Phenylphosphonic dichloride

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:

2018-04-24 - 2018-05-25

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Phenylphosphonic dichloride

EC Number:

212-534-3

EC Name:

Phenylphosphonic dichloride

Cas Number:

824-72-6

Molecular formula:

C6H5Cl2OP

IUPAC Name:

phenylphosphonic dichloride

Test material form:

liquid

Specific details on test material used for the study:

Name phenylphosphonic dichloride
Batch no. 201 712 01 - 01
Appearance liquid, clear
Composition phenylphosphonic dichloride: >98%
CAS No. 824-72-6
EINECS-No. 212-534-3
Molecular formula C6H5POCI2
Molecular weight 194.98 g/mol
Purity >98%
Homogenity homogeneous

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Specification
Activated sludge from a biologic sewage treatment plant was used. The chosen plant treats mostly domestic sewage.
Source and Pre-Treatment
Source
The sludge was taken from the activation basin of sewage treatment plant, In den Seewiesen, 67482 Edenkoben.
Date of collection: 26. Apr. 2018, batch no: 20180426.
Pre-Treatment
The sludge was filtrated through a clean cotton cloth, then washed with test medium 2x and resuspended in test medium. It was then aerated until use in the test. Determination of dry matter gave 4320 mg suspended solids/L.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

79.83 mg/L

Based on:

DOC

Remarks:

Test 1

Initial test substance concentration 2

Initial conc.:

79.86 mg/L

Based on:

DOC

Remarks:

Test 2

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

This study was performed in order to evaluate aerobic elimination and degradation poten-tial of phenylphosphonic dichloride in a test for ready biodegradability, using a nominal concentration of 40 mg organic carbon/L.
A solution of the test item in a mineral medium was inoculated and incubated under aero-bic conditions in the dark. The amount of DOC in the test solution due to the inoculum was kept as low as possible compared with the amount of organic carbon due to the test item. Allowance was made for the endogenous activity of the inoculum by running parallel blanks with inoculum but without test item, although the endogenous activity of cells in the presence of a chemical was not exactly matched that in the endogenous control. A positive control was run in parallel to check the operation of the procedures. Degradation was followed by the determination of dissolved organic carbon (DOC) and measurements were taken at sufficiently frequent intervals to allow the identification of the beginning and end of biodegradation. The test lasted for 28 days.

Reference substance

Reference substance:

aniline

Results and discussion

% Degradation

% Degradation 1

Key result

Parameter:

% degradation (DOC removal)

Value:

3.7

Sampling time:

4 d

% Degradation 2

Key result

Parameter:

% degradation (DOC removal)

Value:

1.9

Sampling time:

11 d

% Degradation 3

Key result

Parameter:

% degradation (DOC removal)

Value:

2.1

Sampling time:

20 d

% Degradation 4

Key result

Parameter:

% degradation (DOC removal)

Value:

2

Sampling time:

28 d

Any other information on results incl. tables

Degradation values in %

Day	Positive Control 1	Positive Control 2	Positive Control Mean	Test 1	Test 2	Test Mean	Abiotic Control	Adsorption Control	Toxicity Control
4	69.0	97.0	83.0	3.5	3.8	3.7	1.4	3.0	37.8
7	97.8	95.7	96.8	4.3	3.3	3.8	4.1	1.6	50.2
11	97.6	97.3	97.5	3.5	0.3	1.9	-0.7	0.7	48.1
15	97.3	98.0	97.7	-0.9	-5.1	-3.0	-4.3	-6.9	45.9
20	97.1	98.3	97.7	3.8	0.4	2.1	2.0	-1.6	49.6
26	97.9	98.6	98.3	3.6	-0.7	1.5	-4.3	0.3	48.8
28	98.4	98.6	98.5	2.5	1.5	2.0	-5.3	3.0	50.6

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The test item phenylphosphonic dichloride is not readily biodegradable following OECD 301A/EU C.4-A. As degradation missed 70% in the course of the test, phenylphosphonic dichloride is considered as not ultimately biodegradable, either.

Executive summary:

The test item was tested using a nominal concentration of 40 mg organic carbon/L in test medium following OECD 301A and EU-Guideline C.4-A.

 

Aniline was chosen as positive control.

Activated sludge was used as inoculum (concentration in the test 25.1 mg dry matter/L). The test was left running for 28 days.

All validity criteria were met. Degradation of the positive control was 83 % after 4 days.

 

The following data were determined for the test itemphenylphosphonic dichloride:

 

10-day-window:                                                                                                    not detected

degradation at the end of 10-day-window                                                                   none

degradation at the end of the test                                                                                           2 %

 

Therefore, the test itemphenylphosphonic dichlorideisnotreadily biodegradablefollowing OECD 301A and EU C.4-A respectively.

 

Therefore, when applying the 10-day-window, the test itemphenylphosphonic dichlorideis not readily biodegradable following OECD 301A/EU C.4-A. As degradation missed 70% in the course of the test,phenylphosphonic dichlorideis considered as not ultimately biodegradable,either.