Linda S. Lee
Professor
Area: Environmental Chemistry

Current Graduate Students

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Nadia Carmosini (Ph.D.)	Project Description: Pharmaceuticals (e.g. antibiotics, hormones, antidepressants, caffeine) are a group of substances that may be released into the environment from a variety of sources, such as sewage treatment works and confined animal feeding operations. Little is known about how pharmaceuticals are released from these sources, what their fate is in the environment, or what biological effects are elicited from aquatic organisms. My work will identify sources of pharmaceuticals in Indiana streams, their persistence or transformation products, and the potential for biological effects.
Kavitha Dasu	Project Description: Perfluorinated surface-active compounds, such as perfluorooctane sulfonate (PFOS) and perfluoro octanoic acid (PFOA) are identified worldwide in the biota, human blood and also in the remote areas like Arctic regions and are considered to be potentially toxic. PFOS and PFOA are the degradation products of fluorotelomer based compounds such as those used as coatings on commercial products. My current research involves quantifying in soil sorption and the abiotic and biotic transformation products and rates of the monomers used to make fluorotelomer-urethane polymer, which imparts soil and stain resistance properties for textiles and carpets. The purpose of this study is towards assessing if the degradation products of urethane polymer are contributing to the formation of FTOHs and subsequently to PFOA.
Bushra Khan (Ph.D.)	Project Description: Growth promoting hormones are used extensively to provide increased profits in the beef cattle industry in several meat exporting countries. 17β-trenbolone acetate (TBA) is an approved synthetic androgenic steroid hormone administered as a subcutaneous implant. Excreted manure contains mainly 17α-trenbolone and small amounts of 17β-trenbolone and trendione. Manure is typically land applied as a fertilizer, hence providing a route of hormone entry into the environment. Transport of these hormones to the surface water can readily occur after heavy rains. Androgenic and estrogenic hormones present in the environment may cause endocrine disruption in wildlife. Little is known about the environmental fate and persistence of synthetic androgens and associated metabolites that may be present in beef cattle manure. My research project is focused on quantifying for 17α- and 17β-trenbolone and trendione: (1) sorption and the aerobic degradation products and rates in agricultural soils as a function of soil moisture and temperature; (2) persistence in stream/ditch sediments under anaerobic conditions; and (3) levels in the implanted beef manure and subsequently the animal-waste lagoon systems along with associated estrogens.
Laurel Royer	Project Description: Since the 1950s, fluorotelomer chemicals have been used to manufacture inks, paints, caulks, adhesives, surfactants, fire-fighting foams, hair care products, cosmetics, nonstick surfaces, and protective coatings for clothing, carpets, leather, paper, and upholstery. Research is needed for improving our understanding of the environmental fate of these chemicals that have become an essential part of our daily lives. My work specifically focuses on the environmental fate and transformation of a series of perfluorinated acrylate (PFA) and perfluorinated methacrylate (PFMA) monomers and polymers. By amending soils with these compounds under conditions that mimic those of the environment, I am able to monitor the stability and hence the susceptibility of these compounds to microbial degradation. The results of experiments where PFA and PFMA monomers were incubated in soils and analyzed over time show that microbes attack these compounds and yield pollutants that have been detected in the environment. My experiments with monomers provide insight on how more complex polymers may behave in the environment; however, experiments with larger PFA and PFMA polymers are essential as the use or disposal of consumer products coated with these polymers truly pose a significant risk to the environment and human health. I am also probing fungi-mediated transformation pathways that may play a contributing role in the environmental transformation of the fluorotelomer suite of chemicals of interest to us. Fungi are very complex microorganisms, however their function and mechanism of action to degrade complex biopolymers (e.g., lignin and cellulose) is intriguing. It is this catalytic powerhouse that we hope to exploit. Armed with more information, society will be better equipped to make regulatory decisions and achieve a balance between manufacturing products that enhance our quality of life and protecting our environment.