2,9,16,23-tetrakis(2,5-di-tert-butyl-4-methoxyphenoxy)phthalocyanine

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:

05 Mar 2019 to 04 Apr 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2,9,16,23-tetrakis(2,5-di-tert-butyl-4-methoxyphenoxy)phthalocyanine

EC Number:

831-167-5

Cas Number:

2126827-44-7

Molecular formula:

C92H106N8O8

IUPAC Name:

2,9,16,23-tetrakis(2,5-di-tert-butyl-4-methoxyphenoxy)phthalocyanine

Test material form:

solid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 2715/18/01
- Expiration date of the lot/batch: 01 July 2020
- Purity: 99%:
- CAS number: 2126827-44-7

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature protected from light
- Stability under test conditions: Stable

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Municipal sewage treatment plant: 'Waterschap Aa en Mass','s Hertogenbosch, The Netherlands, receiving predominantly domestic sewage
- Storage conditions: Continuously aerated
- Concentration of sludge: 3.4 g/L suspended solids
- Pre-treatment of slduge: sludge was coarsely sieved (1mm)

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

16 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

12 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: Tap water putified by reverse osmosis (Milli-RO) and subsequently passed over activated carbon. Used to prepare standard mineral medium.
- Test temperature: 22.2 to 22.8°C
- pH: 7.6 to 7.7
- pH adjusted: not stated
- Suspended solids concentration: 10mg/l
- Continuous darkness: yes, in addition to brown vessels

TEST SYSTEM
- Culturing apparatus: 2 litre brown test glass bottles, test item was added via weighed amounts of small watch glasses, this was performed under low light conditions.
- Number of culture flasks/concentration: 2 test flasks with test item and inoculum
- Method used to create aerobic conditions: aeration and continual stirring
- Test performed in closed vessels due to significant volatility of test substance: not stated
- Details of trap for CO2 and volatile organics if used: CO2 was purged from synthetic air used to aerate the system using barium hydroxide before aerating. After the test vessels, three OC2 absorbers (bottles filled with 100ml 0.0125M Ba(OH)2) were connected in series to the exit air line of each test bottle.

SAMPLING
- Sampling frequency: 2, 5, 8, 12, 15, 19, 23, 28 (measured on 29). Titrations for the procedure and toxicity control were made over a period of 14 days.
- Sampling method: The amount of CO2 produced was determined by titrating remaining Ba(OH)2 with 0.05 M standardized HCl (1:20 dilution from 1 M HCl (Titrisol® ampoule), Merck, Darmstadt, Germany). Each time the CO2-absorber nearest to the test bottle was removed for titration; each of the remaining two absorbers were moved one position in the direction of the test bottle. A new CO2-absorber was placed at the far end of the series. Phenolphthalein (1% solution in ethanol, Merck) was used as pH-indicator. On the penultimate day, pH of respective test suspensions was measured and 1 mL of concentrated HCl (37%, Merck) was added to the inoculum blank and test suspension. Bottles were aerated overnight to drive off CO2 present in the test suspension. Final titration was made on day 15 (procedure and toxicity control) and on day 29 (remaining vessels).

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 bottles containing only inoculum.
- Procedure control: duration of test 14 days, last CO2 measurements day 15, 1 bottle containing test item, and inoculum.
- Toxicity control: duration of test 14 days, last CO2 measurements day 15, 1 bottle containing test item, reference item and inoculum.

Reference substance

Reference substance:

other: sodium acetate

Remarks:

CAS number 127-09-3

Results and discussion

Preliminary study:

Not applicable

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

1

Sampling time:

28 d

Remarks on result:

other:

Remarks:

individual vessel

Details on results:

-Toxicity control: 41% biodegradation occurred within 14 days. This indicates the test item was not inhibited by microbial activity.

BOD5 / COD results

Results with reference substance:

- Sodium acetate biodegraded 83% within 14 days which is within the criteria for acceptibility of the test.

Any other information on results incl. tables

CO2 production and percentage biodeegradation of the test item (Bottle A):

Day	0.05 N HCl titrated (mL) - Blank (mean)	0.05 N HCl titrated (mL) - Bottle A	Produced CO2 (mL HCl)	Produced CO2 (mg)	Cumulative CO2 (mg)	Biodegradation (%)b
2	42.09	42.20	0.0	0.0	0.0	0
5	39.11	39.55	0.0	0.0	0.0	0
8	37.74	38.06	0.0	0.0	0.0	0
12	37.73	36.80	0.92	1.0	1.0	1
15	37.58	38.53	0.0	0.0	1.0	1
19	36.08	37.52	0.0	0.0	1.0	1
23	37.04	39.01	0.0	0.0	1.0	1
29 a	35.71	35.87	0.0	0.0	1.0	1
29 a	39.62	39.85	0.0	0.0	1.0	1
29 a	41.26	41.47	0.0	0.0	1.0	1

CO2 production and percentage biodegradation of the test item (Bottle B)

Day	0.05 N HCl titrated (mL) - Blank (mean)	0.05 N HCl titrated (mL) - Bottle A	Produced CO2 (mL HCl)	Produced CO2 (mg)	Cumulative CO2 (mg)	Biodegradation (%)b
2	42.09	42.65	0.0	0.0	0.0	0
5	39.11	39.85	0.0	0.0	0.0	0
8	37.74	38.53	0.0	0.0	0.0	0
12	37.73	37.18	0.54	0.6	0.6	1
15	37.58	38.85	0.0	0.0	0.6	1
19	36.08	37.79	0.0	0.0	0.6	1
23	37.04	39.12	0.0	0.0	0.6	1
29a	35.71	37.68	0.0	0.0	0.6	1
29a	39.62	41.27	0.0	0.0	0.6	1
29a	41.26	41.03	0.23	0.3	0.9	1

a - CO2 measured on day 29 is actually part of CO2 production of day 28, since microbial activity was ended on day 28 by

addition of HCl.

b - Calculated as the ratio between CO2 produced (cumulative) and the ThCO2 of the test item: 89.3 mg CO2/2L.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The test item was measured to undergo 1% biodegradation over 28 days, and is therefore considered to be not readily biodegradable under the conditions of the test. The test substance had no inhibitory effect on degradation, and the reference chemical, sodium acetate, was degraded by >40% within 14 days.

Executive summary:

A reliable study to determine the ready biodegradability of the test item following the internationally acceptable test guideline OECD 301B was carried out according to GLP. The amount of CO2 produced by the test vessels was determined by titration of remaining Ba(OH)2 in the scrubber vessels (located after the test vessels) with 0.05 M standardized HCl. The test item was degraded by <5% (1% for both test vessels) after 28 days and was not readily biodegradable under the conditions of the test (CO2 evolution, modified Sturm test). The test validity criteria were met and there were no significant deviations noted.