摘要：Benzo [a] pyrene(BaP) and cadmium(Cd) fre-quently co-exist in soils, posting a significant threat to both the ecological system and to human health. Experiments were carried out to study the interaction and mechanism of Cd and BaP in soils in Northeast China,and to clarify the combination of Cd in differ-ent typical types of Northeast soil (burozem and phaeozem) and the different soil fractions (light frac-tion, heavy fraction) under the interaction of the above pollutants. Clear the distribution characteris-tics ofCd in different soil particle sizes(coarse sand, fine sand, coarse silt, fine silt and clay)under the in-teraction of Cd and BaP. Results showed that BaP had a certain effect on the adsorption of Cd in soil, and the addition of BaP inhibited Cd adsorption by light and heavy fractions of phaeozem and burozem. The presence of BaP increased the water-soluble plus exchangeable (SE)Cd and decreased residual (RES) Cd, it made Cd easier to migrate. For the soil with higher concentration of Cd, the migration of Cd was stronger, and the migration of Cd in light frac-tions easier than that in the heavy fraction of the two soils. Electron microscopic analysis showed that Cd was more easily adsorbed in heavy fractions of phaeozem and burozem than those of light fractions, and Cd was more easily adsorbed in phaeozem than in burozem. Without BaP, the contribution rates of adsorption of Cd2+ from five partical sizes in bu-rozem were 20.90%,34.90%,27.40%,13.04% and 3.76%,respectively. The contribution rates of Cd+adsorption to the five partical sizes in phaeozem were 18.72%,36.50%.22.42%.13.96%and2.40%. respectively. The contribution rate of 105-54 um and 54-20 um was higher.After the addition of BaP, the ratio of the five particle sizes changeda little,and the adsorption ratio of Cd was also mainly concentrated in the particle sizes of 105-54 um and 54-20 um. The total percentage of 54-20 um and 20-2 um in the presence of BaP accounts for 64.24%、64.52%which is a preferred adsorbent for PAHs.
