IngentaConnect CANCER RISK ASSOCIATED WITH HOUSEHOLD EXPOSURE TO CHLOROFORM

Authors: Lévesque B.¹; Ayotte P.¹; Tardif R.²; Ferron L.³; Gingras S.⁴; Schlouch E.²; Gingras G.³; Levallois P.¹; Dewailly É.¹

Source: Journal of Toxicology and Environmental Health Part A, Volume 65, Number 7, 1 April 2002 , pp. 489-502(14)

Publisher: Taylor and Francis Ltd

Abstract:

Chloroform (CHCl₃), the trihalomethane most prevalent in drinking water, is a proven animal carcinogen and a suspected human carcinogen. Consequently, standards have been issued by health authorities to limit its concentration in drinking water. These limits are based solely on ingestion, without taking into account inhalation and skin contact. Exposure to CHCl₃ was assessed for 18 men (age: mean 38 years; range 23-51) following a 10-min shower in their respective residences located in the Quebec City region (Canada). CHCl₃ concentration was measured in alveolar air samples collected before, immediately after, and 15 min and 30 min following the shower. Indoor air and water concentrations were determined concomitantly. Mean CHCl₃ concentrations in the air of the shower stall and in water were respectively 147 µg/m³ (SD = 56.2 µg/m³) and 20.1 µg/L (SD = 9.0 µg/L). Water concentrations were comparable to those documented in a large proportion of distribution networks in Canada. The mean increase in alveolar air CHCl concentration ( Delta

CHCl₃ALV) at the end of the shower was 33 µg/m³ (SD = 14.7 µg/m³). A multiple-regression analysis revealed that Delta

CHCl₃ALV values were only associated with chloroform concentration in air of the shower stall. Delta

CHCl₃ALV were described using a physiologically based pharmacokinetic (PBPK) model. This model was then used to estimate concentrations of CHCl₃ metabolites bound to liver and kidney macromolecules following a shower, and also according to exposure scenarios that integrate drinking-water ingestion and air inhalation. The concentration predicted in the liver following a worst-case exposure scenario was 0.41 µg CHCl₃ equivalents/kg of tissue, some 6000 times lower than the lowest concentration that did not increase the incidence of hepatic tumors in laboratory animals. Data indicate that for this range of exposure the safety margin appears therefore considerable with respect to the potential carcinogenic effect of household exposure to CHCl₃.

Language: English

Document Type: Research article

Affiliations: 1: Unité de recherche en santé publique, Centre Hospitalier Universitaire de Québec, Beauport, Québec, and Département de médecine sociale et préventive, Faculté de médecine, Université Laval, Ste-Foy, Québec, Canada 2: Département de médecine du travail et d'hygiène du milieu, Université de Montréal, Montréal, Québec, Canada 3: Centre de Toxicologie du Québec, Ste-Foy, Québec, Canada 4: Unité de recherche en santé publique, Centre Hospitalier Universitaire de Québec, Beauport, Québec, Canada

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