Disodium [[N,N'-ethylenediylbis[N-(carboxylatomethyl)glycinato]](4-)-N,N',O,O',ON,ON']zincate(2-)

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

supporting study

Study period:

2007.06.26-2007.08.13

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted according to current technical guidelines (OECD 202, EC method C.2 (92/69/EEC) and US EPA OPPTS 850.1010) without deviation and according to GLP conditions.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 240 mg/L, 60 mg/L, 15 mg/L and control
- Sampling method: samples were taken at 0 hours (initial value) from fresh test solution, after 24 hours from aged test solution and after 48 hours from aged test solution.

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain: STRAUS, Clone V
- Source: Unweltbundesamt, Germany
- Age at study initiation (mean and range, SD): 6-24 h
- Method of breeding: 1 L beakers in water composed of dechlorinated drinking water and deionised water.
- Feeding during test
- Food type: none

ACCLIMATION
- Type and amount of food: single cell green algae (Desmodesmus subspicatus, formerly Scenedismus subspicatus)
- Feeding frequency: at least three times a week

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

20.2-20.9 ºC

pH:

7.7-8.5

Dissolved oxygen:

> 90% of air saturation (approx. 9.0 mg O2/L)

Nominal and measured concentrations:

Nominal concentrations
Range-finding test: 0, 1, 10 and 100 mg/L
Main test: 0, 15, 30, 60, 120 and 240 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: four 100 mL glass beakers per concentration, each filled with 50 mL
- Aeration: none
- No. of organisms per vessel: 20
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Biomass loading rate: 10 mL for each animal

OTHER TEST CONDITIONS
- Adjustment of pH: 7.7 at test initiation
- Photoperiod: 16 h daily
- Light intensity: approx. 1000 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : test temperature, pH-value and oxygen saturation rate were measure at all concentrations at time 0, 24 and 48 h.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study
- Test concentrations: 0, 1, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: after 48 h no immobilisation was observed at 10 mg/L and below, 15% immobilisation observed at 100 mg/L.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

100.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks on result:

other: Measured concentrations not significantly different from nominal

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

30 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks on result:

other: Measured concentrations not significantly different from nominal

Details on results:

- Behavioural abnormalities: at 24 h 15% immobility at 120 mg/L and 50% immobility at 240 mg/L; at 48 h, 5% immobilisation at 60 mg/L, 70% immobilisation at 120 mg/L and 100 % immobilisation at 240 mg/L. No effect on control.
- Mortality of control: no immobilisation

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50/LC50: 0.9-1.9 mg/L

Reported statistics and error estimates:

The EC50 after 24 and 48 h were calculated with the Spearman-Kärber estimator. The EC0 and EC100 were observed values.

Validity criteria fulfilled:

yes

Remarks:

in the control no more than 10% of animals were immobilised and the dissolved oxygen concentration at the end of the test was > 30% of the air saturation value at test temperature

Conclusions:

The EC50 (48 h) of the test item was determined to be 100.9 mg/L (nominal). The NOEC (48 h) was 30 mg/L (nominal)

Executive summary:

The toxicity of FeNaEDTA on Daphnia magna was tested in a 48 h static immobilisation test according to the OECD 202, EC method C.2 (92/69/EEC) and US EPA OPPTS 850.1010.

After a range-finding test, daphnids were exposed to seven concentrations of the test item (0, 15, 30, 60, 120 and 240 mg/L) with 4 replicates per concentration with 5 animals. The reference item, potassium dichromate, was also tested at rates of 0.9 and 1.9 mg/L.

The results of the study showed that the EC50 of the test item was determined to be 100.9 mg/L (nominal) and the NOEC was 30 mg/L.

Description of key information

A short-term toxicity test to aquatic invertebrates with the test substance can be waived because the requirements of Column 2 of Annex VII, Section 9.1.1, second indent are met, i.e. a long-term toxicity test with aquatic invertebrates with an analogue of the test item is available in the registration dossier which provides an adequate and reliable coverage of the key parameter(s) of the corresponding OECD TG 211.

In addition, two reliable 48h EC50 values for invertebrates have been derived from related EDTA complexes, from which one (Borrmann, 2007) is based on measured data. This study is therefore selected as main supporting study. As the test from Borrmann resulted in an 48h EC50 of 100.9 mg EDTA-FeNa/L this result should be corrected for the Molecular Weight  (MW) difference in case the effects need to be compared. The MW ratio of EDTA-ZnK2/EDTA-FeNa is 1.176 (431.8/367.1) is used for the recalculation resulting in a 48h EC50 of 118.6 mg EDTA-ZnK2/L. 

Finally, the study from Sorvari and Sallinpaa (1996) confirms that EDTA-ZnK2 has a low acute ecotoxicity to daphnia 24h EC50 > 100 mg/L.

In this study the acute toxicity of EDTA, Mn(II)-EDTA, Fe(III)-EDTA, Cu(II)-EDTA, Zn(II)-EDTA, Hg(II)-EDTA and Cd(II)-EDTA  towards Daphnia magna was investigated according to ISO standard 6341. The EDTA-metal ion complexes were prepared by adding equimolar amounts of EDTA-Na4 and metal ion solutions together.

The 24h-EC50 values observed are:  17 mg/L expressed as Fe(III)  which equals 112 mg/L Fe(III)Na-EDTA, 38 mg/L expressed as Cu(II) which equals 259.5 mg/L CuK2-EDTA, 910 mg/L expressed as Zn(II) which equals 6010 mg/L Zn(II)K2-EDTA etc.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

118.2 mg/L

Additional information

Although multiple studies are available for daphnids, only two 48h studies are available, the other studies report either 24h or 96h results. Even a value for EDTA-Zn is available confirming the low toxicity to daphnids (24h EC50 = 1140 mg/L).

For this endpoint the 48h values are most relevant and both these values are in the same order of magnitude. As expected 24h EC50 values are somewhat higher, 96h EC50's show to be lower.