Table 2.

Key Features of the 2006 DBP Toxicological Review (External Peer Review Draft)

Features	Summary
Epidemiology Data	Six observational studies reviewed Phthalate metabolites in ejaculate, urine or breast milk were associated with semen and sperm quality in adults, anogenital distance in male infants, and levels of reproductive hormones in infants
Toxicology Data	40 studies covering acute, sub-chronic and chronic exposure durations and multiple test species (rat, mouse, rabbit) Outcomes observed in categories of reproductive performance, male reproductive development, histopathological changes in adult testis and liver
Toxicokinetics	Toxicokinetics are well understood in animals and several models exist; MBP identified as the proposed toxic metabolite
Sensitive Populations/Life Stages	Defined as developing (male) fetus
RfD Derivation	Animal study (Lehmann et al. 2004) showing decreased testosterone in fetal testis with maternal exposure to DBP 30 mg/kg-d defined as NOAEL UFs at 100, no database deficiency UF RfD proposed at 0.3 mg/kg-d

Abbreviations: DBP, di-butyl phthalate; MBP, monobutyl phthalate; mg/kg-d, milligram per kilogram per day; NOAEL, no-observed adverse effect level; RfD, reference dose; UF, uncertainty factor.