US EPA

1470309 

Technical Report 

Environmental hazard assessment: Halogenated naphthalenes 

Crookes, MJ; Howe, PD 

1993 

Department of the Environment, Toxic Substances Division, Building Research Establishment 

Garston, UK 

TSD/13 

English 

Chlorinated naphtalenes. Properties: There are 75 possible congeners of chlorinated naphtalenes. Commercial products are generally mixtures of several congeners and range from thin liquids to hard waxes to high melting point solids. Their main uses have been in cable insulations, wood preservation, engine oil additives, electroplating masking compounds, capacitors refractive index testing oils and as a feedstock for dye production. Environmental fate. Chlorinated naphthalenes are expected to adsorb onto soil and sediments to a large extent. Predicted soil organic carbon-water partition coefficients show an increase as the degree of chlorination in the chlorinated naphthalene increases. Thus the lower chlorinated congeners are likely to show a moderate sorption tendency and the higher chlorinated congeners are likely to show a strong sorption tendency. However, no soil or sediment adsorption experiments have been reported. Chlorinated naphthalenes have been shown to be highly bioaccumulative in fish, but less so in shrimp and algae. The amount of bioaccumulation observed increases with the degree of chlorination of the chlorinated naphthalenes, but the most highly chlorinated naphthalenes (eg octachloronaphthalene) do not appear to bioaccumulate due to their large size. The octanol-water partition coefficients for chlorinated naphtalenes are high, log Pow range from 3.90 to 6.42. Monochloronaphthalenes appear to be readily degradable by soil and water microorganisms under aerobic conditions. No information was found on the biodegradation of higher chlorinated congeners. One report gave an atmospheric half-life of 2.7 days for 1,4-dichloronaphthalene. No other information was found regarding the atmospheric fate of other chlorinated naphthalenes, although all chlorinated naphthalenes do absorb light at environmentally relevant wavelengths and so direct photolysis reactions may possibly occur in water, air or on soil. Effects on aquatic organisms: Fish. Chlorinated naphthalenes appear to be of moderate acute toxicity to fish. The 96 hour LC50 values for Sheepshead minnow (Cyprinodon variegatus) range from 0.69 to560 mg/l, with the lowest value being recorded for 1-chloronaphthalene. Other aquatic organisms. Chlorinated naphthalenes appear to be of moderate toxicity to algae. Aquatic invertebrates appear to be much more sensitive, showing moderate to high toxicity, with 48 hour LC50 values for Daphnids ranging between 0.82 and530 mg/l. The most sensitive invertebrate tested was the brown shrimp with a 96 hour LC50 of 7.5 ug/l for a mixture of tetra-, penta- and hexachloronaphthalene. Brominated naphtalenes. Properties: There are 75 possible congeners of brominated naphtalenes. There are no known commercial uses for brominated naphtalenes other than a possible use in refractive index testing oils. Fate: 1-Bromonaphtalene has been shown to be degraded by soil bacteria. No other information on the fate of brominated naphtalenes has been found. Effects: Certain brominated naphtalenes appear to be highly toxic to the guinea pig. No information was found on the effects of brominated naphtalenes on aquatic organisms.