Zinc EDDHA

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

fish life cycle toxicity

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:

22 mo

Dose descriptor:

other: MATC

Remarks:

hard water (330 mg CaCO3/L)

Effect conc.:

> 4.27 - < 8.53 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Remarks:

converted to target substance

Basis for effect:

mortality

Duration:

22 mo

Dose descriptor:

other: MATC

Remarks:

soft water (25 mg CaCO3/L)

Effect conc.:

> 1.87 - < 3.47 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 %.

MATC soft water, lower limit (Zn ion) = 0.14 mg/L

MATC soft water, lower limit (Target substance) = 0.14/0.075 = 1.87 mg/L

MATC soft water, upper limit (Zn ion) = 0.26 mg/L

MATC soft water, upper limit (Target substance) = 0.26/0.075 = 3.47 mg/L

MATC hard water, lower limit (Zn ion) = 0.32 mg/L

MATC hard water, lower limit (Target substance) = 0.32/0.075 = 4.27 mg/L

MATC hard water, upper limit (Zn ion) = 0.64 mg/L

MATC hard water, upper limit (Target substance) = 0.64/0.075 = 8.53 mg/L

Conclusions:

The chronic toxicity of zinc to rainbow trout decreases as water hardness increases. The MATC obtained in hard water is with 320 - 640 µg Zn/L approximately two-and-one-half times the MATC obtained in soft water (140 - 260 µg 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 MATC obtained in hard water of 4.27 - 8.53 mg/L and a MATC obtained in soft water of 1.87 - 3.47 mg/L.

Executive summary:

The chronic toxicity of zinc to rainbow trout decreases as water hardness increases. The MATC obtained in hard water is with 320 - 640 µg Zn/L approximately two-and-one-half times the MATC obtained in soft water (140 - 260 µg Zn/L).

The target substance contains 7.5 % zinc ions.

Accounting to the Zn content of 7.5%, this corresponds to a MATC obtained in hard water of 4.27 - 8.53 mg/L and a MATC obtained in soft water of 1.87 - 3.47 mg/L.

Reference 2

Endpoint:

fish, juvenile growth test

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:

30 d

Dose descriptor:

LC50

Remarks:

pH 7.76, DOC 22.9 mg/L, Ca 32 mg/L

Effect conc.:

26.27 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Remarks:

converted to target substance

Basis for effect:

mortality

Duration:

30 d

Dose descriptor:

LC50

Remarks:

pH 7.08, DOC 2.84 mg/L, Ca 8.05 mg/L

Effect conc.:

4.49 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Remarks:

converted to target substance

Basis for effect:

mortality

Key result

Duration:

30 d

Dose descriptor:

NOEC

Remarks:

pH 7.76, DOC 22.9 mg/L, Ca 32 mg/L

Effect conc.:

10.28 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Remarks:

converted to target substance

Basis for effect:

mortality

Key result

Duration:

30 d

Dose descriptor:

NOEC

Remarks:

pH 7.08, DOC 2.84 mg/L, Ca 8.05 mg/L

Effect conc.:

2.65 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 %.

LC50 pH 7.76 (Zn ion) = 1.97 mg/L

LC50 pH 7.76 (targte substance) = 1.97/0.075 = 26.27 mg/L

LC50 pH 7.08 (Zn ion) = 0.337 mg/L

LC50 pH 7.08 (target substance) = 0.337/0.075 = 4.49 mg/L

NOEC pH 7.76 (Zn ion) = 0.771 mg/L

NOEC pH 7.76 (target substance) = 0.771/0.075 = 10.28 mg/L

NOEC pH 7.08 (Zn ion) = 0.199 mg/L

NOEC pH 7.08 (target substance) = 0.199/0.075 = 2.65 mg/L

Conclusions:

Chronic zinc toxicity (expressed as 50 % lethal concentrations [LC50]) varied up to 6-fold for the O. mykiss (30 -d LC50 between 0.337 and 1.970 mg Zn/L). The 30-d NOECs ranged from 0.199 to 0.771 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 30 d LC50 ranging from 4.49 to 26.27 mg/L, the NOEC (30 d) ranging from 2.65 to 10.28 mg/L for O. mykiss.

Executive summary:

Chronic zinc toxicity (expressed as 50 % lethal concentrations [LC50]) varied up to 6-fold for the O. mykiss (30 -d LC50 between 0.337 and 1.970 mg Zn/L). The 30-d NOECs ranged from 0.199 to 0.771 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 30 d LC50 ranging from 4.49 to 26.27 mg/L, the NOEC (30 d) ranging from 2.65 to 10.28 mg/L for O. mykiss.

Description of key information

Read-Across: WoE, Zn ion, O. mykiss, 30 d LC50: 4.49 to 26.27 mg/L; NOEC (30 d): 2.65 to 10.28 mg/L (converted to the target substance taking into account the Zn content of 7.5 %)

Read-Across: WoE, Zn ion, O. mykiss, MATC obtained in hard water of 4.27 - 8.53 mg/L and a MATC obtained in soft water of 1.87 - 3.47 mg/L (converted to the target substance taking into account the Zn content of 7.5 %)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

NOEC

Effect concentration:

2.65 mg/L

Additional information

Read-across - Zn ion

De Schamphelaere et al., 2005

Zinc toxicity to O. mykiss 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). Chronic zinc toxicity (expressed as 50 % lethal concentrations [LC50]) varied up to 6-fold for the O. mykiss (30-d LC50 between 0.337 and 1.970 mg Zn/L). The 30-d NOECs ranged from 0.199 to 0.771 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 LC50 (30 d) ranging from 4.49 to 26.27 mg/L and a NOEC (30 d) ranging from 2.65 to 10.28 mg/L for O. mykiss

Sinley et al., 2005

The chronic toxicity of zinc to rainbow trout (O. mykiss) decreases as water hardness increases. The MATC obtained in hard water is with 320 - 640 µg Zn/L approximately two-and-one-half times the MATC obtained in soft water (140 - 260 µg 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 MATC obtained in hard water of 4.27 - 8 .53 mg/L and a MATC obtained in soft water of 1.87 - 3.47 mg/L.

Conclusion

The study conducted by De Schamphelaere et al., 2005 is regarded as the most reliable. The study using zinc as test item is conducted according to OECD 215 and is well documented. On the contrary, Sinley et al (1974) using zinc sulphate as test item and the study is not in accordance with an OECD Guideline. Addtionally only MATC ("maximal acceptable toxicant concentration") values, but no NOECs are reported. MATC values would need to be recalculated to NOECs. For both studies the GLP compliance is not specified.

Taking all information into account the NOEC as obtained by De Schamphelaere et al., 2005 is set as key value for the chemical safety assessment.