Alkaline co-precipitation products of soluble cobalt, manganese and nickel salts

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

effects on growth of green algae

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 13 May 2022 to 25 July 2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Samples (2 samples of 20 mL) were taken from all test solutions and controls at the beginning of the test prior to addition of the algae. At the end of the growth test, samples (2 samples of 20 mL) were taken directly from representative replicates per nominal loading rate and controls. Therefore, at test initiation and test termination there were two sets of samples (one analytical and one retain sample) for each loading rate and the control.

Vehicle:

no

Details on test solutions:

The sterilised synthetic growth medium (OECD medium) according to OECD 201 was used as growth medium.

mg/L mg/L
NaHCO3 50 H3BO3 0.185
NH4Cl 15 MnCl2 x 4 H2O 0.415
KH2PO4 1.6 ZnCl2 0.003
MgSO4 x 7 H2O 15 CoCl2 x 6 H2O 0.0015
MgCl2 x 6 H2O 12 CuCl2 x 2 H2O 0.00001
CaCl2 x 2 H2O 18 Na2MoO4 x 2 H2O 0.007
FeCl3 x 6 H2O 0.064 Na2EDTA x 2 H2O 0.1
pH ~6.5

Test organisms (species):

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

Details on test organisms:

Species: Raphidocelis subcapitata, Chlorophycea, Chlorophyta
(syn. Pseudokirchneriella subcapitata)

Origin: SAG, Culture Collection of Algae at Pflanzenphysiologisches Institut of the University at Göttingen, Albrecht von Haller Institut, Untere Klarspüle 2, 37073 Göttingen.
Strain number: Catalog No 61.81 SAG.

Cultivation: The stock cultures were maintained fulfilling the criteria of the OECD guide-line (culture medium recommended by Bringmann und Kühn (1980) [8]). Prior to testing a pre-culture was established in OECD growth medium (as described below) to obtain exponentially-growing algae for the test. The culture duration of the pre-cultures was 3 days.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

21 - 24 °C ± 2°C

pH:

6.5

Nominal and measured concentrations:

nominal: control, 0.10, 0.32, 1.00, 3.16 and 10.0 mg test item./L.

Details on test conditions:

TEST SYSTEM
- Test vessel: glass flasks
- Type (delete if not applicable): air-permeable silicone-sponge caps
- fill volume: 250 ml
- Initial cells density: 10 000 cells/mL
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 8

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: yes to 6.5
- Light intensity and quality: 60 - 120 µE m-2 s-1 (4440 - 8880 lux


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3
- Range finding study: three nominal loading rates of 1.00, 10.0 and 100 mg test item/L were tested

Reference substance (positive control):

yes

Remarks:

The sensitivity of the test organism is routinely checked using 3,5-dichlorophenol as primary standard following internal SOPs in a non-GLP test twice a year. The latest in Feb. 2022.

Duration:

72 h

Dose descriptor:

EL10

Effect conc.:

0.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

0.98 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Parameter	[mg test item/L]	EL10	EL20	EL50	LOELR	NOELR
Growth rate	Value	0.10	0.22	0.98	0.32	0.10^a
	Lower 95 %-cl	0.07	0.17	0.86	-	-
	Upper 95 %-cl	0.13	0.27	1.12	-	-
Yield	Value	0.03	0.06	0.15	≤0.10	<0.10
	Lower 95 %-cl	0.02	0.04	0.10	-	-
	Upper 95 %-cl	0.05	0.08	0.24	-	-

Validity criteria fulfilled:

yes

Remarks:

The test fulfilled all validity criteria. A loading-dependent inhibiting effect on the growth of the freshwater green algae was observed over the range of the tested nominal loading rates.

Conclusions:

The test item found to be acutely harmful to algae. A ErL50 value of 0.98 mg mg/L was determined. 

Executive summary:

The test species Raphidocelis subcapitata was exposed to the nominal test item concentrations: control, 0.10, 0.32, 1.00, 3.16 and 10.0 mg test item./L for 72 h in a static system. The study was conducted to OECD guideline 201. All validity criteria according to OECD are fulfilled.

The test item found to be acutely harmful to algae. A ErL50 value of 0.98 mg/L was determined. 

 

 

Reference 2

Endpoint:

effects on growth of green algae

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 20 June 2022 to 07 July 2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Samples (2 samples of 20 mL) were taken from all test solutions and controls at the beginning of the test prior to addition of the algae. At the end of the growth test, samples (2 samples of 20 mL) were taken directly from representative replicates per nominal loading rate and controls. Therefore, at test initiation and test termination there were two sets of samples (one analytical and one retain sample) for each loading rate and the control.

Vehicle:

no

Details on test solutions:

The sterilised synthetic growth medium (OECD medium) according to OECD 201 was used as growth medium.

mg/L mg/L
NaHCO3 50 H3BO3 0.185
NH4Cl 15 MnCl2 x 4 H2O 0.415
KH2PO4 1.6 ZnCl2 0.003
MgSO4 x 7 H2O 15 CoCl2 x 6 H2O 0.0015
MgCl2 x 6 H2O 12 CuCl2 x 2 H2O 0.00001
CaCl2 x 2 H2O 18 Na2MoO4 x 2 H2O 0.007
FeCl3 x 6 H2O 0.064 Na2EDTA x 2 H2O 0.1
pH ~6.5

Test organisms (species):

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

Details on test organisms:

Species: Raphidocelis subcapitata, Chlorophycea, Chlorophyta
(syn. Pseudokirchneriella subcapitata)

Origin: SAG, Culture Collection of Algae at Pflanzenphysiologisches Institut of the University at Göttingen, Albrecht von Haller Institut, Untere Klarspüle 2, 37073 Göttingen.
Strain number: Catalog No 61.81 SAG.

Cultivation: The stock cultures were maintained fulfilling the criteria of the OECD guide-line (culture medium recommended by Bringmann und Kühn (1980) [8]). Prior to testing a pre-culture was established in OECD growth medium (as described below) to obtain exponentially-growing algae for the test. The culture duration of the pre-cultures was 3 days.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

21 - 24 °C ± 2°C

pH:

6.5

Nominal and measured concentrations:

nominal: control, 0.19, 0.56, 1.67, 5.00 and 15.0 mg test item./L.

Details on test conditions:

TEST SYSTEM
- Test vessel: glass flasks
- Type (delete if not applicable): air-permeable silicone-sponge caps
- fill volume: 250 ml
- Initial cells density: 10 000 cells/mL
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 8

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: yes to 6.5
- Light intensity and quality: 60 - 120 µE m-2 s-1 (4440 - 8880 lux


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3
- Range finding study: three nominal loading rates of 1.00, 10.0 and 100 mg test item/L were tested

Reference substance (positive control):

yes

Remarks:

The sensitivity of the test organism is routinely checked using 3,5-dichlorophenol as primary standard following internal SOPs in a non-GLP test twice a year. The latest (February 2022).

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.76 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

2.69 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Parameter	[mg test item/L]	EL10	EL20	EL50	LOELR	NOELR
Growth rate	Value	0.76	1.17	2.69	≤0.19	<0.19
	Lower 95 %-cl	0.41	0.75	2.14	-	-
	Upper 95 %-cl	1.08	1.54	3.37	-	-
Yield	Value	0.13	0.25	0.90	≤0.19	<0.19
	Lower 95 %-cl	0.03	0.06	0.15	-	-
	Upper 95 %-cl	0.64	1.17	5.79	-	-

Validity criteria fulfilled:

yes

Remarks:

The test fulfilled all validity criteria. A loading-dependent inhibiting effect on the growth of the freshwater green algae was observed over the range of the tested nominal loading rates.

Conclusions:

The test item found to be acutely harmful to algae. A ErL50 value of 2.69 mg mg/L was determined. 

Executive summary:

The test species Raphidocelis subcapitata was exposed to the nominal test item concentrations: control, 0.19, 0.56, 1.67, 5.00 and 15.0 mg test item./L for 72 h in a static system. The study was conducted to OECD guideline 201. All validity criteria according to OECD are fulfilled.

The test item found to be acutely harmful to algae. A ErL50 value of 2.69 mg mg/L was determined. 

 

 

Description of key information

Two forms with different metal compositions from the set were tested, forming the outer boundaries.
The result of form 1 most sensitive and can be considered as worst case with an EC50 of 0.98 mg/l (72h).
Form 2 has an EC50 of 2.69 mg/L (72h).

 

The test item found to be acutely harmful to algae. A value of 0.98 mg/L results in an acute and chronic classification in Category C1. 

 

Key value for chemical safety assessment

EC50 for freshwater algae:

0.98 mg/L

EC10 or NOEC for freshwater algae:

0.1 mg/L