5

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

The EC3 value (derived by linear interpolation) could not be calculated as the stimulation indices of all concentrations were below 3.
Consequently, according to OECD 429 and the criteria given in Annex I of Regulation (EC) 1272/2008, the test item Oxalic Acid, as described in this report is expected to have no sensitising properties and therefore, should not be regarded as a dermal sensitiser. This result is relevant in a read across approach and is used for assessing magnesium oxalate properties. Consequently, in a read across approach, magnesium oxalate is not to be considered as skin sensitiser.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Justification for classification or non-classification

Since the stimulation indices of all tested concentrations were below 3 in the LLNA assay, no classification is needed.