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Short-term toxicity to aquatic invertebrates

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Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Justification for type of information:
The study is well-documented by the publication and thus acceptable for assessment.
Qualifier:
according to
Guideline:
other:
Version / remarks:
U.S. EPA 1985a, Peltier and Weber, 1985
Principles of method if other than guideline:
The study is well-documented by the publication and thus acceptable for assessment. The study is based on EPA guidelines (Peltier and Weber, 1985).
GLP compliance:
not specified
Specific details on test material used for the study:
reagent grade, Baker Chemical Co., N.Y.
Analytical monitoring:
yes
Details on sampling:
All cobalt samples (approximately 100 ml per sample) were immediately preserved with 4 drops of concentrated nitric acid to a pH < 2.0 (APHA, 1990). Each sample was a composite of all replicates for that treatment.
Vehicle:
not specified
Test organisms (species):
Ceriodaphnia dubia
Details on test organisms:
Tests were performed on two species: Ceriodaphnia dubia and Pimephales promelas
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Hardness:
50, 200, 400, and 800 mgll hardness as CaCO3
Nominal and measured concentrations:
Measured concentrations:
- hardness 50 mg/l: 297.5, 1266, 3405 µg/l based on cobalt
- hardness 200 mg/l: 286.7, 1216, 5926 µg/l based on cobalt
- hardness 400 mg/l: 276.7, 1203, 5920 µg/l based on cobalt
- hardness 800 mg/l: 230.0, 976, 5275 µg/l based on cobalt
Details on test conditions:
Ceriodaphnia dubia used in this study were cultured in 20% dilute mineral water consisting of 20% Perrier® and 80% distilled water, (aerated for 48 h) which was then diluted 1:5 with clean filtered pond water. Both the Perrier® and the pond water supply the necessary nutrients for normal C. dubia growth and reproduction. Organisms were held at 25 °C under a 16 h light:8 h dark photoperiod. C. dubia less than 24 h old were used toxicity tests. Tine feeding regime consisted of 0.1 ml digested cerophyll and TetraMin® and 0.1 ml Selenastrum
(approx. 3 x 106 cells/ml) fed daily to each brood culture and all 15 ml test chambers (Horning and Weber. 1989).

Temperature. pH, dissolved oxygen, and conductivity were measured daily.
At 24 h, test concentrations were renewed with fresh solutions.
Reference substance (positive control):
no
Key result
Duration:
24 h
Dose descriptor:
LC50
Effect conc.:
2.3 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element
Basis for effect:
mortality
Remarks on result:
other: hardness 50 mg/l
Key result
Duration:
24 h
Dose descriptor:
LC50
Effect conc.:
5.3 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element
Basis for effect:
mortality
Remarks on result:
other: hardness 800 mg/l
Validity criteria fulfilled:
not specified
Conclusions:
The 24 h LC50 values based on cobalt ions for C. dubia increased with increasing water hardness, from 2.3 to 5.3 mg/l as the water hardness increased from 50 to 800 mg/l hardness as CaCO3.
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Justification for type of information:
Edetic acid is known to be non-ecotoxic towards aquatic invertebrates as proved by studies. Thus, the toxicity of cobalt disodium ethylenediaminetetraacetate towards aquatic invertebrates is caused by the cobalt moiety only. As a worst-case approach it is assumed that the metal is fully released from the complex within short time. As proved by the evaluation of biodegradation of the substance the metal is released over longer period. Because metal ions bound in complexes are known to be less ecotoxic than the free ions, it can be concluded that the ecotoxicity of cobalt disodium ethylenediaminetetraacetate might be overestimated but not underestimated by this approach.
Reason / purpose:
read-across source
Qualifier:
according to
Guideline:
other:
Version / remarks:
U.S. EPA 1985a, Peltier and Weber, 1985
Principles of method if other than guideline:
The study is well-documented by the publication and thus acceptable for assessment. The study is based on EPA guidelines (Peltier and Weber, 1985).
GLP compliance:
not specified
Specific details on test material used for the study:
reagent grade, Baker Chemical Co., N.Y.
Analytical monitoring:
yes
Details on sampling:
All cobalt samples (approximately 100 ml per sample) were immediately preserved with 4 drops of concentrated nitric acid to a pH < 2.0 (APHA, 1990). Each sample was a composite of all replicates for that treatment.
Vehicle:
not specified
Test organisms (species):
Ceriodaphnia dubia
Details on test organisms:
Tests were performed on two species: Ceriodaphnia dubia and Pimephales promelas
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Hardness:
50, 200, 400, and 800 mgll hardness as CaCO3
Nominal and measured concentrations:
Measured concentrations:
- hardness 50 mg/l: 297.5, 1266, 3405 µg/l based on cobalt
- hardness 200 mg/l: 286.7, 1216, 5926 µg/l based on cobalt
- hardness 400 mg/l: 276.7, 1203, 5920 µg/l based on cobalt
- hardness 800 mg/l: 230.0, 976, 5275 µg/l based on cobalt
Details on test conditions:
Ceriodaphnia dubia used in this study were cultured in 20% dilute mineral water consisting of 20% Perrier® and 80% distilled water, (aerated for 48 h) which was then diluted 1:5 with clean filtered pond water. Both the Perrier® and the pond water supply the necessary nutrients for normal C. dubia growth and reproduction. Organisms were held at 25 °C under a 16 h light:8 h dark photoperiod. C. dubia less than 24 h old were used toxicity tests. Tine feeding regime consisted of 0.1 ml digested cerophyll and TetraMin® and 0.1 ml Selenastrum
(approx. 3 x 106 cells/ml) fed daily to each brood culture and all 15 ml test chambers (Horning and Weber. 1989).

Temperature. pH, dissolved oxygen, and conductivity were measured daily.
At 24 h, test concentrations were renewed with fresh solutions.
Reference substance (positive control):
no
Key result
Duration:
24 h
Dose descriptor:
LC50
Effect conc.:
2.3 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element
Basis for effect:
mortality
Remarks on result:
other: hardness 50 mg/l
Key result
Duration:
24 h
Dose descriptor:
LC50
Effect conc.:
5.3 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element
Basis for effect:
mortality
Remarks on result:
other: hardness 800 mg/l
Validity criteria fulfilled:
not specified
Conclusions:
The 24 h LC50 values based on cobalt ions for C. dubia increased with increasing water hardness, from 2.3 to 5.3 mg/l as the water hardness increased from 50 to 800 mg/l hardness as CaCO3.

Based on molecular weight correction:
LC50, corrected = 393.1 g/mol / 58.9 g/mol x 2.3 mg/L = 15.4 mg/L (lowest value, hardness 50 mg/l as CaCO3)
LC50, corrected = 393.1 g/mol / 58.9 g/mol x 5.3 mg/L = 35.4 mg/L (highest value, hardness 800 mg/l as CaCO3)
The LC50 value for cobalt disodium ethylenediaminetetraacetate can be stated as >= 15.4 mg/L.
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study without detailed documentation
Qualifier:
according to
Guideline:
ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))
GLP compliance:
not specified
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
Daphnia magna
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
24 h
Test temperature:
23 - 27 °C
Details on test conditions:
For each test concentration, three replicates with five daphnia in each were studied. Test vials were kept in the daylight.
Reference substance (positive control):
yes
Remarks:
potassium dichromate
Key result
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
610 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
Confidence interval, 95%: 570 - 640 mg/l
Validity criteria fulfilled:
yes
Conclusions:
The LC50, 24 h of edetic acid was found to be 610 mg/l.
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study without detailed documentation
Justification for type of information:
This study is provided to proof edetic acid to be non-ecotoxic towards aquatic invertebrates.
Reason / purpose:
read-across source
Qualifier:
according to
Guideline:
ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))
GLP compliance:
not specified
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
Daphnia magna
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
24 h
Test temperature:
23 - 27 °C
Details on test conditions:
For each test concentration, three replicates with five daphnia in each were studied. Test vials were kept in the daylight.
Reference substance (positive control):
yes
Remarks:
potassium dichromate
Key result
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
610 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
Confidence interval, 95%: 570 - 640 mg/l
Validity criteria fulfilled:
yes
Conclusions:
The LC50, 24 h of edetic acid was found to be 610 mg/l.
It can be stated that the LC50 value for edetic acid is much higher than for cobalt salts. Thus the aquatic toxicity of cobalt disodium ethylenediaminetetraacetate is determined by the cobalt moiety of the substance.
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Justification for type of information:
The study is well-documented by the publication and thus acceptable for assessment.
Qualifier:
no guideline followed
Principles of method if other than guideline:
The study is well-documented by the publication and thus acceptable for assessment.
GLP compliance:
not specified
Analytical monitoring:
not specified
Vehicle:
no
Test organisms (species):
Daphnia magna
Details on test organisms:
Daphnia magna were obtained from wild population. 30 animals were isolated for breeding. 10 clones with the highest number of individuals were chosen. The clone with the highest number of offspring was used to establish a continuous daphnia breed under standardized laboratory conditions.
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
24 h
Hardness:
16 °
Test temperature:
20 - 22 °C
pH:
7.6 - 7.7
Details on test conditions:
day/light: 12 h/ 12 h
feed: daily
change of water twice a week
three replicate tests with 10 daphnia each
Key result
Duration:
24 h
Dose descriptor:
LC0
Effect conc.:
640 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
24 h
Dose descriptor:
LC50
Effect conc.:
790 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
24 h
Dose descriptor:
LC100
Effect conc.:
1 250 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Validity criteria fulfilled:
not specified
Conclusions:
The LC50, 24 h of edetic acid was found to be 790 mg/l.
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Justification for type of information:
This study is provided to proof edetic acid to be non-ecotoxic towards aquatic invertebrates.
Reason / purpose:
read-across source
Qualifier:
no guideline followed
Principles of method if other than guideline:
The study is well-documented by the publication and thus acceptable for assessment.
GLP compliance:
not specified
Analytical monitoring:
not specified
Vehicle:
no
Test organisms (species):
Daphnia magna
Details on test organisms:
Daphnia magna were obtained from wild population. 30 animals were isolated for breeding. 10 clones with the highest number of individuals were chosen. The clone with the highest number of offspring was used to establish a continuous daphnia breed under standardized laboratory conditions.
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
24 h
Hardness:
16 °
Test temperature:
20 - 22 °C
pH:
7.6 - 7.7
Details on test conditions:
day/light: 12 h/ 12 h
feed: daily
change of water twice a week
three replicate tests with 10 daphnia each
Key result
Duration:
24 h
Dose descriptor:
LC0
Effect conc.:
640 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
24 h
Dose descriptor:
LC50
Effect conc.:
790 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
24 h
Dose descriptor:
LC100
Effect conc.:
1 250 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Validity criteria fulfilled:
not specified
Conclusions:
The LC50, 24 h of edetic acid was found to be 790 mg/l.
It can be stated that the LC50 value for edetic acid is much higher than for cobalt salts. Thus the aquatic toxicity of cobalt disodium ethylenediaminetetraacetate is determined by the cobalt moiety of the substance.

Description of key information

It can be stated that the LC50 value for aquatic invertebrates for edetic acid is much higher than for cobalt salts. Thus, the aquatic toxicity of cobalt disodium ethylenediaminetetraacetate is determined by the cobalt moiety of the substance.

Based on the LC value for cobalt salt and molecular weight correction the LC50 value for cobalt disodium ethylenediaminetetraacetate can be stated as >= 15.4 mg/L.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
15.4 mg/L

Additional information