| Summary: | <p>Endocrine disrupting compounds (EDCs) from agricultural, industrial, and municipal sources can be found in many surface waters with potential adverse implications for human and ecosystem health. The South Platte River represents a significant source of water for the Denver Metro Area, yet little data exists concerning EDCs. The aim of this study is to evaluate the occurrence and effects of EDCs downstream from two major wastewater treatment plants (WWTPs). This study characterizes the estrogenicity gradient of the South Platte River in the Denver Metro area by combining data from qPCR analysis for liver vitellogenin (<i>vtg</i>) mRNA with liver NMR metabolomics after a 5 day in situ caged exposure of fathead minnows. Concurrent water samples collected from the start and end times of the exposures were used to determine the occurrence and concentration of wastewater contaminants. Results found 68 of 122 chemicals downstream of WWTP 1 and 73 downstream of WWTP 2, including known EDCs (e.g. nonylphenol and octylphenol). A steroidal estrogen, estrone, was only found downstream of WWTP 2. Consistent with the highest measured concentrations of wastewater estrogens, the highest levels of <i>vtg</i> mRNA were measured downstream of WWTP 2. Metabolomics data coincided with <i>vtg </i> data and showed little variation except downstream of WWTP 2, where male polar metabolomes showed increased levels of alanine and glutamate, which are utilized in VTG synthesis. PCA of male polar metabolomes showed significant separation of WWTP 2 from WWTP 1 and the reference site, further supported by PLS-DA scores plot. Female polar metabolomes showed significant separation between WWTP 1 and WWTP 2 using PLS-DA scores plot. This study demonstrates that qPCR and metabolomics data can be reliably and concurrently used to illuminate impacts from chemical exposures, although further research will better elucidate target genes and metabolites of interest. </p>
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