PAHs in Air and Seawater along a North–South Atlantic Transect: Trends, Processes and Possible Sources

Abstract

Polycyclic aromatic hydrocarbons (PAHs) were simultaneously measured in air and surface seawater between 49 degrees N and 25 degrees S in the open Atlantic Ocean. Elevated concentrations of PAHs (sigma10 PAHs approximately 1.4-2.5 ng m(-3) air, and 0.7-1 ng L(-1) seawater) occurred in the Biscay Bay and off the northwest coast of Africa. The unexpectedly high concentrations off NW Africa were discussed assessing the possible contribution of the emerging oil industry along the African shore, the role of biomass burning and natural sources of PAHs. In the southern Atlantic, concentrations of PAHs were close to detection limits (sigma10 PAHs approximately 0.02-0.5 ng m(-3) air, and 0.06-0.5 ng L(-1) seawater) and showed decreasing trends with increasing latitudes. Correlations of PAHs' partial pressures versus inverse temperature were not significant in contrast to results for polychlorinated biphenyls from the same transect. This could have been due to the importance of ongoing primary sources and the shorter atmospheric life-times of PAHs. Air-water fugacity ratios (fa/fw) were calculated for selected compounds. They were close to 1 for fluoranthene and pyrene in remote open ocean areas suggesting air-water partitioning near equilibrium. Ratios for anthracene and phenanthrene were < 0.3 in the remote tropical Atlantic, suggesting net volatilization.

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).…”

Deposition and accumulation of airborne organic contaminants in Yosemite National Park, California

“…The PAHs that were detected are ones that have a higher volatility and are commonly identified in air and water samples [33,34]. Losses of the photolysis marker (loss in sampler because of exposure to sunlight) ranging from 55 to 88% at Lower McCabe Lake, Ostrander Lake, and Upper Granite Lake indicate that PAHs may have been present at higher concentrations than measured by the SPMD; however, it is reasonable to assume that any PAHs present in the water column had also photolyzed, just as the ones inside the SPMD did.…”

Photochemistry of 1-Nitronaphthalene: A Potential Source of Singlet Oxygen and Radical Species in Atmospheric Waters

“…These compounds could be able to start photochemical and photosensitized reactions upon radiation absorption. Polycyclic Aromatic Hydrocarbons (PAHs) constitute one of the most widespread classes of organic pollutants in water, soil and atmosphere [2][3][4][5][6][7] , and received particular attention due to their mutagenic effects 8 . The PAH nitroderivatives also cause concern for their direct mutagenicity.…”

“…Radical species such as NO 3 • , • OH and SO 4 •-are also present in and on the surface of cloud droplets. They could react with halide anions yielding halogen radicals (X • ) 1,22,23 and dihalogen radical anions (X 2 •-) (R1).…”