University Lake Research Articles

Phosphorus adsorption on natural sediments with different pH incorporating surface morphology characterization.

Sediment samples from University Lake (U.L.) and Anacostia River (A.R.) were collected to study the phosphorus (P) adsorption with pH at 3.65, 4.75, and 5.65. The surface micro-morphology and pore structures of sediment particles were obtained using a scanning electron microscopy and gas adsorption method, respectively. Fourier analysis was then applied to approximate the surface morphology, which was incorporated into the Langmuir isotherm to directly derive the model parameters for P adsorption simulation. Meanwhile, an empirical function of pH was introduced to represent the pH effect on P adsorption. A stronger P adsorption was observed for the A.R. sediment due to the more clay minerals, smaller median diameter, and a greater percentage of large pores, and the increasing pH resulted in a decrease of adsorption equilibrium constant as well as the P adsorption capacity, which was well reproduced by the adsorption isotherms. This study would benefit the mechanism study of the interactions between sediment particles and pollutants, providing references for understanding the pollutants' transport in aqueous systems.

Volatilization of Contaminants from Suspended Sediment in a Water Column during Dredging

Remedial dredging of contaminated bed sediments in rivers and lakes results in the suspension of sediment solids in the water column, which can potentially be a source for evaporation of hydrophobic organic compounds (HOCs) associated with the sediment solids. Laboratory experiments were conducted in an oscillating grid chamber to simulate the suspension of contaminated sediments and flux to air from the surface of the water column. A contaminated field sediment from Indiana Harbor Canal (IHC) and a laboratory-inoculated University Lake (UL) sediment, Baton Rouge, LA, were used in the experiments, where water and solids concentration and particle size distribution were measured in addition to contaminant fluxes to air. A transient model that takes into account contaminant desorption from sediment to water and evaporation from the water column was used to simulate water and sediment concentrations and air fluxes from the solids suspension. In experiments with both sediments, the total suspended solids (TSS) concentration and the average particle diameter of the suspended solids decreased with time. As expected, the evaporative losses were higher for compounds with higher vapor pressure and lower hydrophobicity. For the laboratory-inoculated sediment (UL), the water concentrations and air fluxes were high initially and decreased steadily implying that contaminant release to the water column from the suspended solids was rapid, followed by evaporative decay. For the field sediments (IHC), the fluxes and water concentrations increased initially and subsequently decreased steadily. This implied that the initial desorption to water was slow and that perhaps the presence of oil and grease and aging influenced the contaminant release. Comparison of the model and experimental data suggested that a realistic determination of the TSS concentration that can be input into the model was the most critical parameter for predicting air emission rates.

Oral History and Public History

This fall the Oral History Association will convene its Fifteenth Annual Colloquium in Durango, Colorado. The first such national meeting was held in September, 1966, under the sponsorship of the University of California at Los Angeles at the university's Lake Arrowhead facility. A variety of persons (librarians, medical doctors, historians, archivists, psychiatrists) from throughout the United States assembled there to engage in a dialogue about a subject of mutual interest. This group numbered slightly less than one hundred. It was graced by the presence of Allan Nevins, known as the 'father of oral history. All sessions were plenary and at the conclusion of the meeting a consensus was reached that a professional association for oral history be established. In November, 1967, the Second National Colloquium was convened at Columbia University's Arden House to continue the deliberations initiated at Lake Arrowhead. Prior to this meeting the Oral History Association had been incorporated in the State of New York. Those attending this gathering numbered 150. By the time of adjournment they had considered a Constitution and Bylaws and elected officers. The Association was in business. Thus, one might say, transpired the founding period of our organization. It was my privilege to attend both meetings. I always find it fascinating to peruse the list of participants and to read the Colloquium proceedings. I recommend examination of the proceedings of the annual meetings of the sixties as interesting reading fare. Most of the questions we so often seem to come back to were raised in these discussions. Many of the people who participated in these meetings retained their interest in oral history and over the years have generously served the Association. In April, 1979, I had the good fortune to attend the first National Symposium on Public History at Santa Barbara, California. This meeting was sponsored by the Rockefeller Foundation and organized by the Graduate Program in Public Historical Studies at the University of California at Santa Barbara. For me there was a sense of deja vu. The first session of the symposium was a discussion of next steps in forming some sort of network or organization for persons interested in Public History. And, indeed, last September a steering committee' met in Washington, D.C., to plan the formation of a

Boat Use Patterns of a University's Lake Recreation Center

Boat Use Patterns of a University's Lake Recreation Center