Formation of nonextractable soil residues:: A stable isotope approach
Formation of nonextractable soil residues:: A stable isotope approach
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DOI：
10.1021/es980927n
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发表时间：
1999-11-01
影响因子：
11.4
通讯作者：
Michaelis, W
中科院分区：
文献类型：
--
作者：
Richnow, HH;Eschenbach, A;Michaelis, W
利用稳定碳同位素技术研究了碳13标记的多环芳烃蒽在土壤生物反应器中的转化过程。C-13标记用于计算碳质量平衡，包括矿化和不可提取的土壤结合残留物的形成。从C-13-标记的碳和C-14-标记的碳质量平衡计算中获得了类似的结果，用于标记蒽的单独批次实验。在真实的多环芳烃污染场地的典型浓度范围内，C-13示踪法的灵敏度符合经典放射性示踪实验的要求。因此，我们的平衡方法的基础上稳定的同位素标记的化学品可以补充或替代放射性示踪剂实验在许多情况下。使用稳定同位素标记示踪剂的一个主要优点是可能应用于转化研究，其中使用放射性物质是环境问题。C-13标记的多环芳烃转化为不可提取的残留物显然取决于土壤微生物区系的代谢活动，并发生在生物降解的早期阶段。土壤连续受到蒽污染，导致微生物区系逐渐适应帆中蒽的完全矿化。残留物形成的程度由微生物菌群降解污染物的能力控制。长期实验结果表明，不可提取残留物随时间推移相对稳定。
Stable carbon isotopic measurements were employed to characterize the transformation of a C-13-labeled polycyclic aromatic hydrocarbon (PAH), anthracene, in a closed soil bioreactor system. The C-13-label was used to calculate a carbon mass balance including mineralization and the formation of nonextractable soil-bound residues. Similar results were obtained from C-13-labeled carbon and C-14-labeled carbon mass balance calculations for separate batch experiments with labeled anthracene. In concentration ranges typical for real PAH-contaminated sites, the sensitivity of the C-13 tracer method meets the requirements of classical radiotracer experiments. Therefore, our balancing method based on stable isotope-labeled chemicals may supplement or substitute radiotracer experiments under many circumstances. One major advantage of using stable isotope-labeled tracers is the possible application in transformation studies where the use of radioactive substances is of environmental concern. The transformation of C-13-labeled PAH into nonextractable residues clearly depends on the metabolic activity of the soil microflora and occurs during an early phase of biodegradation. Successive contamination of the soil by anthracene leads to a progressive adaptation of the microflora to a complete mineralization of anthracene in the sail. The extent of residue formation is controlled by the capability of the microflora to degrade the contaminant. Results of long-term experiments indicate that nonextractable residues are relatively stable over time.