title: Validation of trichloroacetic acid exposure via drinking water during pregnancy using a urinary TCAA biomarker.
abstract: Disinfection by-product (DBP) exposure during pregnancy may be related to reduced fetal growth, but the evidence is inconclusive and improved DBP exposure assessment is required. The authors conducted a nested exposure study on a subset (n=39) of pregnant women in the Born in Bradford cohort to assess validity of TCAA exposure assessment based on tap water sampling and self-reported water-use; water-use questionnaire validity; and use of a one-time urinary TCAA biomarker. TCAA levels in urine and home tap water supply were quantified, and water use was measured via a questionnaire and 7-day diary, at 28 weeks gestation. Diary and urine measures were repeated later in pregnancy (n=14). TCAA level in home tap water supply was not correlated with urinary TCAA (0.18, P=0.29). Cold unfiltered tap water intake at home measured by questionnaire was correlated with urinary TCAA (0.44, P=0.007), but correlation was stronger still for cold unfiltered tap water intake reported over the 3 days prior to urine sampling (0.60, P<0.001). For unemployed women TCAA ingestion at home, derived from tap water sampling and self-reported water-use, correlated strongly with urinary TCAA (0.78, P<0.001), but for employed women the correlation was weak (0.31, P=0.20). Results suggest individual tap water intake is most influential in determining TCAA exposure variability in this cohort, and that TCAA ingestion at home is a valid proxy for TCAA exposure for unemployed women but less satisfactory for employed women.
authors.affiliation: MRC-HPA Centre for Environment and Health, Department of Epidemiology and Biostatistics, Imperial College London, London W2 1PG, UK.
authors.forename: Rachel B
authors.initials: RB
authors.lastname: Smith
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Nieuwenhuijsen
authors.forename: John
authors.initials: J
authors.lastname: Wright
authors.forename: Pauline
authors.initials: P
authors.lastname: Raynor
authors.forename: John
authors.initials: J
authors.lastname: Cocker
authors.forename: Kate
authors.initials: K
authors.lastname: Jones
authors.forename: Maria
authors.initials: M
authors.lastname: Kappaostopoulou-Karadanelli
authors.forename: Mireille B
authors.initials: MB
authors.lastname: Toledano
mesh_terms: D015415:Biomarkers / Q000652:urine; D060766:Drinking Water / Q000008:administration & dosage; D004781:Environmental Exposure / Q000032:analysis*; D005260:Female; D006801:Humans; D011247:Pregnancy; D014238:Trichloroacetic Acid / Q000652:urine*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D015415:Biomarkers; D060766:Drinking Water; D014874:Water Pollutants, Chemical; D014238:Trichloroacetic Acid
keywords: BiB; Biomarker; Born in Bradford; CI; Confidence Interval; DBP; Disinfection by-product; Disinfection by-products; Drinking water; Exposure assessment; FMU; First morning urine; HAA; Haloacetic acid; ICC; Intra-class correlation coefficient; Pregnancy; TCAA; THM; Trichloroacetic acid; Trihalomethane