tailieunhanh - Advanced Topics in Mass Transfer Part 11

Tham khảo tài liệu 'advanced topics in mass transfer part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 390 Advanced Topics in Mass Transfer hydrothermal field is located and a metalliferous deposit is currently forming. We see no enrichment of Cu As Cd Sb Hg and Bi in the coastal seas and bays around the Shimokita Peninsular see the circle numbered in 2 for Cd in Fig. 12a . These facts suggest that sulfide minerals are not supplied directly to coastal seas because the sulfide ores are oxidized consequently releasing Cu Zn As Cd Sb Pb and Bi during transport from terrestrial areas to coastal waters Hudson-Edwards et al. 1996 . It is also possible that Zn and Pb sulfides are extremely resistant to weathering or that their mass concentrations are the highest among these metals. Alternatively aqueous Zn and Pb are easily sorbed on the sediment surface in coastal seas. Shimokita Pen. 2000 m Cd Sea mg kg Land Cd Sea mg kg Land Map area - - - - - - - - - - Map area - - - - - - - - - - Fig. 12. Geochemical maps of Cd In contrast the influence of anthropogenic activity on geochemical maps is somewhat different from that of metalliferous deposits. The P P2O5 Cr Ni Cu Zn Mo Cd Sn Sb Hg Pb and Bi concentrations are elevated in both the metropolitan area and adjacent inner bay. Figure 12b shows that the spatial distribution of Cd in the southeast part of the Honshu Island where the Tokyo metropolitan area exists. The high concentrations of chalcophile elements such as Zn and Cd are found in both the terrestrial area and inner bay. Their spatial distribution patterns suggest that the contaminated materials remain in the bay without extending to the outer sea. This is because of the distribution of .