N-1-naphthylaniline

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well documented publication which meets basic scientific principles

Qualifier:

no guideline followed

Principles of method if other than guideline:

incubation of an aqueous solution of PNA in the dark and periodical analyzation by HPLC

GLP compliance:

not specified

Radiolabelling:

yes

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products: after 0, 142, 309, 477, 669 and 813 hours
- Sampling method: not specified

Buffers:

- Type and final molarity of buffer: 0.1M acetate buffer

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: glass tubes (head space 24 mL)
- Lighting: in darkness
- Measures taken to avoid photolytic effects: in darkness
- Is there any indication of the test material adsorbing to the walls of the test apparatus? Yes, accordingly aa similar experiment was set up with radiolabelled PNA

TEST MEDIUM
- Volume used/treatment: 5 mL
- Kind and purity of water: not stated
- Preparation of test medium: aqueous solution

Duration:

34 d

Initial conc. measured:

582 µg/L

Number of replicates:

2

Positive controls:

no

Negative controls:

no

Transformation products:

no

% Recovery:

>= 45 - <= 52

Duration:

34 d

Remarks on result:

other: PNA is removed from the solution but this removal levels off with time. Behaviour of this type is inconsistent with hydrolytic processes, particularly since no degradation products could be detected.

Details on results:

no further data

Content of PNA in solutions (tube 1- tube 2, in ppb):

0 h              582 - 582

142 h          416 - 390

309 h          365 - 338

477 h        328 - 292

669 h        299 - 272

813 h        302 - 260 

PNA is removed from the solution but this removal levels off with time. Behaviour of this type is inconsistent with hydrolytic processes, particularly since no degradation products could be detected. Probably adsorption to the glass surface could account for the observed decrease in concentration. Accordingly, a similar experiment was set up with 14C-PNA where any disappearance of radioactivity from the solution could only be accounted for by adsorption. Experiment with radiolabelled PNA, Content of PNA in solutions (tube 1- tube 2, in ppb, measured by liquid scintillation counting and consequently a measure of total radioactivity in solution):

0 h            871 - 730

24 h          760 - 730

48 h          780 - 720

120 h        750 - 690

360 h        690 - 620

576 h        680 - 570

Thus, it is concluded that hydrolysis is either unimportant or of very limited importance as environmental pathway.

Validity criteria fulfilled:

not applicable

Description of key information

Hydrolysis is not a relevant degradation pathway of the substance in the environment

Additional information

In the key study, an aqueous solution of N-phenyl-1-naphtylamine was analyzed periodically by HPLC (Sikka et al. 1981). Total recovery of the test substance was 45-52% after 34 days, no degradation products could be detected. Thus, hydrolysis is not considered to be a relevant degradation pathway for N-phenyl-1-naphthylamine in the environmental.