Polycyclic Aromatic Hydrocarbons (PAHs) Quantified in Large-Scale Fire Experiments

2011 ◽  
Vol 48 (2) ◽  
pp. 513-528 ◽  
Author(s):  
Per Blomqvist ◽  
Margaret Simonson McNamee ◽  
Petra Andersson ◽  
Anders Lönnermark
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Large Scale ◽  
Polycyclic Aromatic ◽  
Fire Experiments

Using polycyclic aromatic hydrocarbons to determine post-wildfire contamination and sediment sources in a large watershed in central British Columbia, Canada

2021 ◽  
Author(s):  
Kristen Kieta ◽  
Philip Owens ◽  
Ellen Petticrew
Keyword(s):  
British Columbia ◽  
Magnetic Susceptibility ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Large Scale ◽  
Sediment Samples ◽  
Burned Areas ◽  
Total Pahs ◽  
Polycyclic Aromatic ◽  
The Impact

<p>The Nechako River Basin (NRB) in central British Columbia is a large (52,000 km<sup>2</sup>), regulated basin that supports populations of sockeye and chinook salmon and the endangered Nechako white sturgeon. These important species are experiencing population declines and one potential cause of this decline is excess sediment, which can clog their spawning habitat and reduce juvenile success. This excess sediment is likely the product of a combination of factors, the most visible being the significant land cover changes that have occurred in the basin, which includes pressure from forestry and agriculture, the Mountain Pine Beetle epidemic, and large-scale wildfires in 2018. Focusing specifically on the impact of the 2018 wildfires on sediment transport from upland burned areas to adjacent waterways, this research aimed to determine the spatial and temporal contamination of tributaries and the mainstem of the Nechako River with polycyclic aromatic hydrocarbons (PAHs), which are produced during the combustion of organic matter and have been identified as toxic to aquatic organisms and to humans. Additionally, this study intended to determine if burned areas were a more significant contributor of sediment than unburned areas and better understand the utility of PAHs as a potential tracer. Source soil samples were collected in 2018 and 2020 from burned and unburned sites, and suspended sediment samples were collected throughout the ice-free period from 2018-2020 in three tributaries and three mainstem sites. All samples were analysed for PAHs, magnetic susceptibility, colour, and particle size. Results from the fall 2018 source samples show a significant difference in PAH concentrations between unburned and burned soils, and while concentrations of PAHs in source soils in 2020 were lower than in 2018, they were still elevated compared to unburned soils. Sediment samples showed that concentrations of total PAHs are higher in the mainstem sites than in the tributaries, with the greatest concentrations consistently found at the most downstream site on the mainstem of the Nechako River. Concentrations across sites were highest in samples taken during the spring snowmelt period in 2019, have decreased throughout the rest of the sampling period (2019-2020), and are well below sediment quality guidelines for total PAHs. In addition to determining the spatial and temporal extent of PAH contamination, this study also aims to use PAHs along with colour and measurements of magnetic susceptibility to trace sediments associated with the 2018 wildfires. The high cost of PAH analysis limits the number of samples that can be analysed and thus, these additional tracers will allow for the use of models such as MixSIAR that improve with a more robust number of samples. As large-scale megafires continue to burn across the globe, understanding their potential to contribute PAHs to local waterbodies and potentially be used as a tracer is as prescient as ever.</p>

scholarly journals Bioremediation of Polycyclic Aromatic Hydrocarbons from Industry Contaminated Soil Using Indigenous Bacillus spp.

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1606
Author(s):  
Prisha Mandree ◽  
Wendy Masika ◽  
Justin Naicker ◽  
Ghaneshree Moonsamy ◽  
Santosh Ramchuran ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Control System ◽  
Aromatic Hydrocarbons ◽  
Contaminated Soil ◽  
Environmental Remediation ◽  
Large Scale ◽  
Soil System ◽  
Polycyclic Aromatic ◽  
Bacillus Spp

Polycyclic aromatic hydrocarbons (PAHs) are reportedly toxic, ubiquitous and organic compounds that can persist in the environment and are released largely due to the incomplete combustion of fossil fuel. There is a range of microorganisms that are capable of degrading low molecular weight PAHs, such as naphthalene; however, fewer were reported to degrade higher molecular weight PAHs. Bacillus spp. has shown to be effective in neutralizing polluted streams containing hydrocarbons. Following the growing regulatory requirement to meet the PAH specification upon disposal of contaminated soil, the following study aimed to identify potential Bacillus strains that could effectively remediate low and high molecular weight PAHs from the soil. Six potential hydrocarbon-degrading strains were formulated into two prototypes and tested for the ability to remove PAHs from industry-contaminated soil. Following the dosing of each respective soil system with prototypes 1 and 2, the samples were analyzed for PAH concentration over 11 weeks against an un-augmented control system. After 11 weeks, the control system indicated the presence of naphthalene (3.11 µg·kg−1), phenanthrene (24.47 µg·kg−1), fluoranthene (17.80 µg·kg−1) and pyrene (28.92 µg·kg−1), which illustrated the recalcitrant nature of aromatic hydrocarbons. The soil system dosed with prototype 2 was capable of completely degrading (100%) naphthalene, phenanthrene and pyrene over the experimental period. However, the accumulation of PAHs, namely phenanthrene, fluoranthene and pyrene, were observed using prototype 1. The results showed that prototype 2, consisting of a combination of Bacillus cereus and Bacillus subtilis strains, was more effective in the biodegradation of PAHs and intermediate products. Furthermore, the bio-augmented system dosed with prototype 2 showed an improvement in the overall degradation (10–50%) of PAHs, naphthalene, phenanthrene and pyrene, over the un-augmented control system. The following study demonstrates the potential of using Bacillus spp. in a bioremediation solution for sites contaminated with PAHs and informs the use of biological additives for large-scale environmental remediation.

scholarly journals Carbonaceous aerosol composition in air masses influenced by large-scale biomass burning: a case study in northwestern Vietnam

2021 ◽  
Vol 21 (10) ◽  
pp. 8293-8312
Author(s):  
Dac-Loc Nguyen ◽  
Hendryk Czech ◽  
Simone M. Pieber ◽  
Jürgen Schnelle-Kreis ◽  
Martin Steinbacher ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Organic Compounds ◽  
Biomass Burning ◽  
Aromatic Hydrocarbons ◽  
Large Scale ◽  
Organic Aerosol ◽  
Reference Dataset ◽  
Air Masses ◽  
World Regions ◽  
Polycyclic Aromatic

Abstract. We investigated concentrations of organic carbon (OC), elemental carbon (EC), and a wide range of particle-bound organic compounds in daily sampled PM2.5 at the remote Pha Din (PDI) – Global Atmosphere Watch (GAW) monitoring station in northwestern Vietnam during an intense 3-week sampling campaign from 23 March to 12 April 2015. The site is known to receive trans-regional air masses during large-scale biomass burning (BB) episodes. BB is a globally widespread phenomenon and BB emission characterization is of high scientific and societal relevance. Emissions composition is influenced by multiple factors (e.g., fuel and thereby vegetation type, fuel moisture, fire temperature, available oxygen). Due to regional variations in these parameters, studies in different world regions are needed. OC composition provides valuable information regarding the health- and climate-relevant properties of PM2.5. Yet, OC composition studies from PDI are missing in the scientific literature to date. Therefore, we quantified 51 organic compounds simultaneously by in situ derivatization thermal desorption gas chromatography and time-of-flight mass spectrometry (IDTD-GC-TOFMS). Anhydrosugars, methoxyphenols, n-alkanes, fatty acids, polycyclic aromatic hydrocarbons, oxygenated polycyclic aromatic hydrocarbons, nitrophenols, and OC were used in a hierarchical cluster analysis highlighting distinctive patterns for periods under low, medium, and high BB influence. The highest particle phase concentration of the typical primary organic aerosol (POA) and possible secondary organic aerosol (SOA) constituents, especially nitrophenols, were found on 5 and 6 April. We linked the trace gas mixing ratios of methane (CH4), carbon dioxide (CO2), carbon monoxide (CO), and ozone (O3) to the statistical classification of BB events based on OA composition and found increased CO and O3 levels during medium and high BB influence. Likewise, a backward trajectory analysis indicates different source regions for the identified periods based on the OA clusters, with cleaner air masses arriving from the northeast, i.e., mainland China and the Yellow Sea. The more polluted periods are characterized by trajectories from the southwest, with more continental recirculation of the medium cluster and more westerly advection for the high cluster. These findings highlight that BB activities in northern Southeast Asia significantly enhance the regional organic aerosol loading and also affect the carbonaceous PM2.5 constituents and the trace gases in northwestern Vietnam. The presented analysis adds valuable data on the carbonaceous and chemical composition of PM2.5, in particular of OC, in a region of scarce data availability, and thus offers a reference dataset from Southeast Asian large-scale BB for future studies. Such a reference dataset may be useful for the evaluation of atmospheric transport simulation models, or for comparison with other world regions and BB types, such as Australian bush fires, African savannah fires, or tropical peatland fires.

scholarly journals Spatial variations, origins, and risk assessments of polycyclic aromatic hydrocarbons in French soils

2021 ◽  
Author(s):  
Claire Froger ◽  
Nicolas P. A. Saby ◽  
Claudy C. Jolivet ◽  
Line Boulonne ◽  
Giovanni Caria ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Soil Contamination ◽  
Aromatic Hydrocarbons ◽  
Large Scale ◽  
Steel Production ◽  
Spatial Variations ◽  
Molecular Diagnostic ◽  
Biomass Combustion ◽  
Diagnostic Ratios ◽  
Polycyclic Aromatic

Abstract. Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants produced by anthropogenic activities that contaminate all environmental spheres, including soils. This study focused on PAHs measured in 2154 soils in France, covering the entire territory based on a regular sampling grid. The quantified concentrations in the Σ15PAHs ranged from 5.1 to 31200 µg · kg−1, with a median value of 32.6 µg · kg−1, and PAHs were detected in 70 % of the soil samples. The map of Σ15PAHs concentrations revealed strong spatial variations in soil contamination throughout France, with larger concentrations in soils of industrial regions and near major cities. PAHs molecular diagnostic ratios supports the historical origin of PAHs in the northern part of France being linked to the significant emissions of PAHs in Europe during the industrial period of 1850–1950 with in particular the contribution of coal/biomass combustion and iron-steel production. A health risk assessment conducted for the residential population resulted in a median value of 1.07 × 10−8 in total lifetime cancer risk, with only 20 sites above the limit of 10−6 and one above the limit of 10−5 adopted by the French government. These results reveal the need to conduct large-scale studies on soil contamination to determine the fate of PAHs and evaluate the risks induced by soil pollution at a country-level scale.

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