Spatial and Temporal Distributions of Polycyclic Aromatic Hydrocarbons in Sediments from the Canadian Arctic Archipelago

Abstract

<p>The concentrations of 23 polycyclic aromatic hydrocarbons (PAHs; 16 parent and 7 alkylated PAHs) in 113 surface marine sediment samples, 13 on-land sediment samples and 8 subsampled push cores retrieved from the Canadian Arctic Archipelago (CAA) were calculated. PAHs were extracted via accelerated solvent extraction (ASE) and quantified via gas chromatography-mass spectrometry (GC-MS). The sums of the concentrations 16 PAHs in the surface sediments ranged from 7.8 to 247.7 ng g<sup>-1</sup> (dry weight [dw]) basis). The PAH inputs to the sediments have remained constant during the last century and agree with the results obtained for the surface sediments. Diagnostic ratios indicated that the PAHs in the CAA mainly originate from natural petrogenic sources, with some pyrogenic sources. Temporal trends did not indicate major source shifts and largely indicated petrogenic inputs. Overall, the sediments retrieved from the CAA have low PAH concentrations that are mainly natural.</p>

Pre- and post-industrial levels of polycyclic aromatic hydrocarbons in sediments from the Estuary and Gulf of St. Lawrence (eastern Canada)

“…PAHs were extracted via the one-step integrated accelerated solvent extraction (ASE) method developed by Choi et al (2014) and implemented in other baseline studies targeting PAHs (e.g., Corminboeuf et al, 2021). Copper powder (<425 µm), which was activated with hydrochloric acid (HCl) 6 N, was employed to remove elemental sulfur, after which the samples were shaken for 3 min, rinsed with distilled water until a neutral pH was attained and then rinsed 3 times with both methanol and dichloromethane.…”

“…Regarding data processing, we followed the approach presented in Corminboeuf et al (2021) and used R software (R Core Team, 2021) to perform statistical analysis. Briefly, values below the detection limit were imputed via multiplicative lognormal replacement with the zCompositions package (Palarea-Albaladejo and Martin-Fernandez, 2015) to preserve the geometry of the compositional data while accounting for corresponding detection limit thresholds.…”

“…Because PAHs are emitted as a mixture and since their relative proportions depend on the emission sources, it is possible to determine the origin based on the diagnostic ratios between specific compounds (Tobiszewski and Namieśnik, 2012). The ratios of fluoranthene over the sum of fluoranthene and pyrene (Fla/[Fla+Pyr]) and of benz(a)anthracene over the sum of benz(a)anthracene and chrysene (BaA/[BaA+Chr]) are generally considered for sediments (e.g., Yunker et al, 2002;Foster et al, 2015;Gu et al, 2013Gu et al, , 2016Ma et al, 2017;Corminboeuf et al, 2021). Fla/[Fla+Pyr] values below 0.4 suggest a petrogenic source, while values between 0.4 and 0.5 are characteristic of fossil fuel combustion, and values above 0.5 indicate a biomass combustion source (Yunker et al, 2002).…”

Pre- and post-industrial levels of polycyclic aromatic hydrocarbons in sediments from the Estuary and Gulf of St. Lawrence (eastern Canada)

“…Indeed, the Σ16PAH concentration in the five pre-industrial samples (1006-1822 CE) ranges from 93 to 172 ng g −1 (mean value of 130 ng g −1 ), which is relatively low and comparable to that in worldwide regions under little to no anthropogenic pressure. For example, the Σ16PAH concentration in sediments retrieved from northern Baffin Bay ranges from 26 -199 ng g −1 (mean value of 106 ng g −1 ; Foster et al, 2015), and it ranges from 8 to 248 ng g −1 in the Canadian Arctic Archipelago (mean value of 57 ng g −1 ; Corminboeuf et al, 2021). Conversely, the Σ16PAH concentration in the two postindustrial samples (1937( -1943 is higher, ranging from 1216 to 1621 ng g −1 (mean value of 1419 ng g −1 ), which is 2.5 times higher on average than the PAH concentration in all surface samples (Fig.…”