Diammonium [N,N-bis[2-[bis(carboxymethyl)amino]ethyl]glycinato(5-)]ferrate(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:

key study

Study period:

23-1-2013 - 25-1-2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: A GLP study meeting all of the required quality criteria. Analytical certificate present.Validated chemical analysis method used. Appropriate guideline followed. Considered valid without restrictions.

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
The effect observed for DTPA-FeHNa during an acute daphnia test according to OECD 202 is read across to DTPA-Fe(NH4)2. This read across is considered justified because the effects observed will be caused by the DTPA-Fe complex. Ammonium, potassium, sodium, hydrogen are only counter ions needed to neutralize the product and these ions will easily dissociate from the DTPA-Fe complex when evaluated in aquatic ecotoxicity tests under ambient conditions.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

30 ml samples at the start and at the end of the test as well as before and after refreshment were taken and stored in a refrigerator in the dark until
analysis. Stability samples of 100 mg/L in triplicate were also prepared to demonstrate storage stability

Vehicle:

no

Details on test solutions:

The test chemical is easily soluble and prone to light degradation. For this reason a semi static method with solution refreshment was chosen.
A solution of approximately 100 mg/L was made by adding of an accurately weighed amount of the test substance to the test media and stirring until a homogeneous solution was achieved. For both the first and the second stock solutions 0.050 g of the test substance was weighed and dissolved in 500 ml of test medium measured using a volumetric flask.

The test medium was Dutch Standard Water (DSW), with a pH of approximately 8.2, and a conductivity between 550 and 650 µs/cm s-1, containing per
liter of de-ionized water: 200 mg of CaCl2•2H2O, 180 mg of MgSO4•7H2O, 100 mg of NaHCO3 and 20 mg of KHCO3. The guideline criteria requires the CaCO3 content to be between 10 and 250 mg/L. Hardness and conductivity in the test water was measured measured once at the start of the
study as ºdH using the appropriate Dr Lange test kit and converted to the CaCO3 equivalent. Due to the total hardness kit measuring Calcium (as well as magnesium) the test kit was validated by analyzing a known CaCl2 Standard solution.

Test organisms (species):

Daphnia magna

Details on test organisms:

The test animals were taken from a Daphnia magna stock, cultured in conformity with the relevant Standard Operation Procedure. The animals used in the test were less than 24 hours old were obtained from parent animals aged between 2-4 weeks. Daphnia were originally obtained from Wil Research Hambakenwetering 7 5231 DD ‘s-Hertogenbosch the Netherlands.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Remarks on exposure duration:

Refreshment after 24 hours

Post exposure observation period:

None

Hardness:

233.8 mg/L as CaCO3

Test temperature:

22.2 to 22.9 °C

pH:

7.9-8.1

Dissolved oxygen:

8.6-9.2 mg/L

Salinity:

Not Measured

Nominal and measured concentrations:

Nominal = 100 mg/L
Measured Mean = 82.14 mg/L

Details on test conditions:

The test was performed semi static test for 48 hours. 20 animals divided into 4 batches of 5 animals were tested in the control and at the limit test concentration. Those animals which are not able to swim within 15 seconds after gentle agitation of the test vessel were considered to be im¬mobile. The number of animals trapped at the surface was also considered and recorded if observed. These animals were not regarded as im¬mobile and were made to re-submerge. In summary the daphnids were randomly placed in the test fluids and the test vessels were placed in a random manner within each group. The test vessels were not aerated during the test and the animals were not fed. The test was inspected at 0, 24 and 48 hours. The solutions were replaced after 24 hours with freshly made solutions prepared in an identical manner. Animals were carefully transferred using a glass pipette.

As test vessels 50 mL beakers were used containing approximately 50 mL of test solution.

Reference substance (positive control):

yes

Remarks:

The sensitivity of the Daphnia was checked by performing an inhibition test with a reference compound (potassium dichromate) twice a year. The sensitivity was tested for compliance with the guidelines.

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 82.14 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

No effects of any kind were observed at the limit test concentration.

Results with reference substance (positive control):

The sensitivity of the Daphnia was checked by performing an inhibition test with a reference compound (potassium dichromate) twice a year.
The sensitivity was tested for compliance with the guidelines. Daphnia culture is only released for testing if reference substance criteria are met. This is documented as part of the laboratory GLP system.

Reported statistics and error estimates:

Not applicable. Limit test.

Chemical Analysis Results

Sample Concentration (mg/L) 0 h 24h (old) Geo Mean 24h (new) 48h (old) Geo Mean Time weighted mean Control < LOQ < LOQ - < LOQ < LOQ - - 100 mg/L 97.7 64.9 79.62 101.1 70.9 84.66 82.14

Biological Results

Conc
mg/L (Loading)	0 hours	24 hours	48 hours
Control I	5	5	5
II	5	5	5
III	5	5	5
IV	5	5	5
Total	20	20	20
100    I	5	5	5
II	5	5	5
III	5	5	5
IV	5	5	5
Total	20	20	20

Validity criteria fulfilled:

yes

Conclusions:

The test substance is considered as non toxic to aquatic invertebrates.

Description of key information

The 48-hour LC50 for Daphnia carinata, a freshwater species, was 245 mg/L DTPA acid, which is equivalent to 299 mg/L DTPA-Fe(NH4)2.  The 96-hour LC50 for Crangon crangon, a saltwater species, was 6020 mg/L pentasodium DTPA, which is equivalent to 5744 mg/L DTPA-Fe(NH4)2.

The effect observed for DTPA-FeHNa during an acute daphnia test according to OECD 202is read across to DTPA-Fe(NH4)2. This read across is considered justified because the effects observed will be caused by the DTPA-Fe complex. Ammonium, potassium, sodium, hydrogen are only counter ions needed to neutralize the product and these ions will easily dissociate from the DTPA-Fe complex when evaluated in aquatic ecotoxicity tests under ambient conditions.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

299 mg/L

Marine water invertebrates

Marine water invertebrates

Effect concentration:

5 744 mg/L

Additional information

Five acute toxicity tests with aquatic invertebrates were assessed for this endpoint, and all studies were found to be of good quality and reliable for use in the risk assessment process. Three studies were conducted with the freshwater cladoceran, Daphnia magna, one study was conducted with the freshwater cladoceran, Daphnia carinata,and one study was conducted with the marine brown shrimp, Crangon crangon.

DTPA-FeNaH, the pentapotassium and pentasodium DTPA salts as well as DTPA (free acid) and iron complexed DTPA were used as test substances in these exposure studies. Since the pentapotassium and pentasodium salts of DTPA dissociate when in contact with water, these salts are considered equivalent to DTPA (free acid) in aquatic environments.

The 48 -hour EC50 value for D. magna was > 82.1 for DTPAFeNaH, 890 mg/L for pentapotassium DTPA and > 500 mg/L pentasodium DTPA, while the 48-hour LC50 value for D. carinata (after stoichiometric conversion from DTPA free acid to DTPA-FeHNa) was 299 mg/L DTPA-FeNa2. The 96 -hour LC50 for the brown shrimp, Crangon crangon, was 5744 mg/L DTPA-FeNa2 (after stoichiometric conversion from pentasodium DTPA to DTPA-FeNa2).

The key parameter for the freshwater studies was the 48 -hour LC50 value of 299 mg/L reported for D. carinata, since this is the lowest concrete acute toxicity value reported for a freshwater invertebrate species. The key parameter for the saltwater studies was the 96 -hour LC50 value of 5744 mg/L reported for the brown shrimp.