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Sediment toxicity

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Description of key information

Calculated PNECsediment of 67.2 μg/kg for freshwater.

Key value for chemical safety assessment

Additional information

There are no studies available regarding sediment toxicity of naphthalene.

According to Column 2 of REACH Annex X (standard information requirements for substances manufactured or imported in quantities of 1000 tonnes or more) of Regulation (EC) No 1907/2006 “long-term toxicity testing on sediment dwelling organisms shall be proposed by the registrant if the results of the chemical safety assessment indicates the need to investigate further the effects of the substance and/or degradation products on sediment organisms.”According to Guidance on information requirements and chemical safety assessment (Chapter R.7b: Endpoint specific guidance) substances have to be assessed for toxicity to sediment-dwelling organisms that are potentially capable of depositing on or sorbing to sediments to a significant extent.

Relevant exposure of sediments to naphthalene is unlikely regarding its use pattern. Production, handling and use of naphthalene take place in closed systems under intermediate conditions with very low releases of naphthalene to the environment or to waste water streams and with low probability of any significant release to the environment from products. Even in case of relevant exposure, toxicological long-term effects on sediment dwelling organisms can be excluded since naphthalene is easily degradable (see section 5.2 of the dossier) and therefore does not sorb to sediments to a significant extent or deposit in sediment for a longer period of time when accidentally released to the environment.

Against this background and due to the inherent properties of naphthalene, long-term toxicity testing on sediment dwelling organisms is not required under Regulation (EC) No 1907/2006 (REACH).

According to the European Risk Assessment Report on naphthalene [EU RAR], in the absence of data on the toxic effects of naphthalene on sediment dwelling organisms, it is proposed that a sediment partition method is used to calculate a PNECsediment. The PNECsed has been calculated from the PNEC for water. The equation used in the risk assessment report differs from that given in the Technical Guidance Document. It uses the suspended matter - water coefficient rather than that for sediment. For naphthalene, PNECwater is 2.4 μg/l. This gives a PNECsediment of 67.2 μg/kg for freshwater.

[EC 2003: European Union Risk Assessment Report NAPHTHALENE [CAS No: 91-20-3; EINECS No: 202-049-5] RISK ASSESSMENT European Communities, 2003 [http://ecb.jrc.ec.europa.eu/esis/]