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How suitable are peat cores to study historical deposition of PAHs?

机译：泥炭芯对研究PAHs的历史沉积有多合适？

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Ombrotrophic peat bogs are natural archives of atmospheric pollution, their depth profiles can be used to study the deposition chronology of harmful contaminants. Prerequisites for deriving historical deposition rates from the peat archive are that contaminants are persistent and immobile in the peat and that the applied dating technique is accurate. To examine these requirements and the accuracy of peat archives for polycydic aromatic hydrocarbons (PAHs) 12 peat profiles were sampled in 4 bogs in Ontario, Canada, as well as surface peat in one bog. Additionally we carried out laboratory incubations; no degradation occurred over a 3-year period in these experiments. The standard deviations of PAH concentrations in surface samples and of PAH inventories in whole cores was approximately 30%, and concentrations in surface peat were on average 50% higher in hollows than in hummocks. No indications for mobility of PAHs were observed in peat Temporal deposition trends inferred from peat cores were generally in agreement with trends derived from a sediment core sampled close by but deposition rates to the sediment were substantially higher. A major source of uncertainty was the rather coarse vertical sampling resolution of 5 cm which introduced substantial uncertainty in the dating of the individual segments. This caused variations of the deposition rates up to 70% per PAH between three replicate cores, and it also impedes the identification of deposition peaks. Overall, we conclude that peat cores are suitable archives for inferring atmospheric deposition trends, but due to their relatively low temporal resolution short-term events may not be identified and the development of sampling methods that allow a higher vertical resolution would greatly improve the performance of the method. The analysis of more than one core per site is suggested to provide a realistic estimate of the historic deposition and total inventories.
机译：脐营养泥炭沼泽是大气污染的自然档案，它们的深度剖面可以用于研究有害污染物的沉积时间。从泥炭档案中得出历史沉积速率的先决条件是，泥炭中的污染物是持久的且不可移动，并且所应用的测年技术是准确的。为了检查这些要求以及多环芳烃（PAHs）泥炭档案库的准确性，在加拿大安大略省的4个沼泽中取样了12个泥炭剖面，在一个沼泽中取样了12个泥炭剖面。另外，我们进行了实验室培养。在这些实验中，在3年内未发生降解。表面样品中PAH浓度和整个岩心中PAH存量的标准偏差约为30％，中空地表泥炭中的浓度平均比山岗中高50％。在泥炭中未观察到PAHs迁移的迹象，从泥炭芯推断出的时间沉积趋势与从附近取样的沉积物芯获得的趋势基本一致，但沉积物的沉积速率明显更高。不确定性的主要来源是5 cm的较粗的垂直采样分辨率，这在各个节段的日期中引入了很大的不确定性。这导致三个复制磁芯之间每个PAH的沉积速率变化高达70％，并且还阻碍了沉积峰的识别。总的来说，我们得出的结论是，泥炭岩心是推断大气沉积趋势的合适档案，但是由于它们相对较低的时间分辨率，短期事件可能无法确定，而允许更高垂直分辨率的采样方法的发展将极大地改善泥炭的性能。方法。建议对每个站点的一个以上核心进行分析，以提供对历史沉积和总库存的现实估计。

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