Gasoline-contaminated ground water as a source of residential benzene exposure: a case study.

In a private residence using gasoline-contaminated ground water (approximately 300 micrograms/l benzene), a series of experiments were performed to assess the potential benzene exposures that may occur in the shower stall, bathroom, master bedroom, and living room as a result of a single 20-min, shower. Integrated fixed site SUMMA TM-polished canister and Tenax GC air samples were collected in the target microenvironments over 20, 60, and 240 min. periods. These results were compared with the long-term personal Tenax GC samples (6 h) and grab samples collected with glass, gas-tight syringes at 0, 10, 18, 20, 25, 25.5, and 30 min. Maximum benzene concentrations occurred in the shower stall (758-1670 micrograms/m3) and bathroom (366-498 micrograms/m3) during and immediately after the shower. Inhalation exposures in the shower stall during the 20-min. shower were 2.1-4.9 times higher than corresponding 20-min, bathroom exposures. The total benzene dose resulting from the shower was estimated to be approximately 281 micrograms, with 40% via inhalation and 60% via the dermal pathway. This total is 2 to 3.5 times higher than the mean inhalation dose received during a concurrent 6 h occupation of the house. These results indicate that domestic use of gasoline-contaminated water can produce relatively high benzene exposures that vary significantly according to an individual's proximity to the water use zone. The information in this document has been funded wholly or in part by the U.S. Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. The entire experiment was reviewed and approved by the Research Triangle Institute Human Subjects Review Committee.