外源有机质对土壤中菲的增强固定作用

从吸附、解吸、可萃取态残留变化3个方面,研究了外源有机质对粘壤土、砂粉土和粉壤土中菲的增强固定作用.外源有机质为有机商品肥和泥炭.结果表明,施加外源有机质后,供试土壤对菲的吸附等温线仍呈线性,分配作用为土壤吸附菲的主导机制.有机商品肥或泥炭能显著促进供试土样对菲的吸附.施加同量的外源有机质,土壤吸附菲的K_d值的增加幅度与土壤有机碳含量(f_oc)成正比,表明土壤的f_oc越大,外源有机质对菲吸附的促进效果越好.解吸实验表明,施加外源有机商品肥或泥炭能够抑制土壤中菲的解吸,解吸量显著低于原土.经64 d培养,施加外源有机质的3种土壤中的可萃取态残留菲含量降低;由于泥炭的有机质含量高于有机商品肥,施加泥炭的土样中可萃取态残留菲的降幅更大;原土的f_oc越高,外源有机质对菲可萃取性的抑制效果越明显.可见,施加外源有机质可增强土壤中菲的吸附固定、抑制其解吸、并降低其可萃取态残留.

Enhanced fixation of phenanthrene in soils amended with exotic organic materials.

This paper studied the enhanced fixation of phenanthrene in clay loam soil, sandy silt soil, and silt loam soil under effects of exotic organic materials (EOMs) commercial organic fertilizer and peat. The results showed that after the addition of EOMs, the adsorption isotherms of phenanthrene in test soils were still linear, and distribution was the predominant mechanism for phenanthrene adsorption by soil. The adsorption of phenanthrene was significantly enhanced by the addition of EOMs, and the enhancement of distribution constant (Kd) was positively correlated with the content of soil organic carbon (foc), indicating that the higher the soil foc, the more significant the promotion effect of EOMs addition on phenanthrene adsorption. On the contrary, the desorption of phenanthrene was obviously inhibited by the addition of EOMs. After 64 days of EOMs addition, the extractable amount of phenanthrene was decreased significantly, compared with the control. Since the organic matter content of peat was higher than that of commercial organic fertilizer, the decrease of extractable phenanthrene in soils added with peat was more significant. In addition, the higher the soil foc, the stronger inhibition effect of EOMs on extractability of phenanthrene. On the whole, exotic EOMs could promote the adsorption, while inhibit the desorption and reduce the extractability of phenanthrene in soils.