
Growing scientific evidence suggests that for many chemicals a greater risk may be posed when those same chemicals are emitted from residential water sources and then inhaled, i.e., relative to risks by ingestion. This presentation will address the potential for human inhalation exposure to volatile organic compounds released during ordinary residential water usage. In particular, a previously unexplored source of such emissions will be described: formation and gaseous release following the use of chlorine-containing dishwasher detergents. Mass balances were performed by collecting liquid and gas samples in a residential dishwasher located in a source chamber at the University of Texas at Austin. Peak liquid chloroform concentrations in the dishwasher were often two orders magnitude greater than levels originally in the drinking water. Typical chloroform concentrations in the dishwasher headspace were between 1 and 10 mg/m3. Mathematical models were employed to assess various sources of human exposure to chloroform in homes. Inhalation exposure from dishwasher usage alone was estimated to be similar to ingestion exposure.