Polycyclic aromatic hydrocarbons in two polluted lagoons, eastern coast of the Red Sea: Levels, probable sources, dry deposition fluxes and air-water exchange

Özet

The air-water exchange of polycyclic aromatic hydrocarbons (PAHs) is an important process in determining thefate, transport and chemical loadings of these contaminants in the atmosphere and water bodies. Concentrationlevels of PAHs in air (gaseous and particulate) and surface water were investigated in the environments of twopolluted lagoons along the eastern coast of the Red Sea to study air water exchange and dry deposition fluxes.Nine priority parent PAHs and nine methylated PAHs were identified and quantified by GC-MS. The range oftotal PAHs in surface water was from 120.29 ng L−1 to 524.45 ng L−1 (average: 308.7 ng L−1, n=19). The PAHslevels in air recorded significant rise form the previous study. The probable sources of dissolved PAHs in waterwere found predominantly to be of petrogenic origin in one lagoon and of pyrogenic origin in the other lagoon.The dry deposition fluxes for individual congeners ranged between 0.01 ngm−2d−1 to 2.82 μgm−2d−1. AfterHenry's law constant corrections for temperature and salinity; the air-water exchange fluxes were found in therange of −9.7×104 to 8.6×106 ngm−2d−1 with an average of 6.8×105 ngm−2d−1. Beside the other sourcesof PAHs in the studied lagoons, high temperature and wastewater dumping might affect the magnitude anddirection of air-water exchange fluxes.