Ubiquitous Net Volatilization of Polycyclic Aromatic Hydrocarbons from Soils and Parameters Influencing Their Soil−Air Partitioning

Abstract

Soils are a major reservoir of organic pollutants, and soil-air partitioning and exchange are key processes controlling the regional fate of pollutants. Here, we report and discuss the soil concentrations of polycyclic aromatic hydrocarbons (PAHs), their soil fugacities, the soil-air partition coefficients (K(SA)) and soil-air gradients for rural and semirural soils, in background areas of N-NE Spain and N-NW England. Different sampling campaigns were carried out to assess seasonal variability and differences between sampling sites. K(SA) values were dependent on soil temperature and soil organic quantity and type. Soil fugacities of phenanthrene and its alkyl homologues were 1-2 orders of magnitude higher than their ambient air fugacities for all sampling sites and periods. The soil to air fugacity ratio was correlated with soil temperature and soil redox potential. Similar trends for other PAHs were found but with lower fugacity ratios. The ubiquitous source of PAHs from background soils to the atmosphere found in all temperate regions in different seasons provides an indirect evidence of potential in situ generation of two to four ring PAHs and their alkyl homologues in the surface soil. We discuss this hypothetical biogenic source and other potential processes that could drive the high soil to air fugacity ratios of some PAHs.

Occurrence, sources and transport pathways of natural and anthropogenic hydrocarbons in deep-sea sediments of the eastern Mediterranean Sea

“…PAHs of biogenic origin may also occur in environmental samples. Such evidence has been reported for perylene, retene (Laflamme and Hites, 1978;Wakeham et al, 1980) and phenanthrene (Cabrerizo et al, 2011;Nizzetto et al, 2008).…”

“…In the northern Ionian Sea, station H07 located off the Gulf of Taranto in southern Italy lies in an area subjected to anthropogenic pressure (Cardellicchio et al, 2007). Our hydrocarbon data indicate enhanced fossil inputs, reflected in the PAHs profile, the elevated Phe / COMB ratio values and the abundance of short-chain n-alkanes (Figs.…”

“…They are at least one order of magnitude lower than those reported for coastal areas subjected to enhanced urban and/or fluvial inputs such as Saronikos Gulf, Greece (Sklivagou et al, 2008); the coastal area off Barcelona, Spain (Tolosa et al, 1996); the Danube estuary, Black Sea (Readman et al, 2002;Wakeham, 1996); and the coastal area off Alexandria, Egypt (Aboul-Kassim and Simoneit, 1995). Total sedimentary PAH concentrations are also significantly lower than those reported for surface sediments in coastal/estuarine areas in the Mediterranean Sea and worldwide receiving enhanced anthropogenic inputs (e.g., Bouloubassi et al, 2012;Cardellicchio et al, 2007;Lipiatou and Saliot, 1991;Sklivagou et al, 2008;Tolosa et al, 1996;Witt, 1995). They are also lower than concentrations found in deep-sea settings such as the Black Sea (Wakeham, 1996), Cap Ferret Canyon/Atlantic Ocean (OSPAR QRS, 2000) and the Arctic Ocean (Yunker et al, 2011).…”

“…Aliphatic hydrocarbons and PAHs have been investigated over the last decades in surficial sediments of the EMS, primarily in coastal or shallow basin sites in the Aegean Sea, southern Italy, the coast of Egypt and the Adriatic Sea (Aboul-Kassim and Simoneit, 1995;Alebic-Juretic, 2011;Botsou and Hatzianestis, 2012;Cardellicchio et al, 2007;Gogou et al, 2000;Gonul and Kucuksezgin, 2012;Guzzella and De Paolis, 1994;Marcomini et al, 1986;Nemr et al, 2007;Sklivagou et al, 2008;Yilmaz et al, 1998). However, there is an important lack of data regarding their occurrence in deep basins, which might represent a long-term sink for hydrocarbons.…”

Sources and fate of polycyclic aromatic hydrocarbons in the Antarctic and Southern Ocean atmosphere

“…The exchange of PAHs between relevant terrestrial Antarctic surfaces (soil and snow) and the atmosphere was measured using four surface fugacity samplers [Cabrerizo et al, 2009] distributed at different sites of Livingston Island ( Figure S2, Annex I). The surface fugacity sampler has been previously developed by Cabrerizo et al [2009] and used in both temperate and polar regions [Cabrerizo et al, 2011a[Cabrerizo et al, , 2011b[Cabrerizo et al, , 2011c[Cabrerizo et al, , 2013. Briefly, the air is forced to flow first into a glass fiber filter (47 mm GF/F, Whatman International Ltd., Maidstone, England) to remove aerosols and then through a polyurethane foam plug Global Biogeochemical Cycles…”