U.S. Department of the Interior U.S. Geological Survey Integrated Water-Quality Assessment using Conventional, Passive-Sampling, and Metabolic Assay Techniques: Approaching System-Level Understanding of Risk Valerie Kelly and Kathy McCarthy U.S. Geological Survey Oregon Water Science Center, Portland OR

Drinking Water Source Protection  Typically focused on identifying conditions associated with mobilization of contaminants  Based on discrete samples  Storm runoff  Land use sources—measure effect of spatial scale within river basin  What is missing?  Occurrence of chemicals across range of temporal scale  Synergistic effect of multiple chemicals, often not measured or detectable

Evaluating an Integrated Approach  McKenzie River  High quality drinking water source for City of Eugene, supplied by Eugene Water & electric Board (EWEB)  Data from USGS reconnaissance study to characterize potential threats  Incorporates storm runoff samples, long-term deployment of passive samplers, and metabolic assay

McKenzie River: a complex system  Elements of system—individual chemicals and their origins  Occur across a range of sources and temporal scale  Acute storm concentrations versus chronic long-term concentrations  Interconnections within system—conditions that mobilize and transport chemicals  Land use activities interacting with climatic factors  Function of system—describes behavior, many aspects to consider  Relative to threat assessment: what is detrimental effect of chemical mixture?

Overview of Sampling Methods—Sites Three sites: two tributaries and McKenzie River intake Three time periods: fall 2007 and early/late spring 2010 McKenzie River Cedar Creek Camp Creek Willamette River Drinking water intake City of Springfield/Eugene

Overview of Sampling Methods  Discrete samples: analyzed for pesticides, pharmaceuticals (N=176)  Passive samples: analyzed for pesticides, PAHs, PCBs, WWI (N=159)  sequester chemicals into sorbent over 30 days  Metabolic assay: yeast estrogen screen (conducted on passive sampler extracts)

Influence of Land Use

Results for Three Sets of Samples— Elements of System Number of detections

Results—Looking More Closely at Late Spring 2010

Concentrations Measured in Late Spring 2010 ng/L

Interconnections— Influence of Climate and Flow Conditions  Discrete samples associated with rain event and rising hydrograph, following a mix of spring storm events  Passive sample deployment period included multiple (small) storm events Discrete sample collected Discrete samples collected Daily precipitation at Springfield City Hall Mean daily streamflow in Cedar Creek Passive sample deployment Passive sample deployment

System Function/Behavior—One Measure  Yeast estrogen screen assay  Measures estrogenic activity  Presumed to be due to combined (synergistic) effect of endocrine disrupting compounds  Measurable in Cedar Creek but not in Camp Creek or in McKenzie River at treatment plant intake  Two replicates: 0.35 and 0.43 ng/L  Associated with detections of six potential endocrine disrupting compounds in passive sample, none in discrete sample

What Have We Learned?  Chemicals are present during discrete runoff events that are not detectable over longer-scale measurements  Implies very short term occurrence  Limited effect on McKenzie River  Chemicals accumulate over longer-scale periods at concentrations orders of magnitude below conventional analytical techniques  Lots going on under the conventional radar screen  Present no recognized threat as individual chemicals  Potential estrogenic activity seems to be significantly associated with strong urban signature  Other data document persistent occurrence of pesticides in stormwater discharging to Cedar Creek  Suggests synergistic effect of multiple compounds  Not detected in McKenzie River  We know very little about this issue

Might These Data Be Relevant Elsewhere?  Collecting data over range of scale—including spatial and temporal—provides a more comprehensive view on chemical occurrence  Could be expanded to include other river basins  Including metabolic assay provides a relevant measure of effect of chemical mixtures  Could be useful to compare relative to quantified mixtures of chemicals across range of systems  Great potential for collaboration among drinking water providers  USGS forming Oregon Drinking-Water Providers Science Partnership

Acknowledgements  Study funded by U.S. Geological Survey in cooperation with Eugene Water & Electric Board