In vitro bioacessibility and transport across Caco-2 monolayers of haloacetic acids in drinking water

• Published in: Chemosphere (Oxford) 2016-10, Vol.161, p.19-26
• Main Authors: Melo, A., Faria, M.A., Pinto, E., Mansilha, C., Ferreira, I.M.P.L.V.O.
• Format: Article
• Language: English
• Subjects: Acetates - analysis; Acetates - metabolism; Bioavailability; Caco-2 Cells; Cell Membrane Permeability - drug effects; Dichloroacetic Acid - analysis; Dichloroacetic Acid - metabolism; Disinfection; Drinking Water - chemistry; Drinking Water - standards; Haloacetic acids; Humans; In vitro digestion; LC-MS/MS; Tandem Mass Spectrometry; Tap water; TCAA; Trichloroacetic Acid - analysis; Trichloroacetic Acid - metabolism; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - metabolism; Water Purification - methods; Water Supply
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2016.06.088

Water disinfection plays a crucial role in water safety but it is also a matter of concern as the use of disinfectants promotes the formation of disinfection by-products (DBPs). Haloacetic acids (HAAs) are one of the major classes of DBPs since they are frequently found in treated water, are ubiquitous, pervasive and have high water solubility, so a great concern emerged about their formation, occurrence and toxicity. Exposure to HAAs is influenced by consumption patterns and diet of individuals thus their bioavailability is an important parameter to the overall toxicity. In the current study the bioacessibility of the most representative HAAs (chloroacetic acid – MCAA, bromoacetic acid – MBAA, dichloroacetic acid – DCAA, dibromoacetic acid – DBAA, and trichloroacetic acid – TCAA) after simulated in vitro digestion (SIVD) in tap water and transport across Caco-2 monolayers was evaluated. Compounds were monitored in 8 points throughout the digestion phases by an optimized LC-MS/MS methodology. MCAA and MBAA were not bioaccessible after SIVD whereas DCAA, DBAA and TCAA are highly bioaccessible (85 ± 4%, 97 ± 4% and 106 ± 7% respectively). Concerning transport assays, DCAA and DBAA were highly permeable throughout the Caco-2 monolayer (apparent permeability and calculated fraction absorbed of 13.62 × 10−6 cm/s and 90% for DCAA; and 8.82 × 10−6 cm/s and 84% for DBAA), whereas TCAA showed no relevant permeability. The present results may contribute to efficient risk analysis studies concerning HAAs oral exposure from tap water taking into account the different biological behaviour of these chemically similar substances. [Display omitted] •Bioaccessibility and transport in Caco-2 monolayers was assessed for 5 HAAs.•Monohaloacids (MCAA and MBAA) are not bioaccessible after simulated digestion.•Dihaloacids (DCAA and DBAA) and trihaloacids (TCAA) are highly bioaccessible (>85%).•Dihaloacids (DCAA and DBAA) were highly permeable throughout the Caco-2 monolayer.•TCAA showed no relevant permeability trough Caco-2 monolayers.