N-1-naphthylaniline

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil macroorganisms except arthropods: long-term

Type of information:

read-across from supporting substance (structural analogue or surrogate)

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

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
Please refer also to Read-Across Statement attached in Section 13

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
In this read-across approach data on Naphthalene (CAS 91-20-3, EC 202-049-5) is used to fill data gaps for N-1-naphthylaniline (CAS 90-30-2, EC 201-983-0), in accordance with Regulation No 1907/2006 (REACH), Annex XI. The basis for this read-across approach is the “Read-Across Assessment Framework” (RAAF) (ECHA 2017). The read-across hypothesis for the analogue approach is that N-1-naphthylaniline and Naphthalene exhibit a comparable ecotoxicological hazardous potential as a consequence of structural similarity. The target substance N-1-naphthylamine is a member of Naphthalenes, with the Naphthalene structure being part of the molecule, representing a relevant structure in terms of their ecotoxicological effects. The differences in the molecular structure and the associated differences in physical properties explain the slight differences in the potency of the substance. Nonetheless, from a regulatory point of view, the degree of danger of both substances is comparable.
According to the RAAF this approach is covered by scenario 2, based on “different compounds with qualitatively similar properties”.
“This scenario covers the analogue approach for which the hypothesis is based on different compounds with the same type of effect(s). For the REACH information requirement under consideration, the effects obtained in a study conducted with one source substance are used to predict the effects that would be observed in a study with the target substance if it were to be conducted. The same type of effect(s) or absence of effect is predicted. The predicted strength of the effects may be similar or based on a worst-case approach.”

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Target chemical:
N-1-naphthylaniline, CAS number: 90-30-2, EC number: 201-983-0, Molecular formula: C16H13N, Molecular weight: 219.28 g/mol

Source chemical:
Naphthalene, CAS: 91-20-3, EC number: 202-049-5, Molecular formula: C10H8, Molecular weight: 128.17 g/mol

3. ANALOGUE APPROACH JUSTIFICATION
QSAR profiling reveal no significant differences between the source Naphthalene and the target substance N-1-naphthylaniline, the available data show a comparability of the relevant physico-chemical parameters and a similarity in the ecotoxicological profile, what justifies this read across. Thus, the available studies for the source substances Naphthalene are used to fill data gaps N-1-naphthylaniline for the following ecotoxicological endpoints: Toxicity to sediment organisms, Toxicity to soil microorganisms except arthropods, Toxicity to terrestrial arthropods, Toxicity to terrestrial plants and Toxicity to birds (for further details please refer to attached Read-Across Statement in Section 13).

4. DATA MATRIX
(please refer to attached Read-Across Statement in Section 13)

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

220 other: µmol/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

28 d

Dose descriptor:

EC100

Effect conc.:

2 045 other: µmol/kg soil dw

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

reproduction

Results with reference substance (positive control):

not applicable

Analytical results:

Day 0: 80 to 105% recovery of naphthalene

Day 10: 7 to 20% recovery of naphthalene

Solvent controls showed no effects of solvent on results.

Validity criteria fulfilled:

not specified

Description of key information

NOEC (28d) = 220 µmol/kg soil dw (measured initial, vehicle) for Enchytraeus crypticus (OECD 220, read across)

Additional information

No data are available for the toxicity of N-phenyl-1-naphthylamine to terrestrial organisms. Therefore, information from a supporting, structurally analogue compound (naphthalene) was taken into account.

In this key study, the toxicity of naphthalene (purity >99.0%) to Enchytraeus crypticus was tested following OECD guideline 220 (deviation: study duration, no removal of adults before counting, extraction of animals from soil with 96% ethanol, Droge et al. 2006). Nominal concentrations of 62.5, 125, 250, 500 and 1000 mg/kg were tested, with acetone as solvent. For enchytraeids initially 0.4 to 0.6 cm in length, the adult mortality and the number of produced juveniles was recorded after a four-week period. The NOEC (28d) is determined to be 220 µmol/kg soil dw and the EC100 is determined to be 2045 µmol/kg soil dw for mortality and reproductive output. A LC50 value could not be determined since two consecutive concentrations resulted in no effect and a complete effect.