Laserfiche WebLink
Section 4 <br />Discussion <br />• <br /> <br /> <br />4.2 Selenium <br />The attenuation test data indicates that selenium was not significantly adsorbed by <br />soils present in the Sunday Mines Group area. Given that selenium Kd values are <br />typically even lower than those for arsenic (literature values for Kd are 6-15 L/kg as <br />shown in Table 3-8), this fact combined with the high pH of the solutions helps to <br />explain the lack of significant selenium adsorption. Like arsenic, selenium is an anion <br />at Eh values >400 my and at pH 7.2-8 su (Se04 2, HSe03- and Se03 2, see Figure 4-2.) <br />Therefore, adsorption is limited and Kd values are low. <br />14 <br />1.2 <br />1.0 <br />0.8 <br />0.8 <br />0.4 <br />0.2 <br />0.0 <br />-0.2 <br />-0.4 <br />-0.8 <br />-0.8 <br />-1.0 <br />HSe04 (aq) X V4WR4 <br />~` •.? oWSWR3 <br />A SX R3 <br />oTPWR3 <br />11 SVWR2 <br />H2soop <br />' SPO'a (:r q ). <br />H;,S(,O (aq ) <br />Se032(aq) <br />HSe- (aq ) <br />0 2 4 8 PH 8 10 12 14 <br />Figure 4-2 - Eh pH Diagram for the System Se-O-H at 25e C and 1 atm.. <br />• <br />4.3 Vanadium <br />The vanadium Kd values shown in Table 3-7 (15-26 L/kg) are lower than typically <br />reported in the literature (50-100 L/kg). Vanadium exists mainly as anionic species <br />(H2VO4- and HV04 2) under oxidizing conditions and at pH values between 7.2 and 8 <br />(see Figure 4-3). The lower Kd values are likely due to the repulsion between the <br />negatively charged soil mineral surfaces and the anionic vanadium species. <br />Cm 4-2 <br />T:18498843enison Min %Task Order 3 - DMO Sampling and Analysis Plan%Task 3.12 - Soil, Ore, Rook Data Assessment RapodlSunday Rook ReporPAttachmentsV AWnualion Repod_v rldng draft 040309.doe