Soil factors affecting solubility and mobility of zinc in contaminated soils

In view of modern worldwide research carried out in the context of broadly understood soil chemistry and monitoring of the natural environment, the methods of assessing the risk of Zn contamination in soil and agricultural crops based on the analyses of Zn concentration in the soil solution have gained more recognition. Accordingly, research on the evaluation of the effects of selected soil properties on changes in solid/solution partitioning coefficient (K_d), the total concentration and activity of zinc in the soil solution was undertaken in this study. The study was based on the microplot field experiment. Investigated soil factors were as follows: soil texture, pH, organic carbon content and the degree of Zn contamination. The results indicated that zinc activity in the soil solutions was very high and comparable to the total concentration of zinc. The investigated soil properties significantly influenced the K_d, the total concentration of zinc, as well as the concentration of Zn²⁺ in the soil solution. The total concentration and activity of zinc in the soil solution increased with increasing Zn content in the soil and rising soil acidity, while they decreased with increasing the content of organic carbon and clay particles. The values of K_d increased significantly with rising soil pH and total Zn content and decreased with increasing soil organic content. Observed K_d values were significantly higher in soil with 13 % clay than in soil with 7 % clay.