Effects of Phosphate Fertilizer Applications and Chemistry-Mineralogy of the Iron Oxide System on Phosphate Adsorption-Desorption by Stream Sediments : Final Report

(print) vii, 102 p. : ill., maps ; 28 cm.Item lacks publication date. Issue date supplied from WorldCat bibliographic recordDespite geologic, geomorphic, and land use differences, suspended sediments collected from the Muskingum River and its tributaries during spring flooding were remarkably uniform in mineralogy and size distribution. The greatest evidence of regional differences came from Moxahala Creek, which receives acid drainage from abandoned coal mines. As a result, Black Fork Creek, a tributary to Moxahala Creek, was chosen for detailed water quality and bottom sediment studies. Marked increases in dissolved SO4, Fe, and Al, and decreased. pH were observed in sections of the stream affected by acid mine drainage. In addition, a gelatinous yellow precipitate of iron was abundant in the bottom sediments below sources of pollution. This Fe-oxide or oxyhydroxide precipitate greatly increased surface area and reactivity of bottom sediments and added to the overall sediment load. A standard P adsorption procedure was proposed and the ability of four laboratories to produce consistent results over a wide range of soils was determined. Soil (0.5 or 1.0 g) was shaken in 0.01 mol L-1 CaCl2 at a soil: solution ratio of 1:25 in containers allowing a 50% head space for 24 hours at 24 to 26°C on an end-over-end shaker. Initial dissolved inorganic P concentrations of 0 to 323 u mol P L-1 (as KH2PO4 or NaH2PO4) were used and microbial activity inhibited by 20 g L-1 chloroform. Excellent agreement between the four laboratories was obtained for P adsorbed by the 12 soils studied, with a mean coefficient of variation over all P levels and soils of 0.91%. The laboratories also exhibited a high degree of replication of individual treatments with no laboratory showing a strong consistent bias across all soils and P levels in terms of P adsorption. Langmuir, Freundlich and Tempkin adsorption models were highly correlated with the adsorption data. Respective mean correlations for the 12 soils were 0.98, 0.97 and 0.95. The proposed method has the potential to produce consistent results which can be used to predict partitioning of dissolved inorganic P between solid and solution phases in the environment.Acknowledgements -- Abstract -- Chapter 1: Suspended Sediments of the Muskingum River Basin -- Chapter 2: Water and Bottom Sediment Quality in Streams Affected by Acid Coal Mine Drainage - a Study of the Black Fork Creek Watershed, Ohio -- Chapter 3: Interlaboratory Comparison of a Standardized Phosphorus Adsorption Procedur

Bubbling and bistability in two parameter discrete systems

We present a graphical analysis of the mechanisms underlying the occurrences of bubbling sequences and bistability regions in the bifurcation scenario of a special class of one dimensional two parameter maps. The main result of the analysis is that whether it is bubbling or bistability is decided by the sign of the third derivative at the inflection point of the map function.Comment: LaTeX v2.09, 14 pages with 4 PNG figure