Seasonal Variations of Pcbs in Surface Soils and Air-Soil Exchange in Bursa, Turkey

SUPPORTING INFORMATION

Seasonal Variations of PCBs in Surface Soils and Air-Soil Exchange in Bursa, Turkey

GüraySalihoglu1, NezihKamilSalihoglu1, HüseyinSavasBaskaya1, ErtuğrulAksoy2, YücelTasdemir1*

1Department of Environmental Engineering, Faculty of Engineering & Architecture, UludagUniversity, 16059, Bursa, Turkey

2Department of Soil Science and Plant Nutrition, Faculty of Agriculture, UludagUniversity, 16059, Bursa, Turkey

; *; ; ;

Number of Pages of Supporting Information: 25

Number of Tables: 5

Number of Figures: 10

Number of Pages of Supporting Text: 7

Captions of Supporting Tables

Table S1. Levels (pg/g dw) of the dioxin-like congeners (DLC) measured at the soil samples.

Table S2. Results of the t test for the comparison of seasonal soil PCB levels of 43 locations

Table S3. Pearson correlation matrix for PCB levels, fugacities, net flux, soil temperature and air temperature at the Butal sampling location

Table S4. Pearson correlation matrix for PCB levels, fugacities, net flux, soil temperature and air temperature at the Mudanya sampling location

Table S5. Correlations of PCB levels with organic content of soils measured globally

Captions of Supporting Figures

Figure S1GIS Maps of the PCB levels measured in autumn, winter, and spring in Bursa soils

Figure S2. Seasonal distributions of PCB homologue groups measured at soil samples fromindustrial, urban, and rural locations

Figure S3. Seasonal distributions of PCB homologue groups measured at soil samples fromButal and Mudanyalocations

Figure S4. Seasonal distributions of PCB congeners measured at soil samples from 43 locations

Figure S5. Changes in air PCB levels and air temperature at Butal sampling location

Figure S6. Changes in soil PCB levels and soil temperature at Butal sampling location

Figure S7. Changes in air PCB levels and air temperature at Mudanya sampling location

Figure S8. Changes in soil PCB levels and soil temperature at Mudanya sampling location

Figure S9. Net flux levels of PCB congeners calculated for Butal sampling location

Figure S10. Net flux levels of PCB congeners calculated for Mudanya sampling location

Captions of Supporting Text

Sampling, Extraction and Analysis of Air and Soil Samples

Mapping

Supporting Tables

Table S1. Levels (pg/g dw) of the dioxin-like congeners (DLC) measured at the soil samples.

N.D.: Not detected

Table S2. Results of the t test for the comparison of seasonal soil PCB levels of 43 locations

a)

b)

c)

d)

Table S3. Pearson correlation matrix for PCB levels, fugacities, net flux, soil temperature and air temperature at the Butal sampling location

Table S4. Pearson correlation matrix for PCB levels, fugacities, net flux, soil temperature and air temperature at the Mudanya sampling location

Table S5. Correlations of PCB levels with organic content of soils measured globally

References for Table S5

ArmitageJM, Hanson M, Axelman J, Cousins IT (2006) Levels and vertical distribution of PCBs in agricultural and natural soils from Sweden. Sci Total Environ 371: 344-352.

Backe C, Cousins IT, Larsson P (2004) PCB in soils and estimated soil-air exchange fluxes of selected PCB congeners in the south of Sweden. Environ Pollut 128: 59-72.

Klanova J, Matykiewiczova N, Macka Z, Prosek P, Laksa K, Klan P (2008) Persistent organic pollutants in soils and sediments from James Ross Island, Antarctica. Environ Pollut 152: 416-423.

Cachada A, Lopes LV, HursthouseAS, Biasioli M, Grcman H, Otabbong E, Davidson CM, Duarte AC (2009) The variability of polychlorinated biphenyls levels in urban soils from five European cities. Environ Pollut 157: 511-518.

Desaules A, Ammann S, Blum F, Brandli RC, Bucheli TD, Keller A (2008) PAH and PCB in soils of Switzerland - status and critical review. J Environ Monitor 10: 1265–1277.

Lead WA, Steinnes E, Bacon JR, Jones KC (1997) Polychlorinated biphenyls in U.K. and Norwegian soils: spatial and temporal trends, Sci Total Environ 193: 229–236.

Nam JJ, Gustafsson O, Kurt-Karakus P, Breivik K, Steinnes E, Jones KC (2008) Relationship between organic matter, black carbon and persistent organic pollutants in European background soils: Implications for sources and environmental fate. Environ Pollut 156: 809-817.

Ma WL, Li YF, Sun DZ, Qi H (2009) Polycyclic Aromatic hydrocarbons and polychlorinated biphenyls in topsoils of Harbin, China. Arch Environ Con Tox 57: 670-678.

Meijer SN, OckendenWA, SweetmanAJ, Breivik K, Grimalt JO, Jones KC (2003) Global distribution and budget of PCBs and HCB in background surface soils: implications for sources and environmental processes. Environ Sci Technol 37: 667–672.

Ren N, Que M, Li YF, Liu Y, Wan X, Xu D, Sverko E, Ma J (2007) Polychlorinated biphenyls in Chinese surface soils. Environ Sci Technol 41: 3871-3876.

Wilcke W, Krauss M, Safronov G, Fokin AD, Kaupenjohann M (2006) Polychlorinated biphenls (PCBs) in soils of the Moscow region: Concentrations and small-scale distribution along an urban-rural transect. Environ Pollut 141: 327-335.

Zhang HB, LuoYM, Wong MH, Zhao QG, Zhang GL (2007) Concentrations and possible sources of polychlorinated biphenyls in the soils of Hong Kong. Geoderma 138: 244-251.

Supporting Figures

Figure S1GIS maps of the PCB levels measured in autumn, winter, and spring in the Bursa soils

Figure S2. Seasonal distributions of PCB homologue groups measured at soil samples fromindustrial, urban, and rural locations

Figure S3. Seasonal distributions of PCB homologue groups measured at soil samples fromthe Butal and Mudanyalocations

Figure S4. Seasonal distributions of PCB congeners measured at soil samples from 43 locations

Figure S5. Changes in air PCB levels and air temperature at the Butal sampling location

Figure S6. Changes in soil PCB levels and soil temperature at the Butal sampling location

Figure S7. Changes in air PCB levels and air temperature at the Mudanya sampling location

Figure S8. Changes in soil PCB levels and soil temperature at the Mudanya sampling location

Figure S9. Net flux levels of PCB congeners calculated for the Butal sampling location

Figure S10. Net flux levels of PCB congeners calculated for the Mudanya sampling location

Supporting Text

Sampling, Extraction and Analysis of Air and Soil Samples

A. Air Samples

A.1. Sampling

Air samples were collected between July 2008 and June 2009 by using a high-volume air sampler (HVAS) (Thermo Andersen GPS 11 Model, USA). Samples were collected at two sites of Bursa, namely Butal and Mudanya. During the sampling campaign, the meteorological parameters were simultaneously measured for both sites.

In order to collect particle- and gas-phase PCBs separately, a glass fiber filter (GFF) of diameter 10.2 cm and two pieces 5 cm long and 5.5 cm in diameter of polyurethane foam (PUF) cartridge were used in the HVAS (Cindoruk and Tasdemir 2008; Kim and Masunaga 2005; Simcik et al. 1998; Yeo et al. 2003). Average air volumes collected were 277±15 m3 and 191±60 m3 for Butal and Mudanya sampling sites, respectively. Sampling volumes showed variability depending on sampling periods and loss of pressure.

A.2. Extraction and Analysis

Throughout the study, equipment and glassware were cleaned with tap water, pure water, methanol (MeOH), and acetone (ACE), respectively. PUFs before first use were cleaned with Soxhlet for24 h with pure water, MeOH, acetone/hexane (ACE/HEX1/1), and dichloromethane (DCM), respectively, and were dried at 60oC. PUFs were then covered with aluminum foil and transferred in jars to sampling sites. Literary accepted methods were used for the extraction of PUF cartridges (Cindoruk and Tasdemir 2007; Cotham and Bidleman 1995; Odabasi et al. 1999; Vardar et al. 2004). PUF cartridges were Soxhlet-extracted for 24 hby using DCM/PE (1/4). Four nanograms of surrogate standard (PCB IUPAC congener 14, 65, and 166) were added to every sample before extraction.

Samples that were ready for chromatographic analysis after the processes of extraction, volume reduction, and fractionation were kept in a deep freeze of -20oC. Quantification of PCB congeners were conducted using a HP 7890A GC-µECD (Mikro-Electron Capture Detector) (Hewlett-Packard, USA). The temperature program used in

PCB analysis was as follows: 70oC (2 min), with 25oC/min to 150oC, with 3oC/min to 200oC, with 8oC/min reaching 280oC and holding at 280oC for 8 min, with 10oC/min reaching 300oC and holding for 2 min. The inlet temperature was held at 250oC and the detector temperature was 320oC. Helium, the carrier gas (1.9 mL/min), was used with a makeup gas of high-purity nitrogen. Splitless (after 1 min, a separation vane was opened) injection was used with purge flow of 25 mL/min. A HP5-MS capillary column (30 m 9 0.32 mm 9 0.25 lm; Agilent 19091 J- 413) was used. Five levels of standard solution between 0.05 and 25 ng/mL were used for calibration. The r2 for 83 PCB congeners were obtained as 0.99. System performance was verified by the analysis of the midpoint calibration standard after injection of 25 samples. The instrument detection limit (IDL) was determined as 0.1 pg for an injection of 1 µL.

A.3. Quality Assurance/Quality Control

In order to prevent any organic contamination in all stages during the sampling, extraction, and analysis, Teflon, glass, and stainless-steel materials were used. Surrogate standards containing PCB#14, PCB#65, and PCB#166 (4 ng/mL each) congeners were used to determine the recovery efficiency during the analysis procedure. Recovery efficienciesfor PUF samples are given in Table S1.

Table S1. Average recovery efficiencies for the air samples (%)

PCB#30 and PCB#204 were used as internal standards and they were added before injection. All of the data were reported after recovery and volume correction. In order to determine possible contaminations during sample collection, extraction, and analysis, 8 blank samples were taken for the 51 air samples. The average PCB amount determined in blanks proportion to that in the samples was indicated as 2.5 ± 3.5% for PUFs.

The limit of detection (LOD) for every PCB congener was determined by adding three standard deviation (average + 3 SD) to the average of the blanks. Measured value smaller than the LOD was not included in the calculation. Each PCB congener in the samples was blank corrected. LOD values varied from 0 to 1.4 ng for PUF samples.

B. Soil Samples

B.1. Sampling

Surface soil samples (0-5 cm) were collected. Five cores were collected on a 3 m × 3 m grid surrounding the sampling point. The soil cores were pooled to obtain one representative sample for the sampling location. Overlying vegetation was removed prior to sampling and the soil sample was sieved through a 2-mm mesh, wrapped in aluminum foil and stored at -20 ºC until analysis.

B.2. Extraction and Analysis

10 g of soil sample was weighed and placed in a glass vial and 20 mL dichloromethane / petroleum ether (DCM/PE; 1:1, v/v) was added. Each sample was spiked with 1 mL surrogate standard mix. Surrogate standards containing PCB #14, PCB #65 and PCB #166 (4 ng/mL each) congeners were used to determine the recovery efficiency during the analysis procedure.

The samples were then ultrasonically extracted for 30 minutes. The extracted samples were filtered (GF filter) and ultrasonically extracted for 30 minutes again with 20 mL DCM/PE (1:1, v/v). The sample was filtered again. The vial and filter were rinsed with 10 mL DCM/PE and this was added to the pooled extracted solvents. Extracts were passed through a sodium sulfate column to remove any residual water and impurities. Extracts were concentrated to 5 mL in a rotary evaporator (Cindoruk and Tasdemir 2007). Fifteen mL hexane was added to exchange the solvent and the mixture was evaporated again to 5 mL. An additional 15 mL hexane was used to rinse the rotary evaporator flask and added to the sample (Cindoruk and Tasdemir 2007). The sample was reduced to 2 mL under a gentle nitrogen stream. Then it was passed through a cleanup column containing 3 g silicic acid (deactivated with 100 μL deionized water), 2 g alumina (deactivated with 120 μL de-ionized water), and sodium sulfate (1 cm height). PCBs were eluted with 25 mL of PE (Cindoruk and Tasdemir 2007). After exchanging the solvent for hexane, the final volume of the sample was adjusted to 1 mL under a gentle nitrogen stream. PCBs 30 and 204 were used as internal standards for volume correction and internal standard was added just before the quantification of the PCB compounds.

Quantification of PCB congeners was conducted using an HP 7890A model gas chromatograph equipped with a µECD (Micro-Electron Capture Detector) (Hewlett-Packard, USA). The temperature program used in the PCB analysis was: 70 ºC (2 min), heating at 25 ºC/min to 150 ºC , heating at 3 ºC/min to 200 ºC , heating at 8 ºC/min to 280 ºC and holding at 280 ºC for 8 min, heating at 10 ºC/min to 300 ºC and holding for 2 min. The inlet temperature was held at 250 ºC and the detector temperature was 320 ºC. Helium (1.9 mL/min) was used as the carrier gas with a makeup gas of high-purity nitrogen (25 mL/min). Splitless injection (the separation vane was opened after 1 min) was used with a purge flow of 25 mL/min. An HP5-MS capillary column was used (30 m × 0.32 mm × 0.25 µm, Agilent 19091J- 413). Five levels of standard solutions ranging between 0.05 and 25 ng/mL were used for calibration. The r2 value for each PCB congener was obtained as >0.99. System performance was verified by the analysis of the midpoint calibration standard after 25 sample injections. The instrument detection limit (IDL) was determined as 0.1 pg for an injection of 1 µL. Eighty-three PCB congeners were targeted: IUPAC Nos. 4, 5, 6, 7, 8, 9, 10, 12, 13, 15, 16, 17, 19, 21, 22, 26, 28, 31, 32, 37, 41, 42, 44, 45, 47, 48, 49, 52, 53, 56, 60, 61, 64, 66, 70, 71, 74, 77, 81, 83, 84, 85, 86, 87, 89, 91, 92, 95, 99, 100, 101, 105, 110, 114, 118, 119, 123, 126, 128, 131, 132, 135, 138, 144, 149, 153, 156, 163, 167, 169, 170, 171, 172, 174, 180, 190, 194, 199, 200, 202, 205, 206, and 207.

B.3. Quality Assurance/Quality Control

Forty field blanks were collected to determine if any contamination occurred during the sample handling, transportation, and analyses. They were prepared by filling thimbles with 10 g of sodium sulfate (Kurt-Karakus et al. 2006). Blanks were extracted and cleaned up in the same manner as the samples.

To evaluate the extraction efficiency for the target compounds, all samples were spiked with PCB surrogate standards prior to extraction and the recovery percentages of the surrogate standards were calculated. The average recoveries are given in Table S2.

Table S2. Average recovery efficiencies for the soil samples (%)

The PCB amount determined in blanks proportion to that in the samples was indicated as 2±1.5% and 2.8±2.1% for Butal and Mudanya soils respectively.

The limit of detection (LOD) for every PCB congener was determined by adding three standard deviation (average + 3 SD) to the average of the blanks. Values smaller than the LOD were not included in the calculation. Each PCB congener in the samples was blank corrected. LOD values varied from 0.1 to 4.75 ng for soil samples.

References for the Supporting Text

Cindoruk, S.S., Tasdemir, Y., 2007. The determination of gas phase dry deposition fluxes and mass transfer coefficients (MTCs) of polychlorinated biphenyls (PCBs) using a modified water surface sampler (WSS). The Science of Total Environment, 381, 212-221.

Cindoruk, S.S., Tasdemir, Y., 2008. Atmospheric gas and particle phase concentrations of polychlorinated biphenyls (PCBs) in a suburban site of Bursa, Turkey. Environmental Forensics, 9,153-165.

Cotham, W.E., Bidleman, T.F., 1995. Polycyclic aromatic hydrocarbons and polychlorinated biphenyls in air at an urban and a rural site near Lake Michigan. Environmental Science and Technology, 29, 2782–2789.

Kim, K.S., Masunaga, S., 2005.Behavior and source characteristic of PCBs in urban ambient air of Yokohama, Japan. Environmental Pollution, 138, 290–298.

Kurt-Karakus, P.B., Bidleman, T.F., Staebler, R.M., Jones, K.C., 2006. Measurement of DDT fluxes from a historically treated agricultural soil in Canada. Environmental Science and Technology, 40, 4578-4585.

Odabasi, M., Sofuoglu, A., Vardar, N., Tasdemir, Y., Holsen, T.M., 1999. Measurement of PAH dry deposition and air–water exchange of polycyclic aromatic hydrocarbons with the water surface sampler. Environmental Science and Technology, 33, 426–434.

Simcik, M.F., Franz, T.P., Zhang, H., Eisenreich, S.J., 1998. Gas/particle partitioning of PCBs and PAHs in the Chicago urban and adjacent coastal atmosphere: states of equilibrium. Environmental Science and Technology, 32, 251–257.

Vardar, N., Tasdemir, Y., Odabasi, M., Noll, K.E., 2004.Characterization of atmospheric concentrations and partitioning of PAHs in the Chicago atmosphere. Science of Total Environent, 327, 163–174.

Yeo, H.G., Choi M, Chun, M.Y., Sunwoo, Y., 2003. Gas/particle concentrations and partitioning of PCBs in the atmosphere of Korea. Atmospheric Environment, 37,3561–3570.

Mapping

The inverse distance weighted (IDW) interpolation method with a spatial resolution of 30×30m, weight factor of 2.0 and ArcGIS Version 9.1 (2005) were used to generate the thematic maps indicating the spatial distribution of PCB content of urban soils. Inverse Distance Weighting (IDW) is an exact method that based on the assumption that the nearby values contribute more to the interpolated values than distant observations. In other words, the degree of influence is expressed by the inverse of the distance between points raised to a power. A power of 1.0 means constant rate of change in value between points (linear interpolation). A power of 2.0 or higher suggests that the rate of change in values is higher near a known point and levels off away from it (Chang, 2003). The assigned weight is a function of inverse distance as represented in the following formula (Lam, 1983):

…………………(Lam, 1983)]