Tris(4-chlorophenyl)sulfonium 5-benzoyl-4-hydroxy- 2-methoxybenzenesulfonate

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:

23 May - 21 Jun 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP - Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Test guideline 3

Qualifier:

according to guideline

Guideline:

ISO DIS 9439 (Ultimate Aerobic Biodegradability - Method by Analysis of Released Carbon Dioxide)

GLP compliance:

yes

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): PM-5927
- Physical state: off-white powder
- Lot/batch No.: 07-02
- Expiration date of the lot/batch: 05 Feb 2008
- Storage condition of test material: at room temperature in the dark

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 de Maaskant’, ‘s-Hertogenbosch, The Netherlands
- The sludge was kept under continuous aeration until further treatment.
- Preparation of inoculum for exposure: Before use, the sludge was allowed to settle for 73 min and the liquid decanted for use as inoculum at the amount of 20 mL/L of mineral medium.
- The concentration of suspended solids was 2.5 g/L in the concentrated sludge.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

21 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

12 mg/L

Based on:

other: TOC

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral medium
- Test temperature: 20.6 - 21.7 °C
- pH: 7.5 - 7.7
- Aeration of dilution water: The mixture of mineral components, Milli-RO water (ca. 80% total volume) and inoculum (1% final volume) was aerated with synthetic air overnight to purge the system of CO2.
- Suspended solids concentration: 2.5 g/L
- other: The test media were continuously aerated and stirred during the test. Preparation of the test solutions was as much as possible performed under yellow light.

TEST SYSTEM
- Culturing apparatus: 2 litre all-glass brown coloured bottles
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: CO2-free air was sparged through the scrubbing solutions at a constant rate.
- Details of trap for CO2: A mixture of oxygen (21%) and nitrogen (79%) was passed through a bottle, containing 0.5 – 1 L 0.0125 M Ba(OH)2 solution. The CO2 produced in each test bottle reacted with the barium hydroxide in the gas scrubbing bottle and precipitated out as barium carbonate.

SAMPLING
- Sampling frequency: on day 2, 5, 7, 9, 14, 19, 23, 27, 29
- Sampling method: The amount of CO2 produced was determined by titrating the remaining Ba(OH)2 with 0.05 M standardized HCL. On the 28th day, the pH of the test suspensions was measured and 1 mL of concentrated HCL was added to each bottle. The bottles were aerated overnight to drive off CO2 present in the test suspension. The final titration was made on day 29.

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 replicates
- Positive control: 1 replicate
- Toxicity control: 1 replicate

Reference substance

Reference substance:

acetic acid, sodium salt

Results and discussion

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

5.5

Sampling time:

29 d

BOD5 / COD results

Results with reference substance:

Degradation: 64% after 14 days, 60% pass level was reached.

Any other information on results incl. tables

Table 1: Percentage biodegradation of test substance, reference substance and toxicity control

Day	Test substance (% degradation)			Reference substance (% degradation)	Toxicity control (% degradation)
	Replicate 1	Replicate 2	Ø
2	0	1	1	2	0
5	1	2	1	35	13
7	1	2	2	49	20
9	2	3	2	57	24
14	2	3	3	64	28
19	4	3	3	68	31
23	5	3	4	71	33
27	6	3	5	74	34
29	6	3	5	76	34
29	7	3	5	76	35
29	8	3	5*	77	35

 * value as stated in report, actual mean = 5.5

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

CLP: Aquatic chronic 2, H411 (basis for classification: not rapidly biodegradable and a NOEC (growth rate) of 0.22 mg/L for algae)