Polyphosphoric acids, 2-[(2-methyl-1-oxo-2-propen-1-yl)oxy]ethyl esters

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

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

Adequacy of study:

key study

Study period:

From February 16, 2016 to March 17, 2016

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study with read across substance was conducted according to a slightly modified OECD Guideline 301D, EU Method C4 and ISO Method 10707, in compliance with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: ISO 10707

Test guideline 3

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Principles of method if other than guideline:

Minor deviations from the guidelines of the Closed Bottle test (OECD TG 301) 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

Test material

Test material information

Constituent 1

Reference substance name:

2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with phosphorus oxide (P2O5)

IUPAC Name:

2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with phosphorus oxide (P2O5)

Constituent 2

Reference substance name:

1187441-10-6

Cas Number:

1187441-10-6

IUPAC Name:

1187441-10-6

Test material form:

other: liquid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

River water was sampled from the Rhine near Heveadorp, The Netherlands (11-02-2016). 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. River water without particles was used as inoculum. The particles were removed by sedimentation after 1 day while moderately aerating. The inoculum was not pre-exposed to the test item.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

4 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

The Closed Bottle test (OECD TG 301) 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 4.0, 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 completely 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

Reference substance:

acetic acid, sodium salt

Remarks:

6.7 mg/L

Results and discussion

Test performance:

The validity of the test was demonstrated by an endogenous respiration of 1.3 mg/L at day 28. 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 88. Finally, the validity of the test is shown by oxygen concentrations >0.5 mg/L in all bottles during the test period.

% Degradation

Parameter:

% degradation (DOC removal)

Value:

71

Sampling time:

28 d

Details on results:

PARAD Substance 139 was biodegraded by 71% at day 28 in the Closed Bottle test. The time window was not used as a pass/fail criterion because the test substance consists of many components (UVCB). PARAD Substance 139 should therefore be classified as readily biodegradable.

BOD5 / COD results

Results with reference substance:

The biodegradation percentage of the reference compound, sodium acetate, at day 14 was 88.

Any other information on results incl. tables

Theoretical oxygen demand (ThOD)

The calculated theoretical oxygen demand (ThOD) of PARAD Substance 139 is 1.26 mg/mg.

The ThOD of the test item was calculated with the two reactants used to synthesize the test substance. The ThOD of the reactants is identical to the ThOD of the two reactants because all components formed remained in the reactor during the production. The ThOD of sodium acetate is 0.78 mg/mg.

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 PARAD Substance 139 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 8.0 at the start of the test. The pH of the medium at day 28 was 8.0 (control and test). Temperatures were within the prescribed temperature range of 22 to 24°C.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The read across substance was considered as 'readily biodegradable' in the closed bottle test.

Executive summary:

A study was conducted to determine the ready biodegradability of the read across substance (2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with phosphorus oxide (P2O5)) according to OECD Guideline 301D, EU Method C.4-C and ISO 10707, in compliance with GLP. The test substance did not cause a reduction in the endogenous respiration at Day 7and was therefore considered to be non-inhibitory to the inoculum. The substance was biodegraded by 71% at day 28 in the OECD 301 Closed Bottle test and can therefore be considered as readily biodegradable. The test was valid as shown by an endogenous respiration of 1.3 mg/L and by the total mineralization of the reference compound, sodium acetate. Sodium acetate was degraded by 88% 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. Under the study conditions, the substance was considered as 'readily biodegradable' in a slightly modified closed bottle test (van Ginkel, 2016).