potassium;2-[bis[2-[bis(carboxymethyl)amino]ethyl]amino]acetate;dicalcium

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

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:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

other: ISO 9888 Water quality - Evaluation of ultimate aerobic biodegradability of organic compounds in aqueous medium - Static test (Zahn-Wellens method)

Principles of method if other than guideline:

In this Zahn-Wellens biodegradation study, the toxicity of the test compound to the activated sludge microorganisms was assessed.

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

Samples filtered through 0.45 micron pore-size filters.

Vehicle:

not specified

Details on test solutions:

Biological testing medium containing calcium, magnesium, and iron cations at 0.25, 0.1, and 0.001 mmoles/L.

Test organisms (species):

activated sludge, domestic

Details on inoculum:

The inoculum was either non-adapted activated sludge collected at the municipal water treatment plant in Prague or an activated sludge adapted at different sludge age in the range of 5–30 days, which corresponds to the relations in medium- to low-load biological water treatment plants

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 d

Nominal and measured concentrations:

100 mg/L DTPA (acid form)

Details on test conditions:

Two methods were combined for evaluating the complete biodegradability: the method of assaying dissolved organic carbon (EN ISO 7827) suitable for assessing ready biodegradability (X0 1⁄4 30 mg l-1, S01⁄4 DOC 50 mg l-1) and the Zahn-Wellens Test (EN ISO 9888) for assessing potential biodegradability (X0 1⁄4 30 mg l-1, S01⁄4 DOC 50 mg l-1).

Duration:

30 d

Dose descriptor:

EC0

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: DOC removal

Details on results:

Checks for inhibition and for abiotic processes were performed in parallel with biodegradability tests according to standards (EN ISO 7827 and EN ISO 9888). The results of these checks were negative in all cases. At the concentrations under study, the substances had no inhibitory effects on biological processes and no evidence of abiotic decomposition was obtained.

Validity criteria fulfilled:

not specified

Conclusions:

DTPA did not biodegrade in municipal activated sludge with sludge ages ranging from 5 to 30 days. DTPA was not inhibitory to biological processes at a concentration of 100 mg/L (acid form).

Executive summary:

DTPA did not biodegrade in municipal activated sludge with sludge ages ranging from 5 to 30 days. DTPA was not inhibitory to biological processes at a concentration of 100 mg/L (acid form).

Reference 2

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:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

other: ISO 9888 Water quality - Evaluation of ultimate aerobic biodegradability of organic compounds in aqueous medium - Static test (Zahn-Wellens method)

Principles of method if other than guideline:

In this Zahn-Wellens biodegradation study, the toxicity of the test compound to the activated sludge microorganisms was assessed.

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

Samples filtered through 0.45 micron pore-size filters.

Vehicle:

not specified

Details on test solutions:

Biological testing medium containing calcium, magnesium, and iron cations at 0.25, 0.1, and 0.001 mmoles/L.

Test organisms (species):

activated sludge, domestic

Details on inoculum:

The inoculum was either non-adapted activated sludge collected at the municipal water treatment plant in Prague or an activated sludge adapted at different sludge age in the range of 5–30 days, which corresponds to the relations in medium- to low-load biological water treatment plants

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 d

Nominal and measured concentrations:

100 mg/L EDTA (acid form)

Details on test conditions:

Two methods were combined for evaluating the complete biodegradability: the method of assaying dissolved organic carbon (EN ISO 7827) suitable for assessing ready biodegradability (X0 1⁄4 30 mg l-1, S01⁄4 DOC 50 mg l-1) and the Zahn-Wellens Test (EN ISO 9888) for assessing potential biodegradability (X0 1⁄4 30 mg l-1, S01⁄4 DOC 50 mg l-1).

Duration:

30 d

Dose descriptor:

EC0

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: DOC removal

Details on results:

Checks for inhibition and for abiotic processes were performed in parallel with biodegradability tests according to standards (EN ISO 7827 and EN ISO 9888). The results of these checks were negative in all cases. At the concentrations under study, the substances had no inhibitory effects on biological processes and no evidence of abiotic decomposition was obtained.

Validity criteria fulfilled:

not specified

Conclusions:

EDTA did not biodegrade in municipal activated sludge with sludge ages ranging from 5 to 30 days. EDTA was not inhibitory to biological processes at a concentration of 100 mg/L (acid form).

Executive summary:

EDTA did not biodegrade in municipal activated sludge with sludge ages ranging from 5 to 30 days. EDTA was not inhibitory to biological processes at a concentration of 100 mg/L (acid form).

Reference 3

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:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

other: ISO 9888 Water quality - Evaluation of ultimate aerobic biodegradability of organic compounds in aqueous medium - Static test (Zahn-Wellens method)

Principles of method if other than guideline:

In this Zahn-Wellens biodegradation study, the toxicity of the test compound to the activated sludge microorganisms was assessed.

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

Samples filtered through 0.45 micron pore-size filters.

Vehicle:

not specified

Details on test solutions:

Biological testing medium containing calcium, magnesium, and iron cations at 0.25, 0.1, and 0.001 mmoles/L.

Test organisms (species):

activated sludge, domestic

Details on inoculum:

The inoculum was either non-adapted activated sludge collected at the municipal water treatment plant in Prague or an activated sludge adapted at different sludge age in the range of 5–30 days, which corresponds to the relations in medium- to low-load biological water treatment plants

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 d

Nominal and measured concentrations:

100 mg/L HEDTA (acid form)

Details on test conditions:

Two methods were combined for evaluating the complete biodegradability: the method of assaying dissolved organic carbon (EN ISO 7827) suitable for assessing ready biodegradability (X0 1⁄4 30 mg l-1, S01⁄4 DOC 50 mg l-1) and the Zahn-Wellens Test (EN ISO 9888) for assessing potential biodegradability (X0 1⁄4 30 mg l-1, S01⁄4 DOC 50 mg l-1).

Duration:

30 d

Dose descriptor:

EC0

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: DOC removal

Details on results:

Checks for inhibition and for abiotic processes were performed in parallel with biodegradability tests according to standards (EN ISO 7827 and EN ISO 9888). The results of these checks were negative in all cases. At the concentrations under study, the substances had no inhibitory effects on biological processes and no evidence of abiotic decomposition was obtained.

Validity criteria fulfilled:

not specified

Conclusions:

HEDTA did not biodegrade in municipal activated sludge with sludge ages ranging from 5 to 30 days. HEDTA was not inhibitory to biological processes at a concentration of 100 mg/L (acid form).

Executive summary:

HEDTA did not biodegrade in municipal activated sludge with sludge ages ranging from 5 to 30 days. HEDTA was not inhibitory to biological processes at a concentration of 100 mg/L (acid form).

Description of key information

The toxicity to microorganisms was not determined as emission to STP is unlikely.

Also, toxicity to microorganisms is unlikely because neither DTPA or any of two related chelating agents (EDTA and HEDTA) are toxic to microorganisms (see provided studies) and these chelating agents will capture the metal ions, reducing any toxicity of the captured metal ions.