Phosphoric acid, mixed esters with biphenyl-4,4'-diol and phenol

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: Method for Testing the Biodegradability of Chemical Substances by Microorganisms" in "Testing Methods for New Chemical Substances" (2003; Pharmaceutical and Food Safety Bureau, MHLW; Manufacturing Industries Bureau, METI; Environmental Policy Bureau, MOE

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

other: mixture of sewage and natural river, lake and sea water and sediment

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): mixture of sewage (three city and one industrial sewage plant), and natural river (three sites), lake (one site) and sea water (two sites) from different sites in Japan.
- Sampling method: from the sewage plants return sludge was collected; from rivers, lake and sea surface water and surface soil which was in contact with the atmosphere were collected.
- Preparation method of activated sludge: The filtrate (5 L) of the supernatant of the activated sludge¹ cultivated about for three months was mixed with the mixed filtrate (5 L) of the supernatant of a sludge collected newly at each location. The mixed filtrate (10 L) was aerated² after the pH value of the mixture was adjusted to 7.0±1.0.
¹ The mixed filtrate of the supernatant of sludge collected at the ten locations according to the cultivation methods as described below.
² Prefiltered open air.
- Method of cultivation:
After ceasing aeration of the sludge mixture for approximately 30 minutes, supernatant corresponding to about one third of the whole volume was removed. Dechlorinated water was added to the remaining portion so that the total volume reached 10 L. This mixture was aerated for 30 minutes or more, and then a predetermined amount of synthetic sewage³ was added to the mixture so that the concentration of the
synthetic sewage was 0.1 % in the volume of dechlorinated water added. This procedure was repeated once every day. Cultivation was carried out at 25±2 °C.
³ Synthetic sewage was prepared as follows: Glucose, peptone and potassium dihydrogenphosphate were dissolved in purified water to obtain 50 g/L of the solution for each component. The pH of the solution was adjusted to 7.0±1.0 with sodium hydroxide.

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Initial conc.:

204 mg/L

Based on:

ThOD/L

Parameter followed for biodegradation estimation:

O2 consumption

Parameter followed for biodegradation estimation:

test mat. analysis

Details on study design:

TEST CONDITIONS
- Composition of medium: as described in Japanese Industrial Standards (JIS) K 0102-1998 and OECD TGD 301C; adjusted to pH 7.0
- Test temperature: 25 ± 1 °C
- pH: test media (sludge + test material) at test end: pH 7.3-7.5
- pH adjusted: no
- Suspended solids concentration: 30 mg/L
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: closed system oxygen consumption measuring apparatus
- Number of culture flasks/concentration: 3

SAMPLING
- Sampling frequency: the biochemical oxygen demand (BOD) was measured by autorecording using a data sampler. After the end of the cultivation, the concentration of the test material in the test solutions was determined.

CONTROL AND BLANK SYSTEM
- Inoculum blank: activated sludge + basal medium (1 bottle)
- Abiotic control: test material + purified water (1 bottle)
- Toxicity control: none

Reference substance:

aniline

Key result

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

28 d

Key result

Parameter:

% degradation (test mat. analysis)

Value:

1

Sampling time:

28 d

Details on results:

Degradability based on DOC measurements was not calculated because the test material was insoluble in the test solution.

Results with reference substance:

The reference substance aniline had achieved 59% of the ThOD after 7 days of incubation and 72% after 14 days.

At test start and end the test material was not dissolved and the test solutions were colorless. Growth of the sludge was not observed.

Validity criteria fulfilled:

yes

Remarks:

Rate of degradation of the reference compound was ≥40% after 7 and ≥65% after 14 days; difference of extremes of replicate values of the removal of the test substance was <20%

Interpretation of results:

under test conditions no biodegradation observed

Description of key information

Biodegradation in water: screening tests: biodegradation 1% (BOD, HPLC) in 28 days (OECD 301C)

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed