Human respiratory uptake of chloroform and haloketones during showering

Abstract

Inhalation is an important exposure route for volatile water contaminants, including disinfection by-products (DBPs). A controlled human study was conducted on six subjects to determine the respiratory uptake of haloketones (HKs) and chloroform, a reference compound, during showering. Breath and air concentrations of the DBPs were measured using gas chromatography and electron capture detector during and following the inhalation exposures. A lower percentage of the HKs (10%) is released from shower water to air than that of chloroform (56%) under the experiment conditions due to the lower volatility of the HKs. Breath concentrations of the DBPs were elevated during the inhalation exposure, while breath concentrations decreased rapidly after the exposure. Approximately 85-90% of the inhaled HKs were absorbed, whereas only 70% of the inhaled chloroform was absorbed for the experiment conditions used. The respiratory uptake of the DBPs was estimated using a linear one-compartment model coupled with a plug flow stream model for the shower system. The internal dose of chloroform normalized to its water concentration was approximately four times that of the HKs after a 30-min inhalation exposure. Approximately 0.3-0.4% of the absorbed HKs and 2-9% of the absorbed chloroform were expired through lung excretion after the 30-min exposure. The inhalation exposure from a typical 10-15 min shower contributes significantly to the total dose for chloroform in chlorinated drinking water but only to a moderate extent for HKs.

DNA methylation levels and long-term trihalomethane exposure in drinking water: an epigenome-wide association study

“…Given the different molecular weights and polarity of the DBPs, potential exposure routes include not only ingestion but also inhalation and/or dermal absorption during showering and water related activities (cleaning, swimming, flushing the toilet, etc.). [37][38][39][40][41] These routes, plus the subject water handling and consumption behaviors, may produce differential internal doses and partially explain why subjects apparently exposed to similar THM levels had a wide range of changes in DNA methylation levels in our sample. Exposure misclassification due to unaccounted nonresidential exposure (e.g., workplace) is expected to be low, only affecting the ingested THM fraction.…”

Safe Drinking Water? Effect of Wastewater Inputs and Source Water Impairment and Implications for Water Reuse

“…THMs, HAAs, and haloketones have been measured in human blood, urine, or exhaled breath after showering, bathing, or swimming [131,133,135,136,142,143,146,149]. Inhalation can sometimes give much higher exposure to volatile chemicals.…”

Transdermal drug delivery by coated microneedles: geometry effects on drug concentration in blood

“…One assumption that is being made for the above model is that the drug distribution and concentration equilibrium occur rapidly. [35] It is therefore adequate to describe the pharmacokinetics of drugs that minimally distribute into the body's tissue. [36] As 240 mentioned earlier, the one-compartment model has been used in this paper where we apply the values for the volume of distribution (V b ) and the elimination rate constant (K e ) obtained from literature for insulin.…”