Séquaris J-M, Lavorenti A, Burauel P
Agrosphere Institute, ICG IV, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany.
Environ Pollut. 2005 Jun;135(3):491-500. doi: 10.1016/j.envpol.2004.10.018.
Equilibrium partitioning of hydrophobic (14)C-benzo(a)pyrene and hydrophilic (14)C-benazolin between fractionated phases from an arable topsoil of Merzenhausen (Germany) was investigated. Topsoil samples were collected from lysimeters which were incubated with different residual crops. A physical soil fractionation based on sedimentation and centrifugation steps was performed after water extraction. Four soil phases were obtained designated sediment (SED) phase (>20 microm), microaggregate (MA) phase (2 microm-20 microm), colloid (COL) phase (<2 microm) and electrolyte (EL) phase. The distribution of (14)C-benzo(a)pyrene, (14)C-benazolin and organic carbon between the soil phases was established. Enrichment factors for the two chemicals and organic carbon are higher in the COL and MA phases than in the SED phase. The distribution constant K(d) of chemicals for Merzenhausen topsoil was calculated according to two-phase or three-phase partitioning models. The three-phase partitioning model presumes the contribution of the organic carbon for the binding of chemicals. A log K(oc) of 5.55 can be calculated in the case of (14)C-benzo(a)pyrene, which is typical of the hydrophobic association with the soil organic carbon. In the case of (14)C-benazolin, much higher K(d) and K(oc) values were calculated than found with parent molecules after short-time experiments. Long-term aging processes must be considered. Specific effects on the chemical distribution due to the different crop residues were not detected.
研究了德国梅尔岑豪森耕地表层土壤中疏水性的（14）C - 苯并（a）芘和亲水性的（14）C - 麦锈灵在分级相之间的平衡分配。从装有不同残留作物的蒸渗仪中采集表层土壤样本。水提取后，基于沉降和离心步骤进行物理土壤分级。得到了四个土壤相，分别为沉积物（SED）相（>20微米）、微团聚体（MA）相（2微米 - 20微米）、胶体（COL）相（<2微米）和电解质（EL）相。确定了（14）C - 苯并（a）芘、（14）C - 麦锈灵和有机碳在土壤相之间的分布。两种化学物质和有机碳在COL相和MA相中的富集因子高于SED相。根据两相或三相分配模型计算了梅尔岑豪森表层土壤中化学物质的分配常数K（d）。三相分配模型假定有机碳对化学物质结合的贡献。对于（14）C - 苯并（a）芘，可计算出log K（oc）为5.55，这是与土壤有机碳疏水缔合的典型特征。对于（14）C - 麦锈灵，在短期实验后计算出的K（d）和K（oc）值比母体分子高得多。必须考虑长期老化过程。未检测到不同作物残体对化学物质分布的特定影响。
