Verónica L. Morales

Email: vlm8@cornell.edu
Advisor: Tammo Steenhuis (BEE)
Minor Advisor: Leonard Lion (CEE)
Degree Program: M.S./Ph.D.

Office: 165 Riley-Robb Hall

Year: 2006

I am currently working on my third year as a Ph.D. student in the Soil and Water Lab. I finished my M.S. in Earth and Atmospheric Sciences the summer of 2007 here at Cornell. In 2004 I received a B.S. from the University of California, Santa Barbara in Environmental Science and a B.A. in Spanish Literature. My research interests lie in the general field of water quality and center on the transport and fate of groundwater pollutants; specifically how certain mechanisms facilitate the movement of otherwise immobile or sluggish substances.

Projects

Paradox of Fungal and Bacterial Contributions to Repellent and Subcritically Water Repellent Soils (CU-BARD)

Water repellency and its spatial variability have shown to cause non-uniform wetting in many soils, causing the formation of fingers where water bypasses the soil matrix. The persistent formation of such fingers creates localized environments where moisture and nutrients are available, thus limiting regions in the soil matrix where microorganisms can flourish. Wetting and drying cycles further exacerbate the environmental pressure on soil biota, which release extracellular polymeric substances (EPS) and other exudates as defense mechanisms to combat such environmental stresses. In this study we investigate the relationships between microbiological exudates and finger formation in terms of exudates' cell surface hydrophobicity, feedback mechanisms, chemotaxis, motility, and persistence of water repellency.

Review of Capillary Interactions for Colloidal Transport in Partially Saturated Porous Media (CU-NSF)

Primary hypothesis: capillary forces determine the unique features of colloid retention and release in the thin water films where air-water and water-soil (AW, WS) interfaces closely approach each other in unsaturated porous media. Changes in properties of the porous media (surface roughness), colloid hydrophobicity, and bulk fluid chemistry will result in observable and predictable changes in capillary force-dependent retention behavior.

Long-term TCE Indoor Air Sampling in South Hill (CU-CPB/ELI)

The purpose of this project is to collect and analyze with Gas Chromatography air samples of TCE contaminated basements in South Hill to (1) identify the physical factors that affect TCE behavior in the subsurface (precipitation, groundwater levels, temp, barometric pressure), (2) determine optimum environmental conditions for indoor air sampling, and (3) confirm that the few certified air samples collected previously in tested homes are reliable and accurate indicators of average indoor conditions.

Measuring Ambient Vertical Flow in Wells with SF6 Emitters and Passive Diffusion Bag Samplers (UCD)

Widely used tools for flow measurement have fairly high threshold velocities, thus are not suited for detection of ambient flow. This project reports on a new flow velocity measurement method based on detection of a dissolved tracer (SF₆) conveyed by vertical water movement within the well from a diffusive source to several passive diffusion bags (PDBs) placed above and/or below the diffusive source.

Conferences Attended

American Geophysical Union (Dec 2006)

Session - Quantitative Pore-scale Investigations of Multi-phase Bio/geo/chemical Processes

Poster - Dependence of Colloid Retention in Unsaturated Porous Media on Capillary and Friction Force Perturbations

81^st ACS Colloid & Surface Science Symposium (June 2007)

Session - Colloid and Interfacial Phenomena in Environmental Systems I

Presentation - Grain Surface-Roughness Effects on Colloidal Retention in the Vadose Zone.

Publications

B. Gao, T.S. Steenhuis, Y. Zevi, V.L. Morales, J.L. Nieber, B.K. Richards, J.F. McCarthy and J.Y. Parlange, 2007. Capillary Retention of Colloids in Unsaturated Porous Media. Env. Sci. & Tech. (in print).