p-phenylenebis(methylamine)

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

Study period:

Nov 1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

other: “Study on Degradation of Chemical Substances by Microorganisms” described in the “Methods of Studies on New Chemical Substances” (Kanpogyo Notification No. 5, Yakuhatsu Notification No. 615, and 49 Kikyoku Notification No. 392 issued on July 13, 1974).

GLP compliance:

no

Specific details on test material used for the study:

Purity: 99.9%
Lot No.: Lot 4

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, adapted

Details on inoculum:

- Source of inoculum/activated sludge: purchase from the Chemical Substances Safety Center of the Chemicals Evaluation and Research Institute, Japan.
- Concentration of sludge: 30 mg/L

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

other: BOD, TOC and HPLC analysis

Details on study design:

TEST CONDITIONS
- Composition of medium: Six mL each of Fluid A, Fluid B, Fluid C and Fluid D defined in JIS K 0101-21 was added to water (2 L) and pH was adjusted to 7.00 using HCl (1 + 11) after mixing. Fluid A, Fluid B, Fluid C and Fluid D are, respectively, a buffer solution, magnesium sulfate solution, calcium chloride solution, and iron chloride (III) solution.
- Test temperature: 25±1°C
- pH: 7.0
- pH adjusted: pH was adjusted to 7.00 using HCl (1 + 11).

TEST SYSTEM
- Basic respiration system: The basic culture medium (300 mL) was introduced into a culture bottle (No. 1) using a measuring cylinder (for 300 ml).
- (Sludge + aniline) system: The basic culture medium (300 mL) was introduced into a culture bottle (No. 2) using a measuring cylinder (for 300 ml) and 30.1 mg of aniline was added using a microsyringe (for 50 μl).
- (Water + test substance) system: The test substance (100.0 mg) was taken into a weighing bottle (for 20 ml) and washed into a volumetric flask (for 1L) with water using a Komagome pipette. Water was added and mixed to obtain a 100.0 mg/L solution after the test substance was dissolved. The solution obtained (300 ml) was introduced into a culture bottle (No. 3) using a measuring cylinder (for 300 ml).
- (Sludge + test substance) system: The test substance was added to the basic culture medium to obtain a solution of 100.0 mg/L by operating in the same way as for the (water + test substance) system. The total volume of the solution obtained was transferred into a beaker (for 1 L), and pH was adjusted to 7.01 by adding HCl (1+11) while stirring using a magnetic stirrer. The solution obtained (300 ml) was introduced into culture bottles (No. 4-6) using a measuring cylinder (for 300 ml).

SAMPLING
- BOD was determined for 28 days in the test solutions (No. 1-6) prepared above using a coulometer.
- About 30 ml each of the test solutions (No. 1, 3, 4, 5 and 6) was transferred into a centrifuge tube (for 50 ml) and centrifuged for 5 min at 4,200 rpm. The supernatant (about 20 ml) was placed in a glass-stoppered clinical flask (for 20 ml) and used as sample for TOC and HPLC analysis.

Reference substance:

aniline

Parameter:

other: % degradation (BOD)

Value:

2

Sampling time:

28 d

Parameter:

% degradation (TOC removal)

Value:

1

Sampling time:

28 d

Parameter:

% degradation (test mat. analysis)

Value:

8

Sampling time:

28 d

Remarks on result:

other: based on the residual amount of the test substance

Parameter:

% degradation (test mat. analysis)

Value:

4

Sampling time:

28 d

Remarks on result:

other: based on the residual amount of the test substance + intermediate

Details on results:

The mean % degradation was 2% based on BOC, 1% based on TOC, 8% based on the residual amount of the test substance determined by HPLC, and 4% based the residual amount of (the test substance + intermediates), all low degradation rates. In the HPLC analysis of (sludge + test substance) test solutions, one intermediate was detected, but its amount was minimal, indicating that the test substance remained by and large unchanged.

Validity criteria fulfilled:

not specified

Interpretation of results:

not readily biodegradable

Conclusions:

The mean % degradation was 2% based on BOC, 1% based on TOC, 8% based on the residual amount of the test substance determined by HPLC, and 4% based the residual amount of (the test substance + intermediates), all low degradation rates. In the HPLC analysis of (sludge + test substance) test solutions, one intermediate was detected, but its amount was minimal, indicating that the test substance remained by and large unchanged.
Based on these findings, the test substance was judged to be not readily biodegradable.

Description of key information

A Biodegradation study (by BOD, TOC and HPLC analysis) showed low degradation rates, hence this substance was judged to be not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

A Biodegradation study is available which by BOD, TOC and HPLC analysis. The test period is 28 days.

The mean % degradation was 2% based on BOC, 1% based on TOC, 8% based on the residual amount of the test substance determined by HPLC, and 4% based the residual amount of (the test substance + intermediates), all low degradation rates. In the HPLC analysis of (sludge + test substance) test solutions, one intermediate was detected, but its amount was minimal, indicating that the test substance remained by and large unchanged.

Based on these findings, the test substance was judged to be not readily biodegradable.