- 128.2 g/mol
- Polycyclic aromatic hydrocarbons (PAH)
Compound properties list
|Melting/boiling point|| 80 °C||Solid|
|Relative density||1.14 g/cm3||Sinks in water|
|Vapour pressure||0.1 mm Hg||Low volatility|
|Vapour density||4.4||Denser than air|
|Solubility in water||32 mg/L||Low solubility|
|Henry's law constant||5 x 10-4 atm·m3/mol||Moderate volatilization when dissolved|
|log Koc (Depending on soil or sediment characteristics)||2.7 - 5.0*||Strong adsorption to organic matter|
At 20 0C, naphthalene is a solid with low volatility. Characterized by its low solubility,
it will moderately volatilize once dissolved and adsorbs strongly to organic matter. When present in
soil, this compound will undergo light volatilization and solubilize slowly. Once dissolved, it will
either enter into the groundwater table or migrate towards a waterway, where it will be diluted
before partially volatilizing. Fragments of naphthalene can also be carried into a waterway where
they will deposit at the bottom and slowly dissolve. Once the source has been removed, the adsorbed
naphthalene will take a long some time to disappear, being released in its gaseous or dissolved
forms. The resulting plumes (gaseous or dissolved) will be relatively small in size.
Naphthalene should be handled with care, as it is toxic and flammable.
Naphthalene is a polycyclic aromatic hydrocarbon (PAH). PAHs are a group of organic
compounds that contain two or more benzene rings in their structure. There are more than 100
different PAHs that generally occur as complex mixtures (example, combustion by-products such as soot).
Incomplete combustion of fuels in engines, during coal coking, or when wood is burning (forest
fires, wood stoves) produces PAHs. PAHs are also constituents of petroleum and coal, and they are
more present in some of their derivatives like tars and asphalt. The wood preservative industry
(example, creosote), aluminum smelters using Soderberg electrodes, and hazardous waste disposal sites
are further contributors of anthropogenic PAHs to the environment.
Naphthalene is produced industrially in large amounts from either coal tar (which contains
approximately 10% naphthalene) or petroleum hydrocarbons. The principal use of naphthalene (over
60%) is in the production of phthalic anhydride, which is an intermediate in the production of
phthalate plasticizers (used in different polymers and resins like polyvinyl chloride, polyurethane,
and rubbers), insect repellents, pharmaceuticals and other materials. Naphthalene has also been used
in the production of surfactants (naphthalene sulfonates and derivatives used in paint, dye, and
paper-coating formulations), naphthalene derivatives (example, decalin), some insecticides, moth
repellents, explosives, fuel additives, corrosion inhibitors, and driveway sealants formulations.
Naphthalene is also found mixed with other PAHs in commercial products like coal tar, coal tar
pitch, creosote and bitumen and asphalt. Naphthalene is no longer used directly in tanneries, in the
textile industry, or in the production of beta-naphthol and toilet bowl deodorizers.
Agency for Toxic Substances and Disease Registry (ATSDR). 2005. Toxicological
Profile for Naphthalene, 1-Methylnaphthalene, and 2-Methylnaphthalene. U.S. Department of Health
and Human Services, Public Health Service, Georgia, USA. (Viewed December 2013)
Canadian Council of Ministers of the Environment. 1999. Canadian Water Quality Guidelines for
the Protection of Aquatic Life: Polycyclic Aromatic Hydrocarbons (PAHs). In: Canadian
Environmental Quality Guidelines. Canadian Council of Ministers of the Environment, Manitoba,
(Viewed December 2013)
Montgomery, John H. 2007. Groundwater Chemicals, Desk Reference, Fourth Edition, CRC
Press, Taylor and Francis Group, Florida, USA.
National Toxicology Program. 2005. Report on Carcinogens, Twelfth Edition: Substance Profile
of Polycyclic Aromatic Hydrocarbons. U.S. Department of Health and Human Services, Public Health
Services, USA.(PDF, 142KB) (Viewed December 2013)