【摘要】 研究了来源于稻草腐熟物的外源水溶性有机质(DOM)和土壤本身固有的内源DOM对有机碳含量不同的3种土壤吸附菲的影响.结果表明,不同处理土壤对菲的吸附曲线均为线性,其吸附系数(Kd)与土壤有机碳含量(foc)正相关.去除内源DOM后,黄棕壤、红粘田和黑土吸附菲的Kd值增加了7.08%～21.4%,增加量(ΔKd)和增加幅度与foc正相关,表明土壤中存在的内源DOM抑制土壤对菲的吸附.而外源DOM对土壤吸附菲的影响与其浓度密切相关.在供试浓度范围(0～106mgDOC.L-1)内,红粘田吸附菲的Kd值随加入外源DOM浓度的提高先增大后减小.外源DOM浓度为28mgDOC.L-1时,红粘田吸附菲的Kd值增加了19.5%;而当外源DOM浓度≥52mgDOC.L-1时,则明显抑制菲的吸附.内源和外源DOM对土壤吸附菲的影响,主要与DOM和菲在溶液中的结合作用、在土壤中的累积吸附效应等有关.更多还原

【Abstract】 This paper studied the effects of exotic and native dissolved organic matter (DOM) on the phenanthrene adsorption by three soils differed in soil organic carbon content (foc). The exotic DOM came from decayed rice straw, while the native DOM was extracted from the test soils. In all cases, the adsorption of phenanthrene by treated soils could be well described with linear-type model, and there was a positive correlation between adsorption coefficient (Kd) and foc. Compared with the control, the Kd value of test soils after native DOM removed was increased by 7.08%—21.4%, and the increment (ΔKd) was positively correlated with foc, indicating that the presence of soil native DOM impeded the phenanthrene adsorption by soil. The effects of exotic DOM on phenanthrene adsorption had a close relation with its added concentration in soil-water system. Within the range of 0—106 mg DOC·L-1, the Kd value increased first, and then decreased with the increase of added exotic DOM concentration. Lower concentrations of added exotic DOM promoted the phenanthrene adsorption by soil, while higher concentrations (≥52 mg DOC·L-1) of it obviously impeded this adsorption. These effects of exotic and native DOM on soil phenanthrene adsorption were considered to be related to the association of phenanthrene with DOM in solution, and the ‘cumulative adsorption effect’ between soil solid and aqueous phases.更多还原