Sources of Oxygenated Polycyclic Aromatic Hydrocarbons (OPAHs) in soils – a compound-specific stable isotope approach

土壤中含氧多环芳烃 (OPAH) 的来源 â 化合物特异性稳定同位素方法

• 批准号: 537676254
• 负责人: Professor Dr. Wolfgang Wilcke
• 金额: --
• 依托单位: Institut für Geographie und Geoökologie (IFGG)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/537676254?language=en
• 关键词: Sources; Oxygenated; Polycyclic; Aromatic; Hydrocarbons

Oxygenated polycyclic aromatic hydrocarbons (OPAHs) can be produced during combustion of organic materials or secondary transformations of parent-PAHs in the environment. Several OPAHs show a higher toxicity, bioavailability, and mobility in soil than their parent-PAHs. To assess the environmental risk arising from PAH and OPAH contamination requires the understanding of the production of OPAHs. Thus, there is a need to distinguish the primary (i.e., combustion-derived), secondary photochemical, and secondary microbial sources of OPAHs and to improve our understanding of the transformation of PAHs to OPAHs in soils. We aim to provide a novel stable isotope ratio-based tool to distinguish between the OPAH sources in aerosol and soil at the example of the parent compound-derivative pair anthracene (ANTH) and 9,10-anthraquinone (9,10-AQ), the frequently most abundant OPAH. We will test five hypotheses: (i) Primary and secondary 9,10-AQ can be distinguished with the help of their compound-specific C and H isotope ratios (d13C and d2H values). (ii) Photochemically produced 9,10-AQ shows a specific 2H value. (iii) The differences in the d13C and d2H values of 9,10-AQ from the three sources (primary, secondary photochemical, secondary microbial) allow for the solution of a three-end-member mixing model. (iv) The contribution of biologically produced 9,10-AQ increases with microbial activity in soil measured as CO2-evolution from plant-free microcosms and the contribution of photochemically produced 9,10-AQ is higher in rural than in urban soils. (v) When the soil microorganisms are poisoned, no OPAHs are produced from parent-PAHs during incubation. To test the five hypotheses, we will realize three work packages (WPs). Each WP includes an experimental and an observational component. In the first WP, we will characterize the d13C and d2H values of ANTH, benz(a)pyrene [B(A)P] as an entirely combustion-derived reference PAH and 9,10-AQ in the total in the atmosphere suspended particles (TSPs) from primary emissions (combustion of biomass and fossil fuels). In the second WP, we will determine d13C and d2H values of 9,10-AQ from photochemical secondary formation in the atmosphere and in the third WP from microbial secondary transformation in the soil. We will collect TSPs from the emissions of experimental biomass and fossil fuel combustion and from urban and rural atmosphere. We will expose ANTH sorbed to a muck aerosol to solar irradiation in glass spheres. Moreover, we will conduct microbial turnover experiments in microcosms with rural soils to which ANTH will be spiked. We will study the vertical distribution and compound-specific d13C and d2H values of ANTH, B(A)P, and 9,10-AQ in moder-type forest organic layers where the microbial turnover of PAHs progresses with depth. In all TSP and soil samples, we will determine PAH and OPAH concentrations and compound-specific d13C and d2H values of ANTH, 9,10-AQ, and partly also B(A)P.

含氧多环芳烃（OPAHs）是有机物燃烧或母体多环芳烃在环境中二次转化过程中产生的产物。几种OPAHs在土壤中的毒性、生物有效性和迁移性均高于其母体多环芳烃。为了评估多环芳烃和邻苯二甲酸多环芳烃污染所产生的环境风险，需要了解邻苯二甲酸多环芳烃的产生。因此，需要区分主要的（即，燃烧衍生的），二次光化学，和二次微生物来源的OPAHs和提高我们的理解的多环芳烃转化为OPAHs在土壤中。我们的目标是提供一种新的稳定同位素比率为基础的工具，以区分气溶胶和土壤中的OPAH来源的母化合物衍生物对蒽（ANTH）和9，10-蒽醌（9，10-AQ），经常最丰富的OPAH的例子。我们将测试五个假设：（i）初级和次级9，10-AQ可以借助其化合物特定的C和H同位素比率（d13 C和d2 H值）来区分。(ii)光化学产生的9，10-AQ显示出特定的Δ 2 H值。(iii)在d13 C和d2 H值的差异，9，10-AQ从三个来源（初级，二级光化学，二级微生物）允许的解决方案的三个端元混合模型。(iv)生物产生的9，10-AQ的贡献增加与土壤中的微生物活性测量的CO2-演变从无植物的微观世界和光化学产生的9，10-AQ的贡献是在农村比城市土壤中更高。(v)当土壤微生物被毒害时，在培养过程中没有OPAHs从母体-PAHs产生。为了验证这五个假设，我们将实现三个工作包（WP）。每个WP包括一个实验和观测部分。在第一个WP中，我们将表征ANTH、苯并（a）芘[B（A）P]（作为完全燃烧衍生的参考PAH）和9，10-AQ在大气中的总悬浮颗粒（TSP）中的d13 C和d2 H值，这些悬浮颗粒来自一次排放（生物质和化石燃料的燃烧）。在第二个WP中，我们将从大气中的光化学次级形成中确定9，10-AQ的d13 C和d2 H值，在第三个WP中从土壤中的微生物次级转化中确定9，10-AQ的d13 C和d2 H值。我们将从实验生物质和化石燃料燃烧的排放物以及城市和农村大气中收集TSP。我们将在玻璃球中将吸附在淤泥气溶胶中的ANTH暴露于太阳辐射。此外，我们将进行微生物周转实验与农村土壤的ANTH将被扣球的缩影。我们将研究ANTH、B（A）P和9，10-AQ在中度森林有机层中的垂直分布和化合物特异性d13 C和d2 H值，其中PAHs的微生物周转随深度而进行。在所有TSP和土壤样品中，我们将测定PAH和OPAH浓度以及ANTH、9，10-AQ和部分B（A）P的化合物特异性d13 C和d2 H值。