UFZ - Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstrasse 15, 04318 Leipzig, Germany.
Isodetect GmbH, Deutscher Platz 5b, 04103 Leipzig, Germany.
Water Res. 2015 Feb 1;69:100-109. doi: 10.1016/j.watres.2014.10.045. Epub 2014 Nov 8.
The number of approaches to evaluate the biodegradation of polycyclic aromatic hydrocarbons (PAHs) within contaminated aquifers is limited. Here, we demonstrate the applicability of a novel method based on the combination of in situ and laboratory microcosms using (13)C-labelled PAHs as tracer compounds. The biodegradation of four PAHs (naphthalene, fluorene, phenanthrene, and acenaphthene) was investigated in an oxic aquifer at the site of a former gas plant. In situ biodegradation of naphthalene and fluorene was demonstrated using in situ microcosms (BACTRAP(®)s). BACTRAP(®)s amended with either [(13)C6]-naphthalene or [(13)C5/(13)C6]-fluorene (50:50) were incubated for a period of over two months in two groundwater wells located at the contaminant source and plume fringe, respectively. Amino acids extracted from BACTRAP(®)-grown cells showed significant (13)C-enrichments with (13)C-fractions of up to 30.4% for naphthalene and 3.8% for fluorene, thus providing evidence for the in situ biodegradation and assimilation of those PAHs at the field site. To quantify the mineralisation of PAHs, laboratory microcosms were set up with BACTRAP(®)-grown cells and groundwater. Naphthalene, fluorene, phenanthrene, or acenaphthene were added as (13)C-labelled substrates. (13)C-enrichment of the produced CO2 revealed mineralisation of between 5.9% and 19.7% for fluorene, between 11.1% and 35.1% for acenaphthene, between 14.2% and 33.1% for phenanthrene, and up to 37.0% for naphthalene over a period of 62 days. Observed PAH mineralisation rates ranged between 17 μg L(-1) d(-1) and 1639 μg L(-1) d(-1). The novel approach combining in situ and laboratory microcosms allowed a comprehensive evaluation of PAH biodegradation at the investigated field site, revealing the method's potential for the assessment of PAH degradation within contaminated aquifers.
在受污染的含水层中评估多环芳烃（PAHs）生物降解的方法数量有限。在这里，我们展示了一种基于原位和实验室微宇宙结合使用（13）C 标记 PAHs 作为示踪化合物的新方法的适用性。在一个曾经的煤气厂遗址的好氧含水层中，研究了四种 PAHs（萘、芴、菲和苊）的生物降解。使用原位微宇宙（BACTRAP（®））证明了萘和芴的原位生物降解。在两个位于污染源和羽流边缘的地下水井中，分别用（13）C6-萘或（13）C5/（13）C6-芴（50:50）修饰的 BACTRAP（®）孵育了两个多月。从 BACTRAP（®）生长的细胞中提取的氨基酸显示出明显的（13）C 富集，萘的（13）C 分数高达 30.4%，芴的（13）C 分数为 3.8%，这为现场 PAHs 的原位生物降解和同化提供了证据。为了量化 PAHs 的矿化，使用 BACTRAP（®）生长的细胞和地下水建立了实验室微宇宙。将萘、芴、菲或苊添加为（13）C 标记的底物。产生的 CO2 的（13）C 富集表明，在 62 天的时间内，氟苯的矿化率为 5.9%至 19.7%，苊的矿化率为 11.1%至 35.1%，菲的矿化率为 14.2%至 33.1%，萘的矿化率高达 37.0%。观察到的 PAH 矿化速率范围为 17μg L（-1）d（-1）至 1639μg L（-1）d（-1）。这种结合原位和实验室微宇宙的新方法允许对研究现场的 PAH 生物降解进行全面评估，揭示了该方法在评估受污染含水层中 PAH 降解方面的潜力。
