[ethylenebis[nitrilobis(methylene)]]tetrakisphosphonic acid, calcium sodium salt

Biodegradation in soil

Administrative data

Endpoint:

biodegradation in soil

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented, meets generally accepted scientific principles, acceptable for assessment.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1978

Materials and methods

Principles of method if other than guideline:

Degradation units, each containing 20 g (dry-weight) soil, spiked with either test or reference substance, sparged with CO2-free air and the off-gas passed through CO2 absorbent scrubbers. The C-14 evolved measured by liquid scintillation counting.

GLP compliance:

no

Test type:

laboratory

Test material

Test material information

Constituent 1

Reference substance name:

[ethane-1,2-diylbis[nitrilobis(methylene)]]tetrakisphosphonic acid

EC Number:

215-851-5

EC Name:

[ethane-1,2-diylbis[nitrilobis(methylene)]]tetrakisphosphonic acid

Cas Number:

1429-50-1

Molecular formula:

C6H20N2O12P4

IUPAC Name:

{ethane-1,2-diylbis[nitrilobis(methylene)]}tetrakis(phosphonic acid)

Radiolabelling:

yes

Study design

Soil properties

Soil properties 1

Soil no.:

#1

Soil type:

other: St. Charles Ray Silt Loam

Soil properties 2

Soil no.:

#2

Soil type:

other: Meramec river bank

Details on soil characteristics:

SOIL CHARACTERISTICS:
Source: St. Charles Ray-Silt Loam
pH: 7.05
% organic carbon: 0.56
Water content: 0.14 g/g (dry-weight basis)
Water Holding Capacity: 0.45 g/g

Source: Meramec river bank soil
pH: 7.70
% organic carbon: 0.70
Water content: 0.06 g/g (dry-weight basis)
Water Holding Capacity: 0.39 g/g

Duration of test (contact time)

Duration of test (contact time) 1

Soil No.:

#1

Duration:

148 d

Duration of test (contact time) 2

Soil No.:

#2

Duration:

148 d

Experimental conditions

Experimental conditions 1

Soil No.:

#1

Experimental conditions 2

Soil No.:

#2

Details on experimental conditions:

TEST DETAILS: St. Charles Ray-silt loam - was sieved through a 2 mm screen and the water content adjusted with either distilled water or a dilute sodium azide solution (to approximate a sterile control). Degradation units, each containing 20 g (dry-weight) soil, were spiked with either test substance or linear dodecylbenzene sulfonate (LAS) at a nominal level of 10 µg/g (for test substance, as active acid). Each soil unit was sparged with CO2-free air and the off-gas passed through two scrubbers each containing 5 ml of the CO2 absorbent (monoethanolamine-ethylene glycol) monoethyl ether 1:7 (v/v) solution. Periodically, the first scrubber was removed, the second scrubber moved to position one and replaced with a fresh scrubber. The C-14 evolved was then measured by liquid scintillation counting using a Mark III Liquid Scintillation Spectrometer (Model 6880, Searle Analytic, Inc.). The percent C-14 evolved was calculated from the disintegrations per minute and the initial C-14 charged to each unit.

Results and discussion

% Degradation

% Degradation 1

Soil No.:

#1

% Degr.:

68.66

Parameter:

radiochem. meas.

Remarks:

14CO2 evolution

Sampling time:

148 d

% Degradation 2

Soil No.:

#2

% Degr.:

72.55

Parameter:

radiochem. meas.

Remarks:

14CO2 evolution

Sampling time:

148 d

% Degradation 3

Soil No.:

#1

% Degr.:

18.07

Parameter:

radiochem. meas.

Remarks:

14CO2 evolution (sterile control)

Sampling time:

148 d

% Degradation 4

Soil No.:

#2

% Degr.:

3.11

Parameter:

radiochem. meas.

Remarks:

14CO2 evolution (sterile control)

Sampling time:

148 d

Half-life / dissipation time of parent compound

Type:

(pseudo-)first order (= half-life)

Transformation products:

not measured

Evaporation of parent compound:

no

Volatile metabolites:

no

Any other information on results incl. tables

Table 1: Percent degradation values (¹⁴CO2 evolved, % theory)

Type of suspension	% degradation at sampling time (days)
	2	6	12	16	21	28	35	43	58	72	86	100	114	128	148
Reference substance (LAS) Microbial	0.03	0.14	2.20	4.53	7.69	11.46	15.68	20.49	29.44	36.34	41.92	46.59	50.41	53.60	56.97
Reference substance (LAS) Sterile	0	0.02	0.05	0.05	0.05	0.07	0.07	0.07	0.07	0.08	0.08	0.08	0.08	0.08	0.10
EDTMP - St Charles Ray silt loam - active	23.36	29.16	34.20	37.11	40.08	43.05	45.76	48.77	53.44	56.96	59.94	62.54	64.64	66.39	68.66
EDTMP - St Charles Ray silt loam - Sterile	11.86	14.60	15.56	15.95	16.50	16.90	17.18	17.36	17.60	17.77	17.87	17.93	17.98	18.01	18.07
EDTMP - Meramec river bank - active	13.50	20.76	27.30	31.43	36.40	41.36	45.78	50.64	56.91	61.06	64.15	66.66	68.69	70.43	72.55
EDTMP - Meramec river bank - sterile	1.36	1.39	1.71	2.14	2.25	2.35	2.42	2.48	2.60	2.70	2.78	2.86	2.93	2.99	3.11

 

The data suggest that no induction period is required before degradation occurs.

Applicant's summary and conclusion

Conclusions:

Soil biodegradation rate of 68-73% over 148d in two active soils was determined in a reliable study conducted according to generally accepted scientific principles.