Temporal Variability in Diet and Urinary Concentrations of Pyrethroid and Organophosphate Pesticide Metabolites in Adult Volunteers From a Large U.S. City

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P-354 Introduction: We are investigating the validity of using urinary biomarkers to estimate dietary exposures to pyrethroid and organophosphate pesticides in a pilot sample of adult volunteers (n = 11) from a large urban area of the United States. This information is needed to help determine the most accurate way of measuring exposures to non-persistent pesticides among the general adult population. Methods: We collected four consecutive days of duplicate diet samples and 10 spot urine samples from each subject. First morning void and before bedtime spot urine samples were collected on each day of diet sampling. Additional spot urines were collected the night before the first day of diet sampling and the morning after the last day of diet sampling. Detailed diet information including food description, organic status, preparation details (e.g. raw vs. cooked, peeled vs. unpeeled, etc.) and weight (in grams) was collected for each item consumed over the four-day sampling period. The four-day protocol was repeated twice for each subject, once in summer (July–October 2005) and once in winter (January–March 2006), to examine seasonal differences. Urine samples are currently being analyzed for selected pyrethroid and organophosphate metabolites while method development is underway for quantifying parent pesticide residues in the duplicate diet samples. Results: We present findings on intra- and inter-subject variability in urinary metabolite concentrations across the four-day sampling period, and across the summer and winter sampling cycles. We also present results of multivariate longitudinal regression analyses to determine which food items are most significantly associated with urinary metabolite concentrations among subjects in our pilot sample. Discussion/conclusions: This is the first study we know of to date to measure food intake and urinary pyrethroid and organophosphate metabolites in a multi-day longitudinal sample of non-occupationally exposed adults. For food intakes showing no association, alternative strategies for measuring dietary exposure to non-persistent pesticides must be considered. For those displaying significant association, urinary levels offer a valid tool for estimating dietary exposures among similar adult populations. This study will also provide important reference data on short-term temporal variability in urinary pyrethroid and organophosphate metabolite concentrations among U.S. adults.