Effects of Acidification on Mobilization of Heavy Metals and Radionuclides from the Sediments of a Freshwater Lake

作者：D. W. Schindler, Raymond H. Hesslein, Rudolf Wagemann, Wally S. Broecker · 发表于：Canadian Journal of Fisheries and Aquatic Sciences · 年份：1980 · DOI：10.1139/f80-051 · 被引用次数：196 · 研究领域：Heavy metals in environment、Mine drainage and remediation techniques、Groundwater and Isotope Geochemistry

Large (10 m) diameter enclosures were sealed to the sediments in 2–2.5 m of water in Lake 223. Two tubes were held at control pH (6.7–6.8), one was lowered to pH 5.7 and one to pH 5.1, using H2SO4. Aluminum, manganese, zinc, and iron were released from lake sediments at pH 5 and 6. Concentrations of zinc in the overlying water column exceeded 300 μg∙L−1. Radioisotopes of several heavy metals added to the water of the enclosure showed the following: all metals were removed from the water at log-linear rates, with half-times of 5–25 d. Acidification caused several metals to become more soluble, including Fe-59, Co-60, Mn-54, and Zn-65. Solubility of V-48 and Hg-203 decreased with increasing acidity. Acidification also slowed the loss to sediments of Mn-54 and Zn-65. Losses of Ba-133, Se-75, Cs-134, and V-48 were more rapid under acid conditions. The fractions of any isotope retained by a 0.45-μm filter, activated charcoal and mixed-bed ion exchange resin remained constant throughout the experiment at any given pH.Key words: sediment–water interactions, heavy metals, radionuclides, lake acidification