Ethylenediamine-N,N'-di(acetic acid)

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Peer-reviewed data from EU Risk Assessment Report

Justification for type of information:

Study is read across and slightly updated and presented under "type of information" as experimental study until the lead company has updated the Source RSS
Read across justification is presented in IUCLID chapter 13

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

Equimolar amounts of CaCl2 were added, thus CaEDTA was formed in the stock solutions.

Test organisms (species):

activated sludge, domestic

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 min

Nominal and measured concentrations:

Na2H2EDTA was used in concentrations of 125, 250, and 500 mg/L (referred as H4EDTA).

Details on test conditions:

Type: aquatic

Duration:

30 min

Dose descriptor:

other: EC20

Effect conc.:

> 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

30 min

Dose descriptor:

EC10

Effect conc.:

> 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

At the highest test concentration (500 mg/L) a significant inhibition of the respiration rate could not be detected after 30 minutes. It can be concluded that both the EC10 and NOEC values are above 500 mg/L.

Description of key information

The inhibition of the degradation activity of activated sludge is not anticipated when the test substance introduced in appropriate low concentrations

Key value for chemical safety assessment

EC50 for microorganisms:

429 mg/L

Additional information

No data on the toxicity to microorganisms is available for H2 ED2A. Consistent with the other ecotoxicity endpoints, the available data from H4 EDTA are read-across to fill the datagap. All ecotox, fate and phys-chem data from H4 EDTA, Na2H2 EDTA, Na4 EDTA, HEDTA, H2 ED2A etc have been collated in a document which is compiled to justify the read across. This document is included in IUCLID 6, Chapter 13.

The toxicity of Na2H2 EDTA to microorganisms was tested in an activated sludge respiration inhibition test according to OECD guideline 209 [Van Ginkel & Stroo, 2000. The EC20 value after 30 min was measured to be > 500 mg/L (> 429.5 mg/L H4 EDTA).

For Na4 EDTA a similar low toxicity to activated sludge was measured in an respiration inhibition test according to ISO 8192 [BASF AG, 1988]. In this test a concentration of 1000 mg/L test substance caused no effect on the respiration rate of the bacteria.

Results of nitrification are available by Hu (2003). In a 24 h nitrification inhibition test the EC50 of H4 EDTA to microorganism was determined to be 2.4 mM/L, equivalent to 700 mg/L.