Nickel iron chromite black spinel

Ecotoxicological Summary

Additional information

The pigment nickel iron chromite is environmentally and biologically inert due to the characteristics of thesynthetic process (calcination at high temperatures, approximately 1000°C), rendering the substance to be of a unique, stable crystalline structure in which all atoms are tightly bound and not prone to dissolution in environmental and physiological media.Based on the resulting physico-chemical properties, especially the high insolubility of the pigment under environmental conditions, demonstrated (Knopf, 2013) via transformation/dissolution testing (28 days), the substance can be expected to not have a potential to cross or adsorb to biological membranes. Therefore, no reversible or irreversible adverse toxicological effects on aquatic or terrestrial life-forms are expected, and a PNEC derivation is scientifically not justifiable.

Transformation/dissolution of nickel iron chromite black spinel was measured according to the method OECD test series No. 29 (Guidance document on transformation/dissolution of metals and metal compounds in aqueous media). The transformation/dissolution ofthe pigmentresulted in the following dissolved concentrations:

Full test 7 days at pH 6, 1 mg loading:

dissolved Ni: 1.86µg/L

dissolved Fe: below LoD

dissolved Cr: 0.58 µg/L

dissolved Mn: 1.18 µg/L

Full test 28 days at pH 6, 1 mg loading:

dissolved Ni: 3.50µg/L

dissolved Fe: below LoD

dissolved Cr: 0.76 µg/L

dissolved Mn: 2.29 µg/L

As dissolved Ni, Fe, Cr and Mn concentrations were below 4 µg/L respectively at the highest loading of 1 mg/L, referring to a solubility of < 0.7 %, the pigment can be considered environmentally inert.

Aquatic toxicity: freshwater, short-term

The table below presents an overview of the reliable acute aquatic toxicity data available for the hazard assessment of Nickel iron chromite black spinel. Concentrations are based on water accomodated fractions (WAF).

 

Pseudokirchneriella subcapitata	growth rate	72-h EL50	> 100 mg/L (WAF)	Wenzel, 2014
Daphnia magna	mortality	48-h EL50	> 320 mg/L (WAF)	Schlich, 2014
Brachydanio rerio	mortality	96-h LC50	> 100 mg/L (WAF)	Teigeler, 2014

 

Invertebrates:The acute toxicity to Daphnia magna was determined according to OECD Guideline 202 (Schlich, 2014). Daphnids did not become immobilized during the test period of 48 h at tested concentrations up to 320 mg/L (water accommodated fraction-WAF, 7 days); the respective 48-h EC50 is >= 320 mg/L (WAF).

 

Fish:Information on acute fish toxicity is available from a study performed according to OECD Guideline 203. Fish (Danio rerio) were exposed for 96 hours to water accommodated fractions (7 days) up to 100 mg/L under static conditions. At all tested loadings, neither behavioral abnormalities nor mortality occurred.

 

Algae:The toxic effects of the water accommodated fractions of Nickel iron chromite black spinel on the growth rate of algae (Pseudokirchneriella subcapitata) were studied in a state-of-the-art test according to OECD Guideline 201 (Wenzel, 2014). The EL50 value for the 72-h inhibition of growth rate of P. subcapitata (water accommodated fraction-WAF, 7 days) is >= 100 mg/L (WAF).

 

Aquatic toxicity: freshwater, long-term

The table below presents an overview of the reliable long-term aquatic toxicity data available for the hazard assessment of Nickel iron chromite black spinel. Concentrations are based on water accomodated fractions.

 

Pseudokirchneriella subcapitata

growth rate

72-h EL10

> 100 mg/L (WAF)

Wenzel, 2014

 

Chronic toxicity data of Nickel iron chromite black spinel are available for algae. The long-term toxic effects of the Water Accommodated Fractions (WAF) of Nickel iron chromite black spinel on the growth rate of algae (Pseudokirchneriella subcapitata) were studied in a state-of-the-art test according to OECD Guideline 201 (Wenzel, 2014). The EL10 value for the 72-h inhibition of growth rate of P. subcapitata is  > 100 mg/L (WAF).

 

Acute aquatic toxicity data at three trophic levels (algae, daphnia, fish) and from standard toxicity tests indicate a lack of an acute toxic potential of Nickel iron chromite black spinel in the aquatic environment, i.e. all EL50 values are above 100 mg/L. Chronic toxicity data for algae indicate a lack of a toxicity potential of Nickel iron chromite black spinel in the aquatic environment long-term for this trophic level which may be explained at least in parts with the insolubility of the pigment.

 

Thus, based on available short-term and long-term aquatic toxicity data, classification and labelling for aquatic toxicity is not required in accordance with Directive 67/548 EEC and CLP Regulation (EC) No 1272/2008 (Table  4.1.0 (b) (iii)).

Conclusion on classification

Based on the high insolubility of the pigment under environmental conditions, demonstrated (Knopf, 2013) via transformation/dissolution testing

(28 days), no reversible or irreversible adverse toxicological effects on aquatic or terrestrial organisms are expected.

Chronic toxicity data of Nickel iron chromite black spinel are available for algae. The long-term toxic effects of the Water Accommodated Fractions (WAF) of Nickel iron chromite black spinel on the growth rate of algae (Pseudokirchneriella subcapitata) were studied in a state-of-the-art test

according to OECD Guideline 201 (Wenzel, 2014). The EL10 value for the 72-h inhibition of growth rate of P. subcapitata is  > 100 mg/L (WAF).

 

Acute aquatic toxicity data at three trophic levels (algae, daphnia, fish) and from standard toxicity tests indicate a lack of an acute toxic potential of

Nickel iron chromite black spinel in the aquatic environment, i.e. all EL50 values are above 100 mg/L. Chronic toxicity data for algae indicate a lack

of a toxicity potential of Nickel iron chromite black spinel in the aquatic environment long-term for this trophic level which may be explained at least

in parts with the insolubility of the pigment.

 

Thus, based on available short-term and long-term aquatic toxicity data, classification and labelling for aquatic toxicity is not required in accordance

with Directive 67/548 EEC and CLP Regulation (EC) No 1272/2008 (Table  4.1.0 (b) (iii)).