Aims: To measure accurately urinary elimination half life of trichloroacetic acid (TCAA). Methods: A longitudinal pilot exposure/intervention study measured the elimination half life of TCAA in urine. Beverage consumption was limited to a public water supply and bottled water of known TCAA concentration, and ingestion volume was managed. The five participants limited fluid consumption to only the water provided. Consumption journals were kept by each participant and their daily first morning urine (FMU) samples were analysed for TCAA and creatinine. TCAA elimination half life curves were generated from a two week washout period using TCAA-free bottled water. Results: Individual elimination half lives ranged from 2.1 to 6.3 days, for single compartment exponential decay, the model which fit the data. Conclusion: Urinary TCAA is persistent enough to be viable as a biomarker of medium term (days) exposure to drinking water TCAA ingestion within a range of realistic concentrations.C hlorinated disinfection by-products (DBPs) in drinking water pose a challenge to the epidemiological study of both cancer and adverse reproductive outcomes. 1 Reviews of evidence on adverse reproductive outcomes have consistently cited a major need to improve individual exposure assessment. 1-3 Biomarkers have been suggested as the potential ''gold standard'' for achieving this improvement, 3 and their development and validation has been recommended. 1 Of the many DBPs that are present in chlorinated waters, the trihalomethanes (THMs) and haloacetic acids (HAAs) are the major DBPs. Consequently, these classes of DBPs have received the most attention as potential biomarkers of exposure for DBPs. Initial work by Weisel and co-workers 4 and limited pharmacokinetic literature 5 6 showed promise for trichloroacetic acid (TCAA) for integrating medium term exposure to drinking water DBPs. We previously performed a longitudinal pilot study to measure the urinary elimination half life of TCAA. 7 Limitations in that study design indicated the need for a better controlled study to provide greater confidence in the human TCAA elimination kinetics. METHODS Volunteer recruitmentVolunteers from Edmonton, herein referred to as City A, were sought for participation in the study. Five volunteers in total, three males (ages 27, 37, 52) and two females (ages 28, 29), were recruited. All of the volunteers were either students or staff from our research group. The Health Ethics Research Board of the University of Alberta approved the study protocol, and we obtained informed written consent from participants at enrolment in the trial. Study designDrinking water in City A had very low levels of TCAA (5-20 mg/l); therefore, water was imported from another city (referred to as City B) with higher TCAA (50-180 mg/l).This study was designed to measure the half life of urinary elimination for TCAA. Participants consumed normal tap water from City B for two weeks and then switched to TCAAfree bottled water for two weeks. Bottled water was obtained from the Sierra Spr...

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Objective:Hypertensive disorders of pregnancy are leading causes of maternal and perinatal morbidity and mortality. Automated blood pressure (BP) measurements are being used in clinical practice; however, understanding of how oscillometric waveform vary between pregnant and non-pregnant individuals remains low.Design and Methods:Pregnant individuals over 20 weeks gestational age and healthy, non-pregnant women were recruited. Healthy, non-pregnant women (HNP) were matched to healthy pregnant women (HP), and pregnant women with a hypertensive disorder of pregnancy (HDP) by age (± 10 years), arm circumference (± 6 cm), and BMI at the time of BP measurement (± 13 kg/m2). There were seven individuals in each group for a total of 21 participants. BP measurements were done per the International Organization for Standardization (ISO) protocol using a custom-built oscillometric device as the test device and 2-observer mercury auscultation as the reference measurement. Four pairs of auscultatory measurements and four oscillometric measurements were obtained for each participant. Baseline demographics, auscultatory BP and BP derived from slope-based and fixed ratio algorithms were determined. Oscillometric waveform and envelope features were compared among groups.Results:In HNP, HP, and HDP groups respectively: mean age was 31.3 ± 4.8; 32.1 ± 3.6; 32.0 ± 4.4 years; arm circumference 31.9 ± 3.3; 32.3 ± 4.9; 34.0 ± 3.3 cm; BMI 26.8 ± 3.8; 32.0 ± 7.2; 32.4 ± 3.7 kg/m2; mean auscultatory BP (systolic/diastolic) 103.3 ± 11.1/66.5 ± 7.4; 110.6 ± 4.0/56.9 ± 6.5; 132.6 ± 19.0/83.9 ± 13.3 mmHg. HDP had significantly higher auscultatory systolic (P < 0.05) and diastolic (p < 0.01) BP than the other groups. The pregnant groups (HP, HDP) had significantly higher heart rate (p < 0.01); higher pulses (p < 0.05) in the oscillometric waveform (OMV); lower average width in the pulses (p < 0.01); higher pressure amplitude at which the OMW peaks (p < 0.05) with longer time to reach this maximum pressure amplitude (p < 0.05); greater area under the curve (p < 0.01). Compared to HNP, the HDP showed significantly skewed OMW to the right (p < 0.01); greater spread in the OMW envelope (p < 0.05) and lesser random variation in the OMW envelope (p < 0.01). A typical OMV with the 3 groups superimposed is demonstrated in Figure 1.Conclusion:Significant differences in the oscillometric waveform morphology and parameters were found in pregnancy and in hypertensive disorders of pregnancy compared to healthy controls. These results suggest that pregnancy-specific algorithms may be required to optimize accuracy for oscillometric BP measurement.Figure 1Healthy non-pregnant, healthy pregnant, and pregnant with a hypertensive disorder of pregnancy oscillometric waveforms superimposed.

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