Naphthalene

Endpoint summary

Additional information

According to the European Risk Assessment Report on naphthalene [EU RAR], results of toxicity testing for terrestrial organisms are limited and only short-term tests have been carried out. The PNEC for the terrestrial compartment has therefore been calculated in this report using the equilibrium partitioning method in the Technical Guidance document. The PNEC for soil has been calculated to be 53.3 μg/kg using the PNEC calculated for freshwater. It has been suggested that naphthalene might have an effect on soil organisms exposed through the air and water in soil. The equilibrium partition approach assumes that exposure occurs through the water alone. In the absence of data on naphthalene toxicity to terrestrial organisms, information on 1,4-dichlorobenzene has been examined in the risk assessment of that substance. Although there are structural differences the physical properties of naphthalene and 1,4 -dichlorbenzene are similar, with 1,4-dichlorbenzene having a lower boiling point and higher vapour pressure. A set of short-term terrestrial toxicity tests are available for 1,4-dichlorobenzene, which give a PNEC of 85μg/kg wet weight using an assessment factor of 1000. The equilibrium partitioning approach gives a value of 160μg/kg from the aquatic PNEC, which is derived using a factor of ten on a data set of three long-term tests. Longer term testing on soil organisms might be expected to result in an increase in the PNEC from this calculation route. On the basis of these data, there is no indication of extra toxicity to soil organisms through uptake from solids or air. The same can be expected for naphthalene, and therefore the equilibrium partitioning PNEC has been considered to be trustworthy.

 

According to Column 2 of REACH Annexes IX and X (standard information requirements for substances manufactured or imported in quantities of 100 tonnes per year or more and 1000 tonnes per year or more) of Regulation (EC) No 1907/2006, studies on effects on terrestrial organisms do not need to be conducted if direct and indirect exposure of the soil compartment is unlikely and in the absence of toxicity data for soil organisms, the equilibrium partitioning method may be applied to assess the hazard to soil organisms.

 

The use pattern of naphthalene limits the risk for direct or indirect exposure of the soil compartment. Unlike pesticides e.g., naphthalene is not intentionally released into the environment. Production, handling and use, in most cases take place in closed systems with very low releases to the environment and with low probability of any significant release to the environment from products.

Against this background and according to Regulation (EC) No 1907/2006 performance of further studies on effects of naphthalene on terrestrial organisms is considered to be unnecessary.

 

[EU RAR] 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/]