Levels of haloacetic acids in tap water in an urban Australian city and its relevance to autosomal dominant polycystic kidney disease

Abstract

To the Editor: Subjects with autosomal dominant polycystic kidney disease (ADPKD, stages 1–3) are advised to maintain a high intake of fluids,1 preferably as tap water. Chlorination of tap water is an essential disinfection process, but by-products of this procedure include haloacetic acids (HAAs).2 In developed nations, HAAs in tap water are routinely monitored by regulatory authorities and are below those associated with adverse health effects (e.g., 0.1 mg/l for dichloroacetic acid, DCA).2 However, it has been suggested that ADPKD patients use a filtration device to remove HAAs when consuming tap water, on the basis of evidence showing that cystic renal disease was exacerbated in male PCK rats receiving low doses (relative for rodents) of DCA in drinking water (75 mg/l) for 4 weeks.3 These data led us to measure HAAs in tap water (drawn from two public areas in western Sydney), and determine whether a commercially available water bottle, fitted with a NSF-42-compliant carbon filter, reduces the levels of HAAs.4 As shown in Table 1, HAA levels in unfiltered tap water were low, with five of the six HAA species measured being below the limit of the assay detection (0.01 mg/l). Furthermore, although tricholoracetic acid concentrations were lowered in filtered tap water, the pre-filtration levels were already ~5 × below the acceptable limit of 0.1 mg/l. Therefore, HAAs in unfiltered tap water in western Sydney are present in concentrations that are well below the acceptable limit in healthy individuals, but the chronic effect of low levels of HAAs (if any) on cystic renal disease requires further study.