Literature Cited Choo, C. Y., Sanders, B. H., Symposium on Less Common Separation Methods in Petroleum Industry, Div. of Pet. Chem., 139th Meeting ACS, St. Louis, March (1961). Hammond, R. P., Hunter, J. A., Siedes, E. H., “Deaerators for Desalination Plants,” U S . Office Saline Water Res. Develop. Progress Rept. No. 314, US. Gov’t. Printing Office,
Myers, A. W., Stannett, V., Szwarc, M., J . Poly. Sci. 35,286 (1959). Tuwiner, S. B., “Diffusion and Membrane Technology,” Reinhold, New York, 215, 1962. Vieth, W., Rutgers University, New Brunswick, N.J., private communication (March, 1969).
1967
Li, N. J., Long, R. B., Henley, E. J., Itid. Eng. Chem. 57 (3), 18-29 (1965). McCabe,’ W., Smith, J., “Unit Operations of Chemical Engineering,” 422-3, 430-3, McGraw-Hill, New York, 1956. Michaels. A. S.,Bixler, H. J., Rigopulos, P. H., Proc. 7th World Pet. Congr. 3,219(1967).
Received for reuiew July 14, 1969. Accepted December 31, 1969. Presented at Metro Chem 1969, New York, N . Y . , May 1969. Paper of the Journal Series, New Jersey Agricultural Experiment Station, Rutgers, the State Uiiic.ersity of New Jersey, Department of Eiicironmental Sciences, New Brimwick, New Jersey.
Adsorption and Desorption of Inorganic Phosphorus by Lake Sediments in a 0.1M NaCl System J. D. H. Williams, J. K. Syers, and R. F. Harris Department of Soil Science, University of Wisconsin, Madison, Wis. 53706
D. E. Armstrong Water Chemistry Laboratory, University of Wisconsin, Madison, Wis. 53706
m Noncalcareous lake sediments generally adsorbed and retained more added inorganic P than calcareous lake sediments. Sediments which retained the most added P during adsorption tended to release the least P during a subsequent desorption a t all levels of added P. The net amount of added P adsorbed (following adsorption and desorption) was lowest for calcareous sediments, with one exception, at the highest level of added P (50 pg. of P per ml.). The reactions involved in the adsorption and desorption of added P were not always completely reversible during the time period used in the experiment. A close relationship was found between the order of the capacity of a sediment to retain added P in the laboratory and the levels of native total P and inorganic P in the sediment.
T
he capacity of lake sediments to retain or release P is undoubtedly one of the important factors which influence the concentration of inorganic and organic P in lake waters. Although several reports have discussed the predicted effects of various physical and chemical parameters on the behavior of sediment P (Golterman, 1967; Olsen, 1966) few investigations have involved evaluation under controlled conditions of the amounts of P adsorbed and desorbed by sediments. This paper is concerned with a n investigation of the adsorption and desorption of inorganic P in a 0.1M NaCl system by lake sediments of contrasting chemical composition. Results are discussed in relation to the amounts of native total P and inorganic P i n the Sediments. Materials and Methods Samples. Sediment samples were collected in late 1968 and early 1969 from eight Wisconsin lakes: Lakes Wingra, Monona, and Mendota in southern Wisconsin; Devils Lake in south-central Wisconsin; and Crystal, Little John, Trout,
and Minocqua lakes in northern Wisconsin (Table I). Characteristics of most of these lakes and general features of the sediments have been described elsewhere (Frey, 1963 ; Murray, 1956). Briefly, Wingra and Little John are relatively small and shallow in comparison to the others. Based on visual assessment of productivity and the extent of oxygen depletion in the hypolimnetic waters during the period of thermal stratification, Lakes Wingra, Monona, Mendota, and Little John are considered eutrophic, Trout and Minocqua mesotrophic, and Devils and Crystal oligotrophic. Samples were taken from a single site in the deep-water area of Lakes Monona, Mendota, Devils, Crystal, and Little John. For Lake Wingra, seven sites distributed over the entire lake were sampled. The seven Wingra samples obtained varied little in a wide range of chemical properties such as organic C and total P contents. Three samples (Wingra 1,4, and 7) were chosen as representative of the original seven. The three samples taken from Trout Lake were from widely separated locations; Trout 1 was taken from the deepest area of the lake. Minocqua 1 wias taken from a bay located immediately west of the town of Minocqua. In summer, this bay shows obvious signs of eutrophication, presumably due to the influence of the town. In the remainder of the lake, eutrophication is not evident. Minocqua 2 was taken from one of the deepest locations in the main portion of the lake. Sediments were obtained with an Ekman dredgt. which grouped several dredge samples for the bulk sample from each site. Bulk samples were stored at 4’ C. in sealed glass containers. Subsamples for chemical analyses were either freeze-dried, air-dried a t 25” C., or used directly from the bulk sample in the wet state (“undried” samples). Analytical Methods. Sediment pH was measured with a glass electrode on the undried sediment. Total C was determined by combustion (Piper, 1944) of freeze-dried sediment; values for organic C were obtained by subtracting COS- C, determined according to the manometric procedure of Leo (1963), from the total C content. Total P was determined by Volume 4, Number 6 , J u n e 1970 517
Na2COsfusion (Syers, Williams, et al., 1968) by use of freezedried sediment ground to pass through a 100-mesh sieve. Total organic P was determined on
