Phenyl phosphorodichloridate

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:

From 1997-05-19 to 1997-06-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Phenyl phosphorodichloridate

EC Number:

212-220-6

EC Name:

Phenyl phosphorodichloridate

Cas Number:

770-12-7

Molecular formula:

C6H5Cl2O2P

IUPAC Name:

phenyl dichlorophosphate

Test material form:

liquid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): from the aeration stage of the Severn Trent Water pic sewage treatment plant at Belper, Derbyshire, treating predominantly domestic sewage.
- loading rate: 30 mg suspended solid (ss/L)

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

58.5 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

20 mg/L

Based on:

COD

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Standard culture medium:
Solution a
- KH2PO4 8.50 g/l
- K2HPO4 21.75 g/L
- Na2HPO4.2H2O 33.40 mg/L
- NH4Cl 0.50 g/L
- pH = 7.4
Solution b
- CaCL2 27.50 g/L
Solution c
- MgSO4.7H2O 22.50 g/L
Solution d
- FeCL3.6H2O 0.25 g/L

To 1 litre (Final volume) of purified water* is added the following volumes of solutions a to d
- 10 mL of solution a
- 1 mL of solution b
- 1 mL of solution c
- 1 mL of solutoin d

* Ion exchange and reverse osmosis treated tap water

Test concentrations
a) Inoculated culture medium in duplicate
b) 17.1 mg/L sodium benzoate with inoculum, equivalent to 10 mg carbon/L in duplicate
c) 58.5 mg/L test material with inocumum, equivalent to 20 mg carbon/L in duplicate
d) Toxicity control 58.5 mg/L test material plus 17.1 mg/L sodium benzoate with inoculum equivalent to 30 mg carbon/L, one vessel only.

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (CO2 evolution)

Value:

52

Sampling time:

28 d

% Degradation 2

Parameter:

% degradation (CO2 evolution)

Value:

58

Sampling time:

29 d

Any other information on results incl. tables

Table 1: Inorganic carbon value on each sampling occasion

day	Control (mg IC)				Sodium Benzoate (mg IC)				ITC 716 (mg IC)				ITC 716 plus sodium benzoate toxicity control (mg IC)
	R1		R2		R1		R2		R1		R2
	Abs 1	Abs 2	Abs 1	Abs 2	Abs 1	Abs 2	Abs 1	Abs 2	Abs 1	Abs 2	Abs 1	Abs 2	Abs 1	Abs 2
0	1.23	1.52	1.05	1.17	1.05	1.40	1.40	1.28	0.82	1.05	1.05	1.40	1.40	1.75
1	1.63	-	3.83	-	5.68	-	3.59	-	6.26	-	3.94	-	5.22	-
2	7.96	-	6.11	-	14.42	-	14.30	-	6.34	-	6.23	-	16.84	-
3	7.91	-	7.80	-	20.18	-	29.81	-	13.19	-	20.07	-	41.05	-
6	15.05	-	14.25	-	27.02	-	38.53	-	29.07	-	31.92	-	55.40	-
8	19.49	-	18.93	-	42.84	-	41.14	-	32.41	-	37.29	-	70.95	-
10	21.07	-	20.39	-	43.38	-	46.19	-	32.56	-	42.48	-	76.28	-
14	20.82	-	22.04	-	42.53	-	49.21	-	36.74	-	44.09	-	82.05	-
16	21.58	-	22.80	-	46.04	-	50.46	-	39.51	-	50.69	-	89.64	-
20	23.40	-	23.51	-	49.86	-	50.95	-	42.75	-	52.26	-	98.40	-
22	27.06	-	24.02	-	52.16	-	53.57	-	50.10	-	54.66	-	99.97	-
24	29.27	-	27.11	-	56.70	-	58.21	-	58.21	-	58.32	-	105.08	-
27	33.49	-	31.13	-	60.43	-	63.33	-	63.54	-	60.86	-	112.06	-
28	33.71	-	34.24	-	64.11	-	63.47	-	65.60	-	64.96	-	117.33	-
29	33.49	0.70	34.34	0.46	64.77	0.70	62.86	0.58	70.91	0.35	66.78	0.35	123.81	0.46

R1 – R2 = replicates 1 & 2             Abs = Co2 absorber vessels  - = value not determined

Percentage biodegradation value

Day	% degradation Sodium Benzoate	%degrdation phenyl dichlorophospahte	% degradation phenyl deichlorophosphate + sodium benzoate (toxicity control)
0	0	0	0
1	6	4	3
2	24	0	11
3	57	15	37
6	60	26	45
8	76	26	57
10	80	28	62
14	81	32	67
16	87	38	75
20	90	40	83
22	91	45	83
24	98	50	85
27	99	50	89
28	99	52	93
29*	100	58	100

* Day 29 values corrected to include any carry-over of CO₂detected in absorber 2

 

 

 

 

Total organic carbon (TOC) values in the culture vessels on day 0 and 28

test vessel	TOC * Concentration in culture vessel
	Day 0		Day 28
	mg C/L	% nominal carbon content	mg C/L	% of initial carbon concentration	% degradation
Sodium Benzoate 10 mg C/L R1	11.80	118	1.81	15	85
Sodium Benzoate 10 mg C/L R2	11.98	120	1.79	15	85
Phenyl Dichlorophosphate 20 mg C/L R1	17.95	90	9.42	52	48
Phenyl Dichlorophosphate 20 mg C/L R2	20.16	101	11.55	57	43
Phenyl dichlorophosphate + sodium benzoate (toxicity control) 30 mg C/L	30.38	101	2.66	9	91

* Corrected for control values R1 & R2 = replicates 1 and 2

Applicant's summary and conclusion

Validity criteria fulfilled:

no

Interpretation of results:

not readily biodegradable

Conclusions:

The percentage of degradation of phenyl dichlorophosphine is 52% after 28 days. The substance was not considered to be readily biodegradable

Executive summary:

Biodegradation of Phenyldichlorophosphate has been determined according to OECD test guideline 301B. The biodegradation of Phenyldichlorophosphate was determined to be equal 52% after 28 days. The substance cannot be considered to be readily biodegradable.