20 Years of Air-Water Gas Exchange
Observations for Pesticides in the Western
Arctic Ocean
Liisa Jantunen, Fiona Wong, Anya Gawor, Henrik Kylin, Paul Helm, Gary Stern, William Strachan, Deborah Burniston and Terry Bidleman
Linköping University Post Print
N.B.: When citing this work, cite the original article.
Original Publication:
Liisa Jantunen, Fiona Wong, Anya Gawor, Henrik Kylin, Paul Helm, Gary Stern, William Strachan, Deborah Burniston and Terry Bidleman, 20 Years of Air-Water Gas Exchange Observations for Pesticides in the Western Arctic Ocean, 2015, Environmental Science and Technology, (49), 23, 13844-13852.
http://dx.doi.org/10.1021/acs.est.5b01303
Copyright: American Chemical Society
http://pubs.acs.org/
Postprint available at: Linköping University Electronic Press
Published in Environmental Science & Technology (2015) 49:13844-13852
DOI 10.1021/acs.est.5b01303
© 2015 American Chemical Society
Twenty years of air-water gas exchange observations for pesticides
in the western Arctic Ocean
Liisa M. Jantunen1*, Fiona Wong2, Anya Gawor1, Henrik Kylin3,4, Paul A. Helm5, Gary A. Stern6, William M.J. Strachan7, Deborah A. Burniston8 and Terry F. Bidleman1,9
1. Air Quality Processes Research Section, Environment Canada, 6842 Eighth Line, Egbert ON, L0L 1N0, Canada.
2. Department of Applied Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden.
3. Department of Thematic Studies – Environmental Change, Linköping University, SE-581 83 Linköping, Sweden.
4. Research Unit: Environmental Sciences and Development, North-West University, P Bag X 6001, Potchefstroom 2520, South Africa.
5. Environmental Monitoring and Reporting Branch, Ontario Ministry of the Environment, 125 Resources Road, West Wing, Toronto, Ontario, M9P 3V6 Canada.
6. Centre for Earth Observation Science, University of Manitoba, 474 Wallace Building, 125 Dysard Road, Winnipeg, R3T 2N2, Canada.
7. Aquatic Ecosystem Protection Research Division, Science and Technology Branch, Environment Canada, 867 Lakeshore Rd., Burlington, ON, L7S 1A1.
8. Water Quality Monitoring and Surveillance, Science and Technology Branch, Environment Canada, 867 Lakeshore Rd., Burlington, ON, L7S 1A1.
Abstract
The arctic has been contaminated by legacy organochlorine pesticides (OCPs) and currently used pesticides (CUPs) through atmospheric transport and oceanic currents. Here we report time trends and air-water exchange of OCPs and CUPs from research expeditions conducted between 1993- 2013. Compounds determined in both air and water were trans- and cis-chlordanes (TC, CC),
trans- and cis-nonachlors (TN, CN), heptachlor exo-epoxide (HEPX), dieldrin (DIEL),
chlorobornanes (ΣCHBs, toxaphene), dacthal (DAC), endosulfans and metabolite endosulfan sulfate (ENDO-I, ENDO-II, ENDO SUL), chlorothalonil (CHT), chlorpyrifos (CPF) and trifluralin (TFN). Pentachloronitrobenzene (PCNB, quintozene) and its soil metabolite pentachlorothianisole (PCTA) were also found in air. Concentrations of most OCPs declined in surface water, whereas some CUPs increased (ENDO-I, CHT and TFN) or showed no significant change (CPF, DAC), while most compounds declined in air. Chlordane compound fractions TC/(TC+CC) and TC/(TC+CC+TN) decreased in water and air, while CC/(TC+CC+TN) and TN/(TC+CC+TN) increased, suggesting selective removal of more labile TC over time and/or a shift in chlordane sources. Water/air fugacity ratios indicated net volatilization (FR >1.0) or near equilibrium (FR not significantly different from 1.0) for most OCPs, but net deposition (FR <1.0) for ΣCHBs. Net deposition was shown for ENDO-I on all expeditions, while the net exchange direction of other CUPs varied. Understanding the processes and current state of air-surface exchange helps to interpret environmental exposure, evaluate the effectiveness of International Protocols and provides insights for the environmental fate of new and emerging chemicals.
Introduction
Atmospheric deposition has been recognized as a large, and in some cases the
dominant, loading process for persistent organic pollutants (POPs) to the oceans.1-3 This is also true for the Arctic Ocean, although awareness is growing that ocean currents can transport persistent and relatively soluble chemicals including some current use pesticides (CUPs).3-8 Air-water gas exchange of chemicals is a ‘two-way street’ and can alternate between net deposition and net volatilization in response to seasonally changing temperatures, atmospheric levels,9-10 cycles of biological productivity, particle sinking dynamics and hydroxyl radical (OH) reactions.11-13 Over longer time periods, declining atmospheric concentrations have led to re-emission of hexachlorocyclohexanes (HCHs) from the Arctic Ocean.14-20 Exchange of HCHs and other OCPs in subarctic, temperate and tropical oceans have varied from net deposition to equilibrium to net volatilization.12,22-26 Modeling suggests that the global ocean has been losing DDT since 1977, with volatilization as the main loss process.27
Few assessments of gas exchange have been made for OCPs other than HCHs, and even fewer for CUPs, in the Arctic. Exchanges (net, unless stated otherwise) in the central Canadian
Archipelago in 1993 were volatilization for hexachlorobenzene (HCB) and dieldrin (DIEL) and deposition for endosulfan-I (ENDO-I), while the exchange direction varied with season for
chlordanes and chlorobornanes (CHBs; e.g., toxaphene).28 Deposition of cis-chlordane (CC), HCB and variable exchange of trans-chlordane (TC) were found during 2004 in the eastern Arctic Ocean between Greenland and Svalbard24 and HCB was depositing in the southern Beaufort Sea in 2008.20
ENDO-I is the most studied CUP in the Arctic whereas data for other CUPs are fewer. ENDO compounds are widespread in Arctic Ocean water, snow, ice caps and air.29-36 Based on measurements from 1993-2000, deposition of ENDO-I was estimated across the Arctic Ocean.32 Gas exchange estimates for the Bering/Chukchi Seas/North Pacific in 2010 indicated net deposition of the CUPs trifluralin (TFN), dicofol, ENDO, dacthal (DAC) and chlorpyrifos (CPF).35 CUPs have been reported in arctic and subarctic lakes, ice caps, snow and air.29,31,37-42 CUPs DAC, CPF and ENDOs have been reported in fish from Alaskan lakes,43 ENDOs in arctic cod, ringed seal and beluga33 and ENDO-I in zooplankton and fish in two lakes in the Norwegian Arctic.44 A similar suite of CUPs was found in wolves, caribou, marine invertebrates and fish from the Canadian Arctic, where ENDO-I and metabolite endosulfan sulfate (ENDO SUL) were the dominant
compounds.
restrictions or bans on usage. Long-term trends of OCPs at global air monitoring stations, including those in the arctic, indicate that of 257 time series data sets 93% and 71% give half-lives less than 20 and 10 y, respectively.49 We previously reported spatial distributions and gas
exchange of HCHs in arctic-subarctic surface water.15-17,20,50 Concentrations of other OCPs were reported in water from 1993-94 expeditions30,51,52 but not in air, and air-water exchange was not assessed.
This paper reports spatial distributions of OCPs other than HCHs and of several CUPs in surface water measured on arctic-subarctic expeditions between 1993-2013. Water and air concentrations from concurrent shipboard measurements were paired to estimate gas exchange departure from air- water equilibrium.
Experimental Section
Sampling locations
Sampling of air and surface water was carried out on several expeditions in: 1) the Bering and Chukchi seas (Bering-Pacific, BERPAC-1993), 2) the northern Canada Basin (Arctic Ocean Sections, AOS-1994), and 3) the Canadian Archipelago (Tundra Northwest, TNW-1999; International Polar Year, IPY-2007/2008 and ArcticNet-2010/2011/2013). Additional air samples were collected from central Archipelago at Resolute Bay in 1999, and air and water samples from near-Archipelago regions of the Labrador Sea and Gulf of St. Lawrence in 2007. See Supporting Information (Table S1) for details. A map of the cruise tracks is shown in Figure 1.
Sampling, analysis and quality control
Air samples of 500-1500 m3 were collected from shipboard in all years and at Resolute Bay (Cornwallis Island, Nunavut, 74.70N, 94.83W) in 1999 with a glass fiber filter (GFF) to retain “particulate” compounds followed by polyurethane foam (PUF) to trap the “gaseous” fraction, up until and including 1999 when the sample train was changed to a GFF-PUF/XAD-2 sandwich to capture the more volatile compounds with greater efficiency. Shipboard air sampling was done on the deck above the bridge in 1993-1994 cruises but to avoid potential interference from the smoke stack, sampling was later moved to the tip of the bow. Surface water (≤7 m) was collected into stainless steel cans with an overboard submersible pump or through a stainless steel line running 7 m below the ship. Canisters of water were kept sealed as much as possible during extraction to
avoid contamination from the ship. Water was processed through a GFF; 40-200 L was passed through a column of XAD-2 resin to retain “dissolved” species30 except on BERPAC-1993 where unfiltered water was extracted with dichloromethane in a Goulden apparatus.51 Analysis was by capillary gas chromatography – low-resolution electron capture negative ion mass spectrometry. Quality control consisted of analyzing blanks (field, sampling media and procedural), determining instrumental detection limits (IDLs) and monitoring recoveries of spiked compounds. Details of analysis and quality control are provided in Supporting Information text, Tables S2 and S3.
Results and Discussion
Compounds sought in air and water since the early campaigns were DIEL, components of technical chlordane (TC, CC, trans-nonachlor - TN) and metabolite heptachlor exo-epoxide (HEPX). The ΣCHBs (as technical toxaphene) and cis-nonachlor (CN) were quantified in 1993, 1994 and 1999, but below detection in 2007-2008 and not sought in later campaigns. The number of target CUPs increased over time. ENDO-I was the only CUPs measured on BERPAC-1993 and ENDO-II was added on AOS-1994. Chlorothalonil (CHT) and DAC were added on TNW-1999. Between 2007-2013, CUPs sought in air/water (A/W) were CPF (A/W), CHT (A/W), DAC (A/W), TFN (A/W), ENDOs and ENDO SUL (A/W), pentachlorothioanisole (PCTA) (A) and pentachloronitrobenzene (PCNB, quintozene) (A). Other compounds sought, but not detected, and instrumental detection limits (IDLs) for all compounds in air and water are given in Table S2. Concentrations of operationally defined “dissolved” OCPs and CUPs in water and “gaseous” compounds in air from all expeditions are summarized in Tables S4 and S5 as mean ± standard deviation (where NDs were replace by IDLs), and positive/total samples.
Pesticides in arctic-subarctic water
Early expeditions traversed the Bering-Chukchi seas (BERPAC-1993) and central Canada basin to the North Pole (AOS-1994). Later campaigns (TNW-1999, IPY-2007, IPY-2008, ArcticNet- 2010, ArcticNet-2011, ArcticNet-2013) sampled the Canadian Archipelago repeatedly, but not all sites were visited each year, nor were all target compounds sought on every expedition. Table S6 lists years when a specific compound was sought. For example, IPY-2007 covered the eastern Archipelago whereas IPY-2008 focused on the southern Beaufort Sea off Banks Island. HEPX was sought on most Archipelago expeditions, but not on TNW-1999. Concentrations of several OCPs in
water (CW) have decreased over time and are currently approaching or below IDLs of 0.1 pg L-1 for chlordane compounds, 0.2 pg L-1 for HEPX and DIEL, and 5 pg L-1 for ΣCHBs, assuming a 100-L sample (Table S2). Mean detectabilities in water over all years were: HEPX 67%; TC, CC and TN 74-75%, DIEL 75%; ΣCHBs 51%; DAC 98%; CHT 78%; CPF 95%; ENDO-I 97%; ENDO-II 76%; ENDO SUL 68%; TFN 60%. Mean CW (pg L-1) ± standard deviation were: TC = 0.68 ± 0.60, CC = 0.82 ± 0.53, TN = 0.53 ± 0.38, HEPX = 12 ± 17, DIEL = 20 ± 20, ENDO-I = 3.1 ± 1.9, ENDO-II 1.4 ± 1.6, ENDO SUL 11 ± 13, ΣCHBs = 53 ± 41, DAC = 19 ± 12, CPF = 13 ± 12, CHT = 244 ± 619, TFN = 1.9 ± 2.9. In 2011, CHT concentrations varied greatly, the highest concentrations were associated with samples taken in regions with no ice cover and low salinity (26-30 psu) indicating recent snow/ice melt whereas lower concentrations were associated with the highest salinities (32-34 psu) and extensive ice cover. Precipitation very efficiently scavenges CHT from the atmosphere. CHT concentrations in the 1000s pg L-1 were found in snow from Resolute Bay (Pućko, University of Manitoba, personal communication) and predicted for ice melt ponds from Henry’s law
partitioning.53 CHT concentrations in the range 510-2400 pg L-1 were reported in snow and rain at high-elevation national parks in the U.S.54 and 2800 pg L-1 was found in a melt pond on Ward Hunt Island in the Canadian high arctic41.
Pearson correlations between pesticides in water are shown in Table S7, for pairs where both species were quantifiable (NDs omitted). DAC showed the highest number of significant
correlations (p <0.05) with TC, ENDO-I, ENDO-II, ENDO SUL and TFN. Correlations were found among three chlordanes (TC, CC and TN) and three ENDOs (ENDO-I, ENDO-II and ENDO SUL). ENDO-I and ENDO-II were not related to any other pesticides except DIEL (for ENDO-I). HEPX, a soil metabolite52 was correlated with ENDO SUL, another soil metabolite,33 and with DIEL and ΣCHBs, but not with other chlordanes. DIEL correlated with HEPX, ENDO-I, ENDO-SUL and ΣCHBs.
Apparent first-order changes in water concentrations were examined by regression of log CW versus year. IDLs were substituted for NDs. Results are summarized in Tables 1 and S7, where numbers of detectable/total samples are also given. The Bering and Chukchi seas and northern Canada Basin were sampled only in 1993-1994, whereas several expeditions traversed the Archipelago between 1999-2013. Time trends in water were derived by considering all measurements from 1993-2013 and only those from the Archipelago. Times for 50% change (t0.5,
while changes for DIEL were not significant. ENDO-I increased, with a doubling time of 21 y. CHBs were measureable in water on BERPAC-1993 and AOS-1994, sought in six TNW-1999 samples, and not detected on IPY-2007. Thereafter CHBs were not sought, and no time trends were estimated.
The t0.5 were shorter within the Archipelago; 4.2 – 5.6 y for depletion of TC, CC, TN and ENDO-II, and DIEL also decreased with t0.5 of 2.5 y. ENDO-I showed a doubling t0.5 of 11 y. The shorter t0.5 for the Archipelago were a consequence of low or ND concentrations on the later expeditions (Table S4). Apparent depletion t0.5 were very short, although significant, for HEPX and ENDO SUL (0.72 and 0.79 y). CHT (1999-2013) and TFN (2007-2013) increased in the
Archipelago (doubling t0.5 of 3.5 and 2.4 y), while changes in DAC (1999-2013) and CPF (2007- 2013) were insignificant.
Our measurements are compared to previous reports in arctic-subarctic seawater for OCPs and ENDO-I (Table S8). Overall means ± SD (pg L-1) for arctic waters derived from means reported by all research groups are: TC = 1.5 ± 2.0, CC = 1.6 ± 1.2, TN = 1.1 ± 1.1, HEPX = 7.1 ± 8.5, DIEL = 13 ± 9, ENDO-I = 3.1 ± 2.0, and ΣCHBs = 95 ± 74. Relative standard deviations (RSD) for these compounds in arctic-subarctic seawater over two decades of measurements in diverse locations were 65-133%.
Fewer measurements have been reported for CUPs other than ENDO-I. These are compiled in Table S9 for ENDO-II, ENDO SUL, DAC, CPF, CHT and TFN. The order of ENDOs abundance was generally ENDO SUL ≥ ENDO-I > ENDO-II. Proportions of the ENDOs in northern Baltic Sea water during 2011-2013 were ENDO SUL : ENDO-I : ENDO-II = 1.0 : 0.043 : 0.013.55 Mean CW for DAC reported in the Archipelago by two groups45,56 ranged from 4-24 pg L-1, but a third group35 found only 0.2 pg L-1 in the Bering-Chukchi seas. The mean CW for CPF in the Archipelago during 2007-2013 was 14 pg L-1 from our measurements, whereas only 0.2 - 0.4 pg L-1 were reported for the Archipelago the Bering-Chukchi seas.35,45,56 The only other report of CPF in the Bering-Chukchi region is <0.8 – 67 (mean 21) pg L-1 in 1993.57 Our means for CHT in the Archipelago were 6.6, 41 and 530 pg L-1 in 1999, 2007-2008 and 2010-2013, but <0.2 pg L-1 in the Bering-Chukchi seas in 199357 and 0.05 pg L-1 in 2010.35
Several CUPs have been reported in arctic-subarctic lakes in Canada at levels above those in ocean water. CW for ENDO-I and ENDO SUL ranged from 1-45 and 19-43 pg L-1 in 1993-
2005.33,41,58 CHT ranged from <2 – 2800 pg L-1 in 13 lakes sampled in 1999-2001, with a detection frequency of 31%.41 DAC was quantified at 10 – 110 pg L-1 in all lakes sampled in 1999-200141,
while CPF was detected in only one lake at 1600 pg L-1 and was <17 pg L-1 in 12 other lakes .41
Pesticides in arctic-subarctic air
Concentrations of OCPs and CUPs in air (CA) from 1993-2013 are summarized in Table S5. In addition to the compounds sought in water, the fungicide PCNB and its soil metabolite PCTA59-60 were sought in air from 2007-2013. As for water (Table S4), OCPs were less frequently or not detected in the later expeditions; e.g. ΣCHBs after 1999; HEPX and DIEL after 2008, TC, CC and TN after 2011. Detectabilities in air over all years were: HEPX 53%; TC, CC and TN 87-90%,
DIEL 73%; ΣCHBs 39%; DAC 95%; CHT 35%; CPF 85%; ENDO-I 97%; ENDO-II 35%; ENDO
SUL 54%; TFN 45% and PCTA 81%. PCNB was less frequently detected and averaged 0.41±0.37 pg m-3 (n=21/50).
Temporal trends of OCPs and CUPs in air from sampling onboard ship and at Resolute Bay were assessed by regression of log CA vs. year. Air parcels traverse wide areas of the western Arctic,55 and data from all expeditions, not only within the Archipelago, were used to establish these trends. Estimated times for 50% reduction are reported in Tables 1 and S7. Compounds showing significant declines (t0.5, y, p <0.05) over time were: HEPX (1993-2013, 8.8 y), TC (1993- 2013, 8.3 y), CC (1993-2013, 16 y), TN (1993-2013, 23 y), DIEL (1994-2013, 5.5 y), ENDO-I (1993-2013, 19 y), DAC (1999-2013, 9.1 y), CPF (2007-2013, 1.5 y) and PCTA (2007-2013, 2.9 y). ENDO-II, ENDO SUL, CHT and TFN had low overall detectabilities, and CHBs were found only on BERPAC-1993 and at Resolute Bay in 1999. Temporal trends were not assessed for these compounds. The t0.5 for chlordanes and ENDO-I are similar to estimates from arctic air monitoring stations (Tables 1 and S7).
Beginning in December 2010, during our sampling years, the usage of PCNB was phased out in both Canada and the USA.61-62 The levels of PCTA averaged 0.21±0.11 pg m-3 between 2007-2010 where levels dropped in 2011/2013, averaging 0.051±0.020 pg m-3.
Our results for legacy OCPs and ENDO-I in air are comparable to reports from circumpolar air monitoring stations and other shipboard measurements (Table S10). Fewer comparisons are
available for CUPs . Our average CA (pg m-3) from 2007-2013 were TFN = 0.39 ± 0.69, ENDO-I = 2.5 ± 1.5, CPF = 1.1 ± 1.3, CHT = 0.90 ± 1.8, DAC = 1.1 ± 1.6, ENDO-II = 0.12 ± 0.19 and ENDO SUL = 0.26 ± 0.55. Mean CA over the Bering, Chukchi and Beaufort seas in 2010 were TFN = 1.2 ± 0.6, ENDO-I = 0.89 ± 0.44, CPF = 1.3 ± 0.5, CHT = 0.41 ± 0.69 and DAC = 0.06 ± 0.03, while ENDO-II was below detection.35 Annual means of TFN at air monitoring stations in Canada and
Russia ranged from 0.05-0.18 pg m-3 in 1993-1995,40 but TFN was mostly below detection in 2000-2003.34 Average CA at Alert in 2006-2009 were TFN = 0.037 ± 0.051, ENDO-I = 3.8 ± 3.7, CPF = 0.39 ± 0.95, CHT = 0.90 ± 1.8, DAC = 0.048 ± 0.059 and ENDO SUL = 1.5 ± 3.7.63 Average CA at Station Nord in Greenland in 2008-2010 for ENDO-I = 3.8, ENDO-II = 0.083 and ENDOSULF = 0.090.64 ENDO-I, ENDO-II, ENDO-SUL, CHT and DAC were determined in passive air samples at arctic-subarctic stations but generally yield much higher concentrations than hi-volume samples reported above.42,65,66 From the global atmospheric passive sampling (GAPS) network at Alert and Barrow Alaska concentrations of DAC ranged from 4.7-37, CHT nd-110 and ENDO 11- 60 pg m-3.65-66
Pesticides in the Gulf of St. Lawrence
Surprisingly, concentrations of most CUPs and OCPs in Gulf of St. Lawrence water in 2007 were similar to those on the IPY 2007 transect (Table S4). Average CW (pg L-1) of OCPs in Lake Ontario, which outflows into the St. Lawrence River, in June 2000 were similar or slightly higher: heptachlor exo-epoxide (10), trans-chlordane (3.2), cis-chlordane (4.2), trans-nonachlor (1.5), and dieldrin (83).18
OCPs in air measured enroute from Quebec City through the Gulf in 2007 were similar to those over the Great Lakes Basin18,67 and elevated by factors of 2-7 over those on IPY 2007 (Table S5). CUPs were substantially higher, with elevation factors ranging from 2-18 for CPF, DAC and TFN, 6-40 for ENDOs I and II, and over 100 for CHT, which is intensely applied to potato crops in eastern Canada.68 CUPs and OCPs used in agriculture and as termiticides in urban areas have regional sources in eastern Canada and the USA. High levels of CUPs in air have been reported in vegetable-growing regions in eastern and western Canada68-70 and passive air samples on Sable Island off the eastern coast of Canada indicate the presence of CHT (20-30 pg m-3) and DAC (12-20 pg m-3).66 A coupled atmospheric transport – surface exchange model showed episodic transport of toxaphene from the southern U.S. to the Great Lakes region and subarctic eastern Canada71 and air transport events of DAC from the U.S. were identified.70
Compound fractions in water and air
Fractions of chlordane compounds were plotted versus year to investigate temporal trends. These were calculated from 1993-2008 for water and 1993-2011 for air, after which chlordanes became
low or not detectable. Fractions TC/(TC+CC) and TC/(TC+CC+TN) decreased in water and air, while CC/(TC+CC+TN) and TN/(TC+CC+TN) increased (Figure 2). The statistical significance of these changes was very high, with p-values of 6 x 10-4 or lower (Figure 2). Mean fractions of ENDO-I/(ENDO-I + ENDO-II) in air ranged from 91 ± 0.04% to 99 ± 0.01% throughout the study, with an overall mean of 96 ± 0.06%.
The TC/(TC+CC) in technical chlordane from the U.S. is 0.54, where as0.58 is the expected ratio in air when adjusted for differences in vapor pressures.72 Lower values are often found in the environment and thought to result from preferential degradation of TC,34,48,55,73 but a change in chlordane sources may also be a factor. World production of technical chlordane was stopped by the U.S. manufacturer in 1997,74 but China continued to produce and use chlordane through 2008.
75
The TC/(TC+CC) reported for one product in China is lower, 0.43-0.47.76
Air-water gas exchange
The net direction of air-water gas exchange for the target compounds was indicated by their water/air fugacity ratios, FR = fW/fA, calculated from concentrations of dissolved compounds in water, CW (ng m-3) (XAD-2), gaseous compounds in air CA (pg m-3) (PUF or PUF/XAD cartridge) and the Henry’s law constants (H, Pa m3 mol-1), adjusted for temperature and salinity. 20,20,55 The uncertainties in fW and fA were assessed by propagating uncertainties in CW, CA and H. Relative standard deviations (RSD) in CW and CA were obtained from the means and SDs in Tables S4 and S5. The RSD in H was assumed to be 0.2, on the basis of experimental measurements.77-78 If the 95% confidence intervals for fW and fA did not overlap , the net exchange was deemed significantly different from equilibrium.55 Relevant equations are given in Supporting Information and selected values of H are listed in Table S11.
FRs of legacy OCPs and CUPs are displayed in Figure 3. These were calculated for
expeditions when both or one of CW and CA were quantifiable, using mean values in Tables S4 and S5. When the mean for one concentration was below detection, it was replaced by its IDL, Table S2. FRs were not calculated when both CW and CA were <IDL; e.g., chlordanes and DIEL on ArcticNet-2013. Exchanges were not estimated for CHT, ENDO-II, ENDO SUL and TFN due to one or more of the following problems: highly variable concentrations in water and/or air, low detection frequencies, and poorly known Henry’s law constants.
equilibrium on IPY-2008. Exchanges of TC, CC and TN were not significantly different from equilibrium on most expeditions, except ArcticNet-2010 and 2011, when water concentrations were <IDL but air concentrations were still measureable in the majority of samples. DIEL was depositing on BERPAC-1993, volatilizing on IPY-2007 and near equilibrium on other expeditions. In general,
FRs for DIEL increased from earlier to later years (Figure 3), due to increasing CW and decreasing
CA over time (Table 1).
Exchange of ΣCHBs could only be evaluated from 1999 and earlier studies when CW was quantifiable. The ΣCHBs in air was also quantifiable on BERPAC-1993 and TNW-1999 (including Resolute Bay). Interferences prevented determination of CHBs in air (but not water) on AOS-1994. For 1994, CA for ΣCHBs was estimated as 5.5 pg m-3, the mean of 4.1 pg m-3 on BERPAC-1993 and 6.9 pg m-3 at Resolute Bay in 1992 (Table S10). Net deposition of ΣCHBs was found in 1993, 1994 and 1999. Exchange of CUPs tended toward net deposition; e.g. ENDO-I in all years, DAC in 1999, 2011 and 2013 and CPF in 2007 and 2008. Exchanges were not significantly different from equilibrium for DAC in 2007 and 2008 and CPF in 2011 and 2013, while both were volatilizing in 2010. CHT gas exchange estimates were not calculated due to the high variability in water concentrations and uncertainties in the HLC values.
The campaigns reported here are from a research, not a monitoring program. Results are limited by far fewer measurements than at atmospheric monitoring stations46,63,73 and that campaigns took place only in the warm seasons. On the other hand, our air measurements were made closer to the sea surface than at monitoring stations and better reflect the air-sea exchange situation. Although net exchange directions varied over the years (Figure 3), air-water equilibrium for legacy OCPs was approached within a factor of two in most cases (FR between 0.5 and 2.0). FRs dropped below equilibrium values for TC in 2010 and CC and TN in 2010-2011, reflecting their more rapid decline in Archipelago surface water than in air (Table 1). Net exchanges of CPF and DAC were more variable (Figure 3), possibly because of their different usage patterns in regions affecting the Archipelago and in different months of the growing season.70 A CliMoChem model for ENDO in the Arctic reproduced measured air concentrations well, but predicted seawater concentrations were an order of magnitude too low.79 It was noted that the model approached measurements if the persistence of ENDO-I and II in seawater was raised, by increasing the energy of activation for basic hydrolysis to 100 kJ mol-1 rather than the model values of 45.5-54.5 kJ mol-1. This indicates that air-sea exchange of ENDO is sensitive to its persistence in seawater. ENDO-I was consistently
depositing during the 20 years of this study (Figure 3), and ENDO-I concentrations increased in the Archipelago over time (Table 1). Technical ENDO was added to the Stockholm Convention in 2011, with specific exemptions.80 ENDO-I concentrations in air were stable between 1993-2005 and only begun to decline after 2006.56 Global usage and a sink in ocean water probably were responsible for its continuing net deposition.
Acknowledgments
We thank Environment Canada, ArcticNet and Northern Contaminants Program (Aboriginal Affairs and Northern Development Canada) for financial support. Additionally, Canadian Coast Guard, ArcticNet, IPY-Circumpolar Flaw Lead Study, Swedish Polar Research and the Russian Academy of Science for ship time. The crew of the CCGS Amundsen, CCGS Louis S. St. Laurent and R/V Okean for technical support while on board. We are grateful to the University of Laval, Allison MacHutchson (DFO), Joanne Delaronde (DFO), Alexis Burt (UofM) and Garry Codling (Lancaster University, UK) for help in sampling during IPY and ANET. The Centre for Global Science, University of Toronto and the Northern Science Training Program, Aboriginal Affairs and Northern Development Canada for supporting Fiona Wong. Tim Papakyriakou, Brent Else and Bruce Johnston at the University of Manitoba for meteorological data, field support and data processing during IPY-07/08 and ANET. Yves Gratton and his group for hydrological data and water samples form the rosette during IPY and ANET. Finally, we thank Martina Koblizkova for help during sampling and Sonya Wrigglesworth, Autur Pajda and Justen Poole for laboratory support. Terry Bidleman was supported by EcoChange, a program of the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (Formas), and granted leave from Environment Canada, during preparation of this paper.
References
1. Jurado, E.; Jaward, F.M.; Lohmann, R.; Jones, K.C.; Simó, R.; Dachs, J. Atmospheric dry deposition of persistent organic pollutants to the Atlantic and inferences for the global oceans. Environ. Sci. Technol. 2004, 38, 5505-5513.
2. Jurado, E.; Jaward, M.F.; Lohmann, R.; Jones, K.C.; Simó, R.;, Dachs, J. Wet deposition of persistent organic pollutants to the global oceans. Environ. Sci. Technol. 2005, 39, 2426– 2435.
directions. Environ. Pollut. 2007, 150, 150-165.
4. Armitage, A.M.; MacLeod, M.; Cousins, I.T. Modeling the global fate and transport of perfluorooctanoic acid (PFOA) and perfluorooctanoate (PFO) emitted from direct sources using a multispecies mass balance model. Environ. Sci. Technol. 2009, 43, 1134-1140.
5. Gouin, T.; Wania, F. Time trends of arctic contamination in relation to emission history and chemical persistence and partitioning properties. Environ. Sci. Technol. 2007, 41, 5986-5992.
6. Li, Y.F.; Macdonald, R.W.; Ma, J.M.; Hung, H.; Venkatesh, S. Historical α-HCH budget in the Arctic Ocean: The Arctic Mass Balance Box Model (AMBBM). Sci. Total Environ.
2004, 324, 115-139.
7. Matthies, M.; Klasmeier, J.; Beyer, A.; Behling, C. Assessing persistence and long-range transport of current use pesticides. Environ. Sci. Technol., 2009, 43, 9223-9229.
8. Zarfl, C.; Scheringer, M.; Matthies, M. Screening criteria for long-range transport potential of organic substances in water. Environ. Sci. Technol. 2011, 45, 10075-10081.
9. Hornbuckle, K.C.; Jeremiason, J.D.; Sweet, C.W.; Eisenreich, S.J. Seasonal variations in air- water exchange of polychlorinated biphenyls in Lake Superior. Environ. Sci. Technol.
1994, 28, 1491-1501.
10. Jantunen, L.M.; Bidleman, T.F. Air-water gas exchange of toxaphene in Lake Superior.
Environ. Toxicol. Chem. 2003, 22, 1229-1237.
11. Galbán-Malagón, C.; Berrojalbiz, N.; Gioia, R.; Dachs, J. The “degradative” and “biological” pumps controls on the atmospheric deposition and sequestration of
hexachlorocyclohexanes and hexachlorobenzene in the North Atlantic and Arctic Oceans.
Environ. Sci. Technol. 2013, 47, 7195-7203.
12. Gioia, R.; Li, J.; Schuster, J.; Zhang, L.; Zhang, G.; Li, X.; Spiro, B.; Bhatia, R.S.; Dachs, J.; Jones, K.C. Factors affecting the occurrence and transport of atmospheric organochlorines in the China Sea and the northern Indian and southeast Atlantic Oceans. Environ. Sci. Technol.
2012, 46, 10012-10021.
13. Nizzetto, L.; Lohmann, R.; Gioia, R.; Dachs, J.; Jones, K.C. Atlantic Ocean surface waters buffer declining atmospheric concentrations of persistent organic pollutants. Environ. Sci.
Technol. 2010, 44, 6978-6984.
14. Ding, X.; Wang, X.-M.; Xie, Z.-G.; Xiang, C.-H.; Mai, B.-X.; Sun, L.-G.; Zheng, M.; Sheng, G.-Y.; Fu, J.M. Atmospheric hexachlorocyclohexanes in the North Pacific Ocean and the adjacent arctic region: Spatial patterns, chiral signatures, and sea−air exchanges. Environ.
Sci. Technol. 2007, 41, 5204-5209.
15. Harner, T.; Kylin, H.; Bidleman, T.F.; Strachan, W.M.J. Removal of α- and γ-
hexachlorocyclohexanes (HCHs) and enantiomers of α-HCH in the eastern Arctic Ocean.
Environ. Sci. Technol. 1999, 33, 1157-1164.
16. Jantunen, L.M.; Bidleman, T.F. Reversal of the air-water gas exchange direction of hexachlorocyclohexanes in the Bering and Chukchi seas: 1993 versus 1988. Environ. Sci.
Technol. 1995, 29, 1081-1089.
17. Jantunen, L.M.; Bidleman, T.F. Air-water gas exchange of HCHs and the enantiomers of α- HCH in arctic regions. J. Geophys. Res.1996, 101, 28837-28846. Corrections: Ibid.
1997, 102, 19279-19282.
18. Jantunen, L.M.; Helm, P.A.; Ridal, J.J.; Bidleman, T.F. Air-water gas exchange of chiral and achiral organochlorine pesticides in the Great Lakes. Atmos. Environ. 2008, 42, 8533-8542.
19. Lakaschus, S.; Weber, K.; Wania, F.; Bruhn, R.; Schrems, O. The air-sea equilibrium and time trend of hexachlorocyclohexanes in the Atlantic Ocean between the Arctic and Antarctica. Environ. Sci. Technol. 2002, 36, 138-145.
20. Wong, F.; Jantunen, L.M.; Pućko, M.; Papakyriakou, T.; Stern, G.A.; Bidleman, T.F. Air- water exchange of anthropogenic and natural organohalogens on International Polar Year (IPY) expeditions in the Canadian Arctic. Environ. Sci. Technol. 2011, 45, 876-881.
21. Wu, X.; Lam, J.C.W.; Xia, C.; Kang, H.; Sun, L.G.; Xie, Z.Q.; Lam, P.S. Atmospheric HCH concentrations over the marine boundary layer from Shanghai, China to the Arctic Ocean: role of human activity and climate change. Environ. Sci. Technol. 2010, 44, 8422–8428. 22. Huang, Y.; Xu, Y.; Li, J.; Xu, W.; Zhang, G.; Cheng, Z.; Liu, J.; Wang, Y.; Tian, C.
Organochlorine pesticides in the atmosphere and surface water from the equatorial Indian Ocean: enantiomeric signatures, sources, and fate. Environ. Sci. Technol. 2013, 48, 13395-13403.
23. Lin, T.; Li, J.; Xu, Y.; Liu, X.; Luo, C.; Cheng, H.; Chen, Y.; Zhang, G. Organochlorine pesticides in seawater and the surrounding atmosphere of the marginal seas of China: Spatial distribution, sources and air–water exchange. Sci. Total Environ. 2012, 435-436, 244-252. 24. Lohmann, R.; Gioia, R.; Jones, K.C.; Nizzetto, L.; Temme, C.; Xie, Z.; Schulz-Bull, D.;
Hand, I.; Morgan, E.; Jantunen, L. Organochlorine pesticides and PAHs in the surface water and atmosphere of the north Atlantic and Arctic Ocean. Environ. Sci. Technol. 2009, 43, 5633-5639.
25. Xie, Z.; Koch, B.P.; Möller, A.; Sturm, R.; Ebinghaus, R. Transport and fate of
hexachlorocyclohexanes in the oceanic air and surface seawater. Biogeosci. 2011, 8, 2621-2633.
26. Zhang, L.; Bidleman, T.F.; Perry, M.J.; Lohmann, R. The fate of chiral and achiral
organochlorine pesticides in the North Atlantic Bloom Experiment. Environ. Sci. Technol.
2012, 46, 8106-8114.
27. Stemmler, I.; Lammel, G. Cycling of DDT in the global oceans 1950-2002: World ocean returns the pollutant. Geophys. Res. Lett. 2009, 36, L24602. doi: 10.1029/2009GL041340 28. Hargrave, B.T.; Barrie, L.A.; Bidleman, T.F.; Welch, H.E. Seasonality in exchange of
organochlorines between arctic air and seawater. Environ. Sci. Technol. 1997, 31, 3258-3266. 29. Hoferkamp, L.; Hermanson, M.H.; Muir, D.C.G. Current use pesticides in arctic media;
2000-2007. Sci. Tot. Environ. 2010, 408, 2985-2994.
pesticides in Arctic Ocean water. Arch. Environ. Contam. Toxicol. 1998, 35, 218-228. 31. Ruggirello, R.M.; Hermanson, M.H.; Isaksson, E.; Teixeira, C.; Forsström, S.; Muir,
D.C.G.; Pohjola, V.; van de Wal, R.; Meijer, H.A.J. Current use and legacy pesticide deposition to ice caps on Svalbard, Norway. J. Geophys. Res. Atmos. 2010, 115 (D18318), 1–11. doi:10.1029/2010JD014005.
32. Weber, J.; Halsall, C.J.; Muir, D.C.G.; Teixeira, C.; Burniston, D.A.; Strachan, W.M.J.; Hung H.; Mackay, N.; Arnold, D.; Kylin, H. Endosulfan and γ-HCH in the Arctic: An assessment of surface seawater concentrations and air-sea exchange. Environ. Sci. Technol.
2006, 40, 7570- 7576.
33. Weber, J.; Halsall, C.J.; Muir, D.; Teixeira, C.; Small, J.; Solomon, K.; Hermanson, M.; Hung H.; Bidleman, T. Endosulfan, a global pesticide: A review of its fate in the
environment and occurrence in the Arctic. Sci. Total Environ. 2010, 408, 2966-2984. 34. Su, Y.; Hung, H.; Blanchard, P.; Patton, G.W.; Kallenborn, R.; Konoplev, A.; Fellin P.; Li,
H.; Geen, C.; Stern, G.; Rosenberg, B.; Barrie, L.A. A circumpolar perspective of
atmospheric organochlorine pesticides (OCPs): Results from six arctic monitoring stations in 2000–2003. Atmos. Environ. 2008, 42, 4682-4698.
35. Zhong, G.; Xie, Z.; Cai, M.; Möller, A.; Sturm, R.; Tang, J.; Zhang, G.; He, J.; Ebinghaus, R. Distribution and air-sea exchange of current-use pesticides (CUPs) from east Asia to the high Arctic Ocean. Environ. Sci. Technol. 2012, 46, 259–267.
36. Zhang; X.; Meyer, T.; Muir, D.C.G.; Teixeira, C.; Wang, X.; Wania, F. Atmospheric deposition of current use pesticides in the Arctic: Snow core records from the Devon Island Ice Cap, Nunavut, Canada. Environ. Sci. Proc. Imp. 2013, 15, 2304-2311.
37. Garbarino, J.R.; Snyder-Conn, E.; Leiker, T.J.; Hoffman, G.L. Contaminants in arctic snow collected over northwest Alaskan sea ice. Water, Air, Soil Pollut. 2002, 139, 183-214. 38. Hageman, K.J.; Hafner, W.D.; Campbell, D.H.; Jaffe, D.A.; Landers, D.H.; Simonich,
S.L.M. Variability in pesticide deposition and source contributions to snowpack in western U.S. national parks. Environ. Sci. Technol. 2010, 44, 4452-4458.
39. Hermanson, M.; Isaksson, E.; Texeira, C.; Muir, D.C.G.; Compher, K.M.; Li, Y.-F.; Igarashi, M.; Kamiyama, K. current-use and legacy pesticide history in the Austfonna Ice Cap, Svalbard, Norway. Environ. Sci. Technol. 2005, 39, 8163-8169.
40. Hung, H.; Blanchard, P.; Halsall, C.J.; Bidleman, T.F.; Stern, G.A.; Fellin, P.; Muir, D.C.G.; Barrie, L.A.; Jantunen, L.M.; Helm, P.A.; Ma, J.; Konoplev, A. Temporal and spatial
variabilities of atmospheric polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides and polycyclic aromatic hydrocarbons (PAHs) in the Canadian Arctic: Results from a decade of monitoring. Sci. Total Environ. 2005, 342, 119-144
41. Muir, D.C.G.; Teixeira, C.; Wania, F. Empirical and modeling evidence of regional atmospheric transport of current-use pesticides. Environ. Toxicol. Chem. 2004, 23, 2421-2432.
42. Shunthirasingham, C.; Oyiliagu, C.E.; Cao, X.; Gouin, T.; Wania, F.; Lee, S.C.; Pozo, K.; Harner, T.; Muir, D.C.G. Spatial and temporal pattern of pesticides in the global atmosphere.
43. Ackerman, L.K.; Schwindt, A.R.; Simonich, S.L.M.; Koch, D.C.; Blett, T.F.; Schreck, C.B.; Kent, M.L.; Landers, D.H. Atmospherically deposited PBDEs, pesticides, PCBs, and PAHs in western U.S. national park fish: concentrations and consumption guidelines.
Environ. Sci. Technol. 2008, 42, 2334-2341.
44. Evenset, A.; Guttorm, N.; Christensen, G.N.; Skotvold, T.; Fjeld, E.; Schlabach, M.; Wartena, E.; Gregor, D. A comparison of organic contaminants in two high Arctic lake ecosystems, Bjørnøya (Bear Island), Norway. Sci. Total Environ. 2004, 318, 125-141. 45. Morris, A.D.; Muir, D.C.G.; Solomon, K.R.; Letcher, R.J., Fisk, A.T., McMeans, B.,
McKinney, M., Teixeira, C., Wang, X., Duric, M., Amarualik, P. Current use pesticides in the Canadian Arctic marine environment and polar bear-ringed seal food chains. Environ. Tox.
Chem. 2015, submitted.
46. Hung, H.; Kallenborn, R.; Breivik, K.; Su, Y.; Brorström-Lundén, E.; Olafsdottir, K.; Thorlacius, J.M.; Leppänen, S.; Bossi, R.; Skov, H.; Manø, S.; Patton, G.W.; Stern, G.; Sverko, E.; Fellin, P. Atmospheric monitoring of organic pollutants in the Arctic under the Arctic Monitoring and Assessment Programme (AMAP): 1993–2006. Sci. Total Environ.
2010, 408, 2854-2873.
47. Ma, J.; Hung, H.; Tian, C.; Kallenborn, R. Revolatilization of persistent organic pollutants in the Arctic induced by climate change. Nature Climate Change 2011, 1, DOI: 10.1038. 48. Rigét, F.; Bignert, A.; Braune, B.; Stow, J.; Wilson, S. Temporal trends of legacy POPs in
arctic biota, an update. Sci. Total Environ. 2010, 408, 2874-2884.
49. Kong, D.; MacLeod, M.; Hung, H.; Cousins, I.T. Statistical analysis of long-term monitoring data for persistent organic pollutants in the atmosphere at 20 monitoring stations broadly indicates declining concentrations. Environ. Sci. Technol. 2014, 48, 12492−12499. 50. Bidleman, T.F.; Kylin, H.; Jantunen, L.M.; Helm, P.A.; Macdonald, R.W.
Hexachlorocyclohexanes (HCHs) in the Canadian archipelago, 1. Spatial distribution and pathways of α-, β-, and γ-HCHs in surface waters. Environ. Sci. Technol. 2007, 41, 2688-2695.
51. Strachan, W.M.J.; Burniston, D.A.; Williamson, M.; Bohdanowicz, H. Spatial differences in persistent organochlorine pollutant concentrations between the Bering and Chukchi Seas (1993). Mar. Pollut. Bull. 2001, 43, 132-142.
52. Bidleman, T.F.; Jantunen, L.M.; Wiberg, K.;Harner, T.; Brice, K.; Su, K.; Falconer, R.L.; Leone, A.D.; Aigner, E.J.; Parkhurst, W.J. Soil as a source of atmospheric heptachlor epoxide.
Environ. Sci. Technol. 1998, 32, 1546-1548.
53. Pućko, M.; Stern, G.A.; Macdonad, R.W.; Jantunen, L.M.; Bidleman, T.F.; Wong, F.; Barber, D.G.; Rysgaard, S. The delivery of organic contaminants to the Arctic food web: Why sea ice matters. Sci. Total Environ. 2015, 506/507, 444-452.
54. Mast, M.A.; Foreman, W.T.; Skaates, S.V. Current-use pesticides and organochlorine compounds in precipitation and lake sediment from two high-elevation national parks in the western United States. Arch. Environ. Contam. Toxicol. 2007, 52, 294–305.
55. Bidleman, T.; Agosta, K.; Andersson, A.; Brorström-Lundén, E.; Haglund, P.; Hansson, K.; Laudon, H.; Newton, S.; Nygren, O.; Ripszam, M.; Tysklind, M.; Wiberg, K.
Atmospheric pathways of chlorinated pesticides and natural bromoanisoles in the northern Baltic Sea and its catchment. Ambio 2015, accepted.
56. Morris, A.D.; Muir, D.; Teixeira, C.; Epp, J.; Sturman, S., Solomon, K.R. Bioaccumulation and distribution of brominated flame retardants and current-use pesticides in an Arctic marine food-web. Proceedings, 28th Annual SETAC North America Meeting, Milwaukee, WS, USA November 11–15, 2007.
57. Chernyak, S.M.; Rice, C.P.; McConnell, L.L. Evidence of currently used pesticides in air, ice, fog, seawater and surface microlayer in the Bering and Chukchi seas. Mar. Pollut. Bull.
1996, 32, 410-419.
58. Helm, P.A. The influences of sources, source regions and fate and transport processes on the occurrence of polychlorinated naphthalenes and coplanar polychlorinated biphenyls in urban and arctic environments. PhD Thesis, 2003.
59. Fushiwaki, Y.; Tase, N.; Kotoda, K.; Urano, K. Biodegradability of fungicide pentachloronitrobenzene in the water environment. Eisei Kagaku 1991, 37, 529–536 60. Metcalfe, T.L.; Dillon, P.J.; Metcalfe, C.D. Detecting the transport of toxic pesticides from
golf courses into watersheds in the Precambrian Shield region of Ontario, Canada. Environ.
Toxicol. Chem. 2008, 27, 811-818.
61. Hung, H.; Kurt-Karakus, P.; Ahrens, L.; Bidleman, T.; Evans, M.; Halsall, C.; Harner, T.; Jantunen, L.; Lee, S.C.; Muir, D.; Shoeib, M.; Stern, G.; Sverko, E.; Su, Y.; Vlahos, P.; Xiao, H.. Chap. 3, Occurrence and trends in the physical environment. Canadian Arctic
Contaminants Assessment Report On Persistent Organic Pollutants – 2013. Muir, D.;
Kurt-Karakus, P.; Stow, J. (eds). Northern Contaminants Program, Aboriginal Affairs and Northern Development Canada, Ottawa ON. xxiii + 487 pp + Annex. p. 160.
62. Bossi, R.; Skjøth, C.A.; Skov, H. Three years (2008–2010) of measurements of atmospheric concentrations of organochlorine pesticides (OCPs) at Station Nord, North-East Greenland.
Environ. Sci. Process Impacts, 2013, 15, 2213-2219.
63. US-EPA, Federal Register, Vol. 74, No. 134 , Wednesday, July 15, 2009, Notices, 34337- 34339.
64. Health Canada, Pest Management Regulatory Agency, Proposed Re-evaluation
Decision: Qunitozene, February 13, 2009. ISBN: 978-1-100-11460-6 (978-1-100-11461-3). 65. Pozo, K.; Harner, T.; Lee, S.C.; Wania, F.; Muir, D.C.G.; Jones, K.C. Seasonally resolved
concentrations of persistent organic pollutants in the global atmosphere from the first year of the GAPS Study. Environ. Sci. Technol. 2009, 43, 796-803.
66. Koblizkova, M.; Genualdi, S.; Lee, S.C.; Harner, T. Application of sorbent impregnated polyurethane foam (SIP) disk passive air aamplers for investigating organochlorine pesticides and polybrominated diphenyl ethers at the global scale. Environ. Sci. Technol.
2012, 46, 391– 396.
67. Sun, P.; Blanchard, P.; Brice, K.A.; Hites, R.A. Atmospheric organochlorine pesticide concentrations near the Great Lakes: temporal and spatial trends. Environ. Sci. Technol.
68. White, L.M.; Ernst, W.R.; Julien, G.; Garron, C.; Leger, M. Ambient air concentrations of pesticides used in potato cultivation in Prince Edward Island, Canada. Pest. Manag. Sci.
2006, 62, 126-136.
69. Aulagnier, F.; Poissant, L.; Bruneta, D.; Beauvaisa, C.; Pilot, M.; Debois, C.; Dassylva, N. Pesticides measured in air and precipitation in the Yamaska Basin (Québec): occurrence and concentrations in 2004. Sci. Total Environ. 2008, 394, 338-348.
70. Yao, Y.; Harner, T.; Blanchard, P.; Tuduri, L.; Waite, D.; Poissant, L.; Murphy, C.; Belzer, W.; Aulagnier, F.; Sverko, E. Pesticides in the atmosphere across Canadian agricultural regions. Environ. Sci. Technol. 2008, 42, 5931-5937.
71. Ma, J.; Venkatesh, S.; Li, Y-F.; Cao, Z.; Daggupaty, S. Tracking toxaphene in the North American Great Lakes Basin. 2. a strong episodic long-range transport event. Environ. Sci.
Technol., 2005, 39, 8132-8141.
72. Jantunen, L.M.; Bidleman, T. Temperature dependent Henry’s law constant for technical toxaphene. Chemosphere: Global Change Science 2000, 2, 225-231.
73. Becker, S.; Halsall, C.J.; Tych, W.; Kallenborn, R.; Schlabach, M.; Manø, S. Changing sources and environmental factors reduce the rates of decline of organochlorine pesticides in the Arctic atmosphere. Atmos. Chem. Phys. 2012, 12, 4033–4044.
74. PANNA 1997. Velsicol ceases production of chlordane and heptachlor. Pesticide Action Network Newsletter, May 23.
75. Wang, Q.; Zhao, L.; Fang, X.; Xu, J.; Li, Y-F.; Shi, Y.; Hu, J. Gridded usage inventories of chlordane in China. Front. Environ. Sci. Eng. 2013, 7, 10-18.
76. Li, J.; Zhang, G.; Qi, S.; Li, X.; Peng, X. Concentrations, enantiomeric compositions, and sources of HCH, DDT and chlordane in soils from the Pearl River Delta, South China. Sci.
Total Environ. 2006, 372, 215-224, 2006.
77. Cetin, B.; Ozer, S.; Sofuoglu, A.; Odabasi, M. Determination of Henry’s law constants of organochlorine pesticides in deionized and saline water as a function of temperature. Atmos.
Environ. 2006,40, 4538-4546.
78. Sahsuvar, L.; Helm, P.A.; Jantunen, L.M.M.; Bidleman, T. Henry’s law constants for α-, β-, and γ-hexachlorocyclohexanes (HCHs) as a function of temperature. Atmos. Environ. 2003,
37, 983-992.
79. Becker, L.; Scheringer, M.; Schenker, U.; Hungerbühler, K. Assessment of the environmental persistence and long-range transport of endosulfan. Environ. Pollut. 2011, 159, 1737-1743. 80. UNEP. SC-5/3: Listing of technical endosulfan and its related isomers, 2011. United Nations
Environment Programme, Geneva.
Table 1. Times for 50% change in pesticide concentrations in water and air (t0.5, y)a. Wate r, log CW/(pg L --1 ) = m*YEAR + b. r2 Archipelagob t0.5, y SD r 2 All locationsb t0.5, y d SD HEPX 0.67 0.72 0.07 0.16 6.0 1.6 TC 0.65 4.0 0.37 0.62 5.9 0.50 CC 0.46 4.2 0.56 0.34 7.9 1.2 TN 0.50 4.9 0.61 0.35 9.3 1.4 ENDO-I 0.13 11c 3.6 0.091 20.5 7.0 ENDO-II 0.17 5.6 1.4 0.20 8.2 2.1 ENDO SUL 0.59 0.79 0.11 DIEL 0.21 2.5 0.66 0.022 NS DAC 0.006 NS CPF 0.047 NS CHT 0.12 3.5 1.5 TFN 0.13 2.4 0.9 Air, log CA/(pg m -3
) = m*YEAR + b, all locations.
r2 this work t0.5, y SD Alertd Ze ppelind 1993-2009 1993-2006 HEPX 0.068 8.8 2.8 TC 0.19 8.3 1.4 11 9.3 CC 0.046 16 6.1 14 16 TN 0.031 23 11 12 26 ENDO-I 0.046 19 7.3 37 DIEL 0.13 5.5 1.5 DAC 0.089 9.1 2.7 CPF 0.31 1.5 0.25 PCTA 0.20 2.9 0.65 a) Abbreviations in Table S2.
b) Compounds sought between 1999-2013 in the Archipelago and 1993-2013 in all locations. See Table S7 for a list of compounds sought in each year. IDLs were substituted for NDs; n/ntot = numbers of detectable/total samples.
c) Bolded numbers indicate increasing concentrations over time. d) Time for 50% decrease in CA, digital filtration analysis (46, 49).
List of Figures
Figure 1: Cruise map of samples taken between 1999-2013 in the Canadian Archipelago.
Figure 2: Fractions of trans-chlordane (TC), cis-chlordane (CC) and trans-nonachlor (TN). Top
row (blue), arctic surface water. A. r2 = 0.46, p = 5 x 10-10, C. r2 = 0.31, p = 2 x 10-6, B. r2 = 0.66, p = 3 x 10-16, D. r2 = 0.22, p = 9 x 10-5. Bottom row (green: arctic air. E. r2 = 0.23, p = 1 x 10-8, F. r2 = 0.24, p = 5 x 10-9, G. r2 = 0.091, p = 6 x 10-4, H. r2 = 0.22, p = 3 x 10-8.
Figure 3: Water/air fugacity ratios, FR = fW/fA, of pesticides on arctic expeditions. Compound
abbreviations in Table S2. Solid bars indicate significant (p <0.05) net volatilization (FR >1) or deposition (FR <1), while striped bars indicate exchanges not significantly different from air/water equilibrium (FR = 1).
Twenty years of air-water gas exchange observations for pesticides in the western Arctic Ocean
Supporting Information
Liisa M. Jantunen1*, Fiona Wong2, Anya Gawor1, Henrik Kylin3,4, Paul A. Helm5, Gary A. Stern6, William M.J. Strachan7, Deborah A. Burniston8 and Terry F. Bidleman1,9 1. Air Quality Processes Research Section, Environment Canada, 6842 Eighth Line, Egbert ON,
L0L 1N0, Canada.
2. Department of Applied Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden.
3. Department of Thematic Studies – Environmental Change, Linköping University, SE-581 83 Linköping, Sweden.
4. Research Unit: Environmental Sciences and Development, North-West University, P Bag X 6001, Potchefstroom 2520, South Africa.
5. Environmental Monitoring and Reporting Branch, Ontario Ministry of the Environment, 125 Resources Road, West Wing, Toronto, Ontario, M9P 3V6 Canada.
6. Centre for Earth Observation Science, University of Manitoba, 474 Wallace Building, 125 Dysard Road, Winnipeg, R3T 2N2, Canada.
7. Aquatic Ecosystem Protection Research Division, Science and Technology Branch, Environment Canada, 867 Lakeshore Rd., Burlington, ON, L7S 1A1.
8. Water Quality Monitoring and Surveillance, Science and Technology Branch, Environment Canada, 867 Lakeshore Rd., Burlington, ON, L7S 1A1.
Table of Contents
Sampling locations. Sample collection
Analysis and quality control
Pesticide concentrations in water and air Compound fractions in water and air Air-water gas exchange calculations
Table S1. Sampling methods and water volumes.
Table S2. Target analytes, abbreviations, ions monitored in ECNI-MS and instrumental detection limits (IDLs).
Table S3. Surrogate compounds and recovery percentages.
Table S4. Pesticides in surface water of arctic-subarctic regions. Table S5. Pesticides in air of arctic-subarctic regions.
Table S6. Regression analysis of pesticides in surface water and air.
Table S7. Pearson correlation of pesticide concentrations in water, r2 values. Table S8. Comparison of OCP concentrations in arctic-subarctic waters. Table S9. Comparison of CUPs concentrations in in arctic-subarctic waters.. Table S10. Comparison of OCP concentrations in arctic-subarctic air. Table S11. Selected Henry’s law constants for gas exchange calculations. Figure S1. Box-and-whisker plots of OCPs and CUPs in water.
References
Sampling locations
Sampling of air and surface water was carried out on several expeditions described below. Cruise tracks are shown in Figure 1 of the main paper.
1. Bering-Pacific (BERPAC-1993) was a joint Russian-American expedition to the Bering and Chukchi seas on board the Russian R/V Okean, summer 1993 (Chernyak et al., 1996; Jantunen and Bidleman, 1995; Strachan et al., 2001).
2. Arctic Ocean Sections (AOS-1994) was a trans-polar cruise of the CCGS Louis S. St-Laurent from Victoria, British Columbia to Halifax, Nova Scotia during the summer of 1994, covering the Canada Basin north of the Canadian Archipelago (Jantunen and Bidleman, 1996, 1998).
3. The Tundra North West (TNW-1999) expedition took place in the Labrador Sea and Canadian Archipelago during July-September 1999, also on board the CCGS Louis S. St-Laurent (Bidleman et al., 2007; Jantunen et al., 2008). Concurrent air samples were collected at Resolute Bay (74o68’N; 94o90’W) on Cornwallis Island in the central Canadian Archipelago from June to August 1999 (Jantunen et al., 2008).
during the International Polar Year. IPY-2007 sampling in August was done in the Labrador Sea, eastern Archipelago and Hudson Bay. IPY-2008 sampling in May-June was done off Banks Island in the western Archipelago (Wong et al., 2011).
5. Subsequent ArcticNet cruises departed from Kugluktuk NT and sampled in the central and eastern Archipelago. Termination points for the 2010 and 2011 expeditions were Iqaluit, NT and Quebec City, respectively. In 2013, the ship left Resolute Bay in the central Archipelago, headed west to the Beaufort Sea and returned to Resolute Bay.
Sample collection
High volume air samples were continuously collected on the deck above the bridge (BERPAC-1993 and AOS-1994) or bow of the ship (TNW-1999, IPY-2007/2008 and ANET-2010-2013). It is ship’s protocol to point the bow into the wind while on station whenever possible, to avoid ship contamination from the smoke stack and incinerator. Air sampling at Resolute Bay in 1999 was conducted inland from Lancaster Sound, 6 km from the village of Resolute and 3 km from the local airport behind a ridge of hills (Jantunen et al., 2008). Over the many sampling campaigns, the sampling train remained the same, consisting of a glass fiber filter (GFF, 20 x 25 cm Whatman EPM 2000 or equivalent, >99% collection of particles >0.3mm,) followed by two polyurethane foam plugs (PUF, 7.8 cm diameter x 7.5 cm). Air volumes ranged from ~500-3500 m3 at a flow rate of ~0.4 m3 min-1.
During BERPAC-1993, AOS-1994 and TNW-1999, water samples were collected via submersible pump into stainless steel cans (Jantunen and Bidleman, 1995, 1998). Additional samples on BERPAC-1993 were collected via submersible pump into polyethylene containers holding about 1.6 m3. Portions of water were centrifuged to remove particles and subsequently processed using a Goulden extractor with dichloromethane (DCM) (Strachan et al., 2001). During IPY and ArcticNet expeditions, surface water was obtained from a stainless steel line which ran from 7 m below the water surface to the interior of the ship (Wong et al., 2011) and additional water was collected via a submersible pump into polyethylene containers. Except for the Goulden extractions on BERPAC-1993, all water was filtered through a 142-mm diameter GFF/Fs and the dissolved analytes were concentrated on a column of XAD-2 resin (polystyrene-divinylbenzene copolymer, 20-60 mesh, 50-75 mL settled volume) (Bidleman et al., 2007; Jantunen and Bidleman 1998; Wong et al., 2011). A summary of sampling and processing
methods and water volumes is given in Table S1. PUF and XAD-2 precleaning methods and sample extraction are described in (Jantunen and Bidleman, 1998; Jantunen et al., 2004, Wong et al., 2011).
Table S1. Sampling methods and water volumes.
Expedition Collection Volume Processing
BERPAC-1993 Submersible pump 160 L Goulden, DCM
AOS-1994 Submersible pump 200 GFF/F, XAD-2
TNW-1999 Submersible pump 80-200 GFF/F, XAD-2
IPY-2007 Stainless steel line
Submersible pump 80-100 GFF/F, XAD-2
IPY-2008 Stainless steel line
Submersible pump 30-40 GFF/F, XAD-2
ArcticNet-2010/2011/2013
Stainless steel line
Submersible pump 70-200 GFF/F, XAD-2
GFF/Fs were not analyzed, except on AOS-1994 where filter-retained percentages were 0.3–27% for cyclodiene pesticides and 2–27% for chlorobornanes (Jantunen and Bidleman, 1998). GFFs were checked for OCPs on early expeditions, but since levels were generally undetectable and the purpose of these studies was air-sea gas exchange, the GFFs from later expeditions were not analyzed.
Analysis and quality control
Extracts from BERPAC-1993, AOS-1994 and TNW-1999 for determination of legacy
organochlorine pesticides (OCPs) and endosulfans were cleaned and fractionated before analysis as described (Bidleman et al., 2007; Jantunen and Bidleman, 1998; Strachan et al., 2001). No cleanup or fractionation was done on portions of extracts for other currently used pesticides (CUPs) analysis during TNW-1999, nor for CUPs and OCPs during subsequent expeditions.
Except for some BERPAC-1993 water samples which were analyzed by capillary gas chromatography with electron capture detection (GC-ECD) (Strachan et al., 2001), all analyses were done by GC-electron capture negative ion mass spectrometry (GC-ECNI-MS) using an Agilent 6890 GC-5973 or 5975 Mass Selective Detector (MSD) and/or a Hewlett Packard 5890 GC-5989B MS Engine. Quantitative analysis was done on a DB-5 column (J&W, Agilent Technologies, 60 or 30 m, 0.25 mm i.d., 0.25 µm film thickness). A typical temperature program
was: initial temperature 90oC, 15oC min-1 to 160oC, 1.0oC min-1 to 200oC; hold for 2.0 min, 20oC min-1 to 270oC; hold for 10.0 min. Samples were injected splitless (2 µL, split opened after 1.0 min). Other instrument conditions were: helium carrier gas at 40 cm s-1, injector temperature 250oC, transfer line temperature 250oC, ion source 150oC and quadrupole 100-106oC. The mass
spectrometer was operated with methane at 1.0-1.4 Torr and 2.2 mL min-1 on the MS Engine and MSD, respectively. Target compounds, abbreviations and ions monitored in the ECNI mode are listed in Table S2. The sum of chlorobornanes (ΣCHBs) were quantified as technical toxaphene using the “total area - single response factor” method, monitoring ions for 7-Cl (343/345), 8-Cl (379/381) and 9-Cl (413/415) homologs (Jantunen and Bidleman, 1998). The criterion for
acceptability was a target/qualifying ratio within 20% of standards. Mirex (404/410) was added to extracts prior to injection as the internal standard. Random samples were checked for native mirex and found negative.
Blank PUF and XAD-2 sampling media have been analyzed from each expedition. Small peaks matching analyte retention times were found on BERPAC-1993 and AOS-1994, and earlier for sampling at Resolute Bay (Bidleman et al., 1995; Jantunen and Bidleman, 1998). Limits of detection (LOD = mean blank + 3*SD) from these studies ranged from 0.3-1.5 pg L-1 for HEPX, ENDO-I and chlordane compounds and 8 pg L-1 for ΣCHBs in water and 0.08-0.3 pg m-3 in air (assumes 100 L water, 500 m-3 air and final extract volume of 100 μL). No quantifiable peaks were found in blank sampling media on subsequent expeditions, and instrumental detection limits (IDLs) were determined by injecting low concentrations of analytes until peaks were discernable at a 3:1 signal/noise. IDLs are listed in Table S2 for compounds that were quantified in air and water samples, and also for those that were sought but not found.
Recoveries of target compounds on BERPAC-1993 and AOS-1994 were assessed by spikes of unlabeled compounds into stainless steel cans of water before XAD-2 concentration. Recoveries averaged 44% for chlordanes and HEPX, 75% for ENDO-I and 57% for ΣCHBs. A previous study at Resolute Bay, using the same XAD-2 preconcentration technique, found 56% recovery for chlordanes and 102% for ΣCHBs (Bidleman et al., 1995). On subsequent expeditions, extraction and processing methods were changed to improved recoveries and were assessed by spikes of deuterated or 13C-labeled compounds onto XAD-2 columns and PUF plugs. Mean recoveries on different expeditions ranged from 77-86% for OCPs and 78-94% for CUPs (see Table S3 for individual compound recoveries), and results are corrected for recoveries on an individual basis.
Breakthrough for the air samples was checked by analyzing the front and back PUFs separately, the breakthrough was <3%.
Table S2. Target analytesa, abbreviations, ions monitored in ECNI-MS and instrumental detection limits (IDLs).
Compound Abbreviation Ions
monitored IDL airb, pg m-3 IDL waterc, pg L-1 Quantified heptachlor exo -epoxide HEPX 318/316 388/386 0.04 0.2 trans -chlordane TC 410/412 0.02 0.1 cis -chlordane CC 410/412 0.02 0.1 trans -nonachlor TN 444/446 0.02 0.1 cis -nonachlor CN 444/446 0.02 0.1 endosulfan-I ENDO-I 406/408 0.02 0.1 endosulfan-II ENDO-II 406/408 0.02 0.1 endosulfan
sulfate ENDO SUL 386/388 0.02 0.1 dieldrin DIEL 380/382 0.04 0.2 343/345 379/381 1 5 413/415d dacthal DAC 332/330 0.02 0.1 chlorpyrifos CPF 313/315 0.02 0.1 chlorothalonil CHT 266/264 0.02 0.1 trifluralin TFN 335/336 0.02 0.1 pentachlorothio-anisole PCTA 281/283 0.02 0.1 mirex (internal 404/406
Screened but not found
heptachlor 300/302 0.04 0.2 chlorpyrifos methyl 212/214 0.5 1 chlorpyrifos oxon 297/261 2 20 phorate 75/121 e 1 5 disulfoton 88/89 e 0.2 1 terbufos 57/231 e 1.6 8 diazinon 179/137 e 0.2 1 dimethoate 157/159 2 10 malathion 157/172 0.5 2.5 simazine 201/186 e 0.2 1 atrazine 200/215 e 0.2 1 metribuzin 198/199 0.1 0.5 alachlor 160/188 e 0.2 1 metolachlor 162/238 e 0.04 0.2 pendimethalin 281/282 0.02 0.1 a)Pesticide common names, Entomological Society of America. b)500 m-3 air, final extract volume 100 μL.
c)100 L water, final extract volume 100 μL. d) Ions for 7-Cl, 8-Cl and 9-Cl homologs. e) Analysis was done by EI-MS
toxaphene
Pesticides in water and air
Concentrations of operationally defined “dissolved” OCPs and CUPs in water and “gaseous” compounds in air from all expeditions are summarized in Tables S4 and S5 as mean ± standard deviation, where non-detectables (NDs) were replace by IDLs, and positive/total samples. Mean detectabilities in water over all years were: HEPX 67%; TC, CC and TN 74-75%, DIEL 75%; ΣCHBs 51%; DAC 98%; CHT 78%; CPF 95%; ENDO-I 97%; ENDO-II 76%; ENDO SUL 68%;
Table S3. Surrogate compounds and recovery percentages.
Compounda Ions monitored % Recovery air % Recovery water 13 C10-HEPX 328 79-98 47-83 13 C10-TN 454 83-104 68-94 13 C6-HCB 290 82-112 52-72 d6-a-HCH 261 82-115 56-74 d6-g-HCH 261 85-108 62-112 d10-CPF 323 84-114 68-89 13 C12-DIEL 392 83-111 73-106 13 C-PCNB 253 80-116 76-102 13 C9-ENDO 413 71-117 65-95 13 C9-ENDO-II 413 82-113 68-99 13 C9-ENDO-SUL 395 79-110 69-96 d14-TRF 249 68-135 47-83 13 C-PCB-118 338 72-98 59-87 13 C-PCB-126 338 79-111 61-91 13 C-PCB-52 304 67-99 62-89
Not all labelled compounds were used in all years but the number has increased over the years as more have become available a) See Table S2 for abbreviations.
TFN 60%. Box-and-whisker plots are shown in Figure S1. Mean detectabilities in air over all years were: HEPX 53%; TC, CC and TN 87-90%, DIEL 73%; ΣCHBs 39%; DAC 95%; CHT 35%; CPF 85%; ENDO-I 97%; ENDO-II 35%; ENDO SUL 54%; TFN 45% and PCTA 81%.
Pearson correlations between pesticide concentrations in water are given in Table S6 for pairs where both species were quantifiable (NDs omitted). Significant (p <0.05) correlations are bolded. Apparent first-order trends in water and air concentrations (CW and CA) were examined by regression of log CW or log CA versus year. Results are summarized in Table S7 and discussed in the main paper. Our measurements are compared to previously reported concentrations of OCPs and CUPs in arctic-subarctic water (Tables S8 and S9), and OCPs and ENDO-I in air (Table S10).
Table S4. Pesticides in surface water of arctic-subarctic regionsa,b Expedition and
latitude-longitude range HEPX TC CC TN CN DIEL ΣCHBs
BERPAC-1993 2.5 (0.44) 1.0 (0.87) 0.80 (0.58) 0.50 (0.33) 0.22 (0.19) 3.7 (0.62) 20 (6.3) 53.1-73.1N,164.6W-172.2E 9/9 9/9 9/9 9/9 9/9 9/9 9/9 AOS-1994 13 (4.5) 1.4 (0.45) 1.2 (0.38) 0.79 (0.26) 0.33 (0.08) NAc 51 (25) 67.5-90.0N, 168.5W-142.4E 12/12 12/12 12/12 12/12 12/12 12/12 TNW-1999 NA 1.3 (0.81) 1.3 (0.71) 1.0 (0.79) 0.13 (0.05) 15 (2.7) 114 (31) 62.4-79.0N, 71.8-139.1W 16/16 16/16 16/16 9/16 6/6d 6/6d Gulf of St. Lawrence 2007 9.9-13 0.44-1.6 0.84-2.1 0.56-1.6 NA 22-28 NA 54.X-56.XN, 57.X-58.XW 2/2 2/2 2/2 2/2 2/2 IPY-2007 18 (3.9) 0.34 (0.13) 0.90 (0.20) 0.48 (0.12) NA 33 (7.9) ND 57.X-62.XN, 57.X-93.XW 14/14 13/14 14/14 14/14 14/14 0/14 IPY-2008 30 (32) 0.64 (0.33) 1.0 (0.38) 0.52 (0.23) NA 27 (10) ND 71.X-75.XN, 118.X-134.XW 10/13 13/13 12/13 12/13 13/13 0/13 ArcticNet-2010 0.26 (0.16) ND ND ND NA ND NA 67.X-74.XN, 67.X-101.XW 1/6 0/6 0/6 0/6 0/6 ArcticNet-2011 ND 0.17 (0.22) 0.26 (0.54) ND NA 28 (35) NA 60.5-74.2N, 60.7-106.6W 0/11 1/11 1/11 0/11 6/11 ArcticNet-2013 ND ND ND ND NA ND NA 73.X-74.XN, 102.X-113.XW 0/5 0/5 0/5 0/5 0/5 Expedition and
latitude-longitude range DAC CHT CPF ENDO-I ENDO-II ENDO SUL TFN
BERPAC-1993 NA NA NA 2.0 (0.36) NA NA NA 53.1-73.1N,164.6W-172.2E 9/9 AOS-1994 NA NA NA 2.9 (2.3) 2.2 (2.2) NA NA 67.5-90.0N, 168.5W-142.4E 12/12 11/11 TNW-1999 13 (8.5) 6.6 (4.2) NA 1.6 (0.86) 1.0 (0.26) NA NA 62.4-79.0N, 71.8-139.1W 15/16 15/16 15/16 16/16 Gulf of St. Lawrence 2007 13-23 NA 2.3-4.1 3.7-5.6 0.65-2.1 9.7-21 0.24-0.88 54.X-56.XN, 57.X-58.XW 2/2 2/2 2/2 2/2 2/2 2/2 IPY-2007 33 (9.3) NA 7.1 (2.6) 5.5 (1.9) 3.7 (1.6) 26 (7.9) 0.16 (0.23) 57.X-62.XN, 57.X-93.XW 14/14 7/7 13/14 14/14 14/14 3/14 IPY-2008 14 (6.4) 41 (66) 23 (13) 3.6 (1.5) 0.70 (0.30) 15 (8.7) 1.4 (2.1) 71.X-75.XN, 118.X-134.XW 13/13 7/13 13/13 13/13 13/13 5/5 7/13 ArcticNet-2010 33 (7.4) 278 (31) 18 (2.4) 4.3 (1.5) 1.4 (0.92) 2.6 (2.1) 7.9 (3.1) 67.X-74.XN, 67.X-101.XW 6/6 3/3 3/3 6/6 5/6 3/4 6/6 ArcticNet-2011 11 (2.8) 970 (1260) 13 (10) 2.7 (1.1) 0.15 (0.16) 0.28 (0.59) 0.69 (0.92) 60.5-74.2N, 60.7-106.6W 11/11 5/8 9/11 11/11 1/11 1/11 4/11 ArcticNet-2013 4.6 (1.3) 343 (115) 11 (3.0) 2.0 (0.58) ND 2.6 (2.4) 3.5 (2.2) 73.X-74.XN, 102.X-113.XW 5/5 5/5 5/5 5/5 0/5 3/5 5/5
a) Given are mean and ( standard deviation), where NDs have been replaced with IDLs, number of positive/total samples. b) Abbreviations in Table S2.
c) NA = not analyzed, ND = not detected (<IDL). d) east-central Archipelago only.
Legacy organochlorine pesticides, pg L-1
Table S5. Pesticides in air of arctic-subarctic regionsa,b
Expedition HEPX TC CC TN CN DIEL ΣCHBs
BERPAC-1993g 1.4 (0.25) 1.2 (0.20) 0.75 (0.18) 0.60 (0.11) 0.13 (0.25) 1.1 (0.37) 4.1 (1.3) 7/7 7/7 7/7 7/7 4/7 7/7 7/7 AOS-1994 0.17 (0.40) 0.56 (0.33) 0.89 (0.90) 0.55 (0.27) 0.06 (0.05) NAc NA 1/9 16/16 16/16 16/16 8/16 TNW, Resolute Bay-1999 1.3 (1.8) 1.0 (0.76) 0.96 (0.69) 0.58 (0.38) 0.10 (0.11) 2.2 (0.85) 19 (8) 29/42 34/42 31/42 32/42 28/42 21/22d 29/29e Gulf of St. Lawrence 2007 1.0-2.8 1.1-2.7 1.6-3.8 1.4-3.4 NA 12-22 NA 2/2 2/2 2/2 2/2 2/2 IPY-2007 1.0 (0.80) 0.32 (0.19) 0.63 (0.15) 0.52 (0.13) NA 3.4 (1.3) ND 13/19 19/19 19/19 19/19 19/19 0/19 IPY-2008 2.1 (0.83) 0.39 (0.22) 0.70 (0.25) 0.54 (0.18) NA 2.2 (2.0) ND 19/19 19/19 19/19 19/19 13/19 0/19 ArcticNet-2010 ND 0.38 (0.17) 0.46 (0.26) 0.38 (0.18) NA 1.8 (3.1) NA 0/17 16/17 14/17 16/17 5/17 ArcticNet-2011 0.11 (0.18) 0.16 (0.08) 0.39 (0.16) 0.31 (0.10) NA NA NA 3/19 17/19 19/19 19/19 ArcticNet-2013 ND 0.05 (0.05) 0.06 (0.09) 0.12 (0.24) ND ND NA 0/6 2/6 1/6 1/6 0/6 0/6
Expedition DAC CHT CPF ENDO-I ENDO-II ENDO SUL TFN PCTA
BERPAC-1993g NA NA NA 2.6 (1.5) NA NA NA NA 7/7 NA AOS-1994 NA NA NA 5.4 (3.7) 0.12 (0.18) NA NA NA 16/16 9/16 TNW, Resolute Bay-1999 1.9 (1.6) 0.10 (0.20) NA 4.8 (3.6) 0.20 (0.46) NA NA NA 37/42 8/29 39/43 12/32 Gulf of St. Lawrence 2007 20-46 169-200 5.5-16 24-122 3.8-17 0.11-0.32 0.16-0.24 0.33-0.74 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 IPY-2007 2.6 (2.6) 1.8 (2.4) 1.4 (0.84) 4.0 (1.6) 0.40 (0.21) 0.04 (0.04) 0.07 (0.21) 0.19 (0.08) 18/19 9/19 18/19 19/19 19/19 7/19 2/19 19/19 IPY-2008 0.54 (0.48) 0.70 (2.2) 2.4 (1.7) 2.6 (1.1) ND 1.0 (0.75) 0.74 (0.77) 0.13 (0.08) 19/19 8/19 19/19 19/19 0/19 14/14 14/19 17/19 ArcticNet-2010 0.58 (0.17) 1.2 (1.2) 0.44 (0.25) 2.1 (1.2) 0.05 (0.05) 0.20 (0.58) 0.17 (0.23) 0.28 (0.13) 17/17 10/17 15/17 17/17 4/17 5/17 10/17 16/17 ArcticNet-2011 0.85 (0.13) 0.16 (0.42) 0.17 (0.13) 1.2 (0.47) ND 0.08 (0.05) 0.23 (0.85) 0.03 (0.02) 19/19 2/19 12/19 19/19 0/19 14/19 3/19 6/19 ArcticNet-2013 0.25 (0.06) ND 0.94 (0.74) 2.6 (1.1) ND ND 1.4 (0.22) 0.07 (0.02) a) Given are mean and (standard deviation), where NDs have been replaced with IDLs, and number of positive/total samples.
b) Abbreviations in Table S2.
c) NA = not analyzed, ND = not detected (<IDL).
d) Resolute Bay and four samples from Beaufort Sea - western Archipelago. e) east-central Archipelago and Resolute Bay.
Legacy organochlorine pesticides, pg m-3
