Tripotassium hydrogen ethylenediaminetetraacetate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to national standards (DIN)

Qualifier:

equivalent or similar to guideline

Guideline:

other: DIN 38412, part 11

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

Species: Daphnia magna
Origin: wild population
Breeding: The clone with the highest number of offspring was used to establish a continuous daphnia breed under standardized laboratory conditions.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

24 h

Duration:

24 h

Dose descriptor:

EC0

Effect conc.:

310 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

625 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC100

Effect conc.:

1 250 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

In this short-term test, Ca was present in over-stoichiometric amounts. Thus, in the test system the Ca-complex was formed.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test procedure according to international standard.

Qualifier:

according to guideline

Guideline:

ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Daphnia magna

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

24 h

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

610 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

EC50(24h) calculated (confidence interval 95 %):

----------------------------------------------------

EDTA 610 mg/l (570-640)

Mn(II)+EDTA 940 mg/l (800-1000)

Fe(III)+EDTA 17 mg/l (13-21)

Cu(II)+EDTA 38 mg/l (31-45)

Zn(II)+EDTA 910 mg/l (840-980)

Hg(II)+EDTA 0.00032 mg/l (0.00022-0.00052)

Cd(II)+EDTA 310 mg/l (290-330)

----------------------------------------------------

All the EC50 values, except those obtained for the free EDTA, are expressed as mg/L of total amount of the studied metal. To compare the toxicities of the metal chelates with those of the free EDTA, all the EC50 values were converted to mg/L EDTA.

EC 50 values with 95% confidence limits were calculated by a probit analysis computer program, version 2.3 (National Swedish Environmental Protection Agency). The EC50 values of Fe3+, Cu2+, Mn2+, Zn2+, Cd2+ and Hg2+ complexed by EDTA were compared with those of the respective uncomplexed metals and free EDTA. The experiments gave the following toxicity order: Hg2+, Cu2+, Cd2+, Zn2+, Fe3+, Mn2+ (higher to lower toxicity). After complexation, the toxicities were 1.1-1700 (EDTA) times lower. With Hg2+ complexation did not decrease the toxicity. Compared with the toxicity of free EDTA, metal complexation increased the toxicity of EDTA.

Description of key information

 Acute aquatic invertebrate 24hr EC50 for K3EDTA is 610 mg/L.  

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

610 mg/L

Additional information

Based on read-across from the related substance, tetrasodium ethylenediaminetetraacetate, an acute aqutic invertebrate EC50 of 610 mg/L was determined for tripotassium hydrogen EDTA.

Sodium and potassium are both members of the 1a group of metals in the periodic table. Due to their low electronegativity they form ionic bonds and highly water soluble salts with inorganic and organic acids. The solution of these salts is therefore dominated by the property of the acid anion. This justifies reading across from the sodium to the potassium salt.