Registration Dossier

Environmental fate & pathways

Biodegradation in soil

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
biodegradation in soil, other
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:
no guideline followed
Principles of method if other than guideline:
Laboratory study on biodegradation of EDTA in different agricultural soils over an incubation time of 4 to 45 weeks.
GLP compliance:
no
Test type:
laboratory
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch number of test material: 4813

RADIOLABELLING INFORMATION (if applicable)
- Radiochemical purity: 99%
- Specific activity: 2.54 mCi/mM
- Locations of the label: 14C-carboxyl-EDTA
Radiolabelling:
yes
Oxygen conditions:
aerobic
Soil classification:
not specified
Year:
1977
Soil no.:
#1
Soil type:
other: Brookston loam
pH:
6.8
Soil no.:
#2
Soil type:
other: Conover sandy loam
pH:
6.7
Soil no.:
#3
Soil type:
other: Spinks loamy fine sand
pH:
6.4
Soil no.:
#4
Soil type:
other: Miami sandy loam
pH:
6
Details on soil characteristics:
SOIL COLLECTION AND STORAGE
All soil samples were collected and stored in sealed plastic bags at 2 °C. All samples were taken in Michigan and each were a composite of subsamples collected at three locations within a 10 m2 area.
Soil No.:
#1
Duration:
4 - 45 wk
Soil No.:
#2
Duration:
4 - 45 wk
Soil No.:
#3
Duration:
4 - 15 wk
Soil No.:
#4
Duration:
4 - 15 wk
Soil No.:
#1
Initial conc.:
2.5 - 4.5 mg/kg soil d.w.
Based on:
test mat.
Soil No.:
#2
Initial conc.:
2.5 - 4.5 mg/kg soil d.w.
Based on:
test mat.
Soil No.:
#3
Initial conc.:
2.5 - 4.5 mg/kg soil d.w.
Based on:
test mat.
Soil No.:
#4
Initial conc.:
2.5 - 4.5 mg/kg soil d.w.
Based on:
test mat.
Parameter followed for biodegradation estimation:
CO2 evolution
radiochem. meas.
Details on experimental conditions:
25 g fresh weight of soil was added to 125 mL Erlenmeyer flasks that had been fitted with rubber stoppers which supported a 2 mL plastic beaker containing 1 mL of 1N NaOH. The soils were adjusted to ~ field capacity. Microdrops of neutralized 14C-EDTA solutions were randomly distributed over the soil surface using a 28-gage needle on a 100 µL syringe. All soils were sealed and incubated at room temperature (25-27 °C). All of the reported data are means from duplicate or triplicate.
Key result
Soil No.:
#1
% Degr.:
65
Parameter:
CO2 evolution
Remarks:
[14CO2]
Sampling time:
45 wk
Key result
Soil No.:
#2
% Degr.:
70.5
Parameter:
CO2 evolution
Remarks:
[14CO2]
Sampling time:
45 wk
Soil No.:
#1
% Degr.:
44.5
Parameter:
CO2 evolution
Remarks:
[14CO2]
Sampling time:
15 wk
Soil No.:
#2
% Degr.:
43.5
Parameter:
CO2 evolution
Remarks:
[14CO2]
Sampling time:
15 wk
Soil No.:
#3
% Degr.:
32
Parameter:
CO2 evolution
Remarks:
[14CO2]
Sampling time:
15 wk
Soil No.:
#4
% Degr.:
44.5
Parameter:
CO2 evolution
Remarks:
[14CO2]
Sampling time:
15 wk
Soil No.:
#1
% Degr.:
11
Parameter:
CO2 evolution
Remarks:
[14CO2]
Sampling time:
4 wk
Soil No.:
#2
% Degr.:
12.2
Parameter:
CO2 evolution
Remarks:
[14CO2]
Sampling time:
4 wk
Soil No.:
#3
% Degr.:
11.3
Parameter:
CO2 evolution
Remarks:
[14CO2]
Sampling time:
4 wk
Soil No.:
#4
% Degr.:
10
Parameter:
CO2 evolution
Remarks:
[14CO2]
Sampling time:
4 wk
Transformation products:
no
Evaporation of parent compound:
no
Volatile metabolites:
no
Residues:
no
Details on results:
14C-EDTA was (slowly) biodegraded to 14CO2 by all soils (varying in pH and texture) tested from a major agricultural EDTA use area. No detectable quantities of intermediates accumulated under aerobic conditions.

Generally, the variation between duplicates/triplicates was < 8%.

Conclusions:
EDTA is (slowly) biodegradable in soils.

Description of key information

>= 65% degradation in 45 weeks (read across)

Key value for chemical safety assessment

Additional information

Two studies are available investigating the biodegradability of edetic acid in soil. For the determination of biodegradation in soil non-standard investigations under various conditions show that EDTA can be biodegraded in soil under aerobic conditions. The rate of EDTA degradation was determined in different agricultural soils after 4 - 45 weeks of exposure. While degradation rate was 10-12% only after 4 weeks the degradation continued showing 32-45% degradation after 15 weeks and >= 65% after 45 weeks incubation time. This indicate that EDTA is (slowly) biodegradable in soil and thus not persistent in the terrestrial compartment.