Polycyclic aromatic hydrocarbons (PAHs) in the Mediterranean Sea: atmospheric

Transcription

1 SUPPORTIN INFORMATION Polycyclic aromatic hydrocarbons (PAHs) in the Mediterranean Sea: atmospheric occurrence, deposition and decoupling with settling fluxes in the water column Javier Castro-Jiménez 1 *, Naiara Berrojalbiz 1, Jan Wollgast 2, Jordi Dachs 1 1 Department of Environmental Chemistry (IDAEA - CSIC), Barcelona, Catalunya, Spain. 2 European Commission - Joint Research Centre, Institute for Health and Consumer Protection; Ispra, Varese, Italy * jcjqam@cid.csic.es S1

2 SUPPORTIN INFORMATION List of contents of the supporting information: Information regarding sampling, analysis and QA/QC Figure S1. eneral overview of the two campaign trajectories and the studied areas/ subbasins. Figure S2. Air gas phase (A), aerosol phase (B), long transect aerosol phase (C) and water dissolved phase (D) samples collected across the Mediterranean Sea and in the Black Sea. Text S1: Air sampling strategy and materials Table S1. Air gas phase sampling details Table S2. Aerosol phase sampling details Table S3. Aerosol phase long transects sampling details Text S2: Extraction and instrumental method details Text S3: Quality assurance /Quality control details Table S4. Blank levels in air gas phase samples Table S5 Blank levels in air aerosol phase samples Table S6. High volume sampling reproducibility test. Figure S3. Results from the linear regression analysis (sampling reproducibility test) Text S4. Diffusive air-water exchange Information regarding atmospheric levels, occurrence and spatial distribution Table S7. as phase concentrations (ng m -3 ) of PAH across the Mediterranean Sea and in the Black Sea. Figure S4. PAH pattern in the atmospheric gas (A) and aerosol (B) phases. Figure S5. Spatial distribution of air gas phase concentrations for selected PAH across the Mediterranean Sea and in the Black Sea S2

3 Figure S6. Individual PAH concentrarions measurred in the air gas (A) and aerosol (B) phases corresponding to the samples exhibited the lowest and the highest levels (as sum of PAHs) Figure S7. Location of samples presenting the highest and the lowest PAH gas and aerosol phase concentrations and air mass back trajectories Table S8. Aerosol phase concentrations (pg m -3 ) of PAH across the Mediterranean Sea and in the Black Sea. Figure S8. Spatial distribution of aerosol phase concentrations of selected PAH across the Mediterranean Sea and in the Black Sea Figure S9. PAH molecular diagnostic ratios Information regarding deposition fluxes to the Mediterranean Sea Table S9. Net diffusive fluxes for individual PAHs across the Meditarranean Sean and in the Black Sea. Figure S1. Detail of PAH net air-water diffusive fluxes in all samples across the Mediterranean and in the Black Sea. Text S5. Fugacity ratios Table S1. Air to water fugacity ratios (fg/fw) of PAHs in the Mediterranean and Black Seas Table S11. Dry deposition fluxes for individual PAHs across the Meditarranean Sean and in the Black Sea. Figure S11. Dry deposition fluxes of selected PAHs in all samples collected. Figure S12. Comparison of deposition fluxes (this study) with a compilation of settling fluxes from literature in the Mediterranena Sea. S3

4 Information regarding sampling, analysis and QA/QC Figure S1. eneral overview of the two campaigns spatial coverage (blue line: 26 and red line:27) and the studied areas/ sub-basins. S4

5 Figure S2. Air gas phase (A), aerosol phase (B), long transect aerosol phase (C) and water dissolved phase (D) samples collected across the Mediterranean Sea and in the Black Sea. (A) 21/22/23 (B) P26 P27/28/ / P1 P2 P5 P6/7 P3 P4 P8 P9 P1 P11 P12 P14 P24 P22 P23 P21 P13 P15 P16 P17 P25 P2 P19 P18 (C) (D) WB2-3 C T-1 T-2 T-3 T-4 T-5 T-6 T-7 T-8 T-9 T-1 W1 W2 W3 W4 A W5 W6 W7 W8 W2 WB1 21 W11 W12 W19 W22 W18 W9-1 W13 W24 W14 B W15 W23 W25 W16 W17 W26 W28 W27 S5

6 Text S1: Air sampling strategy and materials Air samplers were installed on the upper deck of the boat (around 6-7 m above the sea level) close to the bow and were operated contemporaneously. The samplers were automatically stopped when wind was blowing from the poop of the vessel to avoid potential contamination of the samples by the ship exhausts. Additionally, the samplers were manually switch off when the boat was stopped under no wind conditions as and aerosol phase sampling: Air samples were taken using a high-volume air sampler (MCV, Barcelona, Spain). Samples (average volume of 5 m 3 ) were generally collected within twelve hours. The air was drawn through a precombusted Quartz fiber filter (QM- A; Whatman, 8x1 inches) to collect aerosol bound compounds and then circulated through a polyurethane foam (PUF) to collect chemicals present in the gas phase. All the samples were stored in freezers at -2 C until analysis. High volume aerosol phase sampling (aerosol phase long transect sampling): as aerosol phase (aerosol) was sampled by using two high volume air samplers (Echo PUF high volume sampler, TCR Tecora, Milan, Italy) operating contemporaneously (duplicate samples). The sampling head module integrated a (QFF) of 12 mm diameter (QM-A type, particle retention: 2.2 µm, Whatman International Ltd, Brentford, Middlesex, UK) for the air aerosol phase collection and a polyurethane foam (PUF) plug of 65 mm diameter, 75 mm length and.22 g cm -3 of density (Tisch Environmental, Inc. Cleves, Ohio, U.S.) for the gas phase trapping. Integrated samples of m 3 were gathered working in these conditions. S6

7 All meteorological parameters (wind speeds, water and air temperatures, etc.) were measured routinely during all the cruises using the Met station on board of RV arcía del Cid and the systems that records continually the characteristics of surface seawater (salinity, chlorophyll, etc). S7

8 Table S1. Air gas phase sampling details Sample Volume (m 3 ) Period Latitude (N) Longitude (E) Latitude (N) Longitude (E) Air T (ºC) a May Jun n.d.a Jul Jul n.d.a Jul n.d.a 6 b Jul n.d.a 7 b Jul Jun Jun Jun n.d.a Jun Jun b Jun May May n.d.a May May Jun Jun Jun b Jun b Jun b Jun n.d.a a Average air temperature during transects adquired from the ship meteo station (n.d.a. =no data available) b Samples taken at station (Ship not cruising) Transect coordinates (degrees) Start End S8

9 Table S2. Aerosol phase sampling details Sample Volume (m 3 ) Period Latitude (N) Longitude (E) Latitude (N) Longitude (E) Air T (ºC) a P May P Jun n.d.a P Jul P Jul n.d.a P Jul n.d.a P6 b Jul P7 b Jul n.d.a P Jun P Jun P Jun n.d.a P Jun P Jun P13 b Jun n.d.a P May P May P May n.d.a P May P May P May n.d.a P May P Jun n.d.a P Jun P Jun n.d.a P Jun n.d.a P Jun n.d.a P Jun n.d.a P27 b Jun P28 b Jun P29 b Jun n.d.a a Average air temperature during transects adquired from the ship meteo station (n.d.a. =no data available) b Samples taken at station (Ship not cruising) Transect coordinates (degrees) Start End S9

10 Table S3. Aerosol phase long transects sampling details Transect coordinates (degrees) Start End Sample Volume (m 3 ) Period Latitude (N) Longitude (E) Latitude (N) Longitude (E) Air T (ºC) b T Jun T Jun T Jun T Jun T Jun/4 July T-6A a May T-6B May T-7A May T-7B May T-8A May T-8B May T-9A May T-9B May T May/6 Jun a During the 27campaign samples were taken with two different samplers (A) and (B) contemporaneously b Average air temperature during transects adquired from the ship meteo station Text S2: Extraction and instrumental method details QFFs and PUFs: Prior to extraction, all samples were spiked with a mix containing 4 deuterated PAHs (Acenaphtene-d1, Phe-d1 Cry-d12 and Per-d12, Sigma-Aldrich) which were used as surrogate standard (5 µl at 1 ng µl -1 ). PUFs were soxhlet extracted with a mixture acetone:hexane for 24 h hours. The extracts were rotary evaporated to 2 ml and purified on a 3% Milli-Q water deactivated alumina column (3 g) with a top layer of anhydrous sodium sulfate. Each column was eluted first with 5 ml of hexane and second with 12 ml of dichloromethane:hexane (2:1; v:v). The second fraction selected for PAH analysis was concentrated to.5 ml by vacuum rotary evaporation, transferred to a 1.7 ml amber vial with hexane and evaporated to 15 µl under a nitrogen stream At this S1

11 step, 5 ng of the internal standard Anth-d1 was added to the extract. QFFs were weighed and Soxhlet extracted with dichloromethane:methanol (2:1, v/v) for 24 h. The extract were rotary evaporated to 1 ml, solvent-exchanged to hexane and purified by column chromatography as indicated for gas phase samples. The second fraction was treated analogously. PAH analysis was conducted by gas chromatography coupled to a mass spectrometer (Thermo Electron, San Jose, CA, USA) and compounds were quantified by the internal standard procedure. The system was operated in electron impact mode (EI, 7eV) and with the splitless injection mode. The separation was achieved with a 3m x.25mm i.d. x.25µm TRB-5MS capillary column (Teknokroma, Spain). The oven temperature was programmed from 9ºC (holding time 1min) to 175ºC at 6ºC/min (holding time 4min) to 235ºC at 3ºC/min, then to 3ºC at 8ºC/min (holding time 8min), and finally to 315ºC at 3ºC/min keeping the final temperature for 8min. QFFs (long transects) : Samples corresponding to the long transect aerosols were Soxhlet extracted with n-hexane/acetone (22:3 v/v) for 24h after being spiked with 25ng of each labeled PAH surrogate (Fluorene-d1, Anthracene-d1, Fluoranthene-d1, Benzo(a)anthracene-d12, Benzo(b)fluoranthene-d12, Benzo(a)pyrene-d12, Indeno(1,2,3- cd)pyrene-d12, Dibenzo(a,h)anthracene-d14, and Benzo(g,h,i)perylene-d12). 1% of the extract was dedicated to PAH analysis. In order to remove residual water, extracts were passed over 1mL glass columns packed with previously prepared (baked at 45 C and kept at >11 C till usage) sodium sulphate. A silica clean-up was performed following the procedure in EPA Method 363c. All extracts were concentrated up to.5ml by using S11

12 and automatic evaporator (Turbovap, Zymark, USA). Syringe standards were added prior analyses (Benzo(k)flouranthene, Benzo(e)pyrene and Pyrene) and extracts further concentrated under a gentle stream of purified N 2 to 5 µl. Instrumental analysis of PAHs in the aerosol (Fluorene, Phenantrhene, Anthracene, Fluoranthene, Pyrene, Benzo(a)anthracene, Chrysene, Benzo(b)fluoranthene, Benzo(j)fluoranthene, Benzo(k)fluoranthene, Benzo(e)pyrene, Benzo(a)pyrene, Perilene, Dibenzo(a,h)anthracene, Benzo(g,h,i)perylene, and Indeno(1,2,3-cd)pyrene)) was carried out using a HP 689 high resolution gas chromatograph equipped with a HP MSD 5973 mass selective detector (all Agilent, Waldbronn, ermany) and a erstel CIS 4 PTV injection system (erstel mbh, ermany) utilising helium as carrier gas (1. ml/min). The C separation was performed on a DB5ms (Agilent) capillary column (6 m length,.25 mm I.D., film thickness.25 µm). Electron impact (EI) ionisation was used with an ionisation potential of 7 ev. The auxiliary transfer line to the MSD was operated at 3 C. The C oven temperature program was held at 1 C for 1 min and ramped from 1 C to 28 C at 7 C /min and was held at 28 C for 12 min. A second heating from 28 C to 31 C was performed at 12 C /min and was held at 31 C for 28 min. The total run time of the C oven was min. The erstel Cooled Injection System (CIS4) was operated as follows: initial temperature, 8 C ; initial time,.5 min; rate, 12 C /min; final temperature, 33 C held for 5 min; cryo cooling was applied; equilibration time,.5 min. The sample volume injected was 1 µl in splitless mode. The mass spectrometer operated in Selecting Ion Monitoring. For both native and labelled PAH isomers the molecular ion was reordered. Quantification was done by isotope dilution method. All organic solvents were dioxin analysis grade from Sigma-Aldrich (Buchs S, S12

13 Switzerland). All gases (Alpha gaz, Italy) used were ultra pure grade suitable for POP analysis. Text S3: Quality assurance /Quality control details Pre-cleaning of material QFF were individually wrapped in (n-hexane cleaned) aluminum foil, baked at 45 ºC for 8 h and then stored at -18 o C in a sealed plastic bag until used. PUFs were Soxhlet extracted with acetone during at least 24hours before use, dried in a dissicator under vacuum and individually wrapped in n-hexane rinsed aluminum foil. PUF were wrapped in (n-hexane cleaned) aluminum foil and placed in a Teflon sealed metallic transport container together with the QFF. Cleaning and storing of water sampling material have been reported elsewhere (Berrojalbiz et al., 211). Blanks Air and water field blanks, consisting on cleaned QFFs, PUF and XAD columns, respectively, were collected. The materials were transported to the sampling area, mounted in the sampler, dismounted and transported back to the ship laboratory and then processed together with the samples. Procedural blanks (sampling) consisting on clean filters and PUFs (packed in the lab and untouched until analysis) were employed in order to evaluate the potential contamination of samples due to handling during the cruises. Procedural blanks (analysis) consisting on only extracting solvent (Soxhlet extracted and cleaned-up as for the samples) were also processed for each batch of fourteen samples. S13

14 Sampling reproducibility test for aerosol phase sampling An air sampling reproducibility study was carried out by operating two samplers (A and B) contemporaneously. Aerosol phase PAH concentrations measured with both samplers were compared by performing a linear regression analysis. Individual congener s aerosol phase concentrations are presented below in Table S7. Results from the statistical test are presented in Figure S2. PAH aerosol concentrations obtained with both sampling devices exhibited a significant correlation (p<.1). Therefore the sampling reproducibly during the cruises was good and the average concentration was selected as a better estimate of the real concentration and used in the discussion. S14

15 Table S4. PAH blank levels (pg m -3 ) in the gas phase (mean + SD, N=4) Acenaphthylene 11.4 ± 15.5 Acenaphtene ± 8.47 Fluorene ± Phenanthrene ± Antrathene 2.89 ± DBT ± MetDBT ± MetDBT ± MetDBT ± 6.67 MetPhe ± 8.87 MetPhe ± 9.56 MetPhe ± 7.5 MetPhe ± 2.55 Dimet Phe1.4 ±.27 Dimet Phe2.25 ±.18 Dimet Phe ±.97 Dimet Phe4.6 ±.4 Dimet Phe5.48 ±.33 Dimet Phe6.17 ±.13 Dimet Phe ± 15.5 Fluoranthrene.21 ±.16 Pyrene.52 ±.25 Chrysene 5.9 ± 6.69 Average volume of 5 m 3 used for the PAH concentration calculation in the blank samples S15

16 Table S5. PAH blank levels (pg m-3) in the aerosol phase long transects (QFF T, mean + SD, N=3 ) and short transects (QFF S ) ( mean + SD; N=9) Compound Concentration in QFF T Concentration in QFF S Fluorene.8 ± ± 2.73 Phenanthrene 3.93 ± ± 6.26 Anthracene.13 ±.9. ±. DBT n.a. ±. MetDBT1 n.a. ±. MetDBT2 n.a. ±. MetDBT3 n.a. ±. MetPhe1 n.a.41 ±.5 MetPhe2 n.a.3 ±.6 MetPhe3 n.a.33 ±.6 MetPhe4 n.a.29 ±.58 Dimet Phe1 n.a.5 ±.11 Dimet Phe2 n.a.5 ±.11 Dimet Phe3 n.a.6 ±.13 Dimet Phe4 n.a. ±. Dimet Phe5 n.a.4 ±.8 Dimet Phe6 n.a. ±. Dimet Phe7 n.a. ±. Fluoranthene.76 ± ±.87 Pyrene 1.79 ± ±.81 Benzo (a) anthracene.3 ±.2. ±. Chrysene.14 ±.3.44 ±.88 Benzo(b)fluoranthene.1 ±.2. ±. Benzo(j)fluoranthene.1 ±.2.74 ± 1.49 Benzo(k)fluoranthene.1 ±.1. ±. Benzo(e)pyrene.77 ±.28. ±. Benzo (a) pyrene.1 ±.1. ±. Perylene.1 ±.1. ±. Dibenzo(a,h)anthracene.7 ±.5. ±. Benzo(g,h,i)perylene.8 ±.3. ±. Indeno(1,2,3-cd)pyrene.9 ±.3. ±. Σ16 PAHs 8.64 ± ± 9.75 a Average volume of 1 m 3 used for the PAH concentration calculation in the blank samples b Average volume of 5 m 3 used for the PAH concentration calculation in the blank samples n.a = Compounds not analysed in aerosol long transect samples S16

17 Table S6. PAH aerosol phase concentrations (pg m -3 ) in the Mediterranean sea measured with two different samplers contemporaneously during the 27 campaign (reproducibility test) T6 T7 T8 T9 A B A B A B A B Fluorene Phenanthrene Anthracene Fluoranthene Pyrene Benzo (a) anthracene Chrysene Benzo(b)fluoranthene Benzo(j)fluoranthene Benzo(k)fluoranthene Benzo(e)pyrene Benzo (a) pyrene Perylene Dibenzo(a,h)anthracene Benzo(g,h,i)perylene Indeno(1,2,3-cd)pyrene Σ16 PAHs Figure S3. Results from the linear regression analysis (sampling reproducibility test) SamplerB (pgm-3) 2 35 T7 3 T y = x y =.8549x R² = R² =.9289 p<.1 p< T T y = 1.243x y = 1.546x R² = R² =.981 p<.1 p< SamplerA (pgm-3) S17

18 Text S4. Non-linear influence of wind speed As stated in the manuscript, the air water diffusive fluxes were estimated by using equations [1-2]. H values and their temperature dependence were taken from Bamford et al. (1999). k AW has been estimated as explained elsewhere (Jurado et al. 24), and the nonlinear influence of wind speed has been taken into account by correcting the waterside mass transfer coefficient as suggested by Nightingale (2) using a Weibull distribution of wind speeds. For the Nightingale 2 parameterization, when taking into account the influence of wind speed variability, the water side mass transfer coefficient k is given by: k = [5.88 η 2 Γ(1+2/ξ) η Γ(s)] Sc -1/2 [4] where Γ is the gamma function and Sc is the Schmidt number. In this study, an assumed Weibull distribution with ξ = 2 (Rayleigh distribution) has been considered which is consistent with oceanic distributions of wind speed variability [Conradsen & Nielsen 1984, Wanninkhof et al 22]. The scale parameter (η) is related to sample period average wind speeds by u 1 = η Γ(s) as described elsewhere [Livingston & Imboden 1993]. S18

19 Information regarding atmospheric levels, occurrence and spatial distribution Table S7. as phase concentrations (ng m -3 ) of individual PAH across the Mediterranean Sea and in the Black Sea. Western Mediterranean Ionian Sea / Sicily South-East Mediterranean Aegean Sea Black Sea Compound Fluorene Phenanthrene Anthracene DBT MethDBT MethPhe DimethPhe Fluoranthrene Pyrene Chrysene PAHs d d HMW PAHs (from BbFA to BghiP) were not detected in the gas phase S19

20 Figure S4. PAH pattern in the atmospheric gas (A) and aerosol (B) phases. S2

21 Figure S5. Spatial distribution of air gas phase concentrations for selected PAH across the Mediterranean Sea and in the Black Sea 1 9 Fluoranthrene AS PHASE concentrations(pgm -3 ) Chrysene MethPhe West Med Ion. Sea SEast Med Aeg. Sea Black Sea S21

22 Figure S6. Individual PAH concentrarions measurred in the air gas (A) and aerosol (B) phases corresponding to the samples exhibited the lowest and the highest levels (A) AS PHASE 6 (West Med) 17 (SE Med) Concentration(pgm -3 ) (B) AEROSOL PHASE 7 P18 (SE Med) 6 P2 (SE Med) S22

23 Figure S7. Location of samples presenting the highest/lowest concentrations of PAH in the gas (6 / 17) and the particle (P18 / P2) phases. BT Trajectories were calculated at 15 and 5m height for a period of 48h P P2 P18 P18 Alexandria Nile Delta as phase (17) and particulate (P2) phase samples were gathered in the same transect S23

24 Table S8. Aerosol phase concentrations (pg m -3 ) of PAH across the Mediterranean Sea and in the Black Sea. Western Mediterranean Ionian Sea / sicily South-East Mediterranean Aegean Sea Black Sea Compound P1 P2 P3 P4 P5 P6 P7 T1 T5 T1 P8 P9 P1 P11 P12 P13 T6 T9 P14 P15 P16 P17 P18 P19 P2 T7 T8 P21 P22 P23 P24 T2 T4 P25 P26 P27 P28 P29 T3 Fluorene n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a Phenanthrene Antrathene DBT n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a MetDBT n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a MetPhe n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a Dimethyl Phe n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a Fluoranthrene Pyrene Benzo(a)anthracene Chrysene Benzo(b)fluoranthene n.d n.d n.d n.d n.d Benzo(j)fluoranthene n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a n.a 2.63 Benzo(k)fluoranthene n.d n.d n.d n.d n.d Benzo(a)pyrene n.d n.d n.d n.d n.d Benzo(e)pyrene n.d n.d n.d n.d n.d perylene n.d n.d n.d n.d n.d n.d n.d n.d n.d.17.1 n.d 2.65 n.d Indeno(1,2,3-cd)pyrene n.d n.d n.d n.d n.d n.d n.d 28.7 n.d Dibenzo(a,h)anthracene n.d n.d n.d n.d n.d n.d n.d n.d n.d n.d n.d n.d n.d n.d n.d n.d n.d n.d n.d n.d n.d n.d n.d n.d 7.54 Benzo(ghi)perylene n.d n.d n.d n.d n.d n.d n.d n.d n.a = not analysed in this sample, n.d =not detected S24

25 S25 Figure S8. Spatial distribution of aerosol phase concentrations of selected PAH across the Mediterranean Sea and in the Black Sea Concentration(pgm -3 ) (B) P1 P2 P3 P4 P5 P6 P7 T1 T5 T1 P8 P9 P1 P11 P12 P13 T6 T9 P14 P15 P16 P17 P18 P19 P2 T7 T8 P21 P22 P23 P24 T2 T4 P25 P26 P27 P28 P29 T3 Perylene P1 P2 P3 P4 P5 P6 P7 T1 T5 T1 P8 P9 P1 P11 P12 P13 T6 T9 P14 P15 P16 P17 P18 P19 P2 T7 T8 P21 P22 P23 P24 T2 T4 P25 P26 P27 P28 P29 T3 Benzo(ghi)perylene (A) P1 P2 P3 P4 P5 P6 P7 T1 T5 T1 P8 P9 P1 P11 P12 P13 T6 T9 P14 P15 P16 P17 P18 P19 P2 T7 T8 P21 P22 P23 P24 T2 T4 P25 P26 P27 P28 P29 T3 Benzo(k)fluoranthene P1 P2 P3 P4 P5 P6 P7 T1 T5 T1 P8 P9 P1 P11 P12 P13 T6 T9 P14 P15 P16 P17 P18 P19 P2 T7 T8 P21 P22 P23 P24 T2 T4 P25 P26 P27 P28 P29 T3 Benzo(a)pyrene P1 P2 P3 P4 P5 P6 P7 T1 T5 T1 P8 P9 P1 P11 P12 P13 T6 T9 P14 P15 P16 P17 P18 P19 P2 T7 T8 P21 P22 P23 P24 T2 T4 P25 P26 P27 P28 P29 T3 Benzo(e)pyrene P1 P2 P3 P4 P5 P6 P7 T1 T5 T1 P8 P9 P1 P11 P12 P13 T6 T9 P14 P15 P16 P17 P18 P19 P2 T7 T8 P21 P22 P23 P24 T2 T4 P25 P26 P27 P28 P29 T3 Fluoranthrene P1 P2 P3 P4 P5 P6 P7 T1 T5 T1 P8 P9 P1 P11 P12 P13 T6 T9 P14 P15 P16 P17 P18 P19 P2 T7 T8 P21 P22 P23 P24 T2 T4 P25 P26 P27 P28 P29 T3 Pyrene

26 Figure S9. PAH molecular diagnostic ratios (A) AS PHASE (B) PARTICULATE PHASE.7.6 FA / (FA+PY) FA / (FA+PY) y =.16x R² =.344 P1 P2 P3 P4 P5 P6 P7 T1 T5 T1 P8 P9 P1 P11 P12 P13 T6 T9 P14 P15 P16 P17 P18 P19 P2 T7 T8 P21 P22 P23 P24 T2 T4 P25 P26 P27 P28 P29 T PHE / MetPHE.7.6 PHE / MetPHE y =.8x R² =.3237 P1 P2 P3 P4 P5 P6 P7 P8 P9 P1 P11 P12 P13 P14 P15 P16 P17 P18 P19 P2 P21 P22 P23 P24 P25 P26 P27 P28 P29 S26

27 Information regarding deposition fluxes to the Mediterranean Sea Table S9. Net diffusive fluxes* (ng m -2 d -1 ) for individual PAHs across the Meditarranean Sean and in the Black Sea. Western Mediterranean Ionian Sea / Sicily South-East Mediterranean Aegean Sea Black Sea Compound A 16A Fluorene Phenanthrene Anthracene Dibenzothiophene MethDBT MethPhe DimethPhe Fluoranthrene Pyrene Chrysene PAHs b a (-) values: net deposition [from atmosphere to sea], (+) values: net volatilization [from sea surface to atmosphere]; b HMW PAHs (from BbFA to BghiP) were not detected in the gas phase S27

28 Figure S1. Detail of PAH net air-water diffusive fluxes in all samples across the Mediterranean and in the Black Sea. West Med Ion. Sea SEast Med Aeg. Sea Black Sea West Med Ion. Sea SEast Med Aeg. Sea Black Sea A 16B PHE A 16B FL ngm -2 d DBT MeDBT AN CHR MePHE DimePHE FA PY S28

29 Text S5: Fugacity ratios The chemical fugacity in the gas and dissolved phases, f and f W, respectively, can be estimated by: f = 1-12 C R T / MW f W = 1-12 C W H R T / MW where C and C W are the gas and dissolved phase concentrations (pg m -3 ), R is the universal gas constant (Pa m 3 mol -1 K -1 ), T is the temperature (K) and MW is the molecular weight (g mol -1 ) of the chemical, and H is the dimensionless, salinity corrected, Henry s Law constant. The fugacity ratio, f /f W, equals unity when air and water are close to equilibrium. However, due to the number of uncertainties on the variables (e.g. uncertainties associated to H values, truly dissolved concentrations and analytical accuracy involved in these estimations) and concentrations used to estimate these fugacities (and the fluxes as well), it is usually accepted that to assure that there is a net absorption or volatilization flux, it is needed than one of the fugacity is 2-3 times higher than the other. Here, we take the criteria that to assure a direction of the flux, we need that the f /f W ratio is higher than 3 (net direction from air to water) or smaller than.3 (net direction from water to air). References: S29

30 Bamford H.A., Poster D., Baker J.E. Temperature dependence of Henry s law constants of thirteen polycyclic aromatic hydrocarbons between 4ºC and 31ºC. Environ. Toxicol. and Chem , Conradsen, K. and L.B. Nielsen, Review of Weibull statistics for estimation of wind speed distributions. J. Appl. Meteor, 23, , Livingstone, D.M. and D.M. Imboden, The non-linear influence of wind speed variability on gas transfer in lakes. Tellus, 45B, , Nightingale, P.D., P.S. Liss, and P. Schlosser, Measurements of air-sea gas transfer during an open ocean algal bloom. eophys. Res. Lett., 27, , 2. Wanninkhof, R., Doney, S.C., Takahashi, T., Mcillis, W.R. The effect of using timeaveraged winds on regional air-sea CO 2 fluxes. In as transfer at water surfaces, Donelan, M.A., Drennan, W.M., Saltzman, E.S., Wanninkhof, R. (Eds.). eophysical Monograph 127, AU, 22, Washington DC, USA. Table S1. Air to water fugacity ratios (fg/fw) of PAHs in the Mediterranean and Black Seas S3

31 Table S1. Air to water fugacity ratios (fg/fw) of PAHs in the Mediterranean and Black Seas Western Mediterranean Ionian Sea / Sicily South-East Mediterranean Aegean Sea Black Sea Compounds A 16B Fluorene Dibenzothiophene MeDBT Anthracene n.c 21.5 n.c Phenanthrene MePhe DimePhe Fluoranthrene Pyrene Chrysene n.c. : not calculated due to no volatilization flux for AN S31

32 Table S11. Dry deposition fluxes (ng m -2 d -1 ) for individual PAHs across the Meditarranean Sean and in the Black Sea. Western Mediterranean Ionian Sea / sicily South-East Mediterranean Aegean Sea Black Sea Compound P1 P2 P3 P4 P5 P6 P7 T1 T5 T1 P8 P9 P1 P11 P12 P13 T6 T9 P14 P15 P16 P17 P18 P19 P2 T7 T8 P21 P22 P23 P24 T2 T4 P25 P26 P27 P28 P29 T3 Fluorene n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r -2.6 Phenanthrene Antrathene DBT n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r MetDBT n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r MetPhe n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r Dimethyl Phe n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r Fluoranthrene Pyrene Benzo(a)anthracene Chrysene Benzo(b)fluoranthene n.r n.r n.r n.r n.r Benzo(j)fluoranthene n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r Benzo(k)fluoranthene n.r n.r n.r n.r n.r Benzo(a)pyrene n.r n.r n.r n.r n.r Benzo(e)pyrene n.r n.r n.r n.r n.r perylene n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r -.46 n.r Indeno(1,2,3-cd)pyrene n.r n.r n.r n.r n.r n.r n.r n.r Dibenzo(a,h)anthracene n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r n.r -1.3 Benzo(ghi)perylene n.r n.r n.r n.r n.r n.r n.r n.r PAHs n.r = not reported; (-) values indicate deposition [from atmosphere to sea] S32

33 Figure S11. Dry deposition fluxes of selected PAHs in all samples collected. ngm -2 d P1 P2 P3 P4 P5 P6 P PPT P PPT P PPT P7 T1 T5 T1 P8 P9 P1 P11 P12 P13 T6 T9 DimePHE P P PHE P P CHR BaAN P P BbFA P14 P15 P16 P17 P18 P19 P PP P PP P PP P PP P2 T7 T8 West Med Ion. Sea P21 P22 P23 SEast Med Aeg. Sea Black Sea West Med Ion. Sea SEast Med Aeg. Sea Black Sea P24 T2 T4 P25 P26 P27 P28 P29 T3 P P P P P1 P2 P3 P4 P5 P6 P7 T1 T5 T1 BaP PE BghiP IP BDahA P8 P9 P1 P11 P12 P13 T6 T9 P14 P15 P16 P17 P18 P19 P2 T7 T8 P21 P22 P23 P24 T2 T4 P25 P26 P27 P28 P29 T3 S33

34 Figure S12. Average atmospheric deposition fluxes (net diffusive and dry) in the Mediterranena Sea from this study together with a compilation of settling fluxes from literature in the Western and Eastern Mediterranan Sea (see Table 3 for sediment trap study identification). Indeno(1,2,3-cd)pyrene Benzo(g,h,i)perylene Dibenzo(a,h)anthracene Perylene BenzoPyrens Benzo (a) pyrene Benzo(e)pyrene Benzofluoranthenes Benzo(k)fluoranthene Benzo(j)fluoranthene Benzo(b)fluoranthene Benzo (a) anthracene Chrysene Pyrene Fluoranthene DimethPhe MethPhe Phenanthrene Anthracene MethDBT Dibenzothiophene Fluorene Net air-water diffusive flux (this study) ngm -2 d Dry deposition flux (this study) East Med (Finokalia) West Med (Alboran Sea) Settling flux (literature) West Med (Ligurian Sea) West Med (Sardinia) S34