Iron(3+) ion dipotassium 2-({2-[bis(carboxylatomethyl)amino]ethyl} (carboxylatomethyl)amino)acetate; hydrate

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:

key 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.

Justification for type of information:

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The results as observed/predicted for EDTA-FeNa are read across to EDTA-Fe(OH)K2 as in diluted form in the aquatic environment both EDTA complexes will have a similar structure and related fate.

2. ANALOGUE APPROACH JUSTIFICATION
It is therefore considered justified to use data/predictions as observed for EDTA-FeNa also for EDTA-Fe(OH)K2.

3. ANALOGUE APPROACH JUSTIFICATION
It is considered justified to use the results as observed/predicted for EDTA-FeNa for read across to EDTA-Fe(OH)K2 because in diluted form in the aquatic environment both EDTA complexes will have a similar structure and related fate.

4. DATA MATRIX
See chapter 13 for Read across document

Reason / purpose for cross-reference:

read-across source

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

The ecotoxicity of EDTA-FeK/EDTA-FeNa are considered to be similar to the ecotoxicity of EDTA-Fe(OH)K2 as these substances will be tested in very diluted form in buffered matrices and under these conditions no significant effects of the additional OH or the difference between sodium and potassium are expected. The ecotoxicity test results as observed for EDTA-FeK/ EDTA-FeNa will therefore be read across to EDTA-Fe(OH)K2.

There are four acute daphnia test results included in this dossier. One with EDTA-FeK and three with EDTA-FeNa.

Two studies were performed under GLP and based on the quality of the study and detail of description, the study from Borrmann (Kl 1) was selected for risk assessment. As a worst-case no molecular weight correction is applied (19% difference).

In the study from Borrmann (2007), 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. The test was carried out under GLP. Test concentrations were measured and were within the range of 80% of the nominal concentration. The EC50 (mobility) was 100.9 mg/L (nominal) and the NOEC was 30 mg/L. 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100.9 mg/L

Additional information

Four studies report on the toxicity to Daphnia magna.

1. The toxicity of the test substance EDTA FeK was assessed in a 48h static guideline, GLP study (Key, Palmer 2002). The EC50 was > 120 mg/L. The NOEC was determined at 43 mg/L.

2. 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 (Key, Borrmann 2007). The test was carried out under GLP. Test concentrations were measured and were within the range of 80% of the nominal concentration. The EC50 (mobility) was 100.9 mg/L (nominal) and the NOEC was 30 mg/L.

3. The acute toxicity (96h-LC50) of sodium ferric EDTA towards Daphnia magna was investigated in a multispecies test system according to EPA-600/3 -75 -009 and ASTM method E729 -80 (published by Ewell et al., 1986). The 96h-LC50 was 32 mg/L (nominal; published, reliability 2).

4. The acute toxicity of EDTA, Mn(II)+EDTA and Fe(III)+EDTA towards Daphnia magna was investigated according to ISO standard 6341 (published by Sorvari and Sillanpaa 1996, Reliability 2). The 24h-EC50 for Fe(III)+EDTA expressed as Fe(III) (= 17 mg/L) equals the value for Fe(III) when tested without EDTA (16 mg/L).

The 24h-EC50 for Fe(III)+EDTA expressed as EDTA is 89.3 mg/L. This is a lower value than the 610 mg/L for EDTA on its own. This may be due to the presence of free Fe present in the EDTA-Fe mixture that is absent in the test with EDTA on its own. The 24h-EC50 expressed as the test substance is 128.3 mg/L.

The key study with 48h-EC50 = 100.9 mg/L was selected because this was the only study carried out according to the guidelines and under GLP. The other studies were either longer (96h) or shorter and had other shortcomings and gaps of information.