Huljev D J
Environ Res. 1986 Aug;40(2):470-8. doi: 10.1016/s0013-9351(86)80122-0.
The interaction of metal ions (carrier-free form) in aquatic medium with humic acids is a complicated process depending on the properties of humic acids (elementary, chemical, and trace element composition), metals studied (valence, charge, chemical form, concentration), and medium used (pH, ionic strength). The use of radionuclides was found to be very suitable for a rapid and precise determination of the distribution coefficient Kd (ratio of the concentration of a certain trace metal association with a gram of humic acid over the concentration of the same trace metal per milliliter of solution) of the investigated system. Isolated humic acids from offshore sediments from the North Adriatic (Lim channel, near Rovinj, Yugoslavia) were characterized according to their elementary composition, the amount of products of hydrolysis, and the trace elements bound. All experiments were carried out between pH 3 and 5. It was found that conditions usually present at the site where humic acid interacts with metal ions (anaerobic conditions, H2S) in brackish (21% S) and standard seawater (38% S) are determined in the pH range 3 to 5. The results of the pick-up (uptake) and replacement (release) experiments are presented as a distribution coefficient (Kd), as a function of contact time. Processes of pick-up and replacement of a number of metals under various physicochemical conditions were investigated and special attention was paid to the influence of salinity. With the increase in NaCl concentration and pH in the system, the fixation of ruthenium, zinc, cobalt, and mercury by humic acids decreased. The liberation and fixation of metal ions along the coastal seawater are important for the marine ecosystem.
水生介质中金属离子（无载体形式）与腐殖酸的相互作用是一个复杂的过程，这取决于腐殖酸的性质（元素组成、化学组成和微量元素组成）、所研究的金属（化合价、电荷、化学形态、浓度）以及所用介质（pH值、离子强度）。人们发现，使用放射性核素非常适合快速、精确地测定所研究体系的分配系数Kd（每克腐殖酸结合的某种痕量金属浓度与每毫升溶液中相同痕量金属浓度之比）。对从亚得里亚海北部（南斯拉夫罗维尼附近的林姆海峡）近海沉积物中分离出的腐殖酸，根据其元素组成、水解产物量以及结合的微量元素进行了表征。所有实验均在pH值3至5的范围内进行。研究发现，在pH值3至5的范围内，可以确定腐殖酸与金属离子相互作用的地点通常存在的条件（厌氧条件、H2S），这些地点位于微咸水（21% S）和标准海水（38% S）中。吸附（摄取）和置换（释放）实验的结果以分配系数（Kd）的形式呈现，作为接触时间的函数。研究了在各种物理化学条件下多种金属的吸附和置换过程，并特别关注盐度的影响。随着体系中NaCl浓度和pH值的增加，腐殖酸对钌、锌、钴和汞的固定作用降低。沿海海水中金属离子的释放和固定对海洋生态系统很重要。
