Sources and Public Perceptions of Contaminants in the Lower Portneuf River Valley: A Case Study for Nitrates and Personal Care Products and Pharmaceuticals by Courtney Alecia Ohr A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in the Department of Geosciences Idaho State University Spring 2016 Use Authorization In presenting this thesis in partial fulfillment of the requirements for an advanced degree at Idaho State University, I agree that the Library shall make it freely available for inspection. I further state that permission to download and/or print my thesis for scholarly purposes may be granted by the Dean of the Graduate School, Dean of my academic division, or by the University Librarian. It is understood that any copying or publication of this thesis for financial gain shall not be allowed without my written permission. Signature ___________________________________ Date _______________________________________ ii Committee Approval To the Graduate Faculty: The members of the committee appointed to examine the thesis of COURTNEY ALECIA OHR find it satisfactory and recommend that it be accepted. _____________________________________________ Sarah E. Godsey, Major Advisor _____________________________________________ John A. Welhan, Committee Member _____________________________________________ Danelle Larson, Committee Member _____________________________________________ Kathleen Lohse, Committee Member ____________________________________________ Dewayne Derryberry, Graduate Faculty Representative iii Table of Contents List of Figures .......................................................................................................................................................... viii List of Tables ............................................................................................................................................................... x List of Equations ....................................................................................................................................................... xi List of Acronyms and Abbreviations ............................................................................................................... xii Abstract ..................................................................................................................................................................... xiii 1 Chapter 1: Introduction ................................................................................................................................ 1 1.1 Motivation ........................................................................................................................................................................ 1 1.2 Broader impacts ............................................................................................................................................................ 2 1.3 Study area ........................................................................................................................................................................ 2 1.3.1 Urban growth ..................................................................................................................................................... 4 1.3.2 Previous studies of the LPRV ...................................................................................................................... 5 1.3.2.1 Private well contamination .............................................................................................................. 5 1.3.2.2 Other known contaminants in the LPRV aquifer .................................................................... 5 1.3.2.3 Recharge ................................................................................................................................................... 6 1.4 Nitrate contamination and legislation in Idaho ............................................................................................... 6 1.5 Background of nitrate in groundwater ................................................................................................................ 7 1.5.1 The nitrogen cycle ............................................................................................................................................ 7 1.5.1.1 Fixation ..................................................................................................................................................... 8 1.5.1.2 Nitrification ............................................................................................................................................. 8 1.5.1.3 Denitrification ........................................................................................................................................ 9 1.5.1.4 N leaching in groundwater ............................................................................................................... 9 1.6 The impact of ex-urban development on PPCPs and the nitrogen cycle ................................................. 9 1.6.1 Septic systems influence on nitrate in groundwater ...................................................................... 11 1.7 Geochemical tracers that can determine sources of nitrate-N ................................................................. 11 1.7.1 Isotopes .............................................................................................................................................................. 11 1.7.1.1 Fingerprinting techniques using 15N and 18O from NO3-N .......................................... 11 1.7.1.2 Using 18O, 2H from well water to interpret groundwater recharge sources ...... 14 1.7.2 Pharmaceuticals and personal care products ................................................................................... 15 1.8 Health effects of nitrate and PPCP contamination ........................................................................................ 18 1.9 Water quality as an ecosystem service ............................................................................................................... 19 1.10 Thesis organization and objectives ................................................................................................................ 20 1.10.1 Chapter 1 ...................................................................................................................................................... 20 1.10.2 Chapter 2 ...................................................................................................................................................... 20 1.10.3 Chapter 3 ...................................................................................................................................................... 20 iv 1.10.4 Chapter 4 ...................................................................................................................................................... 21 References .................................................................................................................................................................................. 22 2 Chapter 2: Sources and patterns of drinking water contamination in the LPRV ................. 31 Abstract ...................................................................................................................................................................................... 31 2.1 Introduction .................................................................................................................................................................. 31 2.2 Study Area ...................................................................................................................................................................... 33 2.3 Methods ........................................................................................................................................................................... 35 2.3.1 Previous sampling campaigns and data ............................................................................................... 35 2.3.2 Sampling methods ......................................................................................................................................... 36 2.3.2.1 Field sampling plan ........................................................................................................................... 36 2.3.2.2 Field sampling methods .................................................................................................................. 39 2.3.3 Lab sample processing and analysis ...................................................................................................... 42 2.3.3.1 Sample pre-processing ..................................................................................................................... 42 2.3.3.2 Geochemistry for nitrate and groundwater analysis.......................................................... 43 2.3.3.3 Emerging Contaminants .................................................................................................................. 43 2.3.4 Statistical and isotopic data analysis ..................................................................................................... 44 2.3.4.1 Temporal trend of nitrate-N concentrations ......................................................................... 44 2.3.4.2