Effect of humic substance on diffusion and toxicity of environmental polutants and application of it as clean up reagent

为了评价腐殖质对环境污染物扩散和毒性的影响，研究了腐殖质与一些污染物之间的相互作用，获得了以下新的信息。此外，还证实了腐殖质作为环境清除剂的可能性。从北海道某点采集的泥炭土壤中提取腐殖质，提纯为腐植酸和黄腐酸。研究发现，这些腐殖质的化学性质各不相同。腐植酸与铬(III)形成络合物，30h后达到络合平衡条件。得到了络合反应的平衡常数和速率。考察了腐殖质和有机酸对铬的氧化还原反应的影响。单宁酸、没食子酸、木醋等低分子化合物将铬(VI)还原为铬(III)的速度较快，而腐殖质对铬(VI)的还原速率较慢。另一方面，在氧气存在下，锰将铬(III)氧化成铬(VI)。腐植酸的存在对铬(III)氧化为铬(VI)有抑制作用。单宁酸、盖乐酸和木醋没有表现出这种作用。这些结果表明，腐植酸与铬(III)的络合能力在抑制氧化反应中起着重要作用。腐殖质与多环芳烃(PAH)化合物结合，提高了其在水中的溶解度。在含有固体颗粒、水和腐殖质的三相体系中，多环芳烃在水中的溶解度增加。在这种情况下，多环芳烃的溶解度受水中腐殖质相和固体颗粒表面腐殖质相的分布控制。

To evaluate the effects of humic substances on the diffusion and toxicity of environmental pollutants, the interaction between humic substances and some pollutants were investigated and the following new information was obtained. Furthermore, the possibility of humic substances as cleanup reagent for environment was confirmed.1. The humic substances were extracted from peat soil sampled at some points in Hokkaido and purified to humic acied and fulvic acid. It was found that the chemical properties of these humic substances differed from one another.2. The humic acid formed a complex with chromium (III), and the equilibrium condition of the complex formation was achieved after 30 hours. The equilibrium constants and rate of the complexing reaction were obtained.3. The effects of humic substances on the redox reaction of chromium were investigated as well as some organic acids. The low molecular compounds such as tannic acid, gallic acid and wood vinegar reduced Cr (VI) to Cr (III) quickly, while the reduction rate of Cr (VI) with humic substances was slow significantly. On the other hand, Cr (III) was oxidized to Cr (VI) with manganese in the presence of oxygen. However, the presence of humic acid showed the suppression effects on the oxidation of Cr (III) to Cr (VI). Tannic acid, gaelic acid and wood vinegar did not show such effect. These results suggested that the complexing ability of humic acid with Cr (III) playd an important role to the suppression of the oxidation reaction.4. Humic substances binded with poly-aromatic hydrocarbon (PAH) compounds and enhanced the solubility in water. The enhancement of the solubility of PAH in water was found in three phases system containing solid particle, water and humic substances. In this case, the solubility of PAH was controlled by the distribution to humic phase in water and humic phase on the surface of solid particle.