Department of Earth and Planetary Sciences

Center for Environmental Biotechnology

Home
Background and Education
Professional Activities
Research Interests
Publications
New(recent) PUBS...2008_McCarthy
Other Links

Research Interests

Transport, fate, and bioavailability of reactive constituents in soil and groundwater systems. Major areas of emphasis include the mechanisms controlling retention and release of colloidal particles and natural organic matter, and the effects of those processes on (i) the mobility of contaminants in the subsurface, and (ii) on the bioavailability of contaminants in surface- and groundwater.

Over the years my research have varied over a range of scientific issues, including:

• Bioavailability of contaminants in surface- and groundwater systems

• The mobility of inorganic colloids in unsaturated subsurface systems

• Use of Naturally Occurring Decay-Series Isotopes as Quantitative Hydro-Geochemical Tracers

• Mechanisms of Organic Preservation in Continental Margin Sediments

• Physical and chemical processes responsible for carbon sequestration in soil microaggregates

Research Interests  (broader statement)

I have conducted and published research on a wide variety of topics encompassing sever disciplines. This eclectic journey can be considered a scientific form of Adult Attention Deficit Disorder, but actually follows a reasonable evolutionary diversification resulting from opportunities to expand my existing expertise to explore novel challenges, development of new collaborations that lead to mutual cross-fertilization and novel and productive science.

My work has included hypothesis-based laboratory sties, and a considerable portion of field research to test and confirm laboratory observations at a larger spatial scales at which the effect of natural heterogeneity and multiple interacting factors (e.g., hydrologic flow, and cation exchange between conductive flow paths and the fine-scale matrix).

However, I would be less than candid if I did not admit that changes in funding opportunism often played a role. Any of my previous and ongoing research on colloids and natural organic matter are directly transferable to concerns about nanotechnology.

A major theme of my early research was transport, fate, and bioavailability of reactive constituents in soil and groundwater systems. Major areas of emphasis include the mechanisms controlling retention and release of colloidal particles and natural organic matter, and the effects of those processes on (i) the mobility of contaminants in the subsurface, and (ii) on the bioavailability of contaminants in surface- and groundwater.

·         I have also conducted collaborative, with colleagues in other UT Departments, such as Civil and Environmental Engineering and Biosystems Engineering, as well as Biotech Engineering. I have also had joint projects with a number of Universities from Cornell to Illinois, Univ of Southern California and UC-Riverside, Univ. Southern Calif. and Western Washing State Univ.

·         A major theme of current research is understanding transport of colloids and pathogens in partially saturated porous media (in collaboration with Tammo Steenhuis (Cornell). In particular we focus on the role of electrostatic and capillary forces on flow and transport.

·         As interest in Global Climate Change grew, I have focused on Physical and chemical processes responsible for carbon sequestration in soil microaggregates. I used a novel method using Utra-Small Angle X-Scattering to quantify the size distribution of the total porosity of the aggregates, as well as the amount and distribution of organic matter (OM) within the microaggregate pores. Two publication attached to the publication list describe this work.

We found that organic matter can be preserved organic-filled pores, and that these OM-rich pores increased water retention (increasing soil quality and stability)..

·         A recent proposal seeks to use Small Angle Neutron Scattering to evaluate changes in the distribution of water in the aggregate pores (H2O and D2O differ greatly in neutron scattering capacity).