Analysis of oxygenated polycyclic aromatic hydrocarbons in contaminated soil and water systems to Inform remediation strategy and risk assessment

Polycyclic aromatic hydrocarbons (PAH) have been regulated as priority pollutants since the 1970’s. Since then, there has been increasing recognition that oxygenated PAH transformation products may present a greater risk than parent PAH. This is a concern for soil remediation sites where formation of oxygenated PAH can be accelerated. Currently, routine monitoring is challenged due to a lack of standard analytical protocols. This thesis applies new analytical methods to investigate the formation and distribution of oxygenated PAH in contaminated soil-water systems under different remediation scenarios. High performance liquid chromatography and gas chromatography - mass spectrometry were used to investigate the effect of lignin phenol amendments on PAH transformation processes in a simulated soil-water system. Samples with highest PAH attenuation were characterised by increased utilisation of lignin phenols and distinct patterns of oxygenated PAH removal/formation, suggesting a potential approach to enhance PAH biodegradation. Challenges for analysing soilbound oxygenated PAH were addressed through the development of a novel aminopropylsilica solid phase extraction method. Strong recoveries of ketone- and hydroxyl-modified PAH were obtained, and the method also supported limited qualitative analysis for acid and aldehyde products. In addition, contamination level and clay content were shown to influence recovery of targeted compounds from different soils. Combining analytical methods for total extractable, leachate, and readily available soil fractions, the distribution of oxygenated PAH in gasworks soils undergoing remediation was monitored over a six-month period. Biochar, compost, and no amendment treatments were compared for effects on contaminant degradation/formation, and contaminant lability. It was shown that the biochar amendment was most likely to increase, and compost amendment most likely to decrease, risks associated with oxygenated PAH in these soils. Together, these studies show how new analytical techniques for the detection of oxygenated PAH can be used to enhance remediation science and support decision making at remediation sites

Analysis of oxygenated polycyclic aromatic hydrocarbons in contaminated soil and water systems to Inform remediation strategy and risk assessment

Polycyclic aromatic hydrocarbons (PAH) have been regulated as priority pollutants since the 1970’s. Since then, there has been increasing recognition that oxygenated PAH transformation products may present a greater risk than parent PAH. This is a concern for soil remediation sites where formation of oxygenated PAH can be accelerated. Currently, routine monitoring is challenged due to a lack of standard analytical protocols. This thesis applies new analytical methods to investigate the formation and distribution of oxygenated PAH in contaminated soil-water systems under different remediation scenarios. High performance liquid chromatography and gas chromatography - mass spectrometry were used to investigate the effect of lignin phenol amendments on PAH transformation processes in a simulated soil-water system. Samples with highest PAH attenuation were characterised by increased utilisation of lignin phenols and distinct patterns of oxygenated PAH removal/formation, suggesting a potential approach to enhance PAH biodegradation. Challenges for analysing soilbound oxygenated PAH were addressed through the development of a novel aminopropylsilica solid phase extraction method. Strong recoveries of ketone- and hydroxyl-modified PAH were obtained, and the method also supported limited qualitative analysis for acid and aldehyde products. In addition, contamination level and clay content were shown to influence recovery of targeted compounds from different soils. Combining analytical methods for total extractable, leachate, and readily available soil fractions, the distribution of oxygenated PAH in gasworks soils undergoing remediation was monitored over a six-month period. Biochar, compost, and no amendment treatments were compared for effects on contaminant degradation/formation, and contaminant lability. It was shown that the biochar amendment was most likely to increase, and compost amendment most likely to decrease, risks associated with oxygenated PAH in these soils. Together, these studies show how new analytical techniques for the detection of oxygenated PAH can be used to enhance remediation science and support decision making at remediation sites

Analytical progress and challenges for the detection of oxygenated polycyclic aromatic hydrocarbon transformation products in aqueous and soil environmental matrices: A review

Over the past 20 years, a growing body of research has raised concerns about the toxicity, fate, and transport of oxygenated transformation products of polycyclic aromatic hydrocarbons. Research targeting these diverse compounds in soil and water systems has been challenged by a lack of standard analytical techniques and suitable reference materials. However, recent efforts towards the consolidation of traditional analytical techniques as well as the development of novel approaches to improve sample preparation and hyphenated instrumental techniques show promise. This review discusses progress and challenges for both trends in analytical method development and makes recommendations for supporting oxygenated PAH research

Recovery of polycyclic aromatic hydrocarbons and their oxygenated derivatives in contaminated soils using aminopropyl silica solid phase extraction

The formation, fate, and toxicology of oxy-, hydroxy-, and carboxy- substituted PAH (OPAH, OHPAH, COOHPAH, respectively) alongside PAH in contaminated soils have received increasing attention over the past two decades; however, there are still to date no standardized methods available for their identification and quantitation in soil. Here we investigated and developed the first method using aminopropylsilica solid phase extraction (SPE) for these compounds. We further investigated the efficacy of the developed method for three soils representing a range of contamination levels and soil textural characteristics and evaluated the impact of different sample preparation steps on the recovery of targeted compounds. Average recovery of PAH, OPAH, and OHPAH standards were 99%, 84%, and 86%, respectively for the SPE method. In contrast, COOHPAH exhibited the lowest recovery (0–82%) and poor inter-batch reproducibility. Soil texture and contamination levels influenced full method efficiency. Specifically, soils with higher proportion of clay contributed to the loss of the higher molecular weight OHPAH prior to SPE. Soil with the highest contamination showed enhanced recovery of some lower-concentration mid weight PAH and OPAH, while the least contaminated soil showed greater sensitivity to evaporative losses during sample preparation. Recommendations for reducing matrix effects as well as the practice of using deuterated PAH surrogate standards for OPAH analysis are further discussed. Quantitation of recovered PAH and oxygenated PAH across the three soils showed high reproducibility (<10% relative standard deviation for a majority of compounds), supporting the use of this method for PAH, OPAH, and OHPAH at contaminated sites

Notes on magnetic susceptibility in the Guil Valley alluvial mire correlated with the Punic invasion of Italia in 218 BC

The enigma of Hannibal’s route across the Alps in 218 BC is one of the most enduring questions of antiquity. Many authorities, some of whom have never ventured into the mountains, have argued for various preferred crossings of the Alps. Earlier efforts to identify the route focused on the two-tier rockfall and regrouping area on the lee side of the Range, originally described by Polybius in his The Rise of the Roman Empire, by Livy in The War with Hannibal, and later by Sir Gavin de Beer who searched out the topography and stream dynamics in the area of several projected crossing routes. Recently, attention shifted to the alluvial mire in the upper Guil River after cores and sections (sites G5 and G5A, Mahaney et al., 2016a) revealed the presence of churned-up or bioturbated beds, called the Mass Animal Deposition (MAD) layer. At approximately 45 ±15 cm depth, the top of the MAD layer contains abundant bacteria belonging to the class Clostridia that are found in the mammalian gut and fecal deposits, all dated by AMS 14C to 2168 cal yr BP (i.e., 218 BC with a 95% confidence interval). Samples for magnetic susceptibility collected from three additional sections (G5B, G5C and G5D) carrying the churned-up beds reveal heightened magnetic intensity within these bioturbated sediments that is suggestive of high magnetite content, one form of iron that often was used to cast weapons in ancient times. Magnetic susceptibility levels are highest within the churned-up beds with minor exceptions in two of the three sections analyzed, possibly indicating the presence of weathered tools, implements or weapons lost or discarded. The available data is sufficient to suggest that a GPR survey of the entire mire might well lead to recovery of the first artifacts from the invasion that would shed enormous light on the culture of ancient Carthage