Partitioning, extractability, and formation of nonextractable PAH residues in soil. 1. Compound differences in aging and sequestration
Partitioning, extractability, and formation of nonextractable PAH residues in soil. 1. Compound differences in aging and sequestration
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DOI：
10.1021/es000071y
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发表时间：
2001-03-15
影响因子：
11.4
通讯作者：
Jones, KC
中科院分区：
文献类型：
--
作者：
Northcott, GL;Jones, KC
研究了无菌污泥改性耕地帆的理化性质对其吸附多环芳烃的影响。放射性标记的菲（C-14-9-Phe），芘（c -14-4,5,9,10- pyr）和苯并[a]芘（C-14-7-B[a]P）在无菌土壤微环境中加标并陈化525天。在不同采样时间，化合物的固存程度通过有机溶剂的可萃取性和碱皂化萃取从土壤残留物中释放来确定。丁醇和二氯甲烷对土壤中多环芳烃的萃取量随复合老化而降低。多环芳烃可提取性随老化而降低，不可提取结合残基的形成随复合分子量、Kow和Koc的增加而增加。连续二氯甲烷soxtec和甲醇皂化提取测定的PAH总可提取量从第10天的98%、97%和94%下降到第525天的C-14-9-Phe、c -14-4,5、9、10- pyr和C-14-7-B[a]P的95%、91%和77%。在相同的老化时期，碱皂化提取过程中土壤中多环芳烃的释放量增加，表明多环芳烃逐渐扩散到土壤的可水解和难降解有机质和矿物相中。本实验中通过固存所计算的多环芳烃表观损失的半衰期取决于从土壤中提取多环芳烃的方法。根据化合物的不同，这些半衰期从96天到1789天不等，并且与以前使用非无菌土壤进行的穗化实验所得的值一致。这些结果表明，在以前的研究中假定已降解的多环芳烃的相当一部分可能已被隔离在有机碳中，并且在较小程度上被隔离在土壤的矿物相中。
This study was carried out to assess the influence of physicochemical properties on PAH sequestration in sterile sewage sludge-amended arable sail. Radiolabeled phenanthrene (C-14-9-Phe), pyrene (C-14-4,5,9,10-Pyr), and benzo[a]pyrene (C-14-7-B[a]P) were spiked and aged for up to 525 days in sterile soil microcosms. The degree of compound sequestration at various sampling times was determined by their extractability with organic solvents and release from soil residues by base saponification extraction. The amount of PAH extractable by butanol and dichloromethane decreased with compound aging in the soil. The decrease in PAH extractability with aging, and the formation of nonextractable bound residues, increased with compound molecular weight, Kow and Koc. The amount of total extractable PAH determined by sequential dichloromethane soxtec and methanolic saponification extraction decreased from 98%, 97%, and 94% at day 10 to 95%, 91%, and 77%, respectively for C-14-9-Phe, C-14-4,5,9,10-Pyr, and C-14-7-B[a]P after 525 days aging. During the same aging period there was an increase in the amount of PAH released from the soil by base saponification extraction, suggesting a progressive diffusion of PAHs into hydrolyzable and recalcitrant organic matter and mineral phases of soil. Calculated half-lives for the apparent loss of PAHs by sequestration in this experiment were dependent on the method used to extract them from soil. These half-lives ranged from 96 to 1789 days depending on the compound, and are in agreement with Values obtained from previous spiking experiments using nonsterile soils. These results suggest that a considerable fraction of PAHs assumed degraded in previous studies may have been sequestered within the organic carbon and, to a lesser extent, mineral phases of soil.