Harmful Elements in Estuarine and Coastal Systems

Estuaries and coastal zones are dynamic transitional systems which provide many economic and ecological benefits to humans, but also are an ideal habitat for other organisms as well. These areas are becoming contaminated by various anthropogenic activities due to a quick economic growth and urbanization. This chapter explores the sources, chemical speciation, sediment accumulation and removal mechanisms of the harmful elements in estuarine and coastal seawaters. It also describes the effects of toxic elements on aquatic flora and fauna. Finally, the toxic element pollution of the Venice Lagoon, a transitional water body located in the northeastern part of Italy, is discussed as a case study, by presenting the procedures adopted to measure the extent of the pollution, the impacts on organisms and the restoration activities

X-Ray Fluorescence Capabilities for Uranium Ore Analysis

A rapid x-ray fluorescence (XRF) method for the quantitative analysis of uranium in ore and process samples is demonstrated. The method requires no uranium ore standards and provides a relative precision of +-2.5 percent. Particle-size and self-absorption effects are evaluated along with current methods of excitation and detection for M, L, and K series uranium x-rays. Sensitivities and detection limits are comparable using either energy dispersive or wavelength dispersive analysis of uranium L x-rays, and wavelength dispersive analysis of uranium M x-rays for both thick and thin samples. The XRF methods are more sensitive than the analysis of uranium by /sup 252/Cf neutron-induced ..gamma..-ray analysis or by direct photon analysis of uranium daughters