Dichlorinated Benzenes (1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4- dichlorobenzene) Cas No. 106-46-7, 541-73-1, 395-50-1

Dichlorinated Benzenes

(1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-

dichlorobenzene)

Cas No. 106-46-7, 541-73-1, 395-50-1

Potential sources and exposures

The major route of human exposure to the dichlorobenzenes is inhalation of

indoor and outdoor air. These compounds are used as room fresheners, moth

repellents, fumigants, and cleaners.

Physical and chemical properties (for 1,4-dichlorobenzene)

Value

Property

Molecular weight

147.01 g/mole

79 mg/l at 25 oC

Water solubility

1.76 mm Hg at 25 oC

Vapor pressure

log Kow

3.52

1.5 10-3 atm-m3/mol at 20 oC

Henry's Law Constant

Toxicity

Short-term inhalation exposures to high concentrations of the

dichlorobenzenes in humans may result in depression of the central nervous

system. The major toxicological effects of inhalation of the dichlorobenzenes are

injury to the liver and kidneys. However, it is highly unlikely that exposure

concentrations to the general public are high enough to elicit these effects.

The oral RfD for 1,2-dichlorobenzene is based on the NOAEL and LOAEL

achieved in chronic and subchronic studies in which rats and mice were given

the compound by oral gavage. 1,2-dichlorobenzene is classified as a group D

carcinogen.

1,4-dichlorobenzene has caused renal tumors in mice and is presently

classified as a group B2 carcinogen. The cancer potency factor that was derived

from this study is under review by USEPA Health Effect Assessment Summary

Tables (HEAST) (1992) and has not been included in the IRIS database.

Toxicokinetics

Quantitative studies on the absorption of the dichlorobenzenes are

unavailable. However, available data on 1,4-dichlorobenzene itself show that

about 20 percent was absorbed via inhalation during a 3-hr exposure period

D34

Appendix D Toxicological Profiles