Dipotassium dihydrogen 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:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test procedure according to German national standards (DIN)

Justification for type of information:

Read across is based on a structurally similar material. An analogue justification is attached in section 13 of dataset.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

other: DIN 38412, part 11

Principles of method if other than guideline:

STATISTICS
Spearman-Kaerber (1984)

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The stock solution was prepared by dissolving 2000 mg test substance in dilution water. The test concentrations were then prepared by dilution with test water.

Test organisms (species):

Daphnia magna

Details on test organisms:

Strain: STRAUS
Breeder: Dr. U. Noack-Laboratorium
Hildesheim Source: Bundesgesundheitsamt, Berlin
Method of breeding: single breeding

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

21 °C

Dissolved oxygen:

8.0 - 8.2 mg/L

Nominal and measured concentrations:

Test concentrations (nominal): 58, 100, 180, 320 and 580 mg/L

Details on test conditions:

TEST SYSTEM
Type: open beaker (50 mL)
Aeration: none
No. of organisms per vessel: 5
No. of replicates: 4
Controls: negative control
Highest concentration after pH adjustment

TEST MEDIUM / WATER PARAMETERS
Dilution water: according to DIN 38412 L11, 8.2
Conductivity: 658 µS/cm
Ca/Mg ratio: 5:1
Na/K ratio: 20:1

TEST CONDITIONS
Adjustment of pH: none
Illumination: 10 uE/qm*s pH
During test: 3.85 - 7.90

The number of immobilized animals were recorded after 3, 6, 24, and 48 hours after test start.
The parameters pH, temperature and oxygen concentration were determined at the end of the test.

Reference substance (positive control):

yes

Remarks:

Potassium chromate

Duration:

48 h

Dose descriptor:

EC0

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.:

140 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 100-180 mg/L

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

180 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

No pH effect observed.

Results with reference substance (positive control):

Reference substance: Potassium chromate
EC50 (24 h): 0.9 mg/L
Date: 12 Sep - 13 Sep 1989

pH values at the end of the test
--------------------------------
580 mg/L             3.85
320 mg/L             4.02
180 mg/L             4.40
100 mg/L             7.30
 58 mg/L             7.73

control              7.90
control-pH           7.49
--------------------------------


Nominal       Mean number of mobile daphnids after
conc.               24h                   48h     
[mg/l]
-----------------------------------------------------------
 580                0/20                  0/20     
 320                0/20                  0/20    
 180                0/20                  0/20
 100               20/20                 19/20
  58               20/20                 19/20
 
 control           20/20                 19/20   
pH-control          0/20                  0/20
-----------------------------------------------------------

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to national standards (DIN)

Justification for type of information:

Read across is based on a structurally similar material. An analogue justification is attached in section 13 of dataset.

Reason / purpose for cross-reference:

read-across source

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

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 overstoichiometric amounts. Thus, in the test system the Ca-complex was formed.

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test procedure according to international standard.

Justification for type of information:

Read across is based on a structurally similar material. An analogue justification is attached in section 13 of dataset.

Reason / purpose for cross-reference:

read-across source

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

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

With high probability the test substance is acutely not harmful to aquatic invertebrates.

Additional information

Tests on acute toxicity with Daphnia magna resulted in EC50 values well above 100 mg/L [EU Risk Assessment, 2004]. Exemplarily in an non-GLP study according to DIN 38412 the measured EC50-value for Na2EDTA was 140 mg/L [BASF AG, 1989], for justification for read-across see IUCLID 5, Chapter 13.