L-Aspartic acid, N,N'-1,2-ethanediylbis-, sodium salt (1:3)

Biodegradation in soil

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in soil: simulation testing

Type of information:

read-across from similar mixture/product

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Principles of method if other than guideline:

The test substance (radiolabelled) was incubated with sludge-amended soil and mineralisation was monitored by producton of 14CO2 for up to 28 days.

GLP compliance:

not specified

Test type:

laboratory

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
PHYSICO-CHEMICAL PROPERTIES
- Vapour pressure: 0.00017 Pa at 25°C
- Henry's law constant (for volatile substances): no data
- Water solubility (under test conditions): ca. 150 mg/L at 25°C and pH 7
- Solubility in organic solvents:
- log Pow: <-1.4
- pKa: no data
- Base or acid catalysis of test material: no data
- log Koc: 1.778
- UV absorption: no data
- Stability of test material at room temperature: stable
- pH dependance on stability: no data

Radiolabelling:

yes

Oxygen conditions:

aerobic

Soil classification:

USDA (US Department of Agriculture)

Details on soil characteristics:

SOIL COLLECTION AND STORAGE
- Geographic location: corn field near Phoenixville, PA, USA
- Silt loam
- pH: 5.6
- Soil preparation (e.g., 2 mm sieved; air dried etc.): The soil was amended with sludge 6 months prior to sampling.

Soil No.:

#1

Initial conc.:

1 mg/kg soil d.w.

Based on:

test mat.

Details on experimental conditions:

DETAILS ON PRETREATMENT
- The sludge-amended soil was incubated with C14-labeled [S,S]-EDDS at a concentration of 1 mg/kg
- Concentration (method): Test chemical was initially dosed to 1 g of dewatered digester sludge solids, which were subsequently mixed with 100 g of soil and adjusted to 35% water content

Test system consisted of 500 mL flasks incubated statically with headspaces continually purged with CO2-free air

Key result

% Degr.:

99

Parameter:

CO2 evolution

Sampling time:

28 d

Transformation products:

yes

No.:

#1

Details on transformation products:

Cumulative CO2 production was determined as a function of time and analysed by nonlinear product formation models using a nonlinear regression software package

Details on results:

Mineralization was rapid and complete within a 28-day period
- First order mineralization rate constant - 0.27
- t1/2 - 2.55 days
ThCO2 - 99%

Biodegradation of [S,S]-EDDS acid was shown to be rapid and complete in a sludge-amended soil, with ThOD reaching 99% within a 28-day exposure period.

Conclusions:

Biodegradation of [S,S]-EDDS acid was shown to be rapid and complete in a sludge-amended soil, with ThOD reaching 99% within a 28-day exposure period

Executive summary:

In this study, 14C-labeled [S,S]-EDDS acid was incubated at a concentration of 1 mg/kg with sludge-amended soil from a corn field in Phoenixville, PA, USA. The objective was to mimic the introduction of chemicals into soil on sludge. Based on ThOD calculations, mineralization was rapid and complete within a 28-day period, therefore biodegradation of [S,S]-EDDS acid was considered to be rapid and complete under these conditions.

[Data on EDDS free acid is considered relevant to use for understanding the potential biodegradation of trisodium EDDS in soil, and is acceptable for using as read-across information].

Description of key information

Biodegradation of [S,S]-EDDS acid was shown to be rapid and complete in a sludge-amended soil, with ThOD reaching 99% within a 28-day exposure period.

In a soil die-away test, mineralisation of radiolabelled [S,S]-EDDS in sludge-amended soil was rapid and complete in 28 days, with a calculated half-life of 2.5 days, suggesting that biodegradation also occurs under realistic environmental conditions (Jaworska et al. 1999).

Key value for chemical safety assessment

Half-life in soil:

2.5 d

Additional information

According to a published study, 14C-labeled [S,S]-EDDS acid was incubated at a concentration of 1 mg/kg with sludge-amended soil from a corn field in Phoenixville, PA, USA. The objective was to mimic the introduction of chemicals into soil on sludge. Based on ThOD calculations, mineralization was rapid and complete within a 28-day period, therefore biodegradation of [S,S]-EDDS acid was considered to be rapid and complete under these conditions (Schowanek et al. 1997).

In a soil die-away test, mineralisation of radiolabelled [S,S]-EDDS in sludge-amended soil was rapid and complete in 28 days, with a calculated half-life of 2.5 days, suggesting that biodegradation also occurrs under realistic environmental conditions (Jaworska et al. 1999).

[Data on EDDS free acid is considered relevant to use for understanding the potential biodegradation of trisodium EDDS in soil, and is acceptable for using as read-across information].