Sampling frequency, location, and reporting limit influence on benchmarking EDC/PPCPs

Abstract

Many water utilities have recently initiated or are considering initiating monitoring programs to establish baseline contaminant concentrations of endocrine‐disrupting compounds (EDCs) and pharmaceuticals/personal care products (PPCPs) in their water supply. Unfortunately, monitoring sites and sampling frequency have often been conducted without regard to end use of the data, loading dynamics, and environmental behavior of trace contaminants. This article provides an a posteriori analysis of more than eight years of monitoring data from Lake Mead, Nev., including more than 80 EDCs/PPCPs to ascertain what effects sample location, sample frequency, and analyte reporting limits have on interpretation of the baseline dataset. The results of this study indicate that, for the Lake Mead dataset, the same general conclusions regarding the mean, median, maximum, and minimum concentrations can be drawn from the complete monthly sample dataset as can be drawn from a two‐year snapshot and/or even quarterly or bimonthly data alone. This finding points to the possible reduction of sampling, campaign frequency, and duration for utilities, although this type of analysis needs to be conducted in other watersheds to determine portability of results.