Sea breeze modulated volatilization of polycyclic aromatic hydrocarbons from the Masnou Harbor (NW Mediterranean Sea) (original) (raw)
Related papers
Journal of Marine Systems, 2010
Several measurements of polycyclic aromatic hydrocarbons (PAHs) in coastal marine compartments (viz. atmosphere, sea surface microlayer, subsurface seawater, sinking particles and sediments), made nearly simultaneously at two stations in the north-eastern Mediterranean, were used to estimate the transport fluxes of individual and total PAHs through the air-seawater-sediment system. Diffusive air-sea exchange fluxes were estimated using both subsurface water (SSW) and sea surface microlayer (SML) concentrations. The air-SML fluxes ranged from 411 to 12,292 ng m − 2 d − 1 (absorption) and from − 506 to -13,746 ng m − 2 d − 1 (volatilisation) for total PAHs (Σ15). Air-seawater column transport of particle-associated PAHs was estimated from the analysis of particulate atmospheric and sediment interceptor trap materials. Air-sea particle deposition fluxes of total PAHs ranged from 13 to 114 ng m − 2 d − 1 and seawater particle settling fluxes (upper 5 m water column) ranged from 184 to 323 ng m − 2 d − 1 . The results of this study indicate that both the magnitude and the direction of the calculated air-sea diffusive fluxes change when PAH concentrations in the SML are considered. As a result, PAHs accumulation in the SML could produce the so-called "flux capping effect". However, the high variability in the coastal air-sea PAHs flux estimations, mainly due to the parameters uncertainty, requires further experimental approaches, including improvement of parameterisations.
2014
Polycyclic aromatic hydrocarbon (PAH) concentration in air of the central and eastern Mediterranean in summer 2010 was 1.45 (0.30-3.25) ng m −3 (sum of 25 PAHs), with 8 (1-17) % in the particulate phase, almost exclusively associated with particles < 0.25 µm. The total deposition flux of particulate PAHs was 0.3-0.5 µ g m −2 yr −1. The diffusive air-sea exchange fluxes of fluoranthene and pyrene were mostly found net-depositional or close to phase equilibrium, while retene was net-volatilisational in a large sea region. Regional fire activity records in combination with box model simulations suggest that seasonal depositional input of retene from biomass burning into the surface waters during summer is followed by an annual reversal of air-sea exchange, while interannual variability is dominated by the variability of the fire season. One-third of primary retene sources to the sea region in the period 2005-2010 returned to the atmosphere as secondary emissions from surface seawaters. It is concluded that future negative emission trends or interannual variability of regional sources may trigger the sea to become a secondary PAH source through reversal of diffusive air-sea exchange. Capsule: In late summer the seawater surface in the Mediterranean has turned into a temporary secondary source of PAH, obviously related to biomass burning in the region.
Environmental Toxicology and Chemistry, 2002
Polycyclic aromatic hydrocarbons (PAHs, n ϭ 36) were measured in the gas and particle phases in the atmosphere and the dissolved and particle phases in the waters of the New York-New Jersey Harbor Estuary, USA, during a weeklong intensive field campaign in July 1998. Mean total (gas ϩ particulate) phenanthrene and pyrene concentrations were 3.3 and 0.33 ng/m 3 , respectively, over Raritan Bay, and 14 and 1.1 ng/m 3 , respectively, over New York Harbor. Similar PAH profiles (p values Ͻ 0.01) in the atmospheric gas phase and the dissolved phase in water demonstrate the close coupling of the air and water compartments. Air-water exchange fluxes of PAHs estimated using shore-based air data lead to erroneous flux estimates when compared to those derived using over-water air samples. The gross absorptive air-water flux dominates atmospheric loadings (wet, dry particle, gas absorption) to the estuary for PAHs of molecular weight Ͻ234 g/mol. Dry particle deposition is increasingly more important for the higher-molecular-weight, particle-bound PAH species. Gross volatilization dominates gross absorption for the majority of PAHs in the New York-New Jersey Harbor Estuary.
Transport of Gas-Phase Polycyclic Aromatic Hydrocarbons to the Venice Lagoon
Environmental Science & Technology, 2004
Concentrations of gas-phase polycyclic aromatic hydrocarbons (PAHs) were studied over one year at two sites of the Venice lagoon (designated Marine and Industrial) and at a mainland station (designated Rural) in Italy. Average ∑PAH concentrations, calculated as sum of 16 PAHs, at Marine are about three and five times lower than those at Industrial and Rural, respectively. The seasonal trends, the temperature-PAH relationship, and principal component analysis indicate that at Industrial and Marine sites several local sources (vehicle and industrial emissions, etc.) could be the PAH sources in the warmer months, whereas in the colder months the main PAH sources could alternate between vehicle emissions and residential heating. At Rural the main PAH sources are: vehicle emissions in the spring and autumn; vehicle emissions, field burning, and wood combustion in the summer; and vehicle emissions and fuel consumption for residential heating in the winter. To evaluate the contribution from different sources to the Venice Lagoon air, horizontal fluxes of PAHs have been obtained. The estimated annual flux of PAHs is about 9 times greater at Industrial (193.5 mg m -2 y -1 ) than at Marine (20.6 mg m -2 y -1 ). These results show that study of the chemical contamination of the Venice atmosphere must take into account the PAH flux derived from marine sources as well as the continental input.
Environmental Forensics
Polycyclic aromatic hydrocarbons (PAHs) in contaminated waterbodies can cause serious pollution to the adjacent atmosphere through volatilization. Gas-particle partitioning of PAHs controls the atmospheric concentrations of these pollutants. PAH levels in gaseous and particulate air samples were investigated near two polluted lagoons along the eastern coast of the Red Sea. Gas chromatography-mass spectrometry was used to analyze nine priority parent PAHs and nine methylated PAHs. Total gaseous and particulate PAHs ranged from 12.2 to 397.5 ng m À3 , with an average of 125.6 ± 117.3 ng m À3 , which was nearly 10-fold higher than that found in a previous study. Particulate PAHs (ranging from 0.04 to 16.32 ng m À3 , with an average of 2.56 ± 1.71 ng m À3) contributed to less than 20% of the total atmospheric PAHs. Applied diagnostic indices showed that gasoline emissions were the main sources of PAHs in the lagoons' atmosphere. Multiparameter statistical analyses indicated that wind speed strongly affected the distribution of atmospheric PAHs. The average PAH gas-particle partitioning coefficient was 0.49 m 3 mg À1 (ranging from 2.1 Â 10 À8 to 51.23 m 3 mg À1) and was significantly correlated with supercooled liquid vapor pressure. In addition to the effects of meteorological parameters and vehicle exhausts in the study area, the discharge of wastewater in the lagoons elevated PAH levels in the surrounding atmosphere.
Mass budget and dynamics of polycyclic aromatic hydrocarbons in the Mediterranean Sea
Deep Sea Research Part II: Topical Studies in Oceanography, 1997
A mass budget was constructed to examine the status and dynamics ofpolycyclic aromatic hydrocarbons (PAHs) in the western Mediterranean Sea. Using gas chromatography-mass spectrometry, 11 PAHs have been quantified in atmospheric aerosols, rivers and seawater, sediment cores and sediment trap samples. Total PAH concentrations in Mediterranean aerosols range from 0.2 to 2 ng me3, with 50-70% associated with the sub-micron particles. Maximum PAH concentrations were observed in winter when the concentrations were double those recorded in the spring. Total PAH inputs from the atmosphere were estimated to be from 35 to 70 t year-' with a mean value of 47.5 t year-' (wet/dry mean ratio of ~2-3). Atmospherically-deposited PAH are dominated by the benzofluoranthenes. The total PAH riverine inputs amount to about 5.3-33 t year-' from the Rhone river and 1.3 t year-' from the Ebro river. The difference in these riverine fluxes is due to differences in annual water discharges and upstream land use. The total PAH accumulation rate in surficial sediments in the whole basin is estimated at 182 t year-'. Nearly 50% of the total PAWS accumulate in the O-200 m water depth area supporting the importance of the coastal zone as a trap of terrigenous material and associated contaminants. Sediment trap experiments gave a mean residence time in the water column of total PAH (considering only particle settling) of 11 years, with higher residence times for high molecular weight PAHs. This supports the hypothesis that lower molecular weight PAHs are more efficiently removed from the water column. Water exchange resulted in a net outflow of 20 t year-' and 2 t year-' through the Gibraltar and Sicilian Straits, respectively. Atmospheric deposition and the Rhone River are the major contributors of PAH in the western Mediterranean. Sedimentation was identified as the major net output of PAH. 0 1997 Elsevier Science Ltd.
Atmospheric Environment, 2002
Polycyclic aromatic hydrocarbons (PAHs) were measured in the Baltimore and adjacent Chesapeake Bay in July 1997. Time series of 4-and 12-h samples were taken at two sites 15 km apart in order to evaluate the influence of a number of processes on the short-term variability of PAH in the Baltimore and northern Chesapeake Bay atmospheres. PAH concentrations were 2-3-fold higher in the Baltimore atmosphere than in the adjacent Chesapeake Bay atmosphere. For example, gas-phase phenanthrene and pyrene concentrations were 12.5 and 2.14 ng m À3 in the Baltimore site and 5.57 and 0.548 ng m À3 in the Chesapeake Bay, respectively. The influence of wind direction, wind speed and temperature was evaluated by multiple linear regressions which indicated that atmospheric gas-phase PAH concentrations over the Chesapeake Bay were significantly higher when the air mass was from the urban/industrial Baltimore area. Furthermore, the increase of gas-phase low-MW PAH concentrations with temperature and wind speed suggests that volatilization from the bay is an important source of pollutants to the atmosphere, at least when air masses are not influenced by the Baltimore urban and industrial area. Indeed, while on the long-term, the Chesapeake Bay is a receptor of atmospherically deposited PAHs, on the short-term and during appropriate meteorological conditions, the bay acts as a source of pollutants to the atmosphere. Aerosol-phase PAH concentrations and temporal trends showed a strong dependence on aerosol soot content due to the high affinity of PAHs to the graphitic structure of soot. These results confirm the important influence of urban areas as a source of pollution to adjacent aquatic environments and as a driving factor of the short-term variability, either directly by transport of urban-generated pollutants or by volatilization of previously deposited pollutants. Conversely, the complex diurnal trends of gas-phase PAHs at the Baltimore site suggests that degradation processes dominate the diurnal trends of PAHs in urban atmospheres. This conclusion is supported by estimated rate constants for PAH reaction with OH radicals which show good agreement with reported values within a factor of two. r
Atmospheric Environment, 2017
Harbors are often characterized by high levels of air pollutants that are emitted from ship traffic and other harbor activities. In the present study, the concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) and trace elements (As, Cd, Ni, Pb, Cr, Mn, Zn, and Fe) bounded to the inhalable particulate matter PM 10 were studied in the harbor of Volos, central Greece, during a 2-year period (2014e2015). Seasonal and daily variations were investigated. Moreover, total carcinogenic and mutagenic activities of PAHs were calculated. The effect of major wind sectors (sea, city, industrial, harbor) was estimated to assess the potential contribution of ship traffic and harbor activities, such as scrap metal handling operations. Results showed that the harbor sector (calm winds 0.5 m s À1) was associated with the highest concentrations of PM 10. The harbor sector was also associated with relatively increased levels of trace elements (As, Fe, Cr, Mn, Ni), however the effect of this sector was lower than the corresponding effect of the industrial wind sector. The sea sector showed only a slight increase in B[a]Py and S 12 PAHs, whereas the highest increasing effect for PAHs and traffic-related elements, such as Pb and Zn, was evidenced for the city sector.
Atmospheric Pollution Research, 2018
The air-water exchange of polycyclic aromatic hydrocarbons (PAHs) is an important process in determining the fate, transport and chemical loadings of these contaminants in the atmosphere and water bodies. Concentration levels of PAHs in air (gaseous and particulate) and surface water were investigated in the environments of two polluted 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 of total 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 PAHs levels in air recorded significant rise form the previous study. The probable sources of dissolved PAHs in water were 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 ng m-2 d-1 to 2.82 µg m-2 d-1. After Henry's law constant corrections for temperature and salinity; the airwater exchange fluxes were found in the range of-9.7x10 4 to 8.6x10 6 ngm-2 d-1 with an average of 6.8x10 5 ngm-2 d-1. Beside the other sources of PAHs in the studied lagoons, high