Reaction mass of copper oxide and manganese dioxide

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

For details on endpoint specific justification please see read-across report in section 13 or find a link in cross-reference “assessment report”.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

assessment report

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 143 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

biomass / yield

Remarks on result:

other: value recalculated based on the ratio of MnO2 and CuO in the reaction mass

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 143 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

biomass / yield

Remarks on result:

other: value recalculated based on the ratio of MnO2 and CuO in the reaction mass

Validity criteria fulfilled:

yes

Conclusions:

The effect of the test material on the growth of Desmodesmus subspicatus was investigated and gave 72h-EC50 values of > 143 mg/L (100% v/v saturated solution prepared at 100 mg/L test item). Correspondingly, the 72h-NOEC was >= 143 mg/L (100% v/v saturated solution prepared at 100 mg/L test item). The study showed that there were no toxic effects at saturation.

Executive summary:

The study used as source investigated toxicity to aquatic algae acc. to OECD 201. The study results of the source compound were considered applicable to the target compound and were used for classification and labelling acc. to REGULATION (EC) No 1272/2008. Justification and applicability of the read-across approach (structural analogue) is outlined in the read-across report in section 13 or find a link in cross reference “assessment report”.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

For details on endpoint specific justification please see read-across report in section 13 or find a link in cross-reference “read-across: supporting information”.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across: supporting information

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.025 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element (dissolved fraction)

Remarks:

copper

Basis for effect:

biomass

Remarks on result:

other: 0.18% of nominal CuO effect concentration

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.018 mg/L

Nominal / measured:

nominal

Conc. based on:

element (dissolved fraction)

Remarks:

copper

Basis for effect:

biomass

Remarks on result:

other: calculated based on 0.18% of nominal CuO effect concentration

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

64 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (total fraction)

Basis for effect:

biomass

Remarks on result:

other: value recalculated based on the ratio of MnO2 and CuO in the reaction mass

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

45 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (total fraction)

Basis for effect:

biomass

Remarks on result:

other:

Remarks:

value recalculated based on the ratio of MnO2 and CuO in the reaction mass

Validity criteria fulfilled:

yes

Remarks:

according to OECD 201 adopted 1984

Conclusions:

The 72h-EbC50 (green algae; biomass) was 64 mg/L (nominal), corresponding to 0.025 mg/L dissolved copper (measured); the derived 72h-NOEC (green algae; biomass) was 45 mg/L (nominal), corresponding to 0.018 mg/L (nominal; calculated based on 0.18% of nominal CuO effect concentration).

Executive summary:

The study used as source reference investigated the toxicity of nanoparticles of CuO, ZnO and TiO2 to microalgae Pseudokirchneriella subcapitata. The bulk form of each metal oxide was used to compare toxic effects between nano and bulk form. The study results of the source compound were considered applicable for the target compound and were used for classification and labelling acc. to REGULATION (EC) No 1272/2008. Justification and applicability of the read-across approach (structural analogue) is outlined in the attached document (see section 13 or find a link in cross reference).

Description of key information

72h-EbC50 (green algae; biomass) = 64 mg/L (nominal, total fraction, submission substance), corresponding to 0.025 mg/L dissolved copper (measured); 72h-NOEbC (green algae; biomass) = 45 mg/L (nominal, total fraction, submission substance), corresponding to 0.018 mg/L dissolved copper (measured / extrapolated) (acc. to OECD 201)

Key value for chemical safety assessment

EC50 for freshwater algae:

0.025 mg/L

EC10 or NOEC for freshwater algae:

0.018 mg/L

Additional information

Two reliable key studies were available for the hazard assessment of toxicity to aquatic algae for the submission substance reaction mass of copper oxide and manganese dioxide. 

In the reliable key study the effect of constituent manganese dioxide on the growth of green alga Desmodesmus subspicatus was investigated (RL1, 2010). The study was performed acc. to OECD 201 (2006) and in compliance with GLP. As the test item was considered to be of very low water solubility, a limit test was performed with a saturated solution prepared at 100 mg/L (100% (v/v) saturated solution). Under the conditions of the study, exposure of Desmodesmus subspicatus to the test material gave EC50 values of > 143 mg/L (value recalculated based on the ratio of MnO2 and CuO in the reaction mass), and a corresponding NOEC of >= 143 mg/L (value recalculated based on the ratio of MnO2 and CuO in the reaction mass). No toxic effects were observed up to the limit of water solubility of the test item.

The second key study investigated the toxicity of constituent copper oxide to microalgae Pseudokirchneriella subcapitata. The study was carried out according to OECD guideline 201, adopted 1984 (RL2, 2009). Six test concentrations were tested. Measured effects (yield of biomass) followed a dose-response pattern. The 72h-EbC50 (green algae; biomass) was 64 mg/L (nominal, value recalculated based on the ratio of MnO2 and CuO in the reaction mass), corresponding to 0.025 mg/L dissolved copper (measured, 0.18% of nominal CuO concentration). The derived 72h-NOEC (green algae; biomass) was 45 mg/L (nominal, value recalculated based on the ratio of MnO2 and CuO in the reaction mass), corresponding to 0.018 mg/L dissolved copper (exrapolated based on measured dissolved copper fraction 0.18% of nominal CuO concentration). Since the study was performed acc. to the OECD guideline 201 adopted 1984, the validity criteria deviated from the updated guideline, and only one endpoint had to be reported (yield of biomass or growth rate). According to the OECD 201 (1984), the validity criteria were fulfilled. Despite of shortcomings in reporting (only one endpoint), results of the study were considered reliable. 

As copper oxide was the toxic constituent of the submission substance, the key value for the environmental hazard assessment of the reaction mass of copper oxide and manganese dioxide was based on the derived effect concentration of copper oxide.