[No public or meaningful name is available]

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17th December 2019 - 15th January, 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Reaction products of 2,2'-(1,3-phenylenebis(oxy))diethanol with 2-(phenoxymethyl)oxirane and 2-isocyanatoethyl methacrylate

Cas Number:

1431303-59-1

Molecular formula:

Not assigned for UVCB substance.

IUPAC Name:

Reaction products of 2,2'-(1,3-phenylenebis(oxy))diethanol with 2-(phenoxymethyl)oxirane and 2-isocyanatoethyl methacrylate

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch number of test material: 3M, 6252020
- Expiration date of the lot/batch: September 2021
- Purity test date: 21st October 2019
- Purity: 100% (MTDID 58376), Complex mixture of ER-1GP IEM, ER-2GP IEM, ER-3GP IEM, ER-4GP IEM

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature in a dark, ventilated cabinet in the original container.
- Stability under storage conditions: Stable

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Sludge was obtained from Wareham Wastewater Treatment Plant, Wareham Massachusetts, receiving predominantly domestic sludge. Collected 16th December, 2019.
- Preparation of inoculum for exposure: Sludge was passed through a 2mm sieve and centrifuged for 10 minutes (1000 rpm). Supernatant was discarded and the sludge was washed with mineral medium. The sludge was then centrifuged again and the supernatant discarded. The moisture content was determined to be 94.36%, for a percent dry solids id 5.64%.
- Pretreatment: Inoculum solution with 15 mg dry solids/mL was prepared by diluting 53.19 g wet sludge to 200mL mineral medium and stirred with a PTFE-coated magnetic bar until use (22°C).
- Concentration of sludge: 30 mg solids/L. Initial carbon content of solution was 0.93 mg/L.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

10 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Standard OECD 301B test medium
- Additional substrate: none
- Test temperature: 20-21.1°C
- pH: 7.4
- pH adjusted: No
- Suspended solids concentration: 30 mg/L
- Continuous darkness: Yes

TEST SYSTEM
- Culturing apparatus: 4L glass bottle with rubber stopper
- Number of culture flasks/concentration: two
- Method used to create aerobic conditions: Vessels were attached to CO2-free compressed air gas tank and aerated under positive pressure.
- Measuring equipment:Two CO2 effluent gas traps. The first with 200mL of 0.2N KOH traps and the second with 100 mL of 0.2N KOH. The samples removed from the KOH trap were analysed using a Shimadzu TOC V-CPH or TOC-L/ASI-L/SSM Carbon Analyzer.
- Test performed in open system: No

SAMPLING
- Sampling frequency: Days 1, 3, 6, 10, 14, 17, 21, 24, 27, 28 and 29
- Sampling method: 7mL of sludge solution was removed from the first KOH carbon dioxide trap on each test and analyzed for CO2 evolution.
- Sample storage before analysis: None

CONTROL AND BLANK SYSTEM
- Inoculum blank: duplicate
- Procedural control: 2991 mL mineral medium, 6.0 mL sludge inoculum, 3mL sodium benzoate
- Toxicity Control: 2991 mL mineral medium, 6.0 mL sludge inoculum, 10mL C/L test substance, 10 mg C/L sodium benzoate

Reference substance

Reference substance:

benzoic acid, sodium salt

Remarks:

10 mg C/L

Results and discussion

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

4.88

Sampling time:

28 d

Details on results:

Detailed results on net percent carbon dioxide evolution of the test substance are provided in Table 2 and are graphically depicted in the illustration.
Detailed results on net percent carbon dioxide evolution by the reference substance and in the toxicity control are provided in Table 2.
Raw data results on inorganic carbon evolution in the blank control are provided in Table 1. Cumulative CO2 evolution in blanks was calculated using formulae shown below Table 1. Mean CO2 evolution in controls was 25.89 mg/L
The reference substance was 74.13% degraded by day 14.
Biodegradation in the toxicity control was 35.67% by day 14 and is therefore MTDID 58376 is not toxic to activated sludge.

Any other information on results incl. tables

Table 1. MTDID 58376 Determination of the Biodegradability- Total Inorganic Carbon (mg C/L) Measured in Potassium Hydroxide Trapping Solutions.

Replicate	TIC (mg C/L) Day 1	TIC (mg C/L) Day 3	TIC (mg C/L) Day 6	TIC (mg C/L) Day 10	TIC (mg C/L) Day 14	TIC (mg C/L) Day 17	TIC (mg C/L) Day 21	TIC (mg C/L) Day 24	TIC (mg C/L) Day 27	TIC (mg C/L) Day 28	TIC (mg C/L) Day 29- Trap 1	TIC (mg C/L) Day 29- Trap 2
Test suspension A	9.584	17.00	35.73	53.71	68.73	85.26	101.9	110.4	117.5	123.6	130.1	20.54
Test suspension B	10.20	18.32	34.83	49.65	62.93	73.36	86.72	95.01	101.7	104.9	114.2	19.41
Inoculum Blank A	12.65	19.21	33.93	50.29	61.75	74.41	88.23	96.85	102.3	107.6	121.3	16.82
Inoculum Blank B	10.25	18.52	35.63	53.89	67.86	78.40	86.08	91.42	96.69	100.8	109.8	16.22
Procedural control *	11.77	49.08	117.9	154.8	185.3	202.2	221.0	238.3	242.4	252.6	261.2	20.64
Toxicity control	14.14	63.03	117.3	149.7	180.0	206.2	228.7	240.4	245.7	256.2	263.0	26.38

* sodium benzoate

Note: The following equation was used to determine evolved CO2:

mg CO2 from test vessel=((TIC mg/L x 3.667) x vol. KOH Tx[L])+ Sum [(TIC mg/L in previous aliquots removed x 0.007 L x 3.667)]

Where: 3.667 is the conversion factor (44/12) for carbon to carbon dioxide.

Vol. KOH Tx is the volume of KOH trap at the particular sampling interval.

0.007 L is the KOH sampling volume (7.0 mL)

Table 2. MTDID 58376 Determination of the Biodegradability- Cumulative Net Percent CO2 Evolved from the Test Vessels (Ultimate Biodegradation)

Vessel	Replicate	Day 1	Day 3	Day 6	Day 10	Day 14	Day 17	Day 21	Day 24	Day 27	Day 28	Day 29
1	Test suspension A	-1.24	-1.24	0.50	0.90	2.22	4.93	8.04	8.80	9.64	10.27	9.51
2	Test suspension B	-0.83	-0.38	-0.01	-1.50	-1.17	-1.82	-0.44	0.22	0.86	0.17	0.24
	Mean	-1.04	-0.81	0.25	-0.30	0.53	1.56	3.80	4.51	5.25	5.22	4.88
	Std Dev	0.29	0.61	0.36	1.70	2.40	4.77	6.00	6.07	6.21	7.15	6.55
5	Procedural control	0.21	19.45	52.25	63.94	74.13	77.05	81.29	86.48	85.88	88.39	88.57
6	Toxicity control	0.90	14.24	26.13	30.63	35.67	39.69	42.78	43.97	43.95	45.28	45.93

The following equation was used to determine % biodegradation:

% Ultimate Biodegradability= (mg CO2 produced/ mg TOC added x 3.667) x 100

Results were calculated using the actual analytical (unrounded) results and not the rounded values presented in this table. All values were corrected for mean inoculum blank CO2 production.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Toxicity control degradation >25% by 14d (35.67%), ref substance degradation >60% by 14d (74.13%), <5% inorganic C in medium at test start (4.3%), diff in test substance degradation <20% (3.39% 14d, 9.27% 29d), CO2 evol in controls ≤40 mg/L (25.89 mg/L)

Interpretation of results:

not readily biodegradable

Conclusions:

MTDID 58376 was 4.88% biodegraded in a 28-day OECD 301B test.

Executive summary:

Ready biodegradability of MTDID 58376 was assessed according to OECD 301B guidelines. Duplicate flasks were used for blanks and the test substance, with single flasks for procedural control (sodium benzoate), and toxicity control samples. The reference substance was biodegraded 74.13% by day 14 and 88.39% by day 28. The test substance was biodegraded (4.88%) by day 28. Thus, MTDID 58376 is not considered readily biodegradable and is not toxic to microorganisms in activated sludge (36% degradation in toxicity control). The test was conducted according to internationally accept guidelines and is GLP compliant. It is reliable without restrictions and is suitable for Risk Assessment, Classification & Labelling, and PBT Analysis.