Disodium dihydrogen ethylenediaminetetraacetate

Toxicity to terrestrial plants

Administrative data

Endpoint:

toxicity to terrestrial plants: long-term

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

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

seedlings of Phaseolus vulgaris were exposed to EDTA for 14 days

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Edetic acid

EC Number:

200-449-4

EC Name:

Edetic acid

Cas Number:

60-00-4

Molecular formula:

C10 H16 N2 O8

IUPAC Name:

2,2',2'',2'''-(ethane-1,2-diyldinitrilo)tetraacetic acid

Test material form:

solid

Sampling and analysis

Analytical monitoring:

not specified

Test substrate

Vehicle:

no

Test organisms

Species:

Phaseolus vulgaris

Plant group:

Dicotyledonae (dicots)

Study design

Test type:

seedling emergence toxicity test

Study type:

laboratory study

Substrate type:

other: seedlings grown in polystyrene squares

Limit test:

no

Total exposure duration:

14 d

Test conditions

Details on test conditions:

Bean seeds received a cold treatment (+ 4 °C) for 3 days to break dormancy and to synchronize germination. They were transferred to a growth chamber to germinate between two layers of water-soaked rock wool for 4 days. Subsequently seed coats were removed and seedlings with a root length of approximately 1.5 cm were grown in 3-mm thick polystyrene squares by fixing the roots through 5-mm holes (9 plants/treatment). The polystyrene was floated on 3 L of aerated full strengths Hoagland's solution (pH 5.0) in 3.5 L polyethylene beakers; Fe was added as FeSO4 * 7H2O. To keep Fe in solution, it was complexed with EDTA (Fe/EDTA ratio 2/1). Nutrient solution was replaced every 2 days; pH was monitored daily. Plants were grown under controlled conditions in a 12-h photoperiod at 65 % relative humidity and day/night temperatures of 22°C. Light was supplied by cool white fluorescent lamps (L = 140W/20SA; Osram, Augsburg, Germany) at a photo synthetic photon flux density of 165 µmol/m2 * s at the leaf level. Final concentrations of 0 (= untreated), 50 and 200 µM EDTA in Hoagland's medium, equivalent to 14.6 and 58.4 mg/kg, respectively. Plants were harvested 14 days after the start of treatment, and morphological parameters (root weight, shoot length, leaf weight) were measured.

Nominal and measured concentrations:

Nominal: 14.6 and 58.4 mg/L

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Key result

Species:

Phaseolus vulgaris

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

>= 58.4 other: mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

seedling emergence

Any other information on results incl. tables

Addition of EDTA alone to the growth medium increased EDTA chelation of most divalent cations, resulting in decreased plant uptake of Fe, Mn and Zn. EDTA application however, did not induce any antioxidative stress response. Addition of 200 µM EDTA resulted in a free EDTA concentration of 10 µM in solution.Obviously this was too low to induce any phytotoxic effects.

Applicant's summary and conclusion

Validity criteria fulfilled:

not applicable

Conclusions:

In a 14 day exposure test EDTA showed no inhibitory effect on seedling emergence and growth of Phaseolus vulgaris up to a concentration of 58.4 mg/kg soil.

Executive summary:

In a 14 day eposure test EDTA showed no inhibitory effect on seedling emergence and growth of Phaseolus vulgaris up to a concentration of 58.4 mg/kg soil.