Alkaline earth metal and zinc hydroxy(substituted)acetate complexes and alkaline earth metal glyoxylate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

weight of evidence

Reason / purpose for cross-reference:

assessment report

Reason / purpose for cross-reference:

read-across source

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: a solution containing 100 mg/L test item in dilution water

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: a solution containing 100 mg/L test item in dilution water

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: a solution containing 100 mg/L test item in dilution water

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: a solution containing 100 mg/L test item in dilution water

Basis for effect:

mobility

Results with reference substance (positive control):

The 24h- EC50 of potassium dichromate was tested in a current reference test. The value was determined as 1.7 mg/L, lying within the demanded range of 0.6 - 1.7 mg/L.

Main Study

Immobilities

In the control, none of the daphnia died or showed any signs of abnormal behaviour throughout the test (see table below).

Table a:      Immobilities

Nominal Concentration in mg/L	Immobility 24 hours					Immobility 48 hours
	abs.				in %	abs.				in %
0	0	0	0	1	5	0	0	0	1	5
100	0	1	0	0	5	0	1	1	0	10

 

 pH and O₂, Temperature

The pH values in the test media and the control ranged from 7.5 to 7.7. The concentration of dissolved oxygen stayed above 8.1 mg/L throughout the test. Temperature range was 23.0 – 24.8^oC. The details are given in the following tables:

Table :b      pH and O₂-values

Nominal Concentration in mg/L	pH		O2-Concentration in mg/L
	0 h	48 h	0 h	48 h
0	7.6	7.6	8.6	8.1
100	7.5	7.7	8.4	8.2

 

Table c:     Temperature

Temperature in^oC
0 h	24 h	48 h
23.0	23.4	24.8

Validity criteria fulfilled:

yes

Conclusions:

The following results were determined for the test item:
24 h-NOEC = 100 mg/L
48 h-NOEC = 100 mg/L
24 h-EC50 > 100 mg/L
48 h-EC50 > 100 mg/L

Executive summary:

The study was performed as a limit test at 100 mg/L following OECD Guideline 202 and GLP. Twenty daphnia were exposed to the test item for 48 hours in a static test system. After 24 and 48 hours, the immobilised daphnia were counted. The treatment showed no significant immobilisation. 5 % of the daphnia were immobilised in the control, 10 % were immobilised in the treatment. The 24h- EC50 of potassium dichromate was tested in a current reference test. The value was determined as 1.7 mg/L, lying within the demanded range of 0.6 - 1.7 mg/L. At the start and at the end of the experiment, the content of the test item in the test solution was determined using titration. The recovery after 48 hours was 95 % of the start concentration, the correlation between nominal and measured concentration was 116 % at the start and 111 % at the end. Therefore, the determination of the biological results was based on the nominal concentration. The following results were determined for the test item:

24 h-NOEC = 100 mg/L

48 h-NOEC = 100 mg/L

24 h-EC50 > 100 mg/L

48 h-EC50 > 100 mg/L

The source substance contains the major organic moieties of the target substance. Therefore, this study shows that no acute toxicity to invertebrates can be attributed to the organic moieties of the target substance.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

weight of evidence

Reason / purpose for cross-reference:

assessment report

Reason / purpose for cross-reference:

read-across source

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

9 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

4 400 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

2 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: The surviving animals in 5 and 10 g/L are very weak by the end of the test, while the vitality of the animals in all other concentrations (up to 2.5 g/L) resemble the control animals.
See also table 1.

Results with reference substance (positive control):

no reference substance used in the study

Reported statistics and error estimates:

none

table 1: Immobilisation rate, skinnings an no. of animals which are trapped at the surface after 48 h

	Control	625 [mg/L]	1250 [mg/L]	2500 [mg/L]	5000 [mg/L]	10000 [mg/L]
Immobilisation [%], 24 h	0	0	0	0	0	60
Immobilisation [%], 48 h	0	0	0	0	85	90
Skinnings [%], 48 h	100	100	100	100	75	50
animals trapped at thesurface [%], 48 h	0	0	0	0	5	0

Validity criteria fulfilled:

yes

Conclusions:

The test item is not acute toxic for daphnia.

Executive summary:

The test item was tested in a study according to OECD Guideline 202 and GLP. The following EC50 values were obtained:

EC₅₀(24h) = 9500 mg/L

EC₅₀(48h) = 4400 mg/L

The surviving animals in 5 and 10 g/L are very weak by the end of the test, while the vitality of the animals in all other concentrations(up to 2.5 g/L) resemble to the control animals.

The source substance contains the major organic moieties of the target substance. Therefore, this study shows that no acute toxicity to invertebrates can be attributed to the organic moieties of the target substance.

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

weight of evidence

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

assessment report

Duration:

48 h

Dose descriptor:

EC50

Remarks:

soft water, clone C

Effect conc.:

1.57 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element (total fraction)

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Remarks:

soft water, clone A

Effect conc.:

0.79 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element (total fraction)

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Remarks:

moderate-hard water, clone C

Effect conc.:

6.06 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element (total fraction)

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Remarks:

moderate-hard water, clone A

Effect conc.:

2.77 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element (total fraction)

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Remarks:

hard water, clone C

Effect conc.:

5.83 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element (total fraction)

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Remarks:

hard water, clone A

Effect conc.:

3.64 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element (total fraction)

Basis for effect:

mobility

The target substance contains 16.5 % Zn ions. Therefore, the hazard value for Zn ion is converted to the target substance considering a Zn content of 16.5 % as worst-case value.

EC50 (Zn ion) = 0.259 mg/L

EC50 (target substance) = 0.259/0.165 = 1.57 mg/L

EC50 (Zn ion) = 0.131 mg/L

EC50 (target substance) = 0.131/0.165 = 0.79 mg/L

EC50 (Zn ion) = 1.06 mg/L

EC 50 (target substance) = 1.06/0.165 = 6.06 mg/L

EC50 (Zn ion) = 0.457 mg/L

EC 50 (target substance) = 0.457/0.165 = 2.77 mg/L

EC50 (Zn ion) = 0.962 mg/L

EC 50 (target substance) = 0.962/0.165 = 5.83 mg/L

EC50 (Zn ion) = 0.601 mg/L

EC50 (target substance) = 0.601/0.165 = 3.64 mg/L

Conclusions:

In general, D. magna clones were more sensitive to zinc in soft water relative to hard water. In addition, a significant genetic variability concerning zinc toxicity was shown. The least sensitive clone had the following EC50 (48 h) values: 259 µg/L (soft water), 1060 µg/L (moderate-hard water), 962 µg/L (hard water). The most sensitive clone had the following EC50 (48 h) values: 131 µg/L (soft water), 457 µg/L (moderate-hard water), 601 µg/L (hard water). This result is also relevant for the target substance, which contains 16.5 % zinc ions.

Executive summary:

D. magna clones were exposed to single-metal solutions of varying concentration at two or three levels of water hardness (soft, moderate–hard and hard) for periods ranging from 12–96 h (12 h increments). EC50 values for each metal-, genotype-, water hardness-, exposure period-combination were determined for (i) total metal concentration and (ii) the free hydrated metal ion concentration (predicted using geochemical speciation modeling) and compared using analysis of covariance with environment (water hardness) and genotype (clone) as fixed factors and exposure time as a covariate. Substantial genetic variability occurred in both essential (Zn, Cu) and non essential (Cd, U) metals.

Concerning Zinc, the least sensitive clone had the following EC50 (48 h) values: 259 µg/L (soft water), 1060 µg/L (moderate-hard water), 962 µg/L (hard water). The most sensitive clone had the following EC50 (48 h) values: 131 µg/L (soft water), 457 µg/L (moderate-hard water), 601 µg/L (hard water). This result is also relevant for the target substance, which contains 16.5 % zinc ions. To account for the Zn content of 16.5 %, these values were converted to the target substance.

As a result, the least sensitive clone had the following EC50 (48 h) values: 1.57 mg/L (soft water), 6.06 mg/L (moderate-hard water), 5.83 mg/L (hard water). The most sensitive clone had the following EC50 (48 h) values: 0.79 mg/L (soft water), 2.77 mg/L (moderate-hard water), 3.64 mg/L (hard water).

Reference 4

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

weight of evidence

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

assessment report

Duration:

48 h

Dose descriptor:

EC50

Remarks:

pH 8, DOC 7.49 mg/L, Ca 52.7 mg/L

Effect conc.:

19.94 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element (dissolved fraction)

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Remarks:

pH 7.3, DOC 2.53 mg/L, Ca 5 mg/L

Effect conc.:

2.15 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

element (dissolved fraction)

Basis for effect:

mobility

The target substance contains 16.5 % Zn ions. Therefore, the hazard value for Zn ion is converted to the target substance considering a Zn content of 16.5 % as worst-case value.

EC50 (Zn ion) = 3.29 mg/L

EC 50 (target substance) = 3.29/0.165 = 19.94 mg/L

EC50 (Zn ion) = 0.354 mg/L

EC 50 (target substance) = 0.354/0.165 = 2.15 mg/L

Conclusions:

Both inorganic and organic Zn complexation reduces Zn2+ activity and thus also reduce toxicity. Inorganic complexation (i. e. ZnCO3) is relatively straightforward, while dissolved organic matter (DOM) vary much in their zinc-binding characteristics. Therefore, for unknown samples, it is suggested to assume that the DOM consists of a fixed fraction of chemically active fulvic acid, i.e., 61 %, which is the mean of optimal %AFA of the five abovementioned samples with which Zn titration studies were performed. This result is also relevant for the target substance, which contains 16.5 % zinc ions.

Executive summary:

Zinc toxicity to Daphnia magna was evaluated in a series of experiments with spiked natural surface waters. The eight selected freshwater samples had varying levels of bioavailability modifying parameters: pH (5.7–8.4), dissolved organic carbon (DOC, 2.48–22.9 mg/L), Ca (1.5–80 mg/L), Mg (0.79–18 mg/L), and Na (3.8–120 mg/L). In those waters, acute zinc toxicity (expressed as 50% effective concentrations [EC50]) varied up to 9-fold for the D. magna (48-h EC50 from 354 to 3290 µg Zn/L). Both inorganic and organic Zn complexation reduces Zn2+ activity and thus also reduce toxicity. Inorganic complexation (i. e. ZnCO3) is relatively straightforward, while dissolved organic matter (DOM) vary much in their zinc-binding characteristics. Therefore, for unknown samples, it is suggested to assume that the DOM consists of a fixed fraction of chemically active fulvic acid, i.e., 61%, which is the mean of optimal %AFA of the five abovementioned samples with which Zn titration studies were performed. This result is also relevant for the target substance, which contains 16.5 % zinc ions. Accounting to the Zn content of 16.5 %, this corresponds to EC 50 values between 2.15 and 19.94 mg/L for the target substance.

Description of key information

Read-Across: WoE, FF6, OECD 202, GLP, D. magna, 48 h, EC50 = 4400 mg/L

Read-Across: WoE, Blancolen, OECD 202, GLP, D. magna, 48 h, EC50 = > 100 mg/L, NOEC = 100 mg/L

Read-Across: WoE, Zn ion, D. magna, 48 h, EC50 = 0.79 mg/L (converted to the target substance taking into account the Zn content of 16.5 % at the most)

Read-Across: WoE, Zn ion, D. magna, 48 h, EC50 = 2.15 mg/L (converted to the target substance taking into account the Zn content of 16.5 % at the most)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.79 mg/L

Additional information

Read-across - FF6

The test item was tested in a study according to OECD Guideline 202 and GLP. The following EC50 values were obtained:

EC₅₀(24h) = 9500 mg/L

EC₅₀(48h) = 4400 mg/L

The surviving animals in 5 and 10 g/L are very weak by the end of the test, while the vitality of the animals in all other concentrations (up to 2.5 g/L) resemble to the control animals.

The source substance contains the major organic moieties of the target substance. Therefore, this study shows that no acute toxicity to invertebrates can be attributed to the organic moieties of the target substance.

Read-across - Blancolen

The study was performed as a limit test at 100 mg/L following OECD Guideline 202 and GLP. Twenty daphnia were exposed to the test item for 48 hours in a static test system. After 24 and 48 hours, the immobilised daphnia were counted. The treatment showed no significant immobilisation. 5 % of the daphnia were immobilised in the control, 10 % were immobilised in the treatment. The 24h-EC50 of potassium dichromate was tested in a current reference test. The value was determined as 1.7 mg/L, lying within the demanded range of 0.6 - 1.7 mg/L. At the start and at the end of the experiment, the content of the test item in the test solution was determined using titration. The recovery after 48 hours was 95 % of the start concentration, the correlation between nominal and measured concentration was 116 % at the start and 111 % at the end. Therefore, the determination of the biological results was based on the nominal concentration. The following results were determined for the test item:

24 h-NOEC = 100 mg/L

48 h-NOEC = 100 mg/L

24 h-EC50 > 100 mg/L

48 h-EC50 > 100 mg/L

The source substance contains the major organic moieties of the target substance. Therefore, this study shows that no acute toxicity to invertebrates can be attributed to the organic moieties of the target substance.

Read-across - Zn ion

Barata 1998

D. magna clones were exposed to single-metal solutions of varying concentration at two or three levels of water hardness (soft, moderate–hard and hard) for periods ranging from 12–96 h (12 h increments). EC50 values for each metal-, genotype-, water hardness-, exposure period-combination were determined for (i) total metal concentration and (ii) the free hydrated metal ion concentration (predicted using geochemical speciation modeling) and compared using analysis of covariance with environment (water hardness) and genotype (clone) as fixed factors and exposure time as a covariate. Substantial genetic variability occurred in both essential (Zn, Cu) and non essential (Cd, U) metals.

Concerning Zinc, the least sensitive clone had the following EC50 (48 h) values: 259 µg/L (soft water), 1060 µg/L (moderate-hard water), 962 µg/L (hard water). The most sensitive clone had the following EC50 (48 h) values: 131 µg/L (soft water), 457 µg/L (moderate-hard water), 601 µg/L (hard water). This result is also relevant for the target substance, which contains 16.5 % zinc ions. To account for the Zn content of 16.5 %, these values were converted to the target substance.

As a result, the least sensitive clone had the following EC50 (48 h) values: 1.57mg/L (soft water), 6.06 mg/L (moderate-hard water), 5.83 mg/L (hard water). The most sensitive clone had the following EC50 (48 h) values: 0.79 mg/L (soft water), 2.77 mg/L (moderate-hard water), 3.64 mg/L (hard water).

De Schamphelaere 2005

Zinc toxicity to Daphnia magna was evaluated in a series of experiments with spiked natural surface waters. The eight selected freshwater samples had varying levels of bioavailability modifying parameters: pH (5.7–8.4), dissolved organic carbon (DOC, 2.48–22.9 mg/L), Ca (1.5–80 mg/L), Mg (0.79–18 mg/L), and Na (3.8–120 mg/L). In those waters, acute zinc toxicity (expressed as 50% effective concentrations [EC50]) varied up to 9-fold for the D. magna (48-h EC50 from 354 to 3290 mg Zn/L). Both inorganic and organic Zn complexation reduces Zn²⁺ activity and thus also reduce toxicity. Inorganic complexation (i. e. ZnCO₃) is relatively straightforward, while dissolved organic matter (DOM) vary much in their zinc-binding characteristics. Therefore, for unknown samples, it is suggested to assume that the DOM consists of a fixed fraction of chemically active fulvic acid, i.e., 61%, which is the mean of optimal %AFA of the five abovementioned samples with which Zn titration studies were performed. This result is also relevant for the target substance, which contains 16.5 % zinc ions. Accounting to the Zn content of 16.5 %, this corresponds to EC50 values between 2.15 and 19.94 mg/L for the target substance.