Dr. Holsen's research interests include the sources, transport, transformations and fate of hydrophobic organic chemicals including emerging contaminants and metals including mercury in a wide array of environmental systems including the Adirondacks and the Great Lakes. Of particular interest is pollutant exchange (wet deposition, dry deposition and air-surface/air-water exchange) between earth's surface and the atmosphere.

Current Projects:

The Great Lakes Fish Monitoring and Surveillance Program: Expanding the Boundaries. In the Great Lakes Fish Monitoring and Surveillance Program (GLFMSP), fish, biota and water are analyzed for contaminants to assess temporal trends in organic contaminants and mercury in the open waters of the Great Lakes, using fish as biomonitors. We are continuing to enhance the program with new analytical instruments and analytical techniques to enhance our state-of-the-art capability to identify and quantify both emerging and legacy pollutants at levels previously impossible to achieve. We are assessing contaminant transfer from the water column through the food chain, expanding the analyte list to include more emerging contaminants and using supplemental approaches (fatty acids, stable isotopes, fish stomach analysis and proteomics) to enhance the program. We are working to augment our collaborations with other state, federal and International programs performing similar work. In total these enhancements give us a much clearer picture of the health of the Great Lakes ecosystem and ensure the GLFMSP remains a world-wide scientific leader in documenting how human activity is impacting the world we live in.

Research and Demonstration of Innovative Drinking Water Treatment Technologies in Small Systems. The main objective of this study is to engineer, develop and demonstrate an integrated process comprised of membrane technology (i.e., ceramic NF, UF or MF) and electrical discharge plasma generated via a novel reticulated vitreous carbon (RVC) electrode material. The reasons for this integration are four-fold: (1) the novel RVC electrode material will significantly improve the efficiency and longevity of the electrical discharge; (2) the membrane process protects the porous electrode material from clogging and removes constituents targeted in conventional water treatment processes and that reduce the effectiveness of the advanced oxidation processes; (3) both the membrane and electrical discharge remove pathogens; and (4) electrical discharge is effective for the destruction of a wide variety of organic contaminants and contaminant precursors.

Atmospheric Deposition, Transport, Transformations and Bioavailability of Mercury across a Northern Forest Landscape. Widespread contamination of mercury in remote aquatic environments due to atmospheric deposition and consequent high concentrations in aquatic biota, suggest that there is an acute need to improve understanding of the mechanisms of mercury transport and transformations in lake/watershed ecosystems. The goal of this interdisciplinary project it to develop a better understanding of how atmospherically deposited mercury is transported through an entire watershed system. Results from field and laboratory experiments will be used to improve an existing mercury transport model.

Measurement of Ambient Ammonia to Identify its Spatial and Temporal Distribution, Source Types, and its Role in Secondary Particle Formation. In this project a network that includes four sites that represent a cross-section of potential NH3 impacts will operate for one year. Two sites will be urban (Queens College II and Rochester) and are impacted by a variety of NH3 sources including emissions from traffic, industrial emissions, and non-point sources. The other two locations are the Pinnacle site in southern NYS which will be impacted primarily by emissions from forested and agricultural areas and upwind areas outside of NYS, and Potsdam in northern NYS which we be impacted primarily by agricultural emissions and upwind sources, most of which will be in NYS although during some periods we may see impacts from greater Toronto.
In this study the problems associated with direct measurements of NH3 will be avoided by employing the proven technique of using a denuder difference technique with a dual-channel nitric oxide-ozone (NO-O3) chemiluminescence detector. In addition we will co-locate passive NH3 samplers as part of the Ammonia Monitoring Network (AMoN) at our sites to compare measurements using these two techniques.