Optical signals of water for prediction of wastewater contamination, human-associated bacteria, and fecal indicator bacteria in surface water of Great Lake tributaries from 2011 to 2016

Publication Date

2021-09-13

Start Date

2011-02-16

End Date

2016-06-09

DeCicco, L.A., Corsi, S.R., Hansen, A.M., Lenaker, P.L., Bergamaschi, B.A., and Pellerin, B.A., 2021, Optical signals of water for prediction of wastewater contamination, human-associated bacteria, and fecal indicator bacteria in surface water of Great Lake tributaries from 2011 to 2016: U.S. Geological Survey data release, https://doi.org/10.5066/P9I0SPDQ.

Type: Related Primary Publication

Water samples were collected to explore the optical properties of dissolved organic matter (DOM) in environmental water samples from tributaries of the Great Lakes at three different drainage basin scales. A fraction of the organic compounds included in natural organic matter and anthropogenic substances interact with light, which allows them to be measured by absorbance and fluorescence methods. The extent to which light of a particular wavelength interacts with the organic material reflects the intrinsic chemical composition of the organic material, and thereby provides information about its source and the source of the water carrying it. Data was used to explore relationships between optical properties (explanatory variables) and human-associated and fecal indicator bacteria concentrations (response variables). The purpose of exploring these relationships was to investigate which optical signals could be used to estimate wastewater prevalence in environmental waters using real-time in-situ field sensors. Explanatory variable selection for these regressions was done in two stages: (1) optical properties measured in the laboratory that represent signals available in current field sensors were considered. (2) explanatory variables were expanded to additional optical signals and variables that were derived from optical properties. These included direct fluorescence or absorbance at specific wavelengths, means of fluorescence or absorbance over specified bandwidths, ratios of these variables, spectral slopes determined as the slope of the absorbance curve over specified wavelengths in exponential space, and several optical indices that have been used in previous research. Given the potential for seasonality in DOM composition in streams, seasonal variables (sine and cosine of julian day/(2π)) were used to develop interaction terms with optical signals. Optical signals that represent signals available in current field sensors included F (often referred to as fDOM or CDOM) and T (often referred to as tryptophan-like fluorescence) as well as turbidity.

• USGS Data Release Products
• Upper Midwest Water Science Center