Zinc EDDHA

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to Read Across Statement attached in Section 13

Reason / purpose for cross-reference:

read-across source

Duration:

21 d

Dose descriptor:

EC50

Remarks:

pH 6.8, DOC 17.3 mg/L, Ca 38.3 mg/L

Effect conc.:

7.15 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Remarks:

converted to target substance

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

EC50

Remarks:

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

Effect conc.:

1.49 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Remarks:

converted to target substance

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

NOEC

Remarks:

pH 6.0, DOC 5.37 mg/L, Ca 3.7 mg/L

Effect conc.:

0.83 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Remarks:

converted to target substance

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

NOEC

Remarks:

pH 6.8, DOC 17.3 mg/L, Ca 38.3 mg/L

Effect conc.:

6.55 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Remarks:

converted to target substance

Basis for effect:

reproduction

The target substance contains 7.5 % Zn ions. Therefore, the hazard value for Zn ion is converted to the target substance considering a Zn content of 7.5 %.

EC50 pH 6.8 (Zn ion) = 0.536 mg/L

EC50 pH 6.8 (target substance) = 0.536/0.075 = 7.15 mg/L

EC50 pH 7.3 (Zn ion) = 0.112 mg/L

EC50 pH 7.3 (target substance) = 0.112/0.075 = 1.49 mg/L

NOEC pH 6.0 (Zn ion) = 0.0626 mg/L

NOEC pH 6.0 (target substance) = 0.0626/0.075 = 0.83 mg/L

NOEC pH 6.8 (Zn ion) = 0.491 mg/L

NOEC pH 6.8 (target substance) = 0.491/0.075 = 6.55 mg/L

Conclusions:

Chronic zinc toxicity (expressed as 50 % effective concentrations [EC50]) varied up to 5-fold for the D. magna (21 d EC50 from 112 to 536 µg Zn/L). The determined NOEC range is 0.0626 - 0.491 mg Zn/L.
This result is also relevant for the target substance, which contains 7.5 % zinc ions. Accounting to the Zn content of 7.5 %, this corresponds to a 21 d EC50 ranging from 1.49 to 7.15 mg/L, the NOEC (21 d) ranging from 0.83 - 6.55 mg/L.

Executive summary:

Chronic zinc toxicity to Daphnia magna (expressed as 50 % effective concentrations [EC50]) varied up to 5-fold (21-d EC50 from 112 to 536 µg Zn/L). The determined NOEC range is 0.0626 - 0.491 mg Zn/L.

This result is also relevant for the target substance, which contains 7.5 % zinc ions. Accounting to the Zn content of 7.5 %, this corresponds to a 21 d EC50 ranging from 1.49 to 7.15 mg/L, the NOEC (21 d) ranging from 0.83 - 6.55 mg/L.

Reference 2

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to Read Across Statement attached in Section 13

Reason / purpose for cross-reference:

read-across source

Duration:

9 d

Dose descriptor:

EC50

Remarks:

acclimation to 3 µg Zn/L for 10 generations

Effect conc.:

4.72 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Remarks:

converted to target substance

Basis for effect:

mortality

Duration:

9 d

Dose descriptor:

EC50

Remarks:

acclimation to 13 µg Zn/L for 10 generations

Effect conc.:

5.16 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Remarks:

converted to target substance

Basis for effect:

mortality

Duration:

9 d

Dose descriptor:

EC50

Remarks:

acclimation to 50 µg Zn/L for 10 generations

Effect conc.:

5.99 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Remarks:

converted to target substance

Basis for effect:

mortality

Duration:

9 d

Dose descriptor:

EC50

Remarks:

acclimation to 100 µg Zn/L for 10 generations

Effect conc.:

6.52 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Remarks:

converted to target substance

Basis for effect:

mortality

The target substance contains 7.5 % Zn ions. Therefore, the hazard value for Zn ion is converted to the target substance considering a Zn content of 7.5 %.

EC50 acclimation to 3 µg Zn/L for 10 generations (Zn ion) = 0.354 mg/L

EC50 acclimation to 3 µg Zn/L for 10 generations (target substance) = 0.354/0.075 = 4.72 mg/L

EC50 acclimation to 13 µg Zn/L for 10 generations (Zn ion) = 0.387 mg/L

EC50 acclimation to 13 µg Zn/L for 10 generations (target substance) = 0.387/0.075 = 5.16 mg/L

EC50acclimation to 50 µg Zn/L for 10 generations (Zn ion) = 0.449 mg/L

EC50acclimation to 50 µg Zn/L for 10 generations (target substance) = 0.449/0.075 = 5.99 mg/L

EC50 acclimation to 100 µg Zn/L for 10 generations (Zn ion) = 0.489 mg/L

EC50 acclimation to 100 µg Zn/L for 10 generations (target substance) = 0.489/0.075 = 6.52 mg/L

Conclusions:

The chronic test results indicate that organisms acclimated to 50 and 100 µg Zn/L performed better (survival and reproduction). The EC50 (9 d) values refering survival were 354 µg/L for organisms acclimated to 3 µg Zn/L, 387 µg/L for organisms acclimated to 13 µg Zn/L and 449 and 489 µg/L for organisms acclimated to 50 and 100 µg Zn/L, respectively.
This result is also relevant for the target substance, which contains 7.5 % zinc ions.

Executive summary:

In this study, the cladoceran Ceriodaphnia dubia was acclimated for 10 generations to four zinc concentrations ranging from 0 to 100 µg Zn/L and changes in zinc tolerance were monitored using chronic (9 days) assays. The chronic test results indicate that organisms acclimated to 50 and 100 µg Zn/L performed better (survival and reproduction). The EC50 (9 d) values refering survival were 354 µg/L for organisms acclimated to 3 µg Zn/L, 387 µg/L for organisms acclimated to 13 µg Zn/L and 449 and 489 µg/L for organisms acclimated to 50 and 100 µg Zn/L, respectively. The reproduction and survival of organisms acclimated to 3 and 13 µg Zn/L was significantly lower than those acclimated to higher zinc concentrations. It can be concluded that culturing test animals in media lacking trace metals such as zinc could give rise to animals that are unnaturally sensitive to those same metals during toxicity tests.

This result is also relevant for the target substance, which contains 7.5 % zinc ions. Accounting to the Zn content of 7.5 %, this corresponds to an EC50 (9 d) values refering survival of 4.72 mg/L for C. dubia acclimated to 3 µg Zn/L, 5.16 mg/L for C. dubia acclimimated to 13 µg Zn/L and 5.99 and 6.52 mg/L for C. dubia acclimated to 50 and 100 µg Zn/L, respectively.

Reference 3

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to Read Across Statement attached in Section 13

Reason / purpose for cross-reference:

read-across source

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

628 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

320 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

LC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

>= 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

- Mortality of parent animals: No mortality or other visible effects were recorded for the parental organisms at any of the test item concentrations tested.
- During the exposure period of 21 days, the mean values for living offspring recorded at test item concentrations up to and including 320 mg/L were within same range as those found in the control group. After the first brood, the parental Daphnia exposed to 1000 mg/L frequently released non-hatched eggs instead of living young. Hence, the reproductive capacity of these organisms was substantially lower than those found in the other groups after 21 days of exposure.

Results with reference substance (positive control):

Not applicable.

Reported statistics and error estimates:

Statistical analysis of the data for reproduction at the end of the 21-day exposure period showed that significant reduction of the reproductive capacity of Daphnia magna occurred at 320 and 1000 mg/L (Bonferroni t-test, P = 0.05). Comparison of the reproduction values between the different groups showed that the mean value recorded at 1000 mg/L was significantly lower than those of all other groups (Tukey test, P = 0.05). Only the effect recorded at 1000 mg/L should be considered as a biologically significant effect.

The LC50-values for parental mortality and the EC50 values for reproduction, the lowest observed effect concentrations (LOEC) and the no observed effect concentrations (NOEC) are shown below:

Parameter	Concentration (mg/L)
21-day LC50 for parental mortality	greater than 1000
LOEC for parental mortality	greater than 1000
NOEC for parental mortality	greater or equal to 1000
12-day EC50 for reproduction^*1	822
14-day EC50 for reproduction^*1	809
18-day EC50 for reproduction^*1	740
21-day EC50 for reproduction^*1	628
LOEC for reproduction	1000
NOEC for reproduction	320
Overall LOEC	1000
Overall NOEC	320

^*1: Based on linear regression analysis

Validity criteria fulfilled:

yes

Remarks:

Validity criteria of Guideline were fulfilled.

Conclusions:

In this valid guideline reproduction study with GLP compliance, the test substance no effect on the survival of Daphnia magna at concentrations up to and including 1000 mg/L. A biologically relevant effect on reproductive capacity of Daphnia magna was noted at 1000 mg/L. The same result is expected for the organic constituents of target substance since it has the same composition as the source substance.

Executive summary:

The effects of the Fe(Na)EDDHMA on survival and reproductive Performance in Daphnia magna during 21 days of exposure were investigated in an OECD Guideline No. 211 "Daphnia magna Reproduction Test".

The nominal concentrations tested were 10, 32, 100, 320 and 1000 mg/L. The test solutions were renewed three times a week. 10 neonate daphnids for the test concentrations and 20 animals for the control group were investigated. At the start of the test and every workday, the condition of the parental daphnids was recorded and during the reproduction phase the number of living offspring, immobile young and the presence of unhatched eggs were recorded. During the study duplicate samples of 10 mL were taken from freshly prepared solutions on days 0, 7, 14 and 19, from 72-hour old solutions on day 3 and from 48-hour old solutions on day 21. Samples were stored in a deep-freeze until possible analysis.

Analysis of the samples showed that the method of preparation of test media provided repeatable recoveries of test substance concentration. Measured concentrations were all in agreement with nominal, except for those measured in the samples taken at 1000 mg/L (85 % - 89 %) during the 2 -day period after the last renewal. Further, the measured concentrations were stable during the periods between renewals of the test solutions.

No mortality or other visible effects were recorded for the parental organisms at any of the test item concentrations tested. During the total exposure period of 21 days, no significant (greater than 10%) immobilisation (including mortality) of newborn young was observed at any of the test concentrations.

In conclusion, the test substance had no effect on the survival of Daphnia magna at concentrations up to and including 1000 mg/L in this reproduction study. The test item affected the reproductive capacity of Daphnia magna at concentrations of 320 and 1000 mg/L. A biologically relevant effect on reproductive capacity of Daphnia magna was noted at 1000 mg/L.

Description of key information

Read-Across: WoE, Zn ion, D. magna, 21 d, EC50: 1.49 to 7.15 mg/L, NOEC: 0.83 - 6.55 mg/L (converted to the target substance taking into account the Zn content of 7.5 % at the most) (De Schamphelaere 2005)

Read-Across: WoE, Zn ion, C. dubia, 9 d, EC 50: 4.72 - 6.52 mg/L (converted to the target substance taking into account the Zn content of 7.5 % at the most) (Muyssen and Janssen 2002)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

NOEC

Effect concentration:

0.83 mg/L

Additional information

Read-across Zn ion

De Schamphelaere et al., 2005

Chronic zinc toxicity to Daphnia magna (expressed as 50 % effective concentrations [EC50]) varied up to 5-fold (21-d EC50 from 112 to 536 mg Zn/L). The determined NOEC range is 0.0626 - 0.491 mg Zn/L.

This result is also relevant for the target substance, which contains 7.5 % zinc ions. Accounting to the Zn content of 7.5 %, this corresponds to a 21 d EC50 ranging from 1.49 to 7.15 mg/L, the NOEC (21 d) ranging from 0.83 - 6.55 mg/L.

Muyssen and Janssen, 2002

In this study, the cladoceran Ceriodaphnia dubia was acclimated for 10 generations to four zinc concentrations ranging from 0 to 100 µg Zn/L and changes in zinc tolerance were monitored using chronic (9 days) assays. The chronic test results indicate that organisms acclimated to 50 and 100 µg Zn/L performed better (survival and reproduction). The EC 50 (9 d) values refering survival were 354 µg/L for organisms acclimated to 3 µg Zn/L, 387 µg/L for organisms acclimated to 13 µg Zn/L and 449 and 489 µg/L for organisms acclimated to 50 and 100 µg Zn/L, respectively. The reproduction and survival of organisms acclimated to 3 and 13 µg Zn/L was significantly lower than those acclimated to higher zinc concentrations. It can be concluded that culturing test animals in media lacking trace metals such as zinc could give rise to animals that are unnaturally sensitive to those same metals during toxicity tests.

This result is also relevant for the target substance, which contains 7.5 % zinc ions. Accounting to the Zn content of 7.5 %, this corresponds to an EC 50 (9 d) values refering survival of 4.72 mg/L for C. dubia acclimated to 3 µg Zn/L, 5.16 mg/L for C. dubia acclimated to 13 µg Zn/L and 5.99 and 6.52 mg/L for C. dubia acclimated to 50 and 100 µg Zn/L, respectively.