tailieunhanh - Heavy Metals Release in Soils - Chapter 2

Anion và cation Giao thông vận tải trong Tuffs Zeolitized từ các trang web thử nghiệm Nevada: Ảnh hưởng của Loại Ion, pH, và cường độ ion Trong thời gian sản xuất và thử nghiệm vũ khí hạt nhân, Mỹ đã tiến hành một loạt thử nghiệm tại một số trang web. Những thử nghiệm này dẫn đến ô nhiễm từ các hạt nhân phóng xạ cũng như từ các kim loại độc hại khác và các hợp chất hữu cơ. Hạt nhân phóng xạ thường thấy tại các khu vực bị ô nhiễm bao gồm uranium và các nguyên tố. | CHAPTER 2 Anion and Cation Transport in Zeolitized Tuffs from the Nevada Test Site Effects of Ion Type pH and Ionic Strength Charalambos Papelis and Wooyong Um INTRODUCTION During the period of nuclear weapon production and testing the . conducted a series of tests at several sites. These tests resulted in contamination from radionuclides as well as from other toxic metals and organic compounds. Common radionuclides found in contaminated areas include uranium and heavy transuranic elements mainly neptunium plutonium and americium as well as lighter radionuclides some of which are fission products of the heavier radioisotopes. In addition to radionuclides some of the nuclear tests resulted in contamination by other inorganic and organic hazardous substances. These contaminants include the metals lead copper and cadmium anions of arsenic and chromium and organic contaminants such as polyvinyl chloride PVC polystyrene and phenols Bryant and Fabryka-Martin 1991 . Some of the above contaminants could be potential health hazards either because of their toxicity or because they are potential carcinogens Francis 1994 Sax 1981 . Assessment of the potential for migration of these contaminants from controlled areas to the accessible environment is based on flow and transport models. These models must account for any possible retardation of the contaminants relative to the groundwater. In addition to hydrologic parameters therefore transport models require parameters that reflect the geochemical interactions of contaminants of concern with aquifer materials. The reliability of predictions based on these codes depends directly on the quality of the input parameters. Uncertainties in parameter estimation can lead to significant uncertainties in radionuclide transport simulations especially given the long time frequently allowed for contaminant migration in model simulations up to 10 000 years . 31 2001 by CRC Press LLC 32 HEAVY METALS RELEASE IN SOILS Sorbate-sorbent .