trisodium ({3-[(carboxylatomethyl)amino]propyl}{3-[(carboxylatomethyl)(C16-18, C18 unsat alkyl)amino]propyl}amino)acetate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

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

Remarks:

test performed accoring OECD 301D guidelines

Adequacy of study:

key study

Study period:

19-02-2019 - 18-07-2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
See chapter 13 for read across document.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

yes

Remarks:

only minor devation

Principles of method if other than guideline:

Minor deviations from the guidelines of the Closed Bottle test (OECD TG 301D) were introduced; a) ammonium chloride was omitted from the medium to prevent oxygen consumption due to nitrification (omission does not result in nitrogen limitation as shown by the biodegradation of the reference compound), and b) river water instead of an effluent/extract/mixture was used as inoculum.

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Chemical name Sodium oleylamphopolycarboxyglycinate
Substance Name: 1,3-Propanediamine, N1-(3-aminopropyl)-N3-[3-(C18, C18 unsat) alkylamino]propyl]-, N-(carboxymethyl) derivs., sodium salts
Old CAS no 97659-53-5
New CAS no 2060541-49-1
Composition 30.1 % active active is corrected for sodium chloride solids (see CoA annex 2)
Batch/lot No.: 1604972
Solubility in wate: Soluble in water
Appearance: yellow liquid
Storage: at ambient temperature in the dark
Expiry date: 23-08-2019

Oxygen conditions:

aerobic

Inoculum or test system:

natural water: freshwater

Details on inoculum:

River water was sampled from the Rhine near Heveadorp, The Netherlands (14-02-2019). The nearest plant (Arnhem-Zuid) treating domestic wastewater biologically was 3 km upstream. The river water was aerated for 7 days before use to reduce the endogenous respiration (van Ginkel and Stroo, 1992). River water without particles was used as inoculum. The particles were removed by sedimentation after 1 day while moderately aerating.

Duration of test (contact time):

28 d

Initial conc.:

1.5 mg/L

Based on:

act. ingr.

Initial conc.:

5 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Test procedures
The Closed Bottle test (OECD TG 301D) was performed according to the study plan. The study plan was developed from ISO Test Guidelines (1994). Use was made of 10 bottles containing only river water, 6 bottles containing river water and sodium acetate, 10 bottles containing river water with test substance. The concentrations of the test substance, and sodium acetate in the bottles were 5 mg/L (1.5 mg/L active) and 6.7 mg/L, respectively. Each of the prepared solutions was dispensed into the respective group of BOD bottles so that all bottles were com¬pletely filled without air bubbles. The zero time bottles were immediately analyzed for dissolved oxygen using an oxygen electrode. The remaining bottles were closed and incubated in the dark. Two duplicate bottles of all series were withdrawn for analyses of the dissolved oxygen concentration at day 7, 14, 21, and 28.

Reference substance:

acetic acid, sodium salt

Remarks:

SIGMA ALDRICH Batch no. BCBP8197V

Key result

Parameter:

% degradation (O2 consumption)

Value:

11

Sampling time:

28 d

Remarks on result:

other: should not be classified as readily biodegradable

Parameter:

% degradation (O2 consumption)

Value:

19

Sampling time:

60 d

Remarks on result:

other: Biodegradation levels off at 19% biodegradation suggesting partial degradation of the test substance

Details on results:

Sodium oleylamphopolycarboxyglycinate was biodegraded by 11% at day 28 in the Closed Bottle test (Table II, Figure). This test substance should therefore not be classified as readily biodegradable. In the prolonged Closed Bottle test sodium oleylamphopolycarboxyglycinate was biodegraded 19% at day 60 (Figure and Tables I-II). The biodegradation curve levels off below 60% biodegradation (Figure) suggesting partial degradation of the test substance. The lack of complete biodegradation in the Closed Bottle test does not mean that part of the test substance is recalcitrant in nature because the stringency of the test procedures could account for the recalcitrance in the Closed Bottle test.

Results with reference substance:

The biodegradation percentage of the reference compound, sodium acetate, at day 14 was 90

Toxicity

Inhibition of the degradation of a well-degradable compound, e.g. sodium acetate by the test substance in the Closed Bottle test was not determined because possible toxicity of the test substances to microorganisms degrading acetate is not relevant. Inhibition of the endogenous respiration of the inoculum by the test substance at day 7 was not detected (Table I). Therefore, no inhibition of the biodegradation due to the "high" initial test substance concentration is expected.

Test conditions

The pH of the media was 8.8 (control and reference compound) and 9.0 (test) at the start of the test. The pH of the medium at day 28 was 8.9 (control) and 9.0 (test). At day 60 the pH of the control and test was 8.8 and 9.0, respectively. The temperature ranged from 22.5 to 22.8°C which is within the prescribed temperature range of 22 to 24°C.

Validity of the test

The validity of the test is demonstrated by an endogenous respiration of 1.2 mg/L at day 28 (Table I). Furthermore, the differences of the replicate values at day 28 were less than 20%. The biodegradation percentage of the reference compound, sodium acetate, at day 14 was 90 (Table II and Figure). Finally, the validity of the test is shown by oxygen concentrations >0.5 mg/L in all bottles during the test period.

Validity criteria fulfilled:

yes

Remarks:

The test is valid because of an endogenous respiration of 1.2 mg/L at day 28. Less than 20% difference of replicates day 28. The biodegradation% the reference compound at day 14 was 90. Final oxygen concentrations were >0.5 mg/L.

Interpretation of results:

inherently biodegradable

Conclusions:

Test performed according guidelines meeting specific criteria. Test performed under GLP and results well documented.

Executive summary:

To assess the biotic degradation of sodium oleylamphopolycarboxyglycinate, a ready biodegradability test was performed which allows the biodegradability to be measured in an aerobic aqueous medium. The ready biodegradability was determined in the Closed Bottle test performed according to slightly modified OECD, EU and ISO Test Guidelines, and in compliance with the OECD principles of Good Laboratory Practice.

The test substance did not cause a reduction in the endogenous respiration at day 7. The test substance is therefore considered to be non-inhibitory to the inoculum. The test substance was biodegraded by 11% at day 28 in the OECD 301D Closed Bottle test and should therefore not be classified as readily biodegradable. In the prolonged Closed Bottle test sodium oleylamphopolycarboxyglycinate was biodegraded 19% at day 60. The biodegradation curve levels off below 60% biodegradation suggesting partial degradation of the test substance. The lack of complete biodegradation in the Closed Bottle test does not mean that part of the test substance is recalcitrant in nature because the stringency of the test procedures could account for the recalcitrance in the Closed Bottle test.

The test is valid as shown by an endogenous respiration of 1.2 mg/L and by the total mineralization of the reference compound, sodium acetate. Sodium acetate was degraded by 90% of its theoretical oxygen demand after 14 days. Finally, the most important criterion was met by oxygen concentrations >0.5 mg/L in all bottles during the test period.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

yes

Remarks:

This test has been performed according to slightly modified EEC, OECD and IS0 Test Guidelines . The test was modified to permit prolonged measurements.

Principles of method if other than guideline:

The Closed Bottle test is chosen as the most appropriate ready biodegradability test available. This test has been performed according to slightly
modified EEC, OECD and IS0 Test Guidelines . The test was modified to permit prolonged measurements.

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: See below

Details on inoculum:

Secondary activated sludge was obtained from the WWTP Nieuwgraaf in Duiven, The Netherlands. The WWTP Nieuwgraaf is an activated sludge plant
treating predominantly domestic waste water. A minor deviation of the test procedures described in the guidelines was introduced: instead of an
effluent/extract/mixture, activated sludge was used as an inoculum. The activated sludge was preconditioned to reduce the endogenous respiration rates. To this end, 200 mg Dry Weight (DW)IL of activated sludge was aerated for one week. The sludge was diluted to a concentration of 2 mg
DW/L in the BOD bottles .

Duration of test (contact time):

140 d

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

The Closed Bottle test was performed according to IS0 Test Guidelines. Use was made of 3 bottles containing only inoculum, and 3 bottles
containing the respective test substances. The concentrations of the test compounds in the bottles were 4.6 to 7.0 mg COD/L.
Some test compounds are toxic to microorganisms. Therefore, sodium carboxymethyltallowpropylamines were also tested in the presence of
silica gel to reduce the concentration in the water phase. During the test period, the test compound should be released slowly from the silica gel (1 glbottle). Although no additional oxygen consumption was expected, controls with silica gel were carried out as well (10 bottles containing test
substance, inoculum and silica gel). The inoculum was diluted to 2 mg DW/L in the closed bottles.Each of the prepared solutions was dispensed into
the respective group of BOD bottles so that allbottles were completely filled without air bubbles. The zero time bottles were immediately analyzed
for dissolved oxygen using an oxygen electrode. Next the bottles were closed and incubated at 21°C in the dark. Bottles of all series were withdrawn for analyses of the dissolved oxygen concentration. The oxygen concentration was measured the bottles using a special funnel. This funnel fitted exactly in the BOD bottle. Subsequently, the oxygen electrode was inserted in the BOD bottle to measure the oxygen concentration.
The medium dissipated by the electrode was collected in the funnel. After withdrawal of the oxygen electrode the medium collected flowed back into
the BOD bottle, followed by removal of the funnel and closing of the BOD bottle.

Test performance:

The pH of the media was 6.9 at the start of the test. The pH of the medium at Day 28 was 6.6 to 6.8. Temperatures ranged from 20 to 22°C. The validity of the test is demonstrated by an endogenous respiration of 1.5 to 1.8 mglL at Day 28 Furthermore, the differences of the replicate values at Day 28 were less than 20%. Finally, the validity of the test is shown by oxygen concentrations >0.5 mglL in all bottles during the test period (Table I and 11).

Details on results:

See results Table below

Results with reference substance:

No DAta

Biodegredation Calculations

The biodegradation was calculated as the ratio of the biochemical oxygen demand (BOD) to the chemical oxygen demand (COD).

COD determination

The COD of the test compound was determined by oxidation with an acid-dichromate mixture in which CR6 + was reduced to CR3+. The assay used high range COD reaction vials in the following procedure. The test substance was added to the reaction vials using the stock solution. A solution of the control standard, potassium hydrogen phthalate, was prepared in deionized water at a concentration of 1.0 g/L. The control standard was measured in the same run. The reaction vials were sealed and placed in a heating block and the contents heated at a temperature of 150°C for two hours. The vials were cooled to room temperature and the increase

in CR3+ was determined spectrophotometrically at 620 nm. The linearity of the response allowed the calculation of the COD of the sample by direct comparison of the absorbance of the sample with that of control, potassium hydrogen phthalate. The spectrophotometer and heating block (Dr. Lange) used were obtained from IMA, Kesteren, The Netherlands.

BOD Calculation

The biological oxygen demand (BOD) mglmg of the test compound was calculated by dividing the oxygen consumption by the concentration of the test substance in the closed bottle.

Interpretation of results:

other: All Inherently biodegradable (with silica gel)

Conclusions:

It can be concluded that in the presence of Silica gel to avoid toxicity that all of the tested compounds showed evidence of inherent Biodegradability. Sodium carboxymethyltallowpropylamines with 1&2 moles of SMCA were toxic to the innoculum therefore showed no degredation without Silica gel. This study was not conducted to GLP and no analysis certificate was included. It can therefore be considered reliable with restrictions.

Executive summary:

From these series of tests it can be concluded that all sodium carboxymethyltallowamines are inherently biodegradable. At present it is impossible to assess which compound has the best biodegradation potential.

Description of key information

The available biodegradation data indicate that Sodium tallowamphopolycarboxy glycinate is <60% biodegraded on day 28. Prolongation of the tests till day 140 shows that Sodium tallowamphopolycarboxy glycinate is ultimately biodegradable (Ginkel, 1996).

Similar results are found for the structural analogue which is based on oleic acid instead of tallow carboxylic acid (Geerts, 2019).

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable, not fulfilling specific criteria

Type of water:

freshwater

Additional information

The available biodegradation data indicate that Sodium tallowamphopolycarboxy glycinate is <60% biodegraded on day 28 (Ginkel,1996; Roberts, 1987 & 1988 and Lebertz 1989 &1992). Prolongation of the tests till day 140 shows that Sodium tallowamphopolycarboxy glycinate is ultimately biodegradable (Ginkel, 1996).

Similar results are found for the structural analogue which is based on oleic acid instead of tallow carboxylic acid (Geerts, 2019).

The studies (OECD 301B) from Danneberg (1992 & 1993) are difficult to interpret and indicate that Sodium tallowamphopolycarboxy glycinate is readily biodegradable at the lower test concentrations but not at higher test concentrations.