ASSESSMENT OF ENVIRONMENTAL HAZARDS OF 1,3,5-TRINITROBENZENE

The remedial investigation/feasibility studies conducted at certain Ar my installations showed a need to clean up contaminated sites, where h igh levels of ammunition chemicals such as 2,4,6-trinitrotoluene (TNT) , 1,3,5-trinitrobenzene (TNB), 1,3-dinitrobenzene (DNB), and their deg radation products/metabolites were detected in surface soil and ground water. TNB is a photodegradation product of TNT; it is not easily degr aded, and persists in the environment. The toxicity data on TNB are sc anty. Hence the U.S. Environmental Protection Agency in 1988 (U.S. EPA , 1997) developed a reference dose (RfD) for TNB (0.00005 mg/kg/d for chronic toxicity) based on the toxicity of DNB, which is structurally similar to TNB. Since then we have completed acute, subacute, subchron ic, chronic, reproductive, and developmental toxicity studies and toxi cokinetics studies. We have reviewed the mammalian toxicity data for T NB and have determined the no observed adverse effect levels (NOAEL) a nd low observed adverse effect levels (LOAEL) for subchronic, chronic, reproductive, and developmental toxicity. Based on the newly determin ed NOAEL and LOAEL values, we have now developed a new RfD for TNB (0. 03 mg/kg/d), based on the chronic toxic effects on hematology and hist opathological changes in testes and kidney.