Iron(II) oxalate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

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

Adequacy of study:

key study

Study period:

1978

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

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 valency of the cation: Fe2+ compared to Mg2+ or Sr2+).
- 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 ferrous oxalate di hydrate takes place immediately, resulting in formation of Ferrous cations (Fe2+) and oxalate anions. Thus, any ingestion or absorption of ferrous oxalate di hydrate by living organisms, in case of systemic consideration, will inevitably result of exposure to the dissociation products.
- Iron is an abundant mineral naturally present in the body. Physiologically, it. exists as an ion in the body as Fe2+ (ferrous ion). It is a necessary trace element used by all known living organisms (Williams 2012, NCBI 2019). Iron-containing enzymes, usually containing heme prosthetic groups, participate in catalysis of oxidation reactions in biology, and in transport of a number of soluble gases (Fraùsto da Silva 2001, NCBI 2019). Iron is an essential constituent of hemoglobin, cytochrome, and other components of respiratory enzyme systems. Its chief functions are in the transport of oxygen to tissue (hemoglobin) and in cellular oxidation mechanisms. Inorganic iron involved in redox reactions is also found in the iron-sulfur clusters of many enzymes, such as nitrogenase (involved in the synthesis of ammonia from nitrogen and hydrogen) and hydrogenase (NCBI 2019). A class of non-heme iron proteins is responsible for a wide range of functions such as ribonucleotide reductase (reduces ribose to deoxyribose; DNA biosynthesis) and purple acid phosphatase (hydrolysis of phosphate esters).
- 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 (ferrous oxalate di hydrate) and the analogues identified cannot present strong differences since the structures are very simple and very similar (formation of Fe2+ 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) confirms the analogue approach performed (same results on analogues).

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


References :
Fraùsto da Silva J.J.R., Williams R.J.P. 2001 The biological chemistry of the elements, 2nd edition. Oxford University Press, Oxford
NCBI, National Center for Biotechnology Information. PubChem Compound Database; CID=27284, https://pubchem.ncbi.nlm.nih.gov/compound/27284 (accessed Mar. 6, 2019).
Williams R.J.P 2012. Iron in evolution. FEBS Letters. Volume 586, Issue 5, 9 March 2012, Pages 479-484.

Reason / purpose for cross-reference:

read-across source

Duration:

48 h

Dose descriptor:

LC0

Effect conc.:

250 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

325 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

48 h

Dose descriptor:

LC100

Effect conc.:

400 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

48 h

Dose descriptor:

LC0

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

160 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

48 h

Dose descriptor:

LC100

Effect conc.:

250 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Conclusions:

The 48h LC50 values were determined to be 160mg/L and 325mg/L for oxalic acid. In a read-across approach, this value is considered for iron oxalate.

Executive summary:

Two 48h LC50 values corresponding to 325 mg/L and 160 mg/L have been determined in two laboratories for the effects of oxalic acid on mortality of the freshwater fish Leuciscus idus melanotus under the test conditions defined according to guideline Deutsche Einheitsverfahren zur Wasser, Abwasser und Schlamm-Untersuchung L 15 Fischtest.

In a read-across approach, this study is considered reliable and the value is used for iron oxalate.

Description of key information

Two 48h LC50 values corresponding to 325 mg/L and 160 mg/L have been determined in two laboratories for the effects of oxalic acid on mortality of the freshwater fish Leuciscus idus melanotus under the test conditions defined according to guideline Deutsche Einheitsverfahren zur Wasser, Abwasser und Schlamm-Untersuchung L 15 Fischtest.

In a read-across approach, this study is considered reliable and the value is used for iron oxalate.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

160 mg/L