Research

Research interests

Ground/surface water remediation, colloid transport, fate and transport of organic contaminants

Current Projects

1. Development of a Long Island Sound-specific water quality index using cluster analysis and discriminant analysis
The objective of this project is to develop a Long Island Sound (LIS) specific water quality index that accurately reflects the trophic status of LIS waters. The new water quality index will be computed using multivariate cluster analysis and discriminant analysis of a set of individual water quality indicators. A numerical water quality index (around -1 to 1) will result, with a value close to 1 indicating good water quality (oligotrophic), a value close to -1 indicating poor water quality (eutrophic), and a slight negative value representing mesotrophic conditions. The new method will be validated using the established ASSETS methodology, and will be applied to all LIS water quality data (past 15 years at ~20 stations) collected by the Connecticut Department of Environmental Protection.

2. Concentrations and enantiomeric fractions of chlordane in sediments from Long Island Sound
The objectives of the proposed project are to: (1) determine the rates of chlordane concentration decline in the surficial sediments from Long Island Sound (LIS); (2) elucidate the mechanisms that may have caused the chlordane concentration decline in LIS sediments; and (3) examine the chiral signature of chlordane residues in the LIS sediments to assess the significance of microbial degradation on chlordane removal. Understanding the removal rates and removal mechanisms of persistent pollutants from estuarine sediments is essential to the development of management strategies to sustain/improve the environmental quality of our nation’s estuarine and costal areas.

3. Minimizing manure-borne hormones in New York City’s water supply system
The environmental presence of hormones has become a concern since low nanogram per liter concentrations of steroidal hormones in water can have adverse effects on the reproductive biology of aquatic organisms (and possibly human) by disrupting the normal function of their endocrine systems. Information regarding the occurrence, fate, and transport of manure-borne hormones (the largest source of hormones) in surface and ground waters, however, is surprisingly scarce. In this research we will investigate the occurrence and extent of manure-borne hormones in the New York City’s water supply system, which consists of three watersheds (the Croton, the Catskill, and the Delaware watersheds) and provides water supply to over 9 million residents. We will further determine the fate and transport of hormones in the watersheds, and compare different waste management systems on the reduction of manure-borne hormones.

4. Using gas chromatography/mass spectrometry to study polybrominated diphenyl ethers and other organohalogen compounds in urban air
Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants and are now ubiquitous in the environment. Potential health risks of PBDEs include thyroid hormone disruption, neurobehavioral toxicity and, for some congeners possibly cancer. We have acquired a gas-chromatograph/mass spectrometer (GC/MS) and will study the concentrations, congener profiles, temporal trends, and particle-to-gas partitioning processes of PBDEs in the atmosphere of New York City (NYC). We will also determine the concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides in NYC’s atmosphere. Results from the proposed study can be used to assess PBDE-related health risks in urban areas, and to determine the ultimate fate and transport of PBDEs and other persistent organic pollutants in the global environment. Additional projects include the use of GC/MS to characterize the degradation products of organophosphates in the environment, and to characterize organo-sulfate aerosols in urban areas.

5. Epi-fluorescence imaging of colloid transport in porous media
The objective of this project is to develop a non-invasive epi-fluorescence imaging technique to continuously monitor the transport of fluorescent colloids in porous media. This novel technique will allow us to study the dynamics and kinetics of colloid transport/immobilization in porous and fractured media with unprecedented temporal and special resolutions, and will significantly advance our knowledge of the processes that control colloid transport and immobilization in these media.

6. Removal of perchlorate from contaminated waters using surfactant-modified zeolite
This project investigates the sorption of perchlorate by surfactant-modified zeolite (SMZ) and the regeneration of the spent-SMZ. The inexpensive SMZ can be used in many configurations (e.g., a simple cartridge system for point-of-use treatment, a disposable filter bag, or a filter pack installed around drinking well screens) to effectively remove perchlorate and other contaminants from contaminated water.