Three-Year Atmospheric Monitoring of ... - ACS Publications

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Three-Year Atmospheric Monitoring of Organochlorine Pesticides and Polychlorinated Biphenyls in Polar Regions and the South Pacific Song-Yee Baek,† Sung-Deuk Choi,‡ and Yoon-Seok Chang*,† †

School of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), San 31, Hyoja-dong, Nam-gu, Pohang 790-784, Republic of Korea ‡ School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon-ri, Eonyang-eup, Ulsan 689-798, Republic of Korea

bS Supporting Information ABSTRACT: XAD-2 resin based passive air samplers (PAS) were deployed for three one-year periods at the Korean polar and South Pacific research stations at Ny-Ålesund (2005
2009), King George Island (2005
2007), and Chuuk (2006
2009) to investigate long-range transport, local sources, and temporal trends of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). The highest hexachlocyclohexane (HCH) concentration (35.2
78.9 pg 3 m
3) over the entire sampling period was detected at Ny-Ålesund, in the Arctic. R-HCH was the dominant OCP (31.1
67.1 pg 3 m
3), contributing about 50% of the total OCP load. Additionally, a high and consistent R/γ-HCH ratio was observed at Ny-Ålesund. HCHs might reach Arctic sites more easily than other OCPs from surrounding countries through long-range atmospheric transport (LRAT). Interestingly, high levels of the current-use OCP endosulfan —particularly endosulfan-I—were detected at almost all sampling sites, including in Antarctica, ranging 12.2
88.5, 17.7
130, and ND
59.7 pg 3 m
3 at King George Island, Ny-Ålesund, and Chuuk, respectively. Specific OCP and PCB patterns, such as low trans/cis-chlordane ratios and a prevalence of lighter PCB congeners, were observed in all three regions (excepting one site at Ny-Ålesund and one site in the South Pacific affected by local sources) during all sampling periods. This indicates that these Polar and remote South Pacific sites are mainly influenced by LRAT. Over the entire sampling period, a decreasing trend of HCHs (R- and γ-HCH) and an increasing trend of endosulfan-I were observed at the NyÅlesund sites.

’ INTRODUCTION Remote sites, such as Polar regions and isolated islands, were previously considered as pristine environments where there were no significant sources of pollutants. However, there has been increasing evidence that these areas are contaminated with certain chemicals, particularly Persistent Organic Pollutants (POPs).1
3 Even though there are no significant local sources of POPs, considerable concentrations of POPs have been detected in these areas. Atmospheric transport processes such as global cold-trapping, fractionation,4 and long-range atmospheric transport (LRAT)3,5,6 are believed to be an important and rapid route of transport for POPs to these otherwise pristine locations. In addition to atmospheric transport, some anthropogenic activities, such as research station operations, should be regarded as a possible local source of POPs.1,7 An increased level of polychlorinated biphenyls (PCBs) was found in both the air and sediments in vicinity of the McMurdo Research Station, Antarctica.1,7 A high concentration of decabromodiphenyl ether was also measured in biota and sediments at this station.8 POP emissions from worldwide sources can directly influence remote areas through LRAT. Extensive use of organochlorine r 2011 American Chemical Society

pesticides (OCPs) and PCBs occurred between the late 1950s and early 1980s and between the 1930s and 1980s, respectively.9 Since PCBs and a number of OCPs—including chlordanes, hexachlocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs), and mirex—were regulated under the Stockholm Convention, their usage and/or emissions have been decreasing. However, use of other OCPs (e.g., endosulfan) is still prevalent and continues to increase.10 An air monitoring study reported that endosulfan was the most abundant OCP measured worldwide.11 In the Arctic, an increasing trend of endosulfan concentrations was observed,10,12 while the concentrations of the banned OCPs showed decreasing or constant trends.10,12 Monitoring programs such as the Northern Contaminants Program (NCP) and the Arctic Monitoring and Assessment Program (AMAP) were established to investigate the long-term temporal trends of POPs in the Arctic13,14 and research has been Received: December 23, 2010 Accepted: April 6, 2011 Revised: March 23, 2011 Published: April 13, 2011 4475

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Figure 1. Location of sampling sites at Korean research stations: (a) Dasan Arctic station, (b) King Sejong Antarctic station, and (c) Korea-South Pacific Ocean Research Center (KSORC).

extensively conducted in the Arctic (e.g., refs 12, 15
18). However, limited data on POPs have been reported in the Antarctic due to the difficulty of access.3,7,19 XAD-2 resin passive air samplers (PAS) were first deployed for one year at the Korean Arctic and Antarctic research stations to investigate the influence of LRAT and local sources of PCBs.20 The results from those early measurements suggested that research stations should be considered as possible local sources of PCBs. We subsequently deployed PAS for three consecutive years at those stations as well as a South Pacific research station to investigate not only the influence of LRAT and local pollution but the temporal trends of OCPs and PCBs in remote areas as well.

’ EXPERIMENTAL SECTION Passive Air Sampling. XAD-2 resin based PAS were used in this study because their sampling rates are largely independent of wind speed and temperature,21 and PCBs and OCPs do not attain equilibrium between the air and the XAD-2 resin for more than one year.21,22 The details of the XAD-2 resin PAS were presented in a previous paper.21 The chemical quantities retained by the resin (pg 3 PAS
1) were converted to air concentrations (pg 3 m
3) using a sampling rate of 0.52 m3 3 day
1 determined by previous studies.21 A detailed description of the sampling method is provided in the Supporting Information (SI). XAD-2 resin based PAS exclusively collect the gas-phase contaminants in the atmosphere.21 For relatively volatile compounds such as HCHs and the lighter PCBs that normally dominate in the gas phase, the measured levels by the XAD-2 resin based PAS are close to their total concentrations in the air. However, this may not be the case for DDTs and the heavier PCBs, which are considerably less volatile. Therefore, the results obtained from our study are the gas phase concentrations rather than the total air concentrations of the target compounds. Sampling Sites. The Dasan station is located in Ny-Ålesund on the high Arctic island of Spitsbergen, Svalbard, Norway

(78°550 N, 11°560 E). The King Sejong station is located on the Barton Peninsula, King George Island, Antarctica (62°130 S, 58°470 W). The Korea-South Pacific Ocean Research Center (KSORC) has been operating since May 2000, located in Chuuk—specifically Moen Island, the main island of several that comprise the Island State of Chuuk—in Micronesia (7°270 N, 151°530 E). These three stations are operated by the Korea Ocean Research and Development Institute (KORDI). PAS were deployed at three sites (A, B, and C) at Ny-Ålesund, three sites (D, E, and F) at King George Island, and three sites (G, H, and I) at Chuuk (Figure 1). One sampler was deployed at each site for every sampling period. To investigate the influence of a local source, the distances of the sampling sites from the main buildings of research station varied (Figure 1). The South Pacific sites G and H were within 100 m of the main building of KSORC, which is located on the northeastern coast of the island. Site I was 1.5 km from KSORC (Figure 1, Figure S1). PAS were deployed for three one-year periods: Dec. 2004
Dec. 2005 (1st), Dec. 2005
Jan. 2007 (2nd), and Jan. 2007
Dec. 2007 (3rd) for the Ny-Ålesund sites; Aug. 2005
Aug. 2006 (1st), Aug. 2006
Aug. 2007 (2nd), and Jun. 2008
Jun. 2009 (3rd) for the King George Island sites; and Feb. 2006
Mar. 2007 (1st), Mar. 2007
Feb. 2008 (2nd), and Dec. 2008
Oct. 2009 (3rd) for the Chuuk sites. Field blanks were deployed at each region for every sampling period, which totalled nine for the three-year deployment. Analysis. A full description of the analytical procedure is provided in the SI. Briefly, the retrieved XAD-2 resin was divided into two fractions of equal weight: one for PCBs and the other for OCPs. The divided resins were Soxhlet-extracted for 20 h with 300 mL of toluene for PCBs and 300 mL of acetone/hexane (1:1, v:v) for OCPs. Cleanup was performed with multilayer silica columns and silica (5 g)/florisil (5 g) columns for PCBs and OCPs, respectively. Samples were analyzed by a gas chromatograph (Agilent-6890) coupled with a high-resolution mass spectrometer (Jeol JMS-700T) for all 209 PCB congeners and the OCPs, R-, β-, γ-HCH, aldrin, dieldrin, heptachlor (HEPT), endosulfan (I and II), endosulfan sulfate, trans-chlordane (TC), 4476

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Environmental Science & Technology cis-chlordane (CC), trans-nonachlor (TN), cis-nonachlor (CN), o,p0 -, p,p0 -DDE, o,p0 -, p,p0 -DDD, and o,p0 -, p,p0 -DDT. Average recoveries of internal standards were between 45 and 95% for each PCB homologue and between 60 and 114% for each OCP. All data presented are field blank- and recovery-corrected. Meteorological Parameters. The Arctic and Antarctic research stations have automated weather systems (AWS) which measure wind speed, wind direction, and air temperature. Windrose diagrams were constructed to determine the prevailing winds during the sampling periods. To identify the origin of air masses arriving at sampling regions, five-day backward trajectories with a starting height of 50 m were calculated using HYSPLIT 4 (http://www.arl.noaa.gov/ready/hysplit4.html). These trajectories were calculated at 00:00 UTC (Coordinated Universal Time) on every fifth day. Monthly mean wind fields for a 850-hPa surface were obtained from the NCEP/NCAR reanalysis at the NOAA/ESRL Physical Sciences Division (http:// www.esrl.noaa.gov/psd/data/reanalysis/reanalysis.html).

’ RESULTS AND DISCUSSION Meteorological Conditions. Temporal variations of air temperature and wind speed for the sampling periods are presented in Figure S2 in the SI. Variations for the third period at the Dasan Arctic station are not shown due to some problems related with QA/QC. Data for the first period were presented in a previous publication.20 The average air temperature and wind speed at the King Sejong Antarctic station were 7.8 m 3 s
1 and
0.9 °C during the second sampling period and 7.5 m 3 s
1 and
3.7 °C during the third sampling period. The average air temperature and wind speed during the second sampling period at the Dasan Arctic station were 3.2 m 3 s
1 and
4.8 °C. Similar meteorological conditions were measured at each station during every sampling period. Wind-rose diagrams for the Polar stations are depicted in Figure S3 in the SI. At Dasan, Ny-Ålesund, the prevailing wind direction was from the southeast during the entire sampling period, while the prevailing winds at King Sejong, King George Island were from the northwest and east. These wind directions suggest that King George Island was predominantly affected by emissions from South America, and Ny-Ålesund was affected by emissions from Northern European countries and Russia during all three years. Because there was no AWS at the South Pacific station, back-trajectory analysis was performed for the first sampling period. The results from the analysis showed that Chuuk was consistently affected by Northeasterly trade winds throughout the year (Figure S4). The results of back-trajectory analysis for the other sampling periods were similar and, hence, are not presented here. OCP Concentrations. Annual OCP concentrations at the nine sites are presented in Table S5 and Figure 2. Two samples (D and F) at King George Island were lost during the third sampling period. The highest total concentration of target OCPs was measured at Ny-Ålesund, ranging from 72.3 to 125, from 90.6 to 102, and from 68.8 to 176 pg 3 m
3 during the first, second, and third sampling periods, respectively. HCHs and endosulfan-I were the most abundant OCPs in this region. Excluding the third period results, an average OCP concentration of 20.0 pg 3 m
3 was measured at King George Island, much lower than those at Ny-Ålesund. Moreover, OCPs other than endosulfan-I were seldom detected in King George Island samples. At Chuuk Island, there were significant differences in OCP concentrations

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among sites G, H, and I. Only site I had concentrations (100
313 pg 3 m
3) comparable with those of Arctic sites. The contributions of DDT and its metabolites were notably high at this site (Table S5), while the other two sites (G and H) had concentrations of OCPs comparable to those in the Antarctic. This difference might be due to the locations of the sampling sites and is further addressed below. All three sites in both Polar Region (Ny-Ålesund and King George Island) showed similar concentrations and patterns of OCPs over the whole sampling period. The lack of OCP concentration gradients with distance from the buildings of the research stations implies that they are likely not a local source of OCPs. HCHs (R-, β-, and γ-HCH). Technical HCH is a mixture of different isomers in which the R-form is the main isomer. γHCH is the main component of lindane, which replaced technical HCH and is still used in some countries.23 The measured air concentrations of R-, β-, and γ-HCH are listed in Table S5. The highest ∑HCH (sum of R-, β-, and γ-HCH) concentration was measured at the Ny-Ålesund sites with a range of 35.2
78.9 pg 3 m
3 over the entire period. In particular, R-HCH was the dominant OCP at these sites (31.1
67.1 pg 3 m
3), comprising about 50% of the total OCP concentrations. Unlike the NyÅlesund sites, the King George Island sites showed relatively low HCH concentrations: ∑HCH and R-HCH ranged from ND to 3.65 pg 3 m
3 and from ND to 2.50 pg 3 m
3, respectively. ∑HCH concentrations at King George Island were an order of magnitude lower than Ny-Ålesund concentrations. β-HCH was seldom detected in Polar Regions. The South Pacific sites had moderate ∑HCH concentrations, averaging 6.64, 1.62, and 5.02 pg 3 m
3 for R-, β-, and γ-HCH, respectively (Figure 2). These HCH concentrations reflect the extensive historical use of technical HCH in the Northern Hemisphere, particularly in China, India, Russia, and France.24 In other words, Arctic sites might receive much more considerable amounts of HCHs than those of other OCPs from surrounding countries in the Northern hemisphere. The R/γ-HCH ratio can be used to trace the sources of technical HCH and lindane.17,25 The different physicochemical properties of R- and γ-HCH, such as the reaction rate with the hydroxyl radical and the Henry’s Law constant, lead to a lower residence time of γ-HCH in the atmosphere.17 The R/γ-HCH ratio has exhibited a significant increasing trend with increasing latitudes.25 The R/γ-HCH ratios of China, Russia, and Iceland were 1.4
3.38, 2.4, and 1.09, respectively.11 Substantially higher than these countries, Arctic samples were found to have an average R/γ-HCH ratio of 5.64, which was in good agreement with previous Arctic results (Table S6).11,13,14 However, the King George Island sites and the Chuuk sites showed relatively low R/ γ-HCH ratios of 2.85 and 1.80, respectively. High HCH concentrations and high and consistent R/γ-HCH ratios suggest that the Arctic is still affected by surrounding countries through LRAT. Li and Bidleman suggested that the Arctic Ocean might also act as a source of R-HCH to the Arctic air.26 Aldrin and Dieldrin. Low levels of dieldrin were found over the entire sampling period, ranging from ND to 2.18 pg 3 m
3 (average: 0.94 pg 3 m
3) at Ny-Ålesund and ND to 1.88 pg 3 m
3 (average: 0.57 pg 3 m
3) at Chuuk. Dieldrin was not detected at King George Island. Aldrin was not detected at any sites in this campaign. Endosulfans. Unlike most other OCPs, endosulfan is still in use. While many studies have measured endosulfan levels in Arctic air,10,18 there have been few reported levels in the Antarctic atmosphere.11 Endosulfan-I and -II were not previously detected 4477

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Figure 2. Average OCP concentrations measured in the air in three different areas: (a) Ny-Ålesund, (b) King George Island, and (c) Chuuk.

at an Italian base in the Antarctic.11 However, in the present study, endosulfan-I was the most prevalent OCP measured at King George Island (12.2
88.5 pg 3 m
3, average: 27.1 pg 3 m
3), comprising about 85% of all the measured OCPs. The Ny-Ålesund sites showed comparable concentrations of endosulfan-I ranging from 17.7 to 130 pg 3 m
3 (average: 41.3 pg 3 m
3). This is in agreement with previous measurements of endosulfan-I at Ny-Ålesund (37 pg 3 m
3).11 These results suggest endosulfan-I is extensively transported to the Polar Regions. At no sites was endosulfan-II detected, while endosulfan sulfate was detected at concentrations below 1 pg 3 m
3. In previous studies, endosulfan-I has been the more abundant isomer, while endosulfan-II has not been detected in most air

samples.11,27 A few areas, including the Canary Islands, Ghana, and Argentina, had very high air concentrations (several hundred pg 3 m
3) of endosulfan-II.11 A significant transformation from endosulfan-II to endosulfan-I can occur at the solid
water28 and air
water interfaces.29 The average I/II-endosulfan ratio has been shown to be higher in samples from background sites, suggesting that endosulfan-II is preferentially lost during atmospheric transport30 and is not anticipated to be present in Polar Regions at measurable levels. Consequently, endosulfan-II is not likely to be detected in Polar Regions. Chlordanes (trans- and cis-Chlordanes and trans- and cisNonachlors) and Heptachlor. Technical chlordane is a mixture primarily composed of trans-chlordane (TC), cis-chlordane (CC), 4478

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Environmental Science & Technology and trans-nonachlor (TN), with trace amounts of heptachlor (HEPT) and cis-nonachlor (CN).31 HEPT which was first isolated from technical chlordane in 1946 was manufactured as an insecticide on its own.32 In previous studies, chlordanes were detected in lower concentrations than the other OCPs in Polar Regions.3,14 In the present study, total chlordanes (sum of TC, CC, TN, CN, and HEPT) ranged from ND to 2.14 pg 3 m
3 at King George Island and from 2.12 to 10.6 pg 3 m
3 at NyÅlesund. TC, CC, and TN were detected at nearly all sites, whereas CN was not detected, reflecting the composition of technical chlordane.31 HEPT was detected at concentrations comparable with those of other chlordane isomers, ranging from ND to 3.84 pg 3 m
3, suggesting the use of HEPT itself. TC/CC ratio of the technical chlordane is 1.56,16 but different atmospheric reaction rates likely cause a decrease in TC/CC ratio with increasing distance from sources.16 Almost all sites in this study had lower TC/CC ratios than that of technical chlordane, averaging 0.52, 0.62, and 0.73 at Ny-Ålesund, King George Island, and sites G and H at Chuuk, respectively (Table S5), indicating LRAT. A relatively high TC/CC ratio (average: 1.24) was observed at site I, again suggesting a local source to this site and discussed below. DDTs. Many countries banned DDT usage in the 1970s, however, some tropical countries still use DDT to control mosquitoes to reduce the spread of malaria. Because DDT is largely converted to its metabolites, DDD and DDE, the ratio p, p0 -DDE/DDT is often used as an indicator of the age of DDTs: a high p,p0 -DDE/DDT ratio is indicative of aged DDT, while a low ratio is indicative of fresh DDT input.33,34 DDT isomer was not detected at King George Island, and their metabolites were detected only at site D and at very low concentrations (Table S5). At Ny-Ålesund, ∑DDT (sum of DDTs and metabolites) was measured over a range from ND to 5.14 pg 3 m
3. Consistent with previous results, p,p0 -DDE was dominant, ranging from ND to 3.22 pg 3 m
3, and a high value of p,p0 -DDE/DDT (4.34
6.08) was observed: p,p0 -DDE/DDT at Zeppelin, Ny Alesund was 4.73 in 2000
2003 and 10.91 in 2006.14,35 The Chuuk sites G and H showed similar concentrations to the Ny-Ålesund sites. Again suggesting local emissions, site I showed significantly higher ∑DDT. Differences in OCP Concentrations among Sites at Chuuk, South Pacific. The concentration of endosulfan-I at site I considerably differed from those at sites G and H (t-test: p < 0.05): 3.52
59.7 pg 3 m
3 of endosulfan-I was detected at site I, whereas ND
3.85 pg 3 m
3 was detected at sites G and H. Most OCPs showed similar patterns. In addition to the high TC/CC ratio, site I showed chlordane levels over 10-times higher (21.8
52.1 pg 3 m
3) than the levels observed at sites G and H (0.61
5.30 pg 3 m
3) (p < 0.05). Furthermore, DDT and its metabolites were particularly high at site I (p < 0.05), with ∑DDT levels of 66.3, 78.9, and 192 pg 3 m
3 during the first, second, and third periods, respectively. As mentioned above, the Chuuk sites are located on the northeastern coast of Moen island (Figure 1, Figure S1), which is influenced by northeasterly trade winds throughout the year (Figure S4). Air masses passing over the Pacific Ocean flow into this area. As a result, sites G and H, which are very near the coast, are mainly subject to onshore winds and receive contaminants primarily by LRAT. However, site I is farther inland and 1.5 km from sites G and H. The high burden of OCPs at site I suggests an influence from a local source and, in fact, chlordanes and DDTs are known to be stored and buried in Chuuk.36,37 Unlike other OCPs, the uniform distribution of HCHs is likely to imply a lack of HCH usage in this area.

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Figure 3. PCB homologue concentration patterns for 9 sites at (a) NyÅlesund, (b) King George Island, and (c) Chuuk.

PCB Concentrations. PCB concentrations in the three regions are presented in Table S5 and Figure 3. Only di- to decaCBs are reported in this study due to the low recovery of monochlorinated CBs. As mentioned above, the two samples (D and F) at King George Island were lost during sampling and the site E sample was lost during extraction for the third sampling period. Therefore, the PCB results from the third sample are not presented here. The site C sample for the second sampling was contaminated during analysis and those data are also not presented. The first sampling period’s PCB results from the two Polar Regions indicated that the research stations could be local sources of PCBs.20 The highest ∑206PCB concentration (150 pg 3 m
3 for 4479

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Environmental Science & Technology the second period and 80.1 pg 3 m
3 for the third period) was again found at site A (on a roof of the Dasan station) in Ny-Ålesund. Site A had a concentration about 4 times higher than sites B and C. Additionally, dominance of heavier PCBs was found at this site during every sampling period (Figure S5). A decreasing trend of PCB concentrations with increasing distance from the main building at the King Sejong station was found during the entire sampling period. The big differences of PCB levels between sites E and F might be also caused by prevailing wind direction and the location of the sites (blows to southeast and west, respectively: Figure S3). These results provide strong evidence that these Polar research stations are important sources of measured PCBs. Unexpectedly, relatively high ∑206PCB concentrations at King George Island, averaging 78.2 and 81.9 pg 3 m
3, were found in the first and second periods. In particular, the PCB-11 concentration was quite high with a range of 22.8
87.1 pg 3 m
3 and an average of 60.3 pg 3 m
3. PCB-11, a non-Aroclor congener, accounted for 74% of total PCBs at King George Island. Recently, PCB-11 has been shown to be ubiquitous in the ambient air38,39 and pigments or dyes are identified as the main source of this congener.40 Without PCB-11, total concentrations (∑205PCB) at King George Island ranged from 11.1 to 31.9 pg 3 m
3 with an average of 19.8 pg 3 m
3 over the entire sampling period. PCB-11 levels (average: 58.4 pg 3 m
3) at Chuuk were similar to those of King George Island. By contrast, only an average PCB-11 concentration of 5.44 pg 3 m
3 was detected at Ny-Ålesund. These results indicate a substantially different PCB-11 distribution between the Northern and Southern Hemispheres. Though yet to be verified, significant sources of PCB-11 may be concentrated in the tropics and the Southern Hemisphere. The Chuuk sites G and H showed average ∑206PCB concentrations of 187 and 143 pg 3 m
3, respectively. During the entire sampling period, the concentrations of these two sites were relatively constant. However, site I showed considerably different concentrations among sampling periods: 148, 85.9, and 308 pg 3 m
3 for the first, second, and third sampling periods, respectively. Additionally, different homologue fractions were observed between the Chuuk sites (Figure S5). Sites G and H showed high contributions (over 80%) of the low-chlorinated di- and tri-CBs, similar to the pattern of Antarctic samples, while site I showed a large contribution from higher molecular weight PCBs. These PCB results and the different OCP distributions noted above could have similar causation. Temporal Trends of OCPs and PCBs. Unlike the Antarctic region, the Arctic is composed of and surrounded by many countries, and, generally, much higher concentrations of OCPs and PCBs have been measured at Arctic sites than at Antarctic sites. In other words, the Arctic region might receive considerable inputs of pollutants from emissions in Russia, Canada, and European countries. Some studies have reported that HCH concentrations have decreased in the Arctic due to countryspecific regulation.13,41 In the present study, a significant decreasing trend of R-HCH was observed over the sampling campaign at the Ny-Ålesund sites (Figure 2, Table S8: regression analysis). Compared with previous studies, however, these HCH concentrations were still relatively high: they were comparable to 1994 levels at Dunai13 and were higher than the concentrations at Ny-Ålesund in 2004 and 2006 (Table S6).11,14 It is difficult to make direct comparisons with those previous measurements because the sampling locations were different.

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Unlike HCHs, endosulfan-I showed an increasing trend at NyÅlesund (Figure 2, Table S8). The results were higher than previous data from measurements at Kinngit, Tagish, and Dunai in 1994,13 at Alert in 1997,12 and at Alert in 2000
200335 (Table S6). Moreover, the King George Island and Chuuk sites—especially site I—also showed increasing trends of endosulfan-I (Figure 2, Table S8). These trends reflect the increasing usage of endosulfan throughout the world. PCBs levels had a decreasing trend with time at sites A and B (Figure S6). With respect to the banned OCPs, chlordanes, a slightly decreasing trend was observed at Ny-Ålesund (Figure 2, Table S8). Excepting endosulfan, there were no significant PCB or OCP trends at the King George Island and Chuuk sites. HCHs and chlordanes were detected only at very low concentrations at King George Island, and thus, almost all OCPs are expected to be undetectable within a few years. Implication. POPs studies in Polar Regions, particularly the Arctic, have traditionally been conducted using active air samplers (AAS). Atmospheric monitoring using AAS during an entire year requires much effort: it requires polyurethane foam plugs (PUFs) and particle filters to be changed every few days, and many PUFs and filter samples must be collected and analyzed. Moreover, because it requires electricity, AAS must be conducted near a research station or a generator. It has been shown that research stations can act as a local source of PCBs in the present study. Thus, to avoid contamination from local sources, samples should be collected far from research stations. In this regard, passive air sampling is a very useful tool for monitoring POPs in truly remote areas. Furthermore, this study shows a decreasing trend for the regulated OCPs and PCBs and an increasing trend for a current-use OCP in the Arctic, over only three years of monitoring. The deployment of passive air samplers over several years can thus provide data on temporal trends to evaluate the effectiveness and feasibility of bans and restrictions on the manufacture and use of historic and candidate POPs.

’ ASSOCIATED CONTENT

bS

Supporting Information. Materials and methods, tables and figures, references. This material is available free of charge via the Internet at http://pubs.acs.org.

’ AUTHOR INFORMATION Corresponding Author

*Phone: (82)-54-279-2281; fax: (82)-54-279-8299; e-mail: [email protected].

’ ACKNOWLEDGMENT This work was supported by the Brain Korea 21 project and the Korea Polar Research Institute (KOPRI) (PE11090). We thank Hyun-Woo Lee at POSTECH and Dr. Heung-Sik Park at KSORC for their efforts in deploying samplers. Thanks also to Dr. Young-Jun Yoon at KOPRI for providing meteorological data. ’ REFERENCES (1) Risebrough, R. W.; De Lappe, B. W.; Younghans-Haug, C. PCB and PCT contamination in Winter Quarters Bay, Antarctica. Mar. Pollut. Bull. 1990, 21, 523–529. (2) Bidleman, T. F.; Walla, M. D.; Roura, R.; Carr, E.; Schmidt, S. Organochlorine pesticides in the atmosphere of the Southern Ocean and Antarctica, January-March, 1990. Mar. Pollut. Bull. 1993, 26, 258–262. 4480

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