Mercury content in sediments obtained from Razdol'naya River, Vtoraya Rechka and Amur Bay

Estuaries are transitional zones between continents and oceans. In terms of geochemistry, they comprise an extremely important geochemical barrier, which separates areas with different conditions of the sedimentation environment (hydrodynamic, physicochemical, biogeochemical, etc.). This results in a sharp change in the intensity of migration of a certain group of chemical elements, their concentrations, and migration forms. The migration forms of an element are controlled, not only by its occurrence in either dissolved or suspended states, but also its affinity for a particular suspended fraction and sorption properties. Fine suspended fractions may serve as an active form of migration and control the migration capacity of an element. […]

河口是连接大陆与海洋的过渡性区域。从地球化学角度而言，河口构成了极为重要的地球化学屏障，能够分隔沉积环境（水动力、物理化学、生物地球化学等）条件各异的区域。这会导致某类化学元素的迁移强度、浓度及赋存迁移形式发生剧烈变化。元素的迁移形式不仅受控于其以溶解态还是悬浮态赋存，还与其对特定悬浮组分的亲和性以及吸附特性密切相关。细小的悬浮组分可作为元素迁移的活性载体，并调控元素的迁移能力。[…]