N-1-naphthylaniline

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

The PBT Assessment for N-1-naphthylaniline (CAS 90-30-2) is based on the criteria set out in the “Guidance on information requirements and chemical safety assessment, Chapter R.11: PBT Assessment” (ECHA, 2012).

Persistence

In two screening tests on ready biodegradability (OECD 301C), N-phenyl-1-naphtylamine was shown to be not biodegradable by activated sludge (0% degradation in 14 and 28 days, respectively; Bayer 1990, MITI 1992). Results from these studies can be interpreted as screening criteria towards persistency. However, due to the fact that the test methodology for the screening tests on ready biodegradability is stringent, a negative result does not necessarily mean that the chemical will not be degraded under environmental conditions.

On the other hand, other available biodegradation studies (Sikka et al. 1981, Rosenberg 1983) report 50% degradation within 5 days and 97% degradation within 18 d (supplemented sewage, half-life 4.2 d). In supplemented sewage, more than 75% degradation was observed after 2 d. No test substance could be detected after 18 d (half-life 1.2 d). In lake water, 50% degradation within 10 d was observed, further nutrient supplementation resulted in continued degradation (90% after 18 d, half-life 7.2 d). Transient degradation products were identified as the dihydroxy derivate of N-phenyl-1-naphtylamine and N-acetyl N-phenyl-1-naphtylamine. The substance showed also to be degraded and mineralized in the terrestrial environment. From carbon-supplemented soil 12.5% of the initial radioactivity were evolved as 14CO2 after 11 days. Similar results were obtained with supplemented soil suspensions. After 11 days 22% of radioactivity was recovered as 14CO2. The reported half-life value is below the persistence criteria of 40 d (water) set in Annex XIII to REACH Regulation (EC) No 1907/2006. Thus, the substance is not considered to be P or vP.

Bioaccumulation

Several studies on the bioaccumulation of N-phenyl-1-naphtylamine in fish and daphnids indicated a moderate bioaccumulation potential of the substance. It was shown that the substance accumulates in carp with BCF values ranging from 427 to 2490. Radiolabelled N-phenyl-1-naphtylamine was readily taken up in bluegill sunfish with bioconcentration factors of 600 for whole fish, 339 for edible flesh and 2063 for viscera. Half of the 14C-N-phenyl-1-naphtylamine-derived radioactivity in the fish was eliminated in about 2 days after transfer to clean flowing water, with about 50% of the radioactivity present as N-phenyl-1-naphtylamine metabolite(s). A major metabolite in the fish extract was identified as a dihydroxy derivative of PNA. For Daphnia magna, a BCF of 637 was measured, with an elimination of half of the 14C-N-phenyl-1-naphtylamine derived radioactivity within about 2 days after transfer to clean water. QSAR calculations using the Arnot-Gobas method (including biotransformation) of BCFBAF v3.01 resulted in BCF value of 592.5 and a BAF value of 594.9 L/kg ww. Based on these data evaluated in a weight-of evidence approach, the BCF value for whole organisms is below the bioascumualtion criterion of 2000 set in Annex XIII to REACH regulation (EC) No 1907/2006. Thus the substance is not considered to be B or vB.

Toxicity

N-1-naphthylaniline (CAS 90-30-2) is considered to be toxic. The long-term toxicity of the substance is > 0.01 mg/L. The substance is not classified for carcinogenicity, mutagenicity or reproductive and developmental toxicity in mammals (see section 5.9). However, the substance is classified for chronic toxicity as for specific target organ toxicity after repeated exposure (STOT RE Cat. 2). The criteria for “T” based on mammalian effects are met and thus, the criteria set out in Annex XIII of Regulation (EC) No. 1907/2006 are met and the substance is considered to be T.

Conclusion

The data show that whilst the properties of the substance meet the criteria for toxic, T, they do not meet the specific criteria detailed in Annex XIII of Regulation (EC) No. 1907/2006 for persistence and bioaccumulation and therefore N-1-naphthylaniline (CAS 90-30-2) is not classified as PBT and vPvB.